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KRAS mutational analysis in ductal adenocarcinoma of the pancreas and its clinical significance
... [34] The majority (94.8%) of our PDAC was Kras mutated. Mutations arose in 87.2% of cases in codon 12; G12D was detected in 46% of cases consisting with literature where mutations frequency ranges from 47-100%, [23,27,28,[35][36][37][38][39][40][41][42][43][44][45][46][47][48] arising in the majority of cases in codon 12 with predominance of G12D mutation. [23,37,39,[41][42][43]45,48] We found G12A in 23% of PDAC, unlike all other studies which detected G12V as the second most frequent mutation. ...
... Mutations arose in 87.2% of cases in codon 12; G12D was detected in 46% of cases consisting with literature where mutations frequency ranges from 47-100%, [23,27,28,[35][36][37][38][39][40][41][42][43][44][45][46][47][48] arising in the majority of cases in codon 12 with predominance of G12D mutation. [23,37,39,[41][42][43]45,48] We found G12A in 23% of PDAC, unlike all other studies which detected G12V as the second most frequent mutation. [23,39,[41][42][43]45,48,49] This difference might be attributed to the ethnic variation, environment factors, or geographical differences. ...
... In our series, there was no mutation in codon 13 consisting with some studies. [37,42,43,45,50] Other teams have found mutations in codon 13 with rare frequencies ranging from 0.4% to 2.4%. [23,41,51] We have shown that codon 61 mutations were rare (4%) consisting with other studies which detected it in 0.7-2% of cases. ...
Aim: Pancreatic cancer is estimated to be the 12th most common cancer in men and the 11 most common in women worldwide. Materials and Method: As other cancers, pancreatic ductal adenocarcinoma (PDAC) accumulates genetic alterations in oncogenes and suppressor genes. In the present study, we analyzed five biomarkers status: Epidermal growth factor receptor (EGFR) and p53 using immunohistochemical labeling in 39 PDAC and Kras, Nras, and Braf, using pyrosequencing in 25 normal pancreatic tissues, 25 pancreatic intraductal neoplasia (PanIN), and 39 PDAC. Result and Discussion: Abnormal immunolabeling of p53 and EGFR was detected in 97.4% and 71.8%, respectively. There was a statistically significant progressive increment (P < 0.001) in the percentage of mutated cases through normal pancreas (8%), PanIN-1A (28.6%), PanIN-1B (33.3%), PanIN-2 (60%), and PanIN-3 (85.7%) to PDAC (94.8%). These mutations were arising in codons 12 and 61 of Kras and in codon 600 of Braf. Most frequent mutations were G12D (46%), G12A (23%), and G12V (18%) of Kras. No mutations were found in codons 13, 59, 117, and 146 of Kras or in codons 12, 13, 59, 61, 117, and 146 of Nras. Conclusion: We confirm that EGFR, Kras, and p53 are the most frequent altered biomarkers in PDAC with difference in predominated Kras mutations subtypes.
... We used a QX200 droplet dPCR system (Bio-Rad Laboratories, Hercules, CA, USA) to analyze the presence of mutations and wild-type status in KRAS, as described previously [16,19]. We used two types of probes for KRAS to analyze G12D and G12V mutations (Bio-Rad Laboratories), as these are the two major KRAS mutations found in pancreatic cancer [19,21,22]. Of 50 μL of DNA extracted from a needle wash solution, 5 μL was added to 10 μL of Droplet PCR Supermix (Bio-Rad Laboratories), 2 μL of primer/ probe mixture, and 5 μL of sterile DNase-and RNase-free water. ...
... No wash samples showed a single G12V mutation. Since the G12V mutation is not as prevalent as G12D [21,22], the amount of DNA obtained with a FNA needle wash may not be enough to detect this infrequent mutation. The direct sequencing method, the gold standard for clinical sequencing, has a mutant allele fraction detection limit. ...
Background and Aims
The sensitivity of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) for diagnosing the recurrence of pancreatic cancer is usually low because of difficulties in obtaining adequate samples for pathological examinations. We evaluated the efficacy of highly sensitive KRAS mutation analysis using EUS-FNA washes to detect cancer recurrence.
Methods
Nineteen consecutive patients with suspected pancreatic cancer recurrence after surgical resection were enrolled. All underwent EUS-FNA, and samples were obtained for pathological examination. After the first session, the inside of the FNA needle was washed with saline for DNA extraction. KRAS mutations were examined using digital droplet PCR (dPCR).
Results
The median needle puncture number used to obtain adequate pathological samples was two (range 1–6). In ten patients pathologically diagnosed with malignant pancreatic cancer, nine patients tested positive for a KRAS mutation. All patients who were not diagnosed with a malignant pancreatic cancer tested negative for a KRAS mutation. About half of surgically resected primary cancers (9/19) showed double KRAS mutations (G12V and G12D); however, all but one wash sample showed a single KRAS mutation, G12D. After including one patient who showed a malignant recurrence during follow-up, the sensitivities of a pathological diagnosis and KRAS analysis to detect recurrence were 90.9% and 81.8%, respectively.
Conclusions
KRAS mutation analysis of needle wash samples using dPCR is a new methodology for the diagnosis of the local recurrence of pancreatic cancer. The diagnostic ability of dPCR with a one-time needle wash sample was comparable to a pathological diagnosis with multiple samplings.
... However, examining exon 2 Kras mutation subtypes in T allele holders indicated that T allele in rs488087 SNP was mainly associated (6/7 patients, 85.7%) with G12D or G12R Kras phenotype, only one T allele holder patient being G12V (14.3%). Data compilation from the literature [30][31][32][33][34] showed that G12D and G12R mutants together represent 55% of Kras codon 12 mutations (Table 3). Taken all in one these data clearly suggested that holders of the germline T allele on rs488087 SNP further favor somatic mutations on Kras, essentially G12D or G12R phenotype. ...
... Therefore we opened this study to lung cancers and to gliomas, two cancers that with pancreatic cancer belong to the stochastic or replicative cluster of cancers [45] and we found that rs488087 may be predictive neither of lung cancers nor of gliomas. Kras somatic mutations were detected in 70-90% of PDAC patients and these mutations which are key factors in early tumor progression [29] mostly affected codon 12 of Kras gene [30][31][32][33][34]. We were able to examine exon 2 Kras subtype mutations in cancer tissue and determined that some 86% of patients who were T allele holders were also G12D or G12R. ...
Pancreatic cancer (PC) is a devastating disease progressing asymptomatically until death within months after diagnosis. Defining at-risk populations should promote its earlier diagnosis and hence also avoid its development. Considering the known involvement in pancreatic disease of exon 11 of the bile salt-dependent lipase (BSDL) gene that encodes variable number of tandem repeat (VNTR) sequences, we hypothesized upon the existence of a genetic link between predisposition to PC and mutations in VNTR loci. To test this, BSDL VNTR were amplified by touchdown-PCR performed on genomic DNA extracted from cancer tissue or blood samples from a French patient cohort and amplicons were Sanger sequenced. A robust method using probes for droplet digital (dd)-PCR was designed to discriminate the C/C major from C/T or T/T minor genotypes. We report that the c.1719C > T transition (SNP rs488087) present in BSDL VNTR may be a useful marker for defining a population at risk of developing PC (occurrence: 63.90% in the PC versus 27.30% in the control group). The odds ratio of 4.7 for the T allele was larger than those already determined for other SNPs suspected to be predictive of PC. Further studies on tumor pancreatic tissue suggested that a germline T allele may favor Kras G12R/G12D somatic mutations which represent negative prognostic factors associated with reduced survival. We propose that the detection of the T allele in rs488087 SNP should lead to an in-depth follow-up of patients in whom an association with other potential risk factors of pancreatic cancer may be present.
... The development of pancreatic cancer cells is usually accompanied by multiple gene mutations, and the most common subtype of oncogenic mutation is KRAS, according to the detailed genetic profile of PDAC that has been provided. KRAS mutations were found in approximately 95% of patients [12][13][14][15]. In addition, lossof-function mutations in p53 often result in accumulation of intracellular genetic damage in pancreatic cancer. ...
Pancreatic cancer has a low incidence but remains one of the deadliest cancers, and its complex microenvironment is easy to coordinate metabolic changes and allow tumor cells to properly escape immunity. This article focuses on the immune microenvironment of pancreatic cancer, the current common immunotherapy methods and the state of clinical immunotherapy for pancreatic cancer and its outlook in the future. This article not only reviews the microenvironmental mechanisms studied by scientists, but also goes into more detail about recent developments in immunotechnology that have expanded our knowledge of how complex pancreatic cancer is. It is hoped that through the review of this article, readers can have a more detailed understanding of pancreatic cancer, which will help improve the survival rate of this too low disease through mechanism studies and clinical trials in the future.
... However, some of these statistics are based on selected populations that introduce a certain bias. Indeed, while Biankin [98]. Therefore, it is reasonable to expect around 80 to 90% of the population having KRAS mutations. ...
Pancreatic cancer is a highly lethal disease with a 5-year survival rate of around 11-12%. Surgery, being the treatment of choice, is only possible in 20% of symptomatic patients. The main reason is that when it becomes symptomatic, IT IS the tumor is usually locally advanced and/or has metastasized to distant organs; thus, early diagnosis is infrequent. The lack of specific early symptoms is an important cause of late diagnosis. Unfortunately, diagnostic tumor markers become positive at a late stage, and there is a lack of early-stage markers. Surgical and non-surgical cases are treated with neoadjuvant and/or adjuvant chemotherapy, and the results are usually poor. However , personalized targeted therapy directed against tumor drivers may improve this situation. Until recently, many pancreatic tumor driver genes/proteins were considered untargetable. Chemical and physical characteristics of mutated KRAS are a formidable challenge to overcome. This situation is slowly changing. For the first time, there are candidate drugs that can target the main driver gene of pancreatic cancer: KRAS. Indeed, KRAS inhibition has been clinically achieved in lung cancer and, at the pre-clinical level, in pancreatic cancer as well. This will probably change the very poor outlook for this disease. This paper reviews the genetic characteristics of sporadic and hereditary predisposition to pancreatic cancer and the possibilities of a personalized treatment according to the genetic signature.
... 15 For more than 30 years, several studies have shown the impact of testing the activating mutations of the Kirsten rat sarcoma viral oncogene homolog (KRAS gene) on EUS-FNA samples to differentiate PDAC from benign lesions, such as chronic pancreatitis (CP) or auto-immune pancreatitis (AIP). 14,[18][19][20][21][22][23][24][25][26][27][28][29][30] In 2009, Bournet et al. 20 compared the performances of EUS-FNA alone to those of EUS-FNA combined with KRAS mutation testing for the differential diagnosis between PDAC and pseudotumoral CP. The performances were significantly improved for sensitivity (83-88%), NPV (56-63%) and diagnostic accuracy (86-90%). ...
Background
The impact of KRAS mutation testing on pancreatic ductal adenocarcinoma (PDAC) samples by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) for reducing the need to repeat EUS-FNA has been demonstrated. Such testing however is not part of standard practice for endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB).
Objectives
We aim to analyse the proportion of non-contributive samples by EUS-FNB and to evaluate the impact of KRAS mutation testing on the diagnosis, theranostics and survival.
Design
In this retrospective study, the impact on diagnosis and survival of KRAS testing for contributive and non-contributive samples by EUS-FNB was analysed.
Methods
The EUS-FNB samples, combined with KRAS testing using the Idylla ® technique on liquid-based cytology from patients with PDAC between February 2019 and May 2023, were retrospectively reviewed. The cytology results were classified according to the guidelines of the World Health Organization System for Reporting Pancreaticobiliary Cytopathology (WHOSRPC).
Results
A total of 85 EUS-FNB specimens were reviewed. In all, 25 EUS-FNB samples did not lead to a formal diagnosis of PDAC according to the WHOSRPC (30.2%). Out of these 25, 11 (44%) could have been considered positive for a PDAC diagnosis thanks to the KRAS mutation test without carrying out further diagnosis procedures. The sensitivity of KRAS mutation testing using the Idylla technique was 98.6%. According to the available data, survival rates were not statistically different depending on the type of mutation.
Conclusion
KRAS mutation testing on liquid-based cytology using the Idylla or equivalent technique, combined with the PDAC EUS-FNB sample, should become a standard for diagnosis to avoid delaying treatment by doing another biopsy. Furthermore, knowledge of the KRAS status from treatment initiation could be used to isolate mutations requiring targeted treatments or inclusion in clinical research trials, especially for wild-type KRAS PDAC.
... There are several studies on the KRAS mutation related prognosis and multiple studies stated that poor outcomes were identified in patients with KRAS G12D mutant pancreatic cancer (35,36). However, other studies found no significant association between the G12D mutation and prognosis in pancreatic cancer patients (37,38). Therefore, we first investigated the relationship between the KRAS mutation subtype and prognosis with the TCGA for pancreatic cancer patients and confirmed the prognosis benefit of the mutation type. ...
To date, driver genes for pancreatic cancer treatment are difficult to pursue therapeutically. Targeting mutated KRAS, the most renowned driver gene in pancreatic cancer, is an active area of study. We discovered a gene named SEMA3C was highly expressed in pancreatic cancer cell lines and patients with a G12D mutation in KRAS. High expression of SEMA3C in patients was significantly associated with the decreased survival of pancreatic cancer patients based on the TCGA database. In pancreatic cancer cells, SEMA3C knockdown or inhibition exhibited growth/colony inhibition and cell cycle arrest. In addition, SEMA3C inhibition sensitized KRAS or MEK1/2 inhibition in pancreatic cancer cells. Overexpression of SEMA3C resulted in the induction of autophagy, whereas depletion of SEMA3C compromised induction of autophagy. SEMA3C modified the PD-L1 expression in tumor and immune cells and is correlated with the M2-like macrophage marker ARG1/CD163 expression, which could reshape the tumor microenvironment. Inhibition of SEMA3C decreased tumor formation in the xenograft model in vivo. Taken together, our data suggest that SEMA3C plays a substantial role in promoting cancer cell survival by regulating the autophagy process and impacting the tumor environment immune response. SEMA3C can be used as a novel target or marker with therapeutic or diagnostic potential in pancreatic cancer especially in tumors harboring the specific KRAS G12D mutation.
... Pancreatic ductal adenocarcinoma (PDAC) is the most common histologic subtype of pancreatic cancer, accounting for ~90% of cases 4,5 . PDAC genetic profiling has found that KRAS is mutated in ~95% of patients, with NRAS and HRAS mutations accounting for <1% each and wild-type KRAS (KRAS WT ) for the remaining 5% [6][7][8] ...
The lack of effective RAS inhibition represents a major unmet medical need in the treatment of pancreatic ductal adenocarcinoma (PDAC). Here, we investigate the anticancer activity of RRSP-DTB, an engineered biologic that cleaves the Switch I of all RAS isoforms, in KRAS-mutant PDAC cell lines and patient-derived xenografts (PDXs). We first demonstrate that RRSP-DTB effectively engages RAS and impacts downstream ERK signaling in multiple KRAS-mutant PDAC cell lines inhibiting cell proliferation at picomolar concentrations. We next tested RRSP-DTB in immunodeficient mice bearing KRAS-mutant PDAC PDXs. Treatment with RRSP-DTB led to 95% tumor regression after 29 days. Residual tumors exhibited disrupted tissue architecture, increased fibrosis and fewer proliferating cells compared to controls. Intratumoral levels of phospho-ERK were also significantly lower, indicating in vivo target engagement. Importantly, tumors that started to regrow without RRSP-DTB shrank when treatment resumed, demonstrating resistance to RRSP-DTB had not developed. Tracking persistence of the toxin activity following intraperitoneal injection showed that RRSP-DTB is active in sera from immunocompetent mice for at least one hour, but absent after 16 hours, justifying use of daily dosing. Overall, we report that RRSP-DTB strongly regresses hard-to-treat KRAS-mutant PDX models of pancreatic cancer, warranting further development of this pan-RAS biologic for the management of RAS-addicted tumors.
... 22,49 Survival analysis of the discovery cohort demonstrated that KRAS mutation, especially KRAS G12D mutation, in ctDNA was strongly correlated with poor OS and RFS, and this has been proven in tissue also. 50 Further recurrence analysis showed that patients with plasma KRAS G12D mutation were more likely to develop distant metastasis, especially liver metastasis, in 6 months after surgery, and this highly suggested the existence of micrometastasis before surgery. Importantly, we found similar poor outcome in the validation cohort. ...
About 25–37% of resectable pancreatic ductal adenocarcinoma (PDAC) had a great chance of early recurrence after radical resection, which is mainly due to preoperative micrometastasis. We herein demonstrated the profiles of ctDNA in resectable PDAC and use of ctDNA to identify patients with potential micrometastasis.
A total of 113 and 44 resectable PDACs were enrolled in discovery and validation cohorts, separately. A panel containing 50 genes was used to screen ctDNA by an NGS-based assessment with high specificity.
In the discovery cohort, the overall detection rate was 38.05% (43/113). Among positive ctDNA, KRAS mutation had the highest detection rate (23.01%, 26/113), while the others were <5%. Survival analysis showed that plasma KRAS mutations, especially KRAS G12D mutation, had significant association with OS and RFS of resectable PDAC. Plasma KRAS G12D mutation showed a strong correlation with early distant metastasis. In the validation cohort, survival analysis showed similar association between plasma KRAS G12D mutation and poor outcomes.
This study demonstrated that plasma KRAS mutations, especially KRAS G12D mutation, served as a useful predictive biomarker for prognosis of resectable PDAC. More importantly, due to high correlation with micrometastasis, preoperative detection of plasma KRAS G12D mutation helps in optimising surgical selection of resectable PDAC.
... KRAS mutations are most common in PDAC, colorectal cancer (CRC) and non-small cell lung cancer (NSCLC) with codon 12 being the mutational site in nearly 90% of cases in PDAC [56]. Extensive research has provided a detailed genetic profile of PDAC with KRAS mutation found in ∼95% of patients [56][57][58][59]. It is an early event in PDAC progression with over 90% of low-grade pancreatic intraepithelial neoplasia (PanIN) lesions harbouring oncogenic KRAS mutations [60]. ...
The pancreas is a gland composed mainly by endocrine and exocrine cells, giving rise to three main tumour types. Pancreatic neuroendocrine tumour or PNET arise from the endocrine portion of the pancreas. On the contrary, pancreatic exocrine neoplasms include pancreatic ductal adenocarcinoma (PDAC) and acinar cell carcinoma. PDAC is the most common type of pancreatic cancer and one of the leading causes of cancer-related death. It has been shown that less than 3% of PDAC patients have an overall survival of up to 5 years in the U.K. This mainly arises since the majority of patients diagnosed with PDAC present with advanced unresectable disease, which is highly resistant to all forms of chemotherapy and radiotherapy. Activating mutations of an isoform of the RAS protein, KRAS, are found in almost all PDAC cases and occur during early stages of malignant transformation. KRAS mutations play a critical role as they are involved in both initiating and maintaining PDAC development. The interaction of RAS with GDP/GTP along with its recruitment to the membrane affects transduction of its activating signals to downstream effectors. In this review, we aim to summarise different mutations of RAS and their prevalence in pancreatic cancer along with other RAS-induced tumours. In addition, we briefly discuss the genetically engineered mouse models that have been developed to study KRAS-mutated adenocarcinomas in the pancreas. These provide an opportunity to also address the importance of targeting RAS for better treatment response in PDAC patients along with the challenges incurred herein.
... Although this result did not reach significance, it suggests that the type of KRAS mutation may have different effects on tumourigenesis. Indeed, an analysis of 27 PDAC tumour samples also suggested that those with a COSM521 mutation had worse survival than those with other KRAS mutations [18]. ...
Objective:
Pancreatic ductal adenocarcinoma (PDAC) is an aggressive tumour associated with poor 5-year survival. We aimed to determine factors which differentiate short and long-term survivors and identify a prognostic biomarker.
Methods:
Over a ten-year period, patients with resected PDAC who developed disease recurrence within 12 months (Group I) and those who had no disease recurrence for 24 months (Group II) were identified. Clinicopathological data was analysed. Ion Torrent high-throughput sequencing on DNA extracted from FFPE tumour samples was used to identify mutations. Additionally, peripheral blood samples were analysed for variants in cell-free DNA, circulating tumour cells (CTCs), and microRNAs.
Results:
Multivariable analysis of clinicopathological factors showed that a positive medial resection margin was significantly associated with short disease-free survival (p = 0.007). Group I patients (n = 21) had a higher frequency of the KRAS mutant mean variant allele (16.93% ± 11.04) compared to those in Group II (n = 13; 7.55% ± 5.76, p = 0.0078). Group I patients also trended towards having a KRAS c.35G>A p.Gly12Asp mutation in addition to variants in other genes, such as TP53, CDKN2A, and SMAD4. Mutational status of cell-free DNA, and number of CTCs, was not found to be useful in this study. A circulating miRNA (hsa-miR-548ah-5p) was found to be significantly differentially expressed.
Conclusions:
Medial resection margin status and the frequency of KRAS mutation in the tumour tissue are independent prognostic indicators for resectable PDAC. Circulating miRNA hsa-miR-548ah-5p has the potential to be used as a prognostic biomarker.
... With regard to the AKT signaling pathway, oncogenic KRAS signals are active in 80% of PDAC patients [52] and propagate through several effector branches [53]. One of these downstream targets of KRAS is phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) [54]. ...
Pancreatic cancer remains a daunting foe despite a vast number of accumulating molecular analyses regarding the mutation and expression status of a variety of genes. Indeed, most pancreatic cancer cases uniformly present with a mutation in the KRAS allele leading to enhanced RAS activation. Yet our understanding of the many epigenetic/environmental factors contributing to disease incidence and progression is waning. Epidemiologic data suggest that diet may be a key factor in pancreatic cancer development and potentially a means of chemoprevention at earlier stages. While diets high in ω3 fatty acids are typically associated with tumor suppression, diets high in ω6 fatty acids have been linked to increased tumor development. Thus, to better understand the contribution of these polyunsaturated fatty acids to pancreatic carcinogenesis, we modeled early stage disease by targeting mutant KRAS to the exocrine pancreas and administered diets rich in these fatty acids to assess tumor formation and altered cell-signaling pathways. We discovered that, consistent with previous reports, the ω3-enriched diet led to reduced lesion penetrance via repression of proliferation associated with reduced phosphorylated AKT (pAKT), whereas the ω6-enriched diet accelerated tumor formation. These data provide a plausible mechanism underlying previously observed effects of fatty acids and suggest that administration of ω3 fatty acids can reduce the pro-survival, pro-growth functions of pAKT. Indeed, counseling subjects at risk to increase their intake of foods containing higher amounts of ω3 fatty acids could aid in the prevention of pancreatic cancer.
... Importantly, HNF-1B expression was expressed in 94.1% of metastatic PDAC with predominantly nuclear staining. KRAS mutation is a frequent molecular abnormality that is identified in up to 90% of PDACs [20]. Interestingly, a recent study showed that mutated KRAS can induce abnormal regulations of pancreatic transcription factors including HNF-1B, which in turn causes abnormal cell growth and proliferation that leads to pancreatic cancer [21]. ...
Background
Diagnosing pancreatic ductal adenocarcinoma (PDAC) in the setting of metastasis with an unknown primary remains very challenging due to the lack of specific biomarkers. HNF-1B has been characterized as an important transcription factor for pancreatic development and was reported as a biomarker for clear cell subtype of PDAC.
Methods
To investigate the diagnostic role of HNF-1B for PDAC, we used tissue microarray (TMA) and immunohistochemistry (IHC) to characterize HNF-1B expression in a large cohort of carcinomas, including 127 primary PDACs, 47 biliary adenocarcinomas, 17 metastatic PDACs, and 231 non-pancreaticobiliary carcinomas.
Results
HNF-1B was expressed in 107 of 127 (84.3%) of PDACs, 13 of 15 (86.7%) of cholangiocarcinomas, 13 of 18 (72%) of ampullary carcinomas, and 13 of 14 (92.9%) of gallbladder adenocarcinomas. Notably, HNF-1B was expressed in 16 of 17 (94.1%) of metastatic PDACs. Among the non-pancreaticobiliary cancers, HNF-1B was expressed in ~ 77% clear cell carcinomas of the kidney and ovarian clear cell carcinomas. Gastroesophageal, lung, and prostate adenocarcinomas occasionally expressed HNF-1B in up to 37% cases. HNF-1B was completely negative in hepatocellular, colorectal, breast, and lung squamous cell carcinomas. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of HNF-1B for primary pancreaticobiliary carcinoma is 84, 68, 66, 85, and 75%, respectively. HNF-1B expression was not significantly associated with overall survival in patients with PDAC, but tumor size ≥2 cm and high tumor grade were significantly associated with worse overall survival in multivariate analyses.
Conclusions
HNF-1B may be used in surgical pathology to aid the diagnosis of metastatic pancreatic and biliary carcinoma with a panel of other markers to exclude lung, kidney, prostate, and Müllerian origins.
... K-RAS mutation is the most frequent among the types of mutation detected at both early and chronic stage of pancreatic cancer [43]. Genetic studies revealed that approximately 90% of the pancreatic cancer patients carry K-RAS mutation (Table 2) [28,[44][45][46][47][48]. In pancreatic adenocarcinoma, mutation is reported to occur at codon 12 wherein glycine (G) is substituted with aspartic acid (D) or with arginine (R) or valine (V) [49]. ...
Abnormally activated RAS proteins are the main oncogenic driver that governs the functioning of major signaling pathways involved in the initiation and development of human malignancies. Mutations in RAS genes and or its regulators, most frequent in human cancers, are the main force for incessant RAS activation and associated pathological conditions including cancer. In general, RAS is the main upstream regulator of the highly conserved signaling mechanisms associated with a plethora of important cellular activities vital for normal homeostasis. Mutated or the oncogenic RAS aberrantly activates a web of interconnected signaling pathways including mitogen-activated protein kinases (MAPK), phosphoinositide-3 kinase (PI3K)/AKT pathways, protein kinase C (PKC) and ral guanine nucleotide dissociation stimulator (RalGDS), etc., leading to uncontrolled transcriptional expression and reprogramming in the functioning of a range of nuclear and cytosolic effectors critically associated with the hallmarks of carcinogenesis. This review highlights the recent literature on how oncogenic RAS negatively use its signaling web in deregulating the expression and functioning of various effector molecules in the pathogenesis of human malignancies.
... Examining pancreatic tissue of patients afflicted with a PAC suggested that the T allele may correlate with Kras G12R/G12D somatic mutations. These Kras mutations are associated with a bad prognosis and reduced survival [162][163][164]. ...
Pancreatic adenocarcinomas and diabetes mellitus are responsible for the deaths of around two million people each year worldwide. Patients with chronic pancreatitis do not die directly of this disease, except where the pathology is hereditary. Much current literature supports the involvement of bile salt-dependent lipase (BSDL), also known as carboxyl ester lipase (CEL), in the pathophysiology of these pancreatic diseases. The purpose of this review is to shed light on connections between chronic pancreatitis, diabetes, and pancreatic adenocarcinomas by gaining an insight into BSDL and its variants. This enzyme is normally secreted by the exocrine pancreas, and is diverted within the intestinal lumen to participate in the hydrolysis of dietary lipids. However, BSDL is also expressed by other cells and tissues, where it participates in lipid homeostasis. Variants of BSDL resulting from germline and/or somatic mutations (nucleotide insertion/deletion or nonallelic homologous recombination) are expressed in the pancreas of patients with pancreatic pathologies such as chronic pancreatitis, MODY-8, and pancreatic adenocarcinomas. We discuss the possible link between the expression of BSDL variants and these dramatic pancreatic pathologies, putting forward the suggestion that BSDL and its variants are implicated in the cell lipid metabolism/reprogramming that leads to the dyslipidemia observed in chronic pancreatitis, MODY-8, and pancreatic adenocarcinomas. We also propose potential strategies for translation to therapeutic applications.
... G12C (3.4-3.7%), and G12S (3.7%). [13][14][15] On the other hand, it was reported that KRAS mutations are detectable in 11.0% to 31.6% of ICCs, with G12D being the most frequently reported; however only mutations at codons 12 and 13 (exon 2) were investigated in these reports. [4,[16][17][18][19] In this case, the discovery of a Q61H mutation in exon 3 of hepatic tumor DNA ruled out PDAC liver metastasis. ...
Introduction: It is often challenging to discriminate between intrahepatic cholangiocarcinoma (ICC) and metastatic liver tumors, especially when the hepatic tumor is small and of a mass-forming type. Herein, we report a case of synchronous pancreatic cancer and ICC diagnosed by KRAS mutational analysis of formalin-fixed paraffin-embedded (FFPE) needle biopsy samples.
Case report: A 69-year-old woman with a small solid tumor in the head of the pancreas was referred to our hospital. Computed tomography revealed poorly enhanced small nodules in both the pancreatic head and liver. Biopsies of both nodules revealed adenocarcinoma; however, it was unclear whether the hepatic lesion was a metastasis of the pancreatic tumor or primary ICC. KRAS mutational analysis from FFPE biopsy samples revealed a discordance of mutation status between the tumors. Therefore, the patient was diagnosed with synchronous pancreatic cancer and ICC, whereupon she underwent hepatopancreatoduodenectomy.
Conclusion: KRAS mutational analysis of FFPE biopsy samples can be utilized for differentiating between ICC and metastatic liver tumor.
... Among these genetic alterations, mutations in the KRAS gene, which often are already present in precursor lesions, play an important role in tumor development and progression [8]. Gain of function mutations in the KRAS gene are detected in about 70 to 90% of PDAC cases [9], commonly as point mutations in exon 2 (codon 12/13), most frequently as p.G12D (c.35G > A) or p.G12 V (p.35G > T). Several studies showed that constitutively activating KRAS mutations are associated with worse OS, whereas KRAS wildtype status is associated with improved OS in PDAC [7,10,11]. ...
Background
Despite the introduction of novel effective treatment regimens like gemcitabine plus nab-paclitaxel and FOLFIRINOX, pancreatic ductal adenocarcinoma (PDAC) remains one of the most aggressive epithelial tumors. Among the genetic alterations frequently found in PDAC, mutations in the KRAS gene might play a prognostic role regarding overall survival and may also have the potential to predict the efficacy of anti-EGFR treatment.
Case presentation
We report the clinical case of a 69 year old Caucasian female that was diagnosed with histologically confirmed locally advanced PDAC with lymph node involvement in August 2010. At the time of first diagnosis, tumor tissue obtained from an open regional lymph node biopsy showed a poorly differentiated adenocarcinoma with a wild type sequence within exon 2 (codon 12/13) of the KRAS gene. The patient initially received single-agent gemcitabine and a subsequent 5-FU-based chemoradiotherapy with a sequential maintenance chemotherapy with oral capecitabine resulting in a long term disease control. Local disease progression occurred in May 2014 and the patient underwent pancreaticoduodenectomy in September 2014. A novel KRAS gene mutation (c.35G > T, p.G12 V) in exon 2 (codon 12) was detected within the surgical specimen. As of January 2016 the patient is still alive and without evidence of the underlying disease.
Conclusions
Specifically in the context of clinical trials and translational research in PDAC a re-assessment of molecular biomarkers, i. e. KRAS, at defined time points (e. g. relapse, disease progression, unusual clinical course) may be indicated in order to detect a potential switch in biomarker status during the course of disease.
... Conversely, oncogenic "driver" mutations presented as immunogenic peptides would likely constitute ideal shared targets, particularly since expression of the mutated protein is presumed to be essential for maintaining the malignant phenotype. Examples of such frequently occurring mutations include codon 12 mutations to KRAS (expressed by >90 % of pancreatic cancers and *30 % of lung cancers) and V600E mutations to BRAF (expressed by nearly half of cutaneous melanomas) [37][38][39][40]. Regardless of the mutation type, identification of mutated tumor-associated epitopes from individual patients remains a critical goal of tumor immunologists, and one that is certainly feasible now that next-generation sequencing technologies have become more widely available. ...
The past several years can be considered a renaissance era in the treatment of metastatic melanoma. Following a 30-year stretch in which oncologists barely put a dent in a very grim overall survival (OS) rate for these patients, things have rapidly changed course with the recent approval of three new melanoma drugs by the FDA. Both oncogene-targeted therapy and immune checkpoint blockade approaches have shown remarkable efficacy in a subset of melanoma patients and have clearly been game-changers in terms of clinical impact. However, most patients still succumb to their disease, and thus, there remains an urgent need to improve upon current therapies. Fortunately, innovations in molecular medicine have led to many silent gains that have greatly increased our understanding of the nature of cancer biology as well as the complex interactions between tumors and the immune system. They have also allowed for the first time a detailed understanding of an individual patient’s cancer at the genomic and proteomic level. This information is now starting to be employed at all stages of cancer treatment, including diagnosis, choice of drug therapy, treatment monitoring, and analysis of resistance mechanisms upon recurrence. This new era of personalized medicine will foreseeably lead to paradigm shifts in immunotherapeutic treatment approaches such as individualized cancer vaccines and adoptive transfer of genetically modified T cells. Advances in xenograft technology will also allow for the testing of drug combinations using in vivo models, a truly necessary development as the number of new drugs needing to be tested is predicted to skyrocket in the coming years. This chapter will provide an overview of recent technological developments in cancer research, and how they are expected to impact future diagnosis, monitoring, and development of novel treatments for metastatic melanoma.
Pancreatic cancer (PC) is one of the most common malignancies. Surgical resection is a potential curative approach for PC, but most patients are unsuitable for operations when at the time of diagnosis. Even with surgery, some patients may still experience tumour metastasis during the operation or shortly after surgery, as precise prognosis evaluation is not always possible. If patients miss the opportunity for surgery and resort to chemotherapy, they may face the challenging issue of chemotherapy resistance. In recent years, liquid biopsy has shown promising prospects in disease diagnosis, treatment monitoring, and prognosis assessment. As a noninvasive detection method, liquid biopsy offers advantages over traditional diagnostic procedures, such as tissue biopsy, in terms of both cost-effectiveness and convenience. The information provided by liquid biopsy helps clinical practitioners understand the molecular mechanisms underlying tumour occurrence and development, enabling the formulation of more precise and personalized treatment decisions for each patient. This review introduces molecular biomarkers and detection methods in liquid biopsy for PC, including circulating tumour cells (CTCs), circulating tumour DNA (ctDNA), noncoding RNAs (ncRNAs), and extracellular vesicles (EVs) or exosomes. Additionally, we summarize the applications of liquid biopsy in the early diagnosis, treatment response, resistance assessment, and prognostic evaluation of PC.
Simple Summary
Pancreatic cancer is a highly fatal disease that does not respond well to current cancer therapies. We previously showed that protein kinase C iota (PKCι) is highly expressed in pancreatic cancer, and inhibition of PKCι signaling in human pancreatic cell lines blocks tumor growth. In this study, we used a genetic mouse model to investigate the role of PKCι in pancreatic cellular homeostasis and pancreatic tumorigenesis. We found that inhibition of PKCι expression in the mouse pancreas blocked autophagy, altered infiltration of immune cells, and prevented pancreatic cancer formation. Taken together, these findings reveal a promotive role for PKCι in pancreatic cancer development.
Abstract
Protein kinase C iota (PKCι) functions as a bonafide human oncogene in lung and ovarian cancer and is required for KrasG12D-mediated lung cancer initiation and progression. PKCι expression is required for pancreatic cancer cell growth and maintenance of the transformed phenotype; however, nothing is known about the role of PKCι in pancreas development or pancreatic tumorigenesis. In this study, we investigated the effect of pancreas-specific ablation of PKCι expression on pancreatic cellular homeostasis, susceptibility to pancreatitis, and KrasG12D-mediated pancreatic cancer development. Knockout of pancreatic Prkci significantly increased pancreatic immune cell infiltration, acinar cell DNA damage, and apoptosis, but reduced sensitivity to caerulein-induced pancreatitis. Prkci-ablated pancreatic acinar cells exhibited P62 aggregation and a loss of autophagic vesicles. Loss of pancreatic Prkci promoted KrasG12D-mediated pancreatic intraepithelial neoplasia formation but blocked progression to adenocarcinoma, consistent with disruption of autophagy. Our results reveal a novel promotive role for PKCι in pancreatic epithelial cell autophagy and pancreatic cancer progression.
Background:
The technique to analyze circulating tumor DNA (ctDNA) in body fluid (so-called "liquid biopsy") is recently developed.
Aims:
Our aim was to assess the utility of liquid biopsy for predicting progression of pancreatic ductal adenocarcinoma (PDAC) after surgical resection or chemotherapy.
Methods:
A total of 72 patients with PDAC were retrospectively enrolled for this study, 33 treated surgically and 39 given chemotherapy, either FOLFIRINOX (oxaliplatin/irinotecan/fluorouracil/leucovorin) or gemcitabine plus nab-paclitaxel. Prior to treatment, patients were screened for the presence of KRAS mutations (G12D and G12V) in plasma using droplet digital polymerase chain reaction, and outcomes were compared.
Results:
KRAS mutations were identified in plasma samples of 12 patients (36%) underwent surgical resection. Patients with plasma KRAS mutations had significantly shorter disease-free survival (DFS) and overall survival (p < .01 and p = .01, respectively). Of 10 clinical variables analyzed, plasma KRAS mutation was the factor predictive of DFS in multivariate analysis (RR = 3.58, 95% CI: 1.36-9.60; p = .01). Although 12 patients (31%) given chemotherapy tested positive for plasma KRAS mutations, there was no demonstrable relation between plasma KRAS mutations and progression-free survival (PFS) or overall survival (OS) (p = .35 and p = .68, respectively).
Conclusions:
In patients with PDAC, detection of KRAS mutations in plasma proved independently predictive of early recurrence after surgical resection but did not correlate with PFS following chemotherapy.
Exosomes are a specific population of extracellular vesicles (EVs) that originate from an endocytic process. Virtually every cell type secretes exosomes and their size ranges from 40 to 150 nm. Exosomes are surrounded by a lipid bilayer and contain functional cargo that comprises proteins, lipids and genetic material such as protein, RNA and DNA. In the recent years, several studies have reported the role of exosomes as mediators of intercellular communication. Exosomes serve as vehicles used by cancer cells and stromal cells to influence both local and distant metastatic sites, by reprogramming recipient cells. This chapter will focus on the mechanisms underlying the role of exosomes in tumor development, metastasis, immune escape, therapy resistance, microenvironment reprogramming and angiogenesis. Furthermore, we will also discuss the potential to target exosomes as a new therapeutic strategy in cancer.
Background/objectives:
The detection of cancer-specific DNA in peripheral blood, known as a liquid biopsy, has been reported recently. Most such studies have used plasma as a sample; however, whether or not serum can be used as effectively is unclear. We attempted to clarify suitable samples for detecting KRAS mutations in circulating DNA in the blood of pancreatic cancer patients using droplet digital polymerase chain reaction (PCR).
Methods:
DNA was extracted from the tissue, plasma, and serum of 40 pancreatic cancer patients. The presence of KRAS mutations G12D, G12V, and G12R was analyzed by droplet digital PCR.
Results:
The amount of DNA isolated from the serum was much higher than that from plasma (1.0- to 42.0-fold). At least 1 KRAS mutation was observed in 93% of cancer tissues, whereas we detected the mutations in only 48% of the serum and plasma DNA samples. The G12D mutation was the most prevalent of the three mutations, followed by the G12V mutation. The presence of the G12D KRAS mutation in the plasma, serum, or tissue did not correlate to the overall survival; however, the prognosis of the patients with a KRAS mutation at G12V in the plasma or serum was significantly poorer than that of the patients without the mutation (P < 0.01).
Conclusions:
Serum and plasma were found to be good materials for detecting cancer-specific DNA in the peripheral blood and the presence of KRAS mutations in blood-derived DNA may be used as a prognostic biomarker for patients with pancreatic cancer.
K-Ras gene mutations have been found in most pancreatic cancers; however, conflicting data on the prognostic value of K-Ras mutations in pancreatic cancer have been published. We conducted a meta-analysis to assess its prognostic significance. Literature searches of PubMed, EMBASE, Cochrane Library, Web of Science and Google Scholar were performed through December 2015 to identify publications exploring the association of K-Ras mutation with overall survival. Forty eligible studies involving 3427 patients with pancreatic cancer were included in the present meta-analysis. Our analysis showed a hazard ratio (HR) of negative association with survival of 1.61 [95 % confidence interval (CI) 1.36–1.90; p < 0.01] in K-Ras mutant pancreatic cancer patients. In subgroup analyses, K-Ras mutations detected in tumor tissues and in liquid biopsies had HRs of 1.37 (95 % CI 1.20–1.57; p < 0.01) and 3.16 (95 % CI 2.1–4.71; p < 0.01), respectively. In addition, the HR was higher when K-Ras mutations were detected in fresh frozen samples (HR = 2.01, 95 % CI 1.28–3.16, p = 0.002) than in formalin-fixed, paraffin-embedded (FFPE) samples (HR = 1.29, 95 % CI 1.12–1.49, p < 0.01). Though K-Ras alterations are more frequent among non-East Asian individuals than East Asian individuals, there were no significant differences in HRs of survival between the two ethnic subgroups. In conclusion, this meta-analysis suggests that K-Ras mutations are associated with a worse overall survival in pancreatic cancer patients, especially when mutations are detected in liquid biopsies or fresh frozen tumor tissue samples.
Aim: For tumors of the periampullary region clinical differentiation between primary and tumorassociated pancreatitis might be difficult. Early diagnosis of these malignancies is essential, as they present with early invasion of surrounding tissue thus limiting therapeutic options. Using molecular markers, the preoperative diagnosis (EUS-guided needle biopsy, brush biopsy pancreatic duct) could be optimized and surgical therapy potentially adapted. Alpha1 (XI) collagen Col11A1 is essential for the extracellular matrix and normal skeletal development and has been associated with carcinogenesis. Materials and Methods: Forty-three patients with adenocarcinoma of the pancreas, 11 with adenocarcinoma of the papilla of Vater and 23 patients with chronic pancreatitis were included in the study. For all patients mRNA expression of Col11A1 was quantified by TaqMan RT-PCR in tumor or pancreatitis specimen, as well as in the corresponding normal uninvolved tissue and correlated with diagnosis of cancer and chronic pancreatitis. Results: Col11A1 mRNA expression was 5.25-fold higher in adenocarcinoma of the pancreas (p=0.006) and 8.25-fold in the papilla of Vater (p=0.002) compared to that of chronic pancreatitis specimen. Conclusion: Differential mRNA expression of Col11A1 may be applied to preoperatively differentiate between tumors of the periampullary region and chronic pancreatitis and this may potentially have a positive effect on patient survival.
Activating mutation of KRAS plays a significant role in the pathogenesis of common human malignancies and molecular testing of KRAS mutation has emerged as an essential biomarker in the current practice of clinical oncology. The presence of KRAS mutation is generally associated with clinical aggressiveness of the cancer and reduced survival of the patient. Therapeutically, KRAS mutation testing has maximum utility in stratifying metastatic colorectal carcinoma and lung cancer patients for treatment with targeted therapy. Diagnostically, KRAS mutation testing is useful in the workup of pancreaticobiliary and thyroid cancers, particularly using cytological specimens. In the era of precision medicine, the role of KRAS mutation testing is poised to expand, likely in a setting of combinatorial therapeutic strategy and requiring additional mutation testing of its upstream and/or downstream effectors.
The value of next-generation sequencing (NGS) of pancreatic cyst fluid relative to the clinical and imaging impression has not been well-studied. The aim of this study was to assess the impact of NGS on the clinical diagnosis from imaging and carcinoembryonic antigen (CEA) and thus the management of pancreatic cysts.
Ninety-two pancreatic cyst fluids from 86 patients were analyzed by cytology, CEA, and targeted NGS. Cysts were classified by imaging as nonmucinous, mucinous, or not specified. NGS results were compared with the imaging impression stratified by CEA and cytology.
NGS impacted the clinical diagnosis by defining a cyst as mucinous in 48% of cysts without elevated CEA levels. The VHL gene in 2 intraductal papillary mucinous neoplasms (IPMNs) supported a serous cystadenoma. Twenty percent of cysts that were nonmucinous by imaging were mucinous by NGS. Of the 14 not-specific cysts, CEA levels were not elevated in 12 (86%), and NGS established a mucinous etiology in 3 (25%). A KRAS or GNAS mutation supported an IPMN with nonmucinous CEA in 71%. A KRAS mutation reclassified 19% of nonneoplastic cysts with nonmucinous CEA as mucinous. Seven cyst fluids (8%) had either a TP53 mutation or loss of CDKN2A or SMAD4 in addition to KRAS and/or GNAS mutations; 5 of 7 (71%) were clinically malignant, and high-grade cytology was detected in all 5. Overall, CEA was more specific for a mucinous etiology (100%), but NGS was more sensitive (86% vs 57%).
NGS of pancreatic cyst fluid impacts clinical diagnosis and patient management by defining, supporting, or changing the clinical diagnosis based on imaging and CEA. NGS was most valuable in identifying mucinous cysts with nonmucinous CEA. An added benefit is the potential to detect mutations late in the progression to malignancy that may increase the risk classification of the cyst based on imaging and cytology.
Copyright © 2015 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.
Background:
As epidermal growth factor receptor (EGFR) is involved in the pathogenesis of malignant pleural mesotheliomas (MPMs), the anti-EGFR drugs may be effective in treating MPM patients. Mutations of the EGFR gene or its downstream effectors may cause constitutive activation leading to cell proliferation, and the inhibition of apoptosis and metastases. Consequently, molecular profiling is essential for select patients with MPM who may respond to anti-EGFR therapies.
Methods:
After manual macrodissection, genomic DNA was extracted from 77 histological samples of MPM: 59 epithelioid, 10 biphasic, and 8 sarcomatoid. Epidermal growth factor receptor gene mutations were sought by means of real-time polymerase chain reaction (PCR) and direct sequencing, KRAS gene mutations by mutant-enriched PCR, and PIK3CA and BRAF gene mutations by direct sequencing.
Results:
Gene mutations were identified in nine cases (12%): five KRAS, three BRAF, and one PI3KCA mutation; no EGFR gene mutations were detected. There was no difference in disease-specific survival between the patients with or without gene mutations (P=0.552).
Conclusions:
Mutations in EGFR downstream pathways are not rare in MPM. Although none of those found in this study seemed to be prognostically significant, they may support a more specific selection of patients for future trials.
To assess prognostic roles of various KRAS oncogene mutations in colorectal cancer, BRAF mutation status must be controlled for because BRAF mutation is associated with poor prognosis, and almost all BRAF mutants are present among KRAS wild-type tumors. Taking into account experimental data supporting a greater oncogenic effect of codon 12 mutations compared with codon 13 mutations, we hypothesized that KRAS codon 12-mutated colorectal cancers might behave more aggressively than KRAS wild-type tumors and codon 13 mutants. Experimental design: Using molecular pathological epidemiology database of 1,261 rectal and colon cancers, we examined clinical outcome and tumor biomarkers of KRAS codon 12 and 13 mutations in 1,075 BRAF wild-type cancers (i.e., controlling for BRAF status). Cox proportional hazards model was used to compute mortality HR, adjusting for potential confounders, including stage, PIK3CA mutations, microsatellite instability, CpG island methylator phenotype, and LINE-1 methylation.
Compared with patients with KRAS wild-type/BRAF wild-type cancers (N = 635), those with KRAS codon 12 mutations (N = 332) experienced significantly higher colorectal cancer-specific mortality [log-rank P = 0.0001; multivariate HR, 1.30; 95% confidence interval (CI), 1.02-1.67; P = 0.037], whereas KRAS codon 13-mutated cases (N = 108) were not significantly associated with prognosis. Among the seven most common KRAS mutations, c.35G>T (p.G12V; N = 93) was associated with significantly higher colorectal cancer-specific mortality (log-rank P = 0.0007; multivariate HR, 2.00; 95% CI, 1.38-2.90, P = 0.0003) compared with KRAS wild-type/BRAF wild-type cases.
KRAS codon 12 mutations (in particular, c.35G>T), but not codon 13 mutations, are associated with inferior survival in BRAF wild-type colorectal cancer. Our data highlight the importance of accurate molecular characterization in colorectal cancer.
KRAS mutation is a negative predictive factor for treatment with anti-epidermal growth factor receptor antibody in metastatic colorectal cancer (CRC). KRAS mutation analysis is usually performed on primary tumour tissue because metastatic tissue is often not available. However, controversial data are available on the concordance of test results between primary tumours and corresponding metastases. We assessed the concordance of KRAS mutation status in a study of 305 primary colorectal tumours and their corresponding liver metastases.
Patients with histologically confirmed CRC who underwent surgical resection of the primary tumour and biopsy or surgical resection of the corresponding liver metastasis were included. KRAS mutation analysis was performed for codons 12 and 13.
KRAS mutation was detected in 108 out of 305 primary tumours (35.4%). In 11 cases (3.6%), we found a discordance between primary tumour and metastasis: 5 primary tumours had a KRAS mutation with a wild-type metastasis, 1 primary tumour was wild type with a KRAS mutation in the metastasis, and in 5 cases the primary tumour and the metastasis had a different KRAS mutation.
We observed a high concordance of KRAS mutation status of 96.4% (95% CI 93.6-98.2%) between primary colorectal tumours and their corresponding liver metastases. In only six patients (2.0%; 95% CI 0.7-4.2%), the discordance was clinically relevant. In this largest and most homogenous study to date, we conclude that both primary tumours and liver metastases can be used for KRAS mutation analysis.
DNAs from human pancreatic adenocarcinomas were analyzed for the presence of mutations in codons 12, 13 and 61 of the NRAS,
KRAS and HRAS gene. Formalin-fixed and paraffin-embedded tissue was used directly in an in vitro amplification reaction to
expand the relevant RAS sequences. The mutations were detected by selective hybridization using mutation-specific synthetic
oligonucleotides. In 28 of the 30 patients we found a mutation in codon 12 of the KRAS gene. This result confirms the findings
of Almoguera et al. [Cell 53 (1988) 549–554] that KRAS mutations occur frequently in adenocarcinomas of the exocrine pancreas. The mutations are predominantly
G-T transversions, in contrast to the KRAS mutations in colon tumors which are mainly G-A transitions. Furthermore, in a portion
of the tumors the mutation appears to be homozygous.
Despite intent to cure surgery with negative resection margins, locoregional recurrence is common in pancreatic cancer.
To determine whether detection of K-ras gene mutation in the histologically negative surgical margins of pancreatic cancer reflects unrecognised disease.
Seventy patients who underwent curative resection for pancreatic ductal adenocarcinoma were evaluated.
All patients had surgical resection margins (pancreatic transection and retroperitoneal) that were histologically free of invasive cancer. DNA was extracted from these paraffin embedded surgical margins and assessed by quantitative real time polymerase chain reaction to detect the K-ras gene mutation at codon 12. Detection of K-ras mutation was correlated with standard clinicopathological factors.
K-ras mutation was detected in histologically negative surgical margins of 37 of 70 (53%) patients. A significant difference in overall survival was demonstrated between patients with margins that were K-ras mutation positive compared with negative (median 15 v 55 months, respectively; p = 0.0008). By univariate and multivariate analyses, detection of K-ras mutation in the margins was a significant prognostic factor for poor survival (hazard ratio (HR) 2.8 (95% confidence interval (CI) 1.5-5.3), p = 0.0009; and HR 2.8 (95% CI 1.4-5.5), p = 0.004, respectively).
Detection of cells harbouring K-ras mutation in histologically negative surgical margins of pancreatic cancer may represent unrecognised disease and correlates with poor disease outcome. The study demonstrates that molecular-genetic evaluation of surgical resection margins can improve pathological staging and prognostic evaluation of patients with pancreatic ductal adenocarcinoma.
Monoclonal antibodies (mAbs) against the extracellular domain of the epidermal growth factor receptor (EGFR) have been introduced for the treatment of metastatic colorectal cancer (mCRC). We have reported recently that increased copy number of the EGFR can predict response to anti-EGFR mAbs and that patients might be selected for treatment based on EGFR copy number. Here, we show that mutations activating the RAS/RAF signaling pathway are also predictive and prognostic indicators in mCRC patients, being inversely correlated with response to anti-EGFR mAbs. In cellular models of CRCs, activation of the RAS signaling pathway by introduction of an activated K-RAS allele (Gly(12)Val) impairs the therapeutic effect of anti-EGFR mAbs. In cancer cells carrying constitutively active RAS, the pharmacologic inhibition of the mitogen-activated protein kinase (MAPK) signaling cascade improves anti-EGFR treatment based on mAbs. These results have implications for the identification of patients who are likely to respond to anti-EGFR treatment. They also provide the rationale for combination therapies, targeted simultaneously to the EGFR and RAS/RAF/MAPK signaling pathways in CRC patients.
Previous studies of molecular prognostic markers following resection for exocrine pancreatic cancer have produced conflicting results. Our aim was to undertake a comprehensive analysis of potentially useful molecular markers in a large, multicentre patient population and to compare these markers with standard pathological prognostic variables. Formalin‐fixed, paraffin‐embedded specimens of pancreatic ductal adenocarcinoma were analysed from 157 patients [100 men and 57 women with a median (range) age of 60 (33–77) years] who had undergone pancreatectomy. Immunohistochemistry was used to detect expression of p16INK4, p53, p21WAF1, cyclin D1, erbB‐2 and erbB‐3. Mutations in codons 12 and 13 of the K‐ras oncogene were detected by SSCP and sequencing following DNA extraction and amplification by PCR. The median (range) survival post‐resection was 12.5 (3–83) months. Abnormalities of p16INK4, p53, p21WAF1, cyclin D1, erbB‐2 and erbB‐3 expression were found in 87%, 41%, 75%, 72%, 33% and 57% of cases, respectively. There was no significant correlation between expression of any of these markers and patient survival. K‐ras mutations were found in 73 (75%) of 97 cases with amplifiable DNA. The presence of K‐ras mutation alone did not correlate with survival, but there were significant differences in survival according to the type of K‐ras mutation (p = 0.0007). Reduced survival was found in patients with GaT, cGT and GcT K‐ras mutations compared to GtT, aGT and GaC mutations. In conclusion, survival was associated with type of K‐ras mutation but not expression of p16INK4, p53, p21WAF1, cyclin D1, erbB‐2 and erbB‐3. Int. J. Cancer 89:469–474, 2000. © 2000 Wiley‐Liss, Inc.
Objective:
To determine the frequency distribution of K-ras-2 point mutation genotypes in pancreatic adenocarcinoma and to evaluate the effectiveness of K-ras-2 genotyping as a means to predict localized disease and potential long-term survival.Design:
Topographic genotyping from archival formalin-fixed, paraffin-embedded large- and biopsy-sized tissue specimens as well as cytologic fluid using polymerase chain reaction products and direct sequencing together with clinicopathologic and statistical analysis.Setting:
Tertiary care medical center with molecular diagnostics pathology laboratory.Patients:
Patients treated between 1988 and 1993 at Rhode Island Hospital, Providence, yielding 55 primary and 56 metastatic specimens of pancreatic adenocarcinoma.Results:
Each primary pancreatic adenocarcinoma was found to contain one of eight specific genotypes that was maintained in all metastatic deposits of that individual tumor. Primary adenocarcinomas confined to the pancreatic bed at diagnosis were predominantly of a normal genotype (56% [14/25]). Pancreatic adenocarcinomas progressing to distant hematogenous metastasis were almost exclusively mutated (88% [7/8];P<.005). Patients undergoing pancreatic resection (Whipple's operation) and having a normal K-ras-2 genotype (58% [11/19]) had a significantly longer survival (21.3 months) than similar patients with mutated tumors (8.2 months).Conclusions:
The findings support the feasibility of K-ras-2 topographic genotyping to identify potentially indolent disease and suggest a potentially useful role in the preoperative evaluation of pancreatic adenocarcinoma.(Arch Surg. 1994;129:367-373)
The Kras gene is mutated to an oncogenic form in most pancreatic tumors. However, early attempts to use this molecule as a specific biomarker of the disease, or inhibit its activity as a cancer therapy, failed. This left a situation in which everyone was aware of the association between this important oncogene and pancreatic cancer, but no one knew what to do about it. Recent findings have changed this picture-many assumptions made about KRAS and its role in pancreatic cancer were found to be incorrect. Several factors have contributed to increased understanding of the activities of KRAS, including creation of genetically engineered mouse models, which have allowed for detailed analyses of pancreatic carcinogenesis in an intact animal with a competent immune system. Cancer genome sequencing projects have increased our understanding of the heterogeneity of individual tumors. We also have a better understanding of which oncogenes are important for tumor maintenance and are therefore called "drivers." We review the advances and limitations of our knowledge about the role of Kras in development of pancreatic cancers and the important areas for future research.
The KRAS oncogene is mutated in approximately 35%-45% of colorectal cancers, and KRAS mutational status testing has been highlighted in recent years. The most frequent mutations in this gene, point substitutions in codons 12 and 13, were validated as negative predictors of response to anti-epidermal growth factor receptor antibodies. Therefore, determining the KRAS mutational status of tumor samples has become an essential tool for managing patients with colorectal cancers. Currently, a variety of detection methods have been established to analyze the mutation status in the key regions of the KRAS gene; however, several challenges remain related to standardized and uniform testing, including the selection of tumor samples, tumor sample processing and optimal testing methods. Moreover, new testing strategies, in combination with the mutation analysis of BRAF, PIK3CA and loss of PTEN proposed by many researchers and pathologists, should be promoted. In addition, we recommend that microsatellite instability, a prognostic factor, be added to the abovementioned concomitant analysis. This review provides an overview of KRAS biology and the recent advances in KRAS mutation testing. This review also addresses other aspects of status testing for determining the appropriate treatment and offers insight into the potential drawbacks of mutational testing.
Previous studies of molecular prognostic markers following resection for exocrine pancreatic cancer have produced conflicting results. Our aim was to undertake a comprehensive analysis of potentially useful molecular markers in a large, multicentre patient population and to compare these markers with standard pathological prognostic variables. Formalin-fixed, paraffin-embedded specimens of pancreatic ductal adenocarcinoma were analysed from 157 patients [100 men and 57 women with a median (range) age of 60 (33–77) years] who had undergone pancreatectomy. Immunohistochemistry was used to detect expression of p16INK4, p53, p21WAF1, cyclin D1, erbB-2 and erbB-3. Mutations in codons 12 and 13 of the K-ras oncogene were detected by SSCP and sequencing following DNA extraction and amplification by PCR. The median (range) survival post-resection was 12.5 (3–83) months. Abnormalities of p16INK4, p53, p21WAF1, cyclin D1, erbB-2 and erbB-3 expression were found in 87%, 41%, 75%, 72%, 33% and 57% of cases, respectively. There was no significant correlation between expression of any of these markers and patient survival. K-ras mutations were found in 73 (75%) of 97 cases with amplifiable DNA. The presence of K-ras mutation alone did not correlate with survival, but there were significant differences in survival according to the type of K-ras mutation (p = 0.0007). Reduced survival was found in patients with GaT, cGT and GcT K-ras mutations compared to GtT, aGT and GaC mutations. In conclusion, survival was associated with type of K-ras mutation but not expression of p16INK4, p53, p21WAF1, cyclin D1, erbB-2 and erbB-3. Int. J. Cancer 89:469–474, 2000. © 2000 Wiley-Liss, Inc.
BACKGROUND
Early diagnosis and complete removal of pancreatic adenocarcinoma (PC) is essential to improve its poor prognosis. It is necessary to find PC when it is small and at an early stage if surgical treatment is to be successful. This is an investigation of the clinicopathologic features of small PC.METHODS
Thirty-one resected and histopathologically examined cases of small PC, 2 cm or less in greatest dimension, were collected from 7 institutions between 1989 and 1994, and their clinicopathologic features were analyzed in detail.RESULTSEighteen patients (58.1%) had some symptoms or signs at the time of diagnosis, however, the other 13 (41.9%) had no symptoms. There was no sensitive blood test for the detection of small PC. The detection rates of the pancreatic tumor mass on ultrasonography, endoscopic ultrasonography, and computed tomography were 64.5% (20/31), 73.7% (14/19), and 64.5% (20/31), respectively. Only 13 patients (41.9%) were in International Union Against Cancer (UICC) Stage I, and the other 18 were in Stage III or IV due to lymph node metastasis or peritoneal dissemination. The overall 4-year postoperative survival rate was 54.5% and that of patients in Stage I was 77.9%.CONCLUSIONS
To detect a small PC, a thorough examination may be required in patients with slightly abnormal findings on laboratory tests or imaging modalities, even if the patient is asymptomatic. PC 2 cm or less and belonging to Stage I may be regarded as an early carcinoma, because of its good prognosis. Cancer 1996;78:986-90.
The frequencies and prognostic role of KRAS and BRAF mutations in patients operated on for pancreatic ductal adenocarcinomas (PDACs) and ampullary adenocarcinomas (A-ACs) are scantily studied.
KRAS and BRAF mutations were analyzed in formalin-fixed, paraffin-embedded tumor samples from primarily chemotherapy-naive patients operated on with radical intentions for PDAC (n = 170) and A-AC (n = 107).
Eighty percent of PDAC patients had KRAS mutations (codon 12 mutations: 74%) and 67% with A-AC (codon 12 mutations: 54%). BRAF mutations were less common, 16% in PDAC and 12% in A-AC, and no V600E mutations were found. Fourteen percent with PDAC and 7% with A-AC had mutations in both KRAS and BRAF. Multivariate analysis, including KRAS status, stage, and American Society of Anesthesiologists physical status classification system score, demonstrated that KRAS mutations in patients with A-AC were associated with short recurrence-free survival (RFS) (hazard ratio, 2.45; 95% confidence interval, 1.19-5.06; P = 0.015) and overall survival (OS) (1.93, 95% 1.12-3.31; P = 0.018). KRAS mutations in patients with PDAC were not associated with RFS and OS. BRAF mutations were not associated with RFS and OS.
KRAS mutations frequencies were high in PDAC and A-AC. KRAS mutations were associated with poor prognosis in patients with A-AC, but not in patients with PDAC.
Pancreatic cancer is the fifth leading cause of cancer death in the United States, and despite improvements in the results of surgical treatment for this disease, little impact has been made upon overall mortality. New advances in treatment will depend upon improved adjuvant therapy, early diagnosis, and a better understanding of tumor biology. This article summarizes the results of molecular genetic studies in pancreatic cancer and their potential clinical significance. Familial predisposition to pancreatic cancer, cytogenic studies, DNA ploidy analysis, and examination of specific oncogenes and tumor suppressor genes are reviewed. The most frequent mutations detected have been in the K-ras oncogene, which occur in 80% of pancreatic cancers. These mutations do not correlate with tumor stage or survival, but can be useful in differentiating pancreatic exocrine from endocrine tumors and chronic pancreatitis. Mutations in the p53 gene occur in approximately 50% of tumors, and appear to be an independent prognostic factor for patient survival. Mutations in the CDKN2 gene are frequently seen in sporadic pancreatic cancers, and have been implicated in cases of familial pancreatic cancer. The significance of mutations in APC, MCC, DCC, c-erbB-2, RB-1, and mismatch repair genes in the genesis of pancreatic cancer is less clear.
Pancreatic and periampullary cancers have a high incidence of activating KRAS mutations. The aim of this study was to determine the incidence of KRAS and EGFR mutations in pancreatic and periampullary cancers and their relationship with survival.
One hundred patients undergoing pancreaticoduodenectomy or pancreatic biopsy for cancer were recruited. Samples of formalin-fixed paraffin-embedded or fresh pancreatic tissue were obtained. EGFR was analyzed by DNA sequencing of exons 18 to 21. KRAS was analyzed by pyrosequencing of codons 12, 13, and 61.
EGFR mutations were found in 2 (2.3%) of 88 assessable cases. One in exon 18 (c.1966C>T, p.Q710X) and 1 in exon 19 (c.2066A>G, p.E734G). A synonymous single-nucleotide polymorphism in exon 20 (c.2361G>A, p.Q787) was identified in 57 (67.8%) of 84 patients studied. Twenty-eight (41.2%) of 68 cases harbored a point mutation in KRAS codon 12 (26 cases) and codon 61 (2 cases). The overall median survival was 308 days (range, 7-2623 days). The presence of KRAS point mutations did not significantly alter median survival time (22.8 vs 28.1 months, P = 0.88).
EGFR somatic mutations are rare in pancreatobiliary malignancies. KRAS mutations are less common than previous reports and do not correlate with survival.
To determine the frequency distribution of K-ras-2 point mutation genotypes in pancreatic adenocarcinoma and to evaluate the effectiveness of K-ras-2 genotyping as a means to predict localized disease and potential long-term survival.
Topographic genotyping from archival formalin-fixed, paraffin-embedded large- and biopsy-sized tissue specimens as well as cytologic fluid using polymerase chain reaction products and direct sequencing together with clinicopathologic and statistical analysis.
Tertiary care medical center with molecular diagnostics pathology laboratory.
Patients treated between 1988 and 1993 at Rhode Island Hospital, Providence, yielding 55 primary and 56 metastatic specimens of pancreatic adenocarcinoma.
Each primary pancreatic adenocarcinoma was found to contain one of eight specific genotypes that was maintained in all metastatic deposits of that individual tumor. Primary adenocarcinomas confined to the pancreatic bed at diagnosis were predominantly of a normal genotype (56% [14/25]). Pancreatic adenocarcinomas progressing to distant hematogenous metastasis were almost exclusively mutated (88% [7/8]; P < .005). Patients undergoing pancreatic resection (Whipple's operation) and having a normal K-ras-2-genotype (58% [11/19]) had a significantly longer survival (21.3 months) than similar patients with mutated tumors (8.2 months).
The findings support the feasibility of K-ras-2 topographic genotyping to identify potentially indolent disease and suggest a potentially useful role in the preoperative evaluation of pancreatic adenocarcinoma.
Seventy-seven pancreatic adenocarcinomas (60 Spanish and 17 Italian) were tested for Ki-ras gene mutations by analysis of polymerase chain reaction amplified sequences. Mutations involving codon 12 (GGT; gly) were detected in 16 Italian and 46 Spanish cases (80.5% in total). All Italian mutations involved the second base and were G to A transitions (GAT; asp) in 8 cases and G to T transversions (GTT; val) in the remaining 8. Forty-two Spanish mutations were characterized. Thirty-eight were at the second and 4 at the first base: asp in 24 cancers, val in 14, arg (CGT) in 2 and cys (TGT) in 2. Previous European studies and our present data show that 149 of the 186 pancreatic cancers harbored a codon 12 Ki-ras mutation (80%), the large majority affecting the second base (73%), with a transitions/transversions ratio of 1.3:1. However, the mutational pattern of cancers of the different European countries shows remarkable differences, both in the site of the mutation (first or second base) and in the ratio of transitions over transversions. Moreover, a significant subgroup of pancreatic carcinomas do not harbor Ki-ras mutations. The classification of pancreatic cancers, according to the presence or absence, and type of Ki-ras mutation, may be of importance in epidemiological studies. A critical reappraisal of existing epidemiological data, through a retrospective genotypic study using paraffin-embedded cancer samples, may reveal significant correlations with specific genotoxic agents.
Pancreatic cancer is one of the most lethal neoplasms. Incidence in the United States has remained fairly stable over the past 25 years, with about 25,000 cases annually. Almost 100% of cases are fatal. Incidence in the developed world parallels that in the United States. Incidence in undeveloped nations is lower but may be underreported. Worldwide incidence is about 185,000 cases per year. There are no striking environmental risk factors, and geographic variation is less than with other gastrointestinal cancers. The most significant risk appears to be cigarette smoking, with a risk ratio of about 2. Alcohol and coffee consumption have been reported as possible risks in some (but not in most) studies. Diet is probably a significant factor, but is difficult to evaluate quantitatively. Other putative associations, including diabetes, probably are unimportant.
Mutations involved in neoplastic progression may be able to serve as markers for the presence of small numbers of neoplastic cells that would otherwise escape detection in diagnostic assays. Previous retrospective studies have suggested that the sensitivity of the cytologic diagnosis of pancreatic and biliary tract carcinomas is improved when analysis includes Ki-ras exon 1, which is commonly mutated in these neoplasms. We report our experience with the systematic prospective application of Ki-ras gene analysis to the evaluation of fine-needle aspirates and brushings from the pancreatobiliary tract.
Between September 1996 and April 1999, 75 pancreatic fine-needle aspirates and common bile duct brushings submitted for routine cytologic diagnosis were also evaluated for mutations in Ki-ras exon 1 by polymerase chain reaction/single-strand conformation polymorphism analysis. After routine preparation of the specimens, residual material was used for molecular analysis. Results are compared with the morphologic diagnosis and available clinical information.
Single-strand conformation polymorphism mutation patterns in Ki-ras were detected in 22 of the 70 consecutive clinical specimens with adequate DNA and at least 6 months of available clinical follow-up. Sensitivity, specificity, and positive predictive value for the presence of concurrent or subsequent pancreatobiliary carcinoma were 33%, 97%, and 93%, respectively, for definitive cytologic diagnosis alone, and 53%, 97%, and 95% for positive Ki-ras single-strand conformation polymorphism mutation pattern alone. If definitive positive cytology or atypical/suspicious cytology with a positive Ki-ras single-strand conformation polymorphism mutation pattern is used, sensitivity is 55%, specificity is 97%, and positive predictive value is 96% for the presence of pancreatobiliary carcinoma.
Results support the routine use of Ki-ras mutational analysis to increase the sensitivity of the cytologic evaluation of pancreatobiliary fine-needle aspirates and common bile duct brushings with atypical or suspicious morphology without compromising specificity.
Pancreatic cancer is a highly fatal cancer with few identified risk factors. Increased risk of pancreatic cancer in tobacco smokers and among diabetic patients is well established, and some reports have suggested associations with coffee consumption and occupational exposure to organochlorines. At present, there is little information regarding the possible association of these risk factors with the known genetic alterations found in pancreatic cancers, such as activation of the K-ras oncogene and inactivation of the p53 tumor suppressor gene. Knowledge of such relationships may help to understand the molecular pathways of pancreatic tumorigenesis. We investigated the association between these molecular defects and risk factors for pancreatic cancer in 61 newly diagnosed patients identified through an ongoing study of pancreatic cancer in the San Francisco Bay Area. Interview information was obtained regarding environmental exposures, medical history, and demographic factors. Serum levels of dichlorodiphenyltrichloroethylene (DDE) and polychlorinated biphenyls were available on a subset of 24 patients. Tumor blocks were located from local hospitals and used for K-ras mutational analysis at codon 12 and for p53 protein immunohistochemistry. The molecular analyses were facilitated through the use of laser capture microdissection, which provides a reliable method to obtain almost pure populations of tumor cells. Mutations in K-ras codon 12 were found in 46 (75%) of 61 pancreatic cancers. A prior diagnosis of diabetes was significantly associated with K-ras negative tumors (P = 0.002, Fisher's exact test). The absence of this mutation was also associated with increased serum levels of DDE, although this association was not statistically significant (P = 0.16, Wilcoxon's test). There was no difference in polychlorinated biphenyl levels between the K-ras wild-type and mutant groups. Immunohistochemical staining for p53 protein did not differ by patient characteristics or clinical history, but significant associations were found with poor glandular differentiation (P = 0.002, chi2 trend test), severe nuclear atypia (P = 0.0007, chi2 trend test), and high tumor grade (P = 0.004, chi2 trend test). Our results are suggestive of the presence of K-ras codon 12 mutation-independent tumorigenesis pathways in patients with prior diabetes and possibly in patients with higher serum levels of DDE. Our results also support a role for the p53 tumor suppressor protein in the maintenance of genomic integrity.
Previous studies of molecular prognostic markers following resection for exocrine pancreatic cancer have produced conflicting results. Our aim was to undertake a comprehensive analysis of potentially useful molecular markers in a large, multicentre patient population and to compare these markers with standard pathological prognostic variables. Formalin-fixed, paraffin-embedded specimens of pancreatic ductal adenocarcinoma were analysed from 157 patients [100 men and 57 women with a median (range) age of 60 (33-77) years] who had undergone pancreatectomy. Immunohistochemistry was used to detect expression of p16(INK4), p53, p21(WAF1), cyclin D1, erbB-2 and erbB-3. Mutations in codons 12 and 13 of the K-ras oncogene were detected by SSCP and sequencing following DNA extraction and amplification by PCR. The median (range) survival post-resection was 12.5 (3-83) months. Abnormalities of p16(INK4), p53, p21(WAF1), cyclin D1, erbB-2 and erbB-3 expression were found in 87%, 41%, 75%, 72%, 33% and 57% of cases, respectively. There was no significant correlation between expression of any of these markers and patient survival. K-ras mutations were found in 73 (75%) of 97 cases with amplifiable DNA. The presence of K-ras mutation alone did not correlate with survival, but there were significant differences in survival according to the type of K-ras mutation (p = 0.0007). Reduced survival was found in patients with GaT, cGT and GcT K-ras mutations compared to GtT, aGT and GaC mutations. In conclusion, survival was associated with type of K-ras mutation but not expression of p16(INK4), p53, p21(WAF1), cyclin D1, erbB-2 and erbB-3.
Mortality rates associated with pancreatic resection for cancer have steadily decreased with time, but improvements in long-term survival are less clear. This prospective study evaluated risk factors for survival after resection for pancreatic adenocarcinoma.
Data from 366 consecutive patients recorded prospectively between November 1993 and September 2001 were analysed using univariate and multivariate models.
Fifty-eight patients (15.8 per cent) underwent surgical exploration only, 97 patients (26.5 per cent) underwent palliative bypass surgery and 211 patients (57.7 per cent) resection for pancreatic adenocarcinoma. Stage I disease was present in 9.0 per cent, stage II in 18.0 per cent, stage III in 68.7 per cent and stage IV in 4.3 per cent of patients who underwent resection. Resection was curative (R0) in 75.8 per cent of patients. Procedures included pylorus-preserving Whipple resection (41.2 per cent), classical Whipple resection (37.0 per cent), left pancreatic resection (13.7 per cent) and total pancreatectomy (8.1 per cent). The in-hospital mortality and cumulative morbidity rates were 2.8 and 44.1 per cent respectively. The overall actuarial 5-year survival rate was 19.8 per cent after resection. Survival was better after curative resection (R0) (24.2 per cent) and in lymph-node negative patients (31.6 per cent). A Cox proportional hazards survival analysis indicated that curative resection was the most powerful independent predictor of long-term survival.
Resection for pancreatic adenocarcinoma can be performed safely. The overall survival rate is determined by the radicality of resection. Patients deemed fit for surgery who have no radiological signs of distant metastasis should undergo surgical exploration. Resection should follow if there is a reasonable likelihood that an R0 resection can be obtained.
The vast majority of tumors of the pancreas are ductal adenocarcinomas. This cancer type has an extremely poor prognosis and in many Western countries, it represents the fifth leading cause of cancer-related death. Pancreatic ductal adenocarcinomas exhibit the highest incidence of activating KRAS (Ki-Ras) mutations observed in any human cancer. It was therefore of interest to examine how this pattern would relate to mutations in the BRAF and EGFR genes, which are involved in the same signaling pathway as KRAS. We screened a series of 43 formalin-fixed, paraffin-embedded ductal adenocarcinomas of the pancreas. When DNA was extracted from whole tissue sections, KRAS codon 12 mutations were detected in 67% of the tumors. When cancerous ducts were isolated by laser-assisted microdissection, 91% were positive for KRAS mutations. Although it did not reach statistical significance, there was a trend in our material that survival after diagnosis varied according to KRAS mutation subtype, GTT-positive patients having the best prognosis. No alterations in BRAF exons 11 and 15 or in EGFR exons 18-21 were detected in KRAS-positive or KRAS-negative cases. We therefore conclude that the BRAF and EGFR mutations commonly seen in a variety of human cancers are generally absent from pancreatic ductal adenocarcinomas. Apparently, these tumors depend on no more than one genetic hit in the EGFR-RAS-RAF signaling pathway.
Erlotinib, in combination with gemcitabine, has shown clinical benefits in pancreatic adenocarcinoma patients. The presence of EGFR mutations and increased EGFR copy numbers in pancreatic adenocarcinoma was explored.
Sixty-six pancreatic cancer patients were included in the analysis. The EGFR mutation was analyzed by DNA sequencing of exons 18-21 in the tyrosine kinase domain. KRAS mutation was analyzed by sequencing codons 12, 13, and 61. Quantitative real-time polymerase chain reaction was performed to analyze the copy number of EGFR.
In the current study the EGFR mutation was harbored in only 1 (1.5%) of the 66 inoperable or metastatic pancreatic adenocarcinoma patients. Amino acid substitution was detected in exon 20 of the EGFR gene. Increased EGFR copy numbers (> or =3.0 per cell) were detected in 26 (41%) patients. There was only 1 patient, who had a highly increased EGFR copy number (> or =6.0 per cell), who died, 2.1 months from the date of diagnosis. The EGFR amplification did not significantly influence survival in pancreatic adenocarcinoma patients (P = .935). Thirty-two (49%) of the 65 pancreatic adenocarcinomas examined harbored a point mutation in codons 12 (n = 31) and 61 (n = 1) of the KRAS gene. The presence of a point mutation in codon 12 adversely influenced survival of pancreatic cancer patients (P = .030).
The incidence of somatic mutations in the tyrosine kinase domains of EGFR was very low and the increased gene copy number of EGFR did not significantly influence survival.
K-RAS oncogene subtype mutations are associated with survival but not expression of p53
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