Fig 1 - uploaded by Kristina Lagerstedt
Content may be subject to copyright.
Flow diagram of the hereditary nonpolyposis colorectal cancer (HNPCC) diagnostic procedure used in this study. Top , inclusion criteria. 1 ) Microsatellite instability (MSI)-positive samples expressing all four mismatch repair (MMR) genes (MLH1, MSH2, MSH6, and PMS2 ) and MSInegative samples from familial cases, among which one patient was younger than age 50 years, were sequenced for MLH1, MSH2, and MSH6. 2 ) MSI-positive samples were sequenced according to which protein had low or no expression by immunohistochemistry (IHC), e.g., MLH1 if loss of MLH1 (with or without simultaneous loss of PMS2), MSH2 if loss of MSH2 (with or without simultaneous loss of MSH6), MSH6 if loss of MSH6, PMS2 if loss of PMS2 only. 3 ) Alternative screening methods were quantitative multiplex polymerase chain reaction of short fl uorescent fragments or multiplex ligation-dependent probe amplifi cation. 4 ) BRAF was sequenced only to verify a potential V600E mutation when no germline MMR gene mutation was found. 5 ) Counseling for HNPCC if a MMR gene germline mutation was found and considered pathogenic. Disease was considered non-HNPCC if no pathogenic germline mutation was found. CRC = colorectal cancer.
Source publication
Preventive programs for individuals who have high lifetime risks of colorectal cancer may reduce disease morbidity and mortality. Thus, it is important to identify the factors that are associated with hereditary colorectal cancer and to monitor the effects of tailored surveillance. In particular, patients with Lynch syndrome, hereditary nonpolyposi...
Contexts in source publication
Context 1
... retrospective study used the protocol in Fig. 1 to diagnose HNPCC patients. Dissection of tumor cells from paraffin-embedded tissue for MSI and gene mutation assays were performed at the Department of Clinical Genetics (Karolinska University Hospital). The technique for MSI testing followed the international Bethesda guidelines ( 28 ) and used at least one colorectal cancer patient ...
Context 2
... from 285 families were evaluated using a new diagnostic protocol ( Fig. 1 ). The study included 60 families who met the Amsterdam criteria, 188 non-Amsterdam families, and 37 single patients with early-onset (younger than age 50 years at diagno- sis) colorectal cancer. ...
Context 3
... MLH3 and the EXO1 genes have been studied in families fulfi lling or not fulfi lling the Amsterdam criteria, and several mis- sense mutations of unclear biologic relevance have been identifi ed ( 42 , 46 ). Because so many MSI-negative patients in our study had MMR gene mutations, it is still possible that we missed HNPCC families by not screening the 173 patients with MSI-negative tumors who were not selected by our new protocol ( Fig. 1 ). Based on this protocol, we selected 30 families with at least one patient younger than age 50 years. ...
Similar publications
Oxyphil or Hurthle cell tumours of the thyroid are characterised by their consistent excessive number of mitochondria. A recently discovered gene, GRIM-19 has been found to fulfil two roles within the cell: as a member of the interferon-beta and retinoic acid-induced pathway of cell death, and as part of the mitochondrial Complex I assembly. In add...
The analytical algorithm of Lynch syndrome (LS) is increasingly complex. BRAF V600E mutation and MLH1 promoter hypermethylation have been proposed as a screening tool for the identification of LS. The aim of this study was to assess the clinical usefulness and cost-effectiveness of both somatic alterations to improve the yield of the diagnostic alg...
Testing has been advocated for all persons with newly diagnosed colorectal cancer to identify families with the Lynch syndrome, an autosomal dominant cancer-predisposition syndrome that is a paradigm for personalized medicine.
To estimate the effectiveness and cost-effectiveness of strategies to identify the Lynch syndrome, with attention to sex, a...
Immunohistochemistry for mismatch repair proteins has shown utility in the identification of Lynch syndrome, but majority of tumors with loss of MLH1 expression are due to sporadic hypermethylation of the MLH1 promoter. These tumors can also show epigenetic silencing of other genes, such as p16. The aim of our study is to evaluate the utility of p1...
Approximately 15% of colorectal cancers develop because of defective function of the DNA mismatch repair (MMR) system. We determined the association of MMR status with colon cancer recurrence and examined the impact of 5-fluorouracil (FU)-based adjuvant therapy on recurrence variables.
We included stage II and III colon carcinoma patients (n = 2141...
Citations
... It's important to note that carriers of these genetic mutations have a risk ranging from 10% to 40% of developing ovarian malignancies by the age of 70. Furthermore, Lynch syndrome is also associated with ovarian cancer, although it is less common in occurrence [15]. Therefore, while in cases diagnosed with Lynch syndrome a MMR deficiency is the rule, in epithelial cancers of the ovary this mutation is encountered in up to 15% of patients [14,15]. ...
... Furthermore, Lynch syndrome is also associated with ovarian cancer, although it is less common in occurrence [15]. Therefore, while in cases diagnosed with Lynch syndrome a MMR deficiency is the rule, in epithelial cancers of the ovary this mutation is encountered in up to 15% of patients [14,15]. ...
... It's important to note that carriers of these genetic mutations have a risk ranging from 10% to 40% of developing ovarian malignancies by the age of 70. Furthermore, Lynch syndrome is also associated with ovarian cancer, although it is less common in occurrence [15]. Therefore, while in cases diagnosed with Lynch syndrome a MMR deficiency is the rule, in epithelial cancers of the ovary this mutation is encountered in up to 15% of patients [14,15]. ...
... Furthermore, Lynch syndrome is also associated with ovarian cancer, although it is less common in occurrence [15]. Therefore, while in cases diagnosed with Lynch syndrome a MMR deficiency is the rule, in epithelial cancers of the ovary this mutation is encountered in up to 15% of patients [14,15]. ...
... These findings indicate that a careful clinical evaluation of personal and family history is crucial for deciding whether or not targeted genetic testing should be performed to establish a molecular diagnosis of LS. Based on the scientific literature, up to 80% of patients with suspected LS carry variants in one of the MMR genes (MLH1, MSH2, MSH6, and PMS2) or the EPCAM gene [24,25]. In our study, 19 patients out of 30 (63.3%) showed PVs and/or LPVs in a MMR gene. ...
Simple Summary
Lynch syndrome (LS) is an inherited genetic condition caused by germline mutations in DNA mismatch repair (MMR) genes. It is associated with a predisposition to different types of cancer, including colorectal cancer (CRC). CRC is the fourth most common cancer worldwide. The screening algorithm for the selection of LS patients is based on the identification of CRC specimens that have MMR loss/high microsatellite instability (MSI-H) and are wild-type for BRAFV600. The aim of this retrospective study was to clinically and molecularly characterize CRC patients with these features. We used a comprehensive approach including tumor testing for the assessment of MSI status, clinical evaluation of patients and their families, and genetic analysis to identify variants in MMR and other cancer-related genes. The clinical and molecular characterization of these patients highlights the importance of personalized medicine to provide tailored genetic counseling, management, and surveillance to families with LS and hereditary cancer.
Abstract
Lynch syndrome (LS) is an inherited cancer susceptibility syndrome caused by germline mutations in a DNA mismatch repair (MMR) gene or in the EPCAM gene. LS is associated with an increased lifetime risk of colorectal cancer (CRC) and other malignancies. The screening algorithm for LS patient selection is based on the identification of CRC specimens that have MMR loss/high microsatellite instability (MSI-H) and are wild-type for BRAFV600. Here, we sought to clinically and molecularly characterize patients with these features. From 2017 to 2023, 841 CRC patients were evaluated for MSI and BRAFV600E mutation status, 100 of which showed MSI-H. Of these, 70 were wild-type for BRAFV600. Among these 70 patients, 30 were genetically tested for germline variants in hereditary cancer predisposition syndrome genes. This analysis showed that 19 of these 30 patients (63.3%) harbored a germline pathogenic or likely pathogenic variant in MMR genes, 2 (6.7%) harbored a variant of unknown significance (VUS) in MMR genes, 3 (10%) harbored a VUS in other cancer-related genes, and 6 (20%) were negative to genetic testing. These findings highlight the importance of personalized medicine for tailored genetic counseling, management, and surveillance of families with LS and other hereditary cancer syndromes.
... APC in familial adenomatous polyposis syndrome. and MLH1, MSH2, MSH6 and PMS2 in hereditary nonpolyposis colorectal cancer syndrome (Lynch syndrome) [37][38][39][40][41][42][43][44][45][46][47][48][49]. Furthermore, Table 1 (Ref. ...
... Furthermore, Table 1 (Ref. [38,[40][41][42][43][44][45][46][47]) summarizes the hereditary gene associations. ...
Background: Cancer research is significantly improved by comprehensive DNA sequencing and profiling. Genes involved in diagnostic, prognostic, or therapeutic consequences have been extensively studied using high-throughput sequencing. Thus, precision medicine based on cancer genotype has been developed, leading to improved survival. The fifth edition of the World Health Organization Classification of Tumors specified a diagnostic molecular pathology section under each disease category. Methods: We highlight the molecular aspects in research and diagnostics of diverse gynecological malignancies using database resources in addition to data mining software tools. Results: This review article presents insight into various gynecological cancers and their different characteristics, offering better profiling for switching to better therapeutic options. Conclusions: Genomic profiling is evolving as a clinically feasible tool for personalizing treatment. It can provide insight regarding treatment plans for common gynecological cancers.
... Some types of CRC are caused by a genetically inherited, autosomal disorder called the Lynch syndrome (LS) that increases the risk of many types of cancer, particularly CRC [18,[41][42][43]. The disorder is diagnosed by molecular or immunohistochemistry (IHC) testing in patients with mutations in one of four mismatch repair (MMR) genes designated MLH1, PMS2, MSH6 and MSH2. ...
... With 83% sensitivity and 89% specificity of IHC testing for absence of expression of MMR proteins in this group, we are confident that there is a connection. Tumours in LS cases also demonstrate microsatellite instability (MSI) owing to loss of DNA MMR, and testing for this by the polymerase chain reaction (PCR), which amplifies a standard panel of DNA sequences containing nucleotide repeats, has a sensitivity and specificity of about 85 and 90%, respectively [43,74]. Loss of the MLH1 expression owing to hypermethylation of this protein is seen in about 15% of sporadic CRCs based on IHC screening [75]. ...
... Loss of the MLH1 expression owing to hypermethylation of this protein is seen in about 15% of sporadic CRCs based on IHC screening [75]. On the other hand, cancers associated with the MSH6 protein may be missed during MSI testing because this gene is preferentially involved in repair of mononucleotide repeats and mononucleotide markers are not included in all MSI panels [43,76]. In spite of the better sensitivity and specificity of MSI testing, IHC is cheap and easily available, can be conducted using small biopsies and has the added value of assisting identification of the MMR protein(s) that may have caused the dMMRrelated tumour. ...
Background
The incidence rate of colorectal cancer (CRC) is increasing among patients below 50 years of age. The reason for this is unclear, but could have to do with the fact that indicative variables, such as tumour location, gender preference and genetic preponderance have not been followed up in a consistent manner. The current study was primarily conducted to improve the hereditary CRC screening programme by assessing the demographic and clinicopathological characteristics of early-onset CRC compared to late-onset CRC in northeast Iran.
Methods
This retrospective study, carried out over a three-year follow-up period (2014–2017), included 562 consecutive CRCs diagnosed in three Mashhad city hospital laboratories in north-eastern Iran. We applied comparative analysis of pathological and hereditary features together with information on the presence of mismatch repair (MMR) gene deficiency with respect to recovery versus mortality. Patients with mutations resulting in absence of the MMR gene MLH1 protein product and normal BRAF status were considered to be at high risk of Lynch syndrome (LS). Analyses using R studio software were performed on early-onset CRC (n = 222) and late-onset CRC (n = 340), corresponding to patients ≤50 years of age and patients > 50 years.
Results
From an age-of-onset point of view, the distribution between the genders differed with females showing a higher proportion of early-onset CRC than men (56% vs. 44%), while the late-onset CRC disparity was less pronounced (48% vs. 52%). The mean age of all participants was 55.6 ± 14.8 years, with 40.3 ± 7.3 years for early-onset CRC and 65.1 ± 9.3 years for late-onset CRC. With respect to anatomical tumour location (distal, rectal and proximal), the frequencies were 61, 28 and 11%, respectively, but the variation did not reach statistical significance. However, there was a dramatic difference with regard to the history of CRC in second-degree relatives between two age categories, with much higher numbers of family-related CRCs in the early-onset group. Expression of the MLH1 and PMS2 genes were significantly different between recovered and deceased, while this finding was not observed with regard to the MSH6 and the MSH2 genes. Mortality was significantly higher in those at high risk of LS.
Conclusion
The variation of demographic, pathological and genetic characteristics between early-onset and late-onset CRC emphasizes the need for a well-defined algorithm to identify high-risk patients.
... ,60 The expression of MMR protein can only be used to screen for LS and is not a diagnostic test.3.2.2 | MSI testingVarious markers can be used to evaluate MSI, including mononucleotide repeats, dinucleotide repeats, pentanucleotide repeats.48,52 Currently, the National Cancer Institute (NCI) panel and the Promega panel are recommended by authoritative guidelines and criteria. ...
Lynch syndrome (LS) is an autosomal dominant inherited disease caused by germline pathogenic variants (PVs) in mismatch repair (MMR) genes. LS‐associated endometrial cancer (LS‐EC) is the most common extraintestinal sentinel cancer caused by germline PVs in MMR genes, including MLH1, MSH2, MSH6 and PMS2. The clinicopathologic features of LS‐EC include early age of onset, lower body mass index (BMI), endometrioid carcinoma and lower uterine segment involvement. There has been significant progress in screening, diagnosis, surveillance, prevention and treatment of LS‐EC. Many studies support universal screening for LS among patients with EC. Screening mainly involves a combination of traditional clinical criteria and molecular techniques, including MMR‐immunohistochemistry (MMR‐IHC), microsatellite instability (MSI) testing, MLH1 promoter methylation testing and gene sequencing. The effectiveness of endometrial biopsy and transvaginal ultrasound (TVS) for clinical monitoring of asymptomatic women with LS are uncertain yet. Preventive strategies include hysterectomy and bilateral salpingo‐oophorectomy (BSO) as well as chemoprophylaxis using exogenous progestin or aspirin. Recent research has revealed the benefits of immunotherapy for LS‐EC. The NCCN guidelines recommend pembrolizumab and nivolumab for treating patients with advanced or recurrent microsatellite instability‐high (MSI‐H)/mismatch repair‐deficient (dMMR) EC.
... Microsatellites, which are also known as short tandem repeats of DNA, are clinically and forensically important. Due to their high mutability, microsatellites have been widely used as predictive (1)(2)(3)(4), diagnostic (5)(6)(7)(8), prognostic (9)(10)(11)(12) and forensic biomarkers (13)(14)(15)(16). They also act as markers in population studies (17)(18)(19)(20) and have diverse functional roles (21). ...
Mononucleotide microsatellites are clinically and forensically crucial DNA sequences due to their high mutability and abundance in the human genome. As a mutagenic intermediate of an indel in a microsatellite and a consequence of probe hybridization after such mutagenesis, a bulge with structural degeneracy sliding within a microsatellite is formed. Stability of such dynamic bulges, however, is still poorly understood despite their critical role in cancer genomics and neurological disease studies. In this paper, we have built a model that predicts the thermodynamics of a sliding bulge at a microsatellite. We first identified 40 common bulge states that can be assembled into any sliding bulges, and then characterized them with toehold exchange energy measurement and the partition function. Our model, which is the first to predict the free energy of sliding bulges with more than three repeats, can infer the stability penalty of a sliding bulge of any sequence and length with a median prediction error of 0.22 kcal/mol. Patterns from the prediction clearly explain landscapes of microsatellites observed in the literature, such as higher mutation rates of longer microsatellites and C/G microsatellites.
... Studies have demonstrated that the rate of BRAF mutations is higher in MSI-high CRCs than in MSS CRCs, especially those associated with MLH1 hypermethylation [16,17]. Because the BRAF mutation is found exclusively in individuals without LS [18][19][20], it can be used as a surrogate marker to differentiate LS from sporadic MSI-high CRC. The mechanisms of carcinogenesis and molecular profiles of LS have been well studied. ...
Background:
The 5'-C-phosphate-G-3' island methylator phenotype (CIMP) is a specific phenotype of colorectal cancer (CRC) associated with microsatellite instability-high (MSI-high) tumors.
Methods:
In this study, we determined the CIMP status using eight methylation markers in 92 MSI-high CRC patients after excluding five germline mismatch repair (MMR) gene mutations analyzed by next-generation sequencing (NGS) and confirmed by Sanger sequencing. The mutation spectra of 22 common CRC-associated genes were analyzed by NGS.
Results:
Of the 92 sporadic MSI-high tumors, 23 (25%) were considered CIMP-high (expressed more than 5 of 8 markers). CIMP-high tumors showed proximal colon preponderance and female predominance. The mutation profiles of CIMP-high tumors were significantly different from those of CIMP-low or CIMP-0 tumors (i.e., higher frequencies of BRAF, POLD1, MSH3, and SMAD4 mutations but lower frequencies of APC, TP53, and KRAS mutations). Multivariate analysis demonstrated that tumor, node, metastasis (TNM) stage was the independent prognostic factor affecting overall survival (OS). Among the MSI-high cases, the CIMP status did not impact the outcome of patients with MSI-high tumors.
Conclusions:
Only TNM stage was a statistically significant predictor of outcomes independent of CIMP profiles in MSI-high CRC patients. Sporadic MSI-high CRCs with different mechanisms of carcinogenesis have specific mutation profiles and clinicopathological features.
... The potential diagnostic value of BRAF V600E mutations to identify sporadic MSI CRC has further been supported by studies reporting a specificity of 100%. 10,13,14 Others, however, occasionally detected BRAF mutations in LS-associated CRC, [15][16][17] according to a meta-analysis amounting to a frequency of 1.4%. 18 We hypothesized that the predictive value of BRAF V600E mutation for the exclusion of LS may depend on the age at diagnosis. ...
BRAF V600E mutations have been reported as a marker of sporadic microsatellite instability (MSI) colorectal cancer (CRC). Current international diagnostic guidelines recommend BRAF mutation testing in MSI CRC patients to predict low risk of Lynch syndrome (LS). We evaluated the age‐specific performance of BRAF testing in LS diagnostics. We systematically compared the prevalence of BRAF mutations in LS‐associated CRCs and unselected MSI CRCs in different age groups as available from published studies, databases and population‐based patient cohorts. Sensitivity/specificity analysis of BRAF testing for exclusion of LS and cost calculations were performed. Among 969 MSI CRCs from LS carriers in the literature and German HNPCC Consortium, 15 (1.6%) harbored BRAF mutations. Six of seven LS patients with BRAF‐mutant CRC and reported age were <50 years. Among 339 of 756 (44.8%) of BRAF mutations detected in unselected MSI CRC, only 2 of 339 (0.6%) BRAF mutations were detected in patients <50 years. The inclusion of BRAF testing led to high risk of missing LS patients and increased costs at age <50 years. BRAF testing in patients <50 years carries a high risk of missing a hereditary cancer predisposition and is cost‐inefficient. We suggest direct referral of MSI CRC patients <50 years to genetic counseling without BRAF testing.
... The main limitation was in detection of patients with MSH6 constitutive mutations, whose tumours were often MSI-L rather than MSI-H. 24,[39][40][41] The ten MSI-L cases in our series all showed normal MMR IHC, supporting the general consensus that MSI-L colon cancers should be grouped with MSS cancers rather than MSI-H. 25 None of the MSI-L cases within our cohort showed abnormal MSH6 expression to suggest ...
Aims
Establishing mismatch repair (MMR) status of colorectal cancers is important to enable detection of underlying Lynch syndrome and inform prognosis and therapy. Current testing typically involves either PCR‐based microsatellite (MSI) testing or MMR protein immunohistochemistry (IHC). We aimed to compare these two approaches in a large, population‐based cohort of stage 2 and 3 colon cancer cases in Northern Ireland.
Methods and Results
Using the Promega pentaplex assay, we determined MSI status to a four antibody MMR IHC panel. IHC was applied to tumour tissue microarrays with triplicate tumour sampling and assessed manually. Of 593 cases with available MSI and MMR IHC results, 136 (22.9%) were MSI‐H and 135 (22.8%) displayed abnormal MMR IHC. Concordance was extremely high, with 97.1% of MSI‐H cases showing abnormal MMR IHC and 97.8% of cases with abnormal IHC showing MSI‐H status. Under‐representation of tumour epithelial cells in samples from heavily inflamed tumours resulted in misclassification of several cases with abnormal MMR IHC as microsatellite stable. MMR IHC revealed rare cases with unusual patterns of MMR protein expression, unusual combinations of expression loss or secondary clonal loss of expression, further illustrated by repeat immunostaining on whole tissue sections.
Conclusions
MSI PCR testing and MMR IHC can be considered equally proficient tests for establishing MMR/MSI status, when aware of the potentials pitfalls of either method. Methodology choice may depend on available services and expertise.
