Fig 1 - uploaded by Manuel Pera
Content may be subject to copyright.
Macroscopic picture of rat esophagus after 35 weeks of re fl ux. The arrow points out the site of the esophagojejunostomy.
Source publication
Recent studies have demonstrated that refluxed duodenal contents cause esophageal carcinoma in rats without exposure to carcinogens. The histopathological spectrum of these carcinomas includes squamous-cell carcinoma, adenocarcinoma and adenosquamous carcinoma. Pure adenocarcinomas are thought to arise in areas of columnar metaplasia adjacent to th...
Context in source publication
Context 1
... mortality rate was 9.5% (four of 42). Two rats died within the fi rst week after surgery for unknown reasons. Two rats died of respiratory distress before the time scheduled for termination. This was probably due to pulmonary aspiration secondary to re fl ux disease. At the end of the experiment period, 38 rats were evaluated. In all the rats, the middle and lower esophagus was abnormally dilated. The esophageal wall was thickened and the inner surface showed longitudinal folds extending along the entire length of the esophagus as well as whitish nodular patches of 1 ϫ 2 mm, which covered the esophageal surface and gave it a cobblestone appearance (Figure 1). Together with these changes, there were super fi cial ulcers located mostly in the middle and lower thirds of the esophagus. All these morphological fi ndings were present in all groups, although the changes were more intense in rats exposed to re fl ux for the longer periods. Macroscopically, no esophageal tumors were observed. The results of this study are shown in Table I. Reactive changes were seen in all rats, almost always accompanied by extensive ulceration of the mucosa. These fi ndings, characteristic of re fl ux esophagitis, mostly affected the middle and lower thirds of the esophagus. Columnar-lined epithelium extending Ͻ 4 mm above the esophagojejunostomy was observed in the distal esophagus in Ͼ 80% of the rats. Glandular metaplasia (Figure 2A, B and D), was observed from week 10 (in 17% of the cases) increasing over time to week 40 (in 83% of the rats). In some cases (Table I) there were multiple foci of glandular metaplasia. In six rats this glandular metaplasia was found in the middle and proximal thirds of the esophagus, far above the anastomosis. No pure squamous cell carcinomas or 1588 adenocarcinomas were observed. Adenosquamous carcinomas, characterized by the presence of both glandular and squamous cell patterns of differentiation, were present from week 20 to week 40, with an increasing number of cases with time (Figure 2C, E and F). These carcinomas had no characteristic macroscopic features, being made up of irregular ulcerations in the surface of the mucosa. Most of the adenocarcinomas (eight of 10) were located in the middle and proximal segments of the esophagus. In three cases there were multiple foci of carcinoma in all three thirds of the esophagus. Our most remarkable fi nding is the high prevalence of glandular metaplasia and adenosquamous carcinoma increasing over the time. Since the rats did not receive any carcinogen, duodenal content re fl ux alone was considered to exert a carcinogenic effect and promote the development of these lesions. It has been shown previously that chronic duodenal-content re fl ux causes columnar metaplasia and adenocarcinoma of the distal esophagus in rats. In 1989, Pera et al. (6) reported that rats with chronic re fl ux esophagitis had an increased incidence of esophageal carcinomas induced by s.c. injection of 2,6- DMNM. Interestingly, 50% of those tumors were adenocarcinomas and adenosquamous carcinomas, whereas control animals given only 2,6-DMNM showed only squamous cell carcinomas, suggesting that duodenal contents induced the glandular differentiation of the tumors. Most recently, it has been demonstrated that long-term duodenal or gastroduodenal re fl ux per se cause esophageal carcinomas in rats without the use of a carcinogen. Miwa et al. (9) reported 83 and 77% prevalence of carcinoma in rats with exposure to gastroduodenal or duodenal re fl ux, respectively, extending to 50 weeks. Columnar re-epithelization-associated adenocarcinoma was the most frequent histological type. In a similar study by Goldstein et al. (10), pure adenocarcinomas arising from columnar- lined esophagus were observed in 73% of rats with an esophagoduodenal anastomosis after 31 weeks. In another recent experiment (13), junctional adenocarcinomas were described in 48% of animals after only 16 weeks of exposure to re fl ux of gastroduodenal or duodenal juice without exogenous carcinogen administration. Therefore, esophageal carcinomas can be induced experimentally after a relatively short period of duodenal-content re fl ux. We con fi rmed this in the present investigation, in which just 20 weeks of re fl ux were enough to induce carcinomas. Overall, the results from the quoted 1589 animal models support the carcinogenic effect of duodenal re fl ux and the temporal progression from intestinal metaplasia to dysplasia and adenocarcinoma. Adenosquamous carcinomas have been described in several experimental studies of esophageal carcinogenesis (6,7,14) but only Miwa et al. (9) have previously reported squamous cell carcinomas with glandular differentiation without carcinogen. However, that investigation was not designed to study the pathogenesis of this type of tumor. In contrast to pure adenocarcinomas, which are known to arise in Barrett ’ s esophagus (2), the histogenesis of adenosquamous carcinomas is unclear. Based on experimental studies and clinical reports, several hypotheses have been proposed. It has been speculated that the glandular component of these neoplasms originates in esophageal glands or their ducts, in the light of the existence of subepithelial tumors covered by non-cancerous squamous epithelium (14,15). However, this idea does not explain the origin of the malignant squamous component. Others advocate a fi eld effect wherein both the squamous epithelium and submucosal glands are similarly affected during carcinogenesis (16). The fi nding of adenosquamous carcinomas in rats with chronic re fl ux esophagitis does not support these two hypotheses, because there are no esophageal submucosal glands in rats. Another hypothesis suggests that carcinomas with glandular differentiation may arise from initiated stem cells of the basal layer of the squamous epithelium (10). There has been considerable discussion about whether stem cells in the esophageal squamous epithelium have the capacity to give rise to glandular epithelial cells. In the histogenesis of Barrett ’ s esophagus, Jankowski et al. (17) proposed that such squamous/glandular epithelial transdifferen- tiation is indeed possible, although Wright (18) was sceptical about this concept and proposed instead that stem cells in the ducts of esophageal glands were the origin of Barrett ’ s epithelium. Our present fi ndings show unequivocally that the stem cells in the squamous epithelium of the esophagus are able to transdifferentiate to a glandular habitus. The destruction of the epithelial tissue architecture under the chronic effect of duodenal secretions may allow the proliferating stem cell population to become exposed to factors contained in the re fl ux material. We have shown previously that duodenal- content re fl ux esophagitis in rats induces an expansion of the proliferative compartment in the squamous epithelium, with an increasing number of proliferating cells in the suprabasal layer (19). This provides a larger cellular target for subsequent mutations for progression from a benign proliferative lesion to full-blown malignancy. While of course a mere expansion of the suprabasal cell compartment will not provide additional targets per se , since many of these cells will be lost through shedding, it is possible that such expansion also initiates an increase in the stem cell population. A minority of initiated cells will eventually proliferate to form a focus with the potential for double differentiation, mucinous and squamous, from the basal layer of the squamous epithelium. These foci will undergo further genetic changes, which lead to the formation of carcinomas with areas of squamous cell carcinoma and adenosquamous carcinoma. The high incidence of glandular metaplastic foci found here suggests this idea. Glandular metaplastic foci are characterized by mucus-secreting structures surrounded by squamous epithelium occurring in the middle and proximal esophagus. In the experiment by Pera et al. (6), glandular foci were observed in the esophagi of 11 animals with chronic esophagitis lasting 1590 for 32 weeks, and the authors suggested that glandular metaplasia might represent the precursor lesion for adenocarcinoma. Miwa et al. (9) found several patches of ectopic columnar tissue in the in fl amed squamous epithelium. Goldstein et al. (10) described islands of columnar metaplasia in the squamous epithelium far above the esophagoduodenal junction in one animal. In our study, glandular metaplasia was fi rst identi fi ed at 20 weeks, simultaneously to adenosquamous neoplasms, suggesting a rapid temporal progression from metaplasia to this type of carcinoma. We propose that chronic duodenal re fl ux may induce the development of metaplastic cells with glandular differentiation from the stem cells of squamous epithelium, and that glandular metaplastic foci are the morphological element from which tumors with a dual differentiation arise. In conclusion, the present investigation is the fi rst time-course experiment on chronic duodenal re fl ux esophagitis. It provides compelling evidence about the carcinogenic effect of duodenal re fl ux and the role of glandular metaplasia as a premalignant lesion of esophageal adenosquamous ...
Citations
... La présence de lésions de métaplasie intestinale chez le rat est en faveur de la théorie de la métaplasie de novo Kumagai, Mukaisho et al. 2003;Su, 50 Chen et al. 2004). En effet, l'oesophage de rat ne comporte pas de glandes sous muqueuses, écartant donc l'hypothèse de la théorie de la métaplasie d'origine canalaire (Pera 2000 (Pera 2000;Oyama, Fujimura et al. 2005;Miyashita, Ohta et al. 2006). Ces variations s'expliquent possiblement par l'administration de cocarcinogènes dans certaines de ces études Goldstein, Yang et al. 1997;Melo, Kruel et al. 1999;Bonde, Sui et al. 2007). ...
... La présence de lésions de métaplasie intestinale chez le rat est en faveur de la théorie de la métaplasie de novo Kumagai, Mukaisho et al. 2003;Su, 50 Chen et al. 2004). En effet, l'oesophage de rat ne comporte pas de glandes sous muqueuses, écartant donc l'hypothèse de la théorie de la métaplasie d'origine canalaire (Pera 2000 (Pera 2000;Oyama, Fujimura et al. 2005;Miyashita, Ohta et al. 2006). Ces variations s'expliquent possiblement par l'administration de cocarcinogènes dans certaines de ces études Goldstein, Yang et al. 1997;Melo, Kruel et al. 1999;Bonde, Sui et al. 2007). ...
Incidence of oesophageal adenocarcinoma developed on Barrett oesophagus increases since 30 years and its prognosis remains poor. Gastro esophageal reflux and biliary acid have been incriminated in Barrett oesophagus metaplasia and its degeneration in adenocarcinoma according to the sequence metaplasia/dysplasia/adencrcinoma. During the carcinogenetic sequence, was observed an increase of expression of the mucins MUC1 and MUC4. MUC1 and MUC4 are membrane bound O-glycoprotein implicated in cell recognition and intracellular signaling. The mechanisms of esophageal reflux leading to esophageal adenocarcinoma (EA) remain poorly understood. In a first part we appraised critically an operatively induced chronic reflux rat model.We randomized 108 Sprague-Dawley rats into 2 experimental groups; one was performing esophagoduodenal (ED) anastomosis with or without gastrectomy to induce duodeno-esophageal reflux (DER group; n = 63), and the other involved duodeno-gastro-esophageal reflux (DGER group; n = 45). Control groups included (i) Roux-en-Y esophagojejunal anastomosis, (ii) laparotomy alone, (iii) subtotal gastrectomy to induce duodenogastric reflux (DGR group), and (iv) the same procedure as in the DGER group plus proton pump inhibition (PPI group). The esophagus underwent histologic and molecular analyses.The prevalence of Barrett's esophagus (BE), dysplasia, and EA in the experimental groups was 41%, 7%, and 11%, respectively. Histologic and molecular analyses in groups DER, DGER, and DGR suggested that BE occurred through de novo intestinal metaplasia and proximal migration of duodenal cells. No distant metastases were identified. The molecular characteristics of both BE and EA were similar to humans. BE was more common, and dysplasia and EA less frequent in the DER groupwhen compared with the DGER group (44% vs 24% [ P = .038] and 7% vs 25% [ P = .012], respectively). Compared with the DGER group, carcinogenic sequence occurred less frequently in the PPI-treated group (P = .019). It was highlighted an overexpression of MUC1 and MUC4 genes, of genes implicated in proliferation, invasion, metastasis, cell adhesion , in PI3K pathways, a diminution of the expression of tumors suppressor genes in metaplasia, adenocarcinoma lesions in the areas most exposed to reflux. Then cell biological properties studies were carried out in vitro in OE33 oesophageal adenocarcinomatous cells. We showed that loss of expression of MUC1 in OE33 cells (i) induced a reduction of their proliferation, migration and invasion in vitro properties , tumor growth in vivo suggesting a major role of MUC1in epithelial tumorigenesis si MUC1 is overexpressed, (ii) is linked with a diminution of the exprssion of nfκb and PI3K and can be correlated with an alteration of the biological properties especially proliferation (iii) is lined with e diminution of expression of TSG101 and MCM6 , potential biomarkers highlighted in the rat model.In conclusion, despite pathophysiologic differences with humans, the rat model of esophagoduodenostomy reproduces accurately histologic and molecular lesions in the carcinogenetic sequence of BE and allowed us to identify novel, tumor-associated proteins that may be potential biomarkers and new therapeutic targets in EA.
... [7][8][9][10][11] Experimental studies have been designed to evaluate the true role of duodenal reflux using surgical models to induce alkaline reflux in rats. [12][13][14][15] The results of these studies have a potential role in directly influencing the future of DGER treatment. However, the effectiveness of the surgical model has never been satisfactorily established. ...
... Most studies assessing carcinogenesis in the esophagus have used longer periods of exposure to reflux, which may worsen the index of corroboration of reflux induction using this surgical method. [12][13][14] In the studies evaluated, DGER seems to require a period of variable exposure to generate histological changes in the esophageal mucosa. Pera et al demonstrated that the presence of esophageal carcinoma is detectable as early as 20 weeks. ...
... Pera et al demonstrated that the presence of esophageal carcinoma is detectable as early as 20 weeks. 13 The series of radiological studies used in this research confirmed esophageal exposure to duodenal contents over a long postoperative period, suggesting that it is a suitable technique for studying the chronic effects of reflux on the esophageal mucosa. ...
Performing experimental studies has played an important role in acquiring knowledge about esophageal carcinogenesis. In this context, the choice of a more reliable experimental model requires proof of its effectiveness in order to lend greater credibility to the results. The objective of this study was to evaluate the patency of duodenal-esophageal anastomosis during long-term postoperative follow-up in rats.
This was an experimental study in which 45 female Wistar rats were used. A side-to-side anastomosis was performed, going from the anterior side of the esophagus to the second duodenal portion. A standardized radiological technique was used to carry out a contrasted radiological study of the esophagus, stomach, and duodenum during weeks 4, 12, 20, and 30 after surgery. Different contrast media were used, and the animals were divided into groups, ie, group 1 (100% barium sulfate), group 2 (50% barium sulfate), and group 3 (60% aqueous iodinated contrast media). Contrast radiographs were taken in each group at weeks 4, 12, 20, and 30 after the surgical procedure. The radiographic images were evaluated by two radiologists who were blinded regarding the contrast groups. Macroscopic evaluation of each animal was compared with the radiological findings.
Postoperative mortality was 13.33%. The remaining animals were divided into study groups. All the contrast radiological examinations showed evidence of the location of the esophagus, stomach, and proximal portion of the intestine, and demonstrated the laterolateral relationship of the distal esophagus and the duodenum in the epigastric region. Patency of the anastomosis was observed at each examination period. The different contrast media used were able to demonstrate this outcome shortly after the first phase of injection. Necropsies corroborated the radiological findings.
Regardless of the contrast agent used, contrasted radiography revealed that side-to-side duodenal-esophageal anastomosis in rats allowed patent communication during long-term postoperative follow-up.
... Barrett's esophagus and esophageal AC are closely associated with duodenogastroesophageal (DGER) reflux (5)(6)(7)(8). Rat experiments demonstrated that duodenal contents cause esophageal carcinoma without exposure to carcinogens (9)(10)(11)(12)(13), whereas gastric contents do not (9). Though the etiology of esophageal AC is unclear, Mirvish et al suggested that the human esophageal AC and Barrett's esophagus was initiated by nitrosoamine (14). ...
Duodenogastroesophageal reflux causes esophageal adenocarcinoma in rats without the use of a carcinogen. This etiology is unclear, but may be associated with endogenous nitrosation in the gastrointestinal tract. Thioproline (TPRO) is an effective nitrite-trapping agent and blocks endogenous nitrosation. We investigated how ingested TPRO affected esophageal adenocarcinogenesis in rats with duodenogastroesophageal reflux (DGER) or gastroesophageal reflux (GER). A series of 200 male Fischer 344 rats received surgery to induce reflux of duodenogastric contents or gastric contents alone into the esophagus. The rats were separated into two divisions according to the surgical procedure employed (DGER or GER), and each division was further subdivided into two groups: one group was fed a special diet (CRF-1 containing 0.5% of TPRO); the other group was fed a standard diet (CRF-1). The rats were given no carcinogen and sacrificed at ten-week intervals from the 25th to the 45th week after surgery. Pathological examination was carried out using hematoxylin-eosin or immunohistochemical staining. Erosion, regenerative thickening, basal cell hyperplasia and columnar-lined epithelium (CLE) were found in both groups of the DGER rats. Adenocarcinoma (AC) appeared only in the DGER rats sacrificed at 35 and 45 weeks following surgery. The incidence of AC at the 45th week was significantly lower in the group of rats fed the diet containing TPRO, as compared to those fed the standard diet, whereas the incidences of CLE were the same for both groups. iNOS protein and nitrotyrosine protein were identified in the CLE and macrophages of the DGER group using immunohistochemical staining. There were no remarkable pathological changes in the esophagi of the rats which underwent the GER procedure. In conclustion, TPRO has an inhibitory effect on esophageal reflux-induced adenocarcinogenesis in rats in that it prevents the progression from CLE to AC.
... [3][4][5] Moreover, chronic refluxed duodenal contents per se caused squamous cell carcinoma, adenosquamous carcinoma, and adenocarcinoma. [6][7][8] Although the precise mechanism by which duodenal reflux causes oesophageal injury and predisposes to neoplasia is uncertain, there is considerable evidence that bile acids can induce mucosal injury, stimulate cell proliferation, and promote tumorigenesis. 9 Two isoforms of cyclooxygenase 1 (COX-1) and COX-2 have been characterised in mammalian and avian species. ...
Background and aim: It is known that bile acids can induce mucosal injury, stimulate cell proliferation, and promote tumorigenesis. A large body of genetic and biochemical evidence indicate that the biosynthetic pathway of prostaglandin E2 (PGE2) may play an important role in human and rodent tumours. Therefore, we examined the expression pattern of cyclooxygenase 1 (COX-1), COX-2, and microsomal prostaglandin E synthase 1 (mPGES-1), as well as EP receptor subtypes in rat oesophageal lesions induced by duodenal contents reflux. Methods: Oesophagoduodenal anastomosis was performed in rats to induce duodenal contents reflux. We examined histological changes and expression of COX-1, COX-2, mPGES-1, and EP receptor subtypes in the oesophagus by immunohistochemistry and reverse transcription-polymerase chain reaction. Results: Normal control oesophageal tissues showed COX-1 expression in subepithelial stromal cells, including endothelial cells and muscular cells, and did not reveal expression of COX-2 or mPGES-1. In the case of squamous cell lesions, immunoreactivity of COX-1 was similar to that of normal lesions, and COX-2 was maximally expressed around the vascular papillae of tissues showing dysplasia and surrounding epithelial layer and basal layer. mPGES-1 was highly expressed in stromal cells with COX-2 expression. In the case of Barrett’s oesophagus, COX-2 and mPGES-1 were predominantly in subepithelial stromal cells. mRNA levels of COX-2, mPGES-1, EP2, EP3, and EP4 were higher in the experimental groups than in controls. Conclusions: We suggest that the biosynthetic pathway of PGE2 may play an important role in oesophageal squamous cell dysplasia and glandular metaplasia induced by duodenal contents reflux.
Adenosquamous carcinoma (ASC) of the esophagus is an uncommon primary esophageal malignancy of uncertain pathogenesis, with several challenges complicating the establishment of a correct diagnosis. Neither the natural history nor the prognostic and therapeutic implications are well understood for this tumor. We report a case of a 71-year-old man who was found to have an ASC at the gastrointestinal junction. The clinicopathologic features as well as what is known of the epidemiology, pathogenesis, and prognosis and treatment of ASC are discussed, along with other possible coexisting disease.
Adenosquamous carcinoma (ASC), containing both adenocarcinoma and squamous cell carcinoma components, is rare in the digestive system. Limited data is available on ASC of the digestive system (AS-ASC), and the current evidence is available mainly in the form of case reports and case series. We performed a thorough search of the available literature and compiled a review on the epidemiology, histopathology, pathogenesis, clinical manifestations, diagnosis, treatment, and prognosis of AS-ASC. Non-specific clinical and imaging presentations and low diagnostic accuracy of biopsy lead to difficulties in preoperative diagnosis in a high proportion of patients and high malignancy. The pathogenesis remains obscure. Surgery remains the mainstay of treatment for AS-ASC. The role of chemoradiotherapy as an adjuvant treatment is still inconclusive.
• Key messages
• Metastatic linings and the lack of efficacious treatments lead to an unfavorable outcome in AS-ASC patients. Further research could help us understand the pathophysiology of AS-ASCand the unique needs of AS-ASC patients.
Barrett's esophagus (BE) is a premalignant condition caused by gastroesophageal reflux disease (GERD), where physiological squamous epithelium is replaced by columnar epithelium. Several in vivo and in vitro BE models were developed with questionable translational relevance when implemented separately. Therefore, we aimed to screen Gene Expression Omnibus 2R (GEO2R) databases to establish whether clinical BE molecular profile was comparable with animal and optimized human esophageal squamous cell lines-based in vitro models. The GEO2R tool and selected databases were used to establish human BE molecular profile. BE-specific mRNAs in human esophageal cell lines (Het-1A and EPC2) were determined after one, three and/or six-day treatment with acidified medium (pH 5.0) and/or 50 and 100 µM bile mixture (BM). Wistar rats underwent microsurgical procedures to generate esophagogastroduodenal anastomosis (EGDA) leading to BE. BE-specific genes (keratin (KRT)1, KRT4, KRT5, KRT6A, KRT13, KRT14, KRT15, KRT16, KRT23, KRT24, KRT7, KRT8, KRT18, KRT20, trefoil factor (TFF)1, TFF2, TFF3, villin (VIL)1, mucin (MUC)2, MUC3A/B, MUC5B, MUC6 and MUC13) mRNA expression was assessed by real-time PCR. Pro/anti-inflammatory factors (interleukin (IL)-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12, IL-13, tumor necrosis factor α, interferon γ, granulocyte-macrophage colony-stimulating factor) serum concentration was assessed by a Luminex assay. Expression profile in vivo reflected about 45% of clinical BE with accompanied inflammatory response. Six-day treatment with 100 µM BM (pH 5.0) altered gene expression in vitro reflecting in 73% human BE profile and making this the most reliable in vitro tool taking into account two tested cell lines. Our optimized and established combined in vitro and in vivo BE models can improve further physiological and pharmacological studies testing pathomechanisms and novel therapeutic targets of this disorder.
Mixed acidic-alkaline refluxate is a major pathogenic factor in chronic esophagitis progressing into Barrett's esophagus (BE) but the involvement of epidermal growth factor (EGF), COX-2 and peroxisome proliferator-activated receptor gamma (PPARg) in BE has not been extensively studied. Rats surgically prepared with esophagogastroduodenal anastomosis (EGDA) with intact or removed salivary glands to deplete salivary EGF were treated either with: 1) vehicle, 2) EGF or pioglitazone with or without tyrphostin A46 or GW9662, respectively, 3) ranitidine or pantoprazole. At three months, the esophageal damage (LI) and the esophageal blood flow (EBF) were determined, and the mucosal expression of EGF, EGFR, COX-2, TNF-α and PPARγ mRNA was analyzed. All EGDA animals developed chronic esophagitis, esophageal ulcerations and intestinal metaplasia followed by the fall in the EBF, an increase in the plasma IL-1β and TNF-α levels, the rise in the mucosal PGE 2 content and the overexpression of COX-2-, EGF- and EGFR mRNAs and these effects were aggravated by EGF and attenuated by pioglitazone. Expression of EGF and COX-2 mRNA was raised in esophageal mucosa of EGDA rats with or without EGF treatment, and inhibited by pioglitazone and further increased in pioglitazone and GW 9662-treated rats. We conclude that 1) EGF can interact with PG/COX-2 in the mechanism of chronic esophagitis; 2) the mechanism of deleterious effect of EGF involves an impairment of EBF and the overexpression of COX-2 and EGFR, and 3) agonists of PPARγ and inhibitors of EGFR can be useful in the treatment of chronic esophagitis progressing into BE.
Background:
Our purpose was to evaluate the prognostic impact of pathologically confirmed esophageal adenosquamous carcinoma (ASC) and its association with HER2 status and clinicopathologic characteristics.
Methods:
Among 796 patients with esophageal or gastroesophageal junction adenocarcinoma who underwent curative resection, surgical pathology reports were reviewed, and suspected ASC was confirmed utilizing p63 and CK5/6 immunostaining. HER2 status was determined using immunohistochemistry and fluorescence in situ hybridization. Cox models were used to assess the impact of ASC on disease-specific survival and overall survival.
Results:
Overall, 2.0% (16/796) of patients had esophageal ASC, mostly demonstrating a close intermingling of squamous and adenocarcinoma cells within the same tumor. The percentage of squamous versus adenocarcinoma cells in the primary was generally recapitulated in nodal metastases, and intrapatient internodal heterogeneity was uncommon. Patients with esophageal ASC were statistically significantly more likely to be female (vs. male), have normal (vs. excess) body mass index, and harbor HER2-negative (vs. positive) tumors, as compared with patients with adenocarcinoma only. No ASC tumor was HER2-positive as compared with 16% of adenocarcinoma only tumors (P=0.018). Compared with patients with adenocarcinoma only, those with ASC demonstrated profoundly worse disease-specific survival (5-year event-free rate, 34% vs. 6%; multivariate hazard ratio, 2.87 [95% confidence interval, 1.59-4.76]; P=0.0010) and overall survival (P=0.0027) that was independent of known prognostic factors and HER2 status.
Conclusion:
ASC identifies a rare aggressive HER2-negative subgroup of esophageal/gastroesophageal junction adenocarcinoma.
Objective:
The aim of this study was to assess the impact of chemoradiation on the immune microenvironment to influence and optimally design future neoadjuvant clinical trials.
Summary background data:
Programmed death (PD)-1 inhibitors in metastatic gastroesophageal cancer have demonstrated response rates of approximately 25% in programmed death ligand-1 (PD-L1+) tumors. Unfortunately, the majority of patients do not respond. Therefore, a rationale strategy of combining immunotherapeutic agents with chemoradiation in earlier stage esophageal cancer may prevent metastatic disease in patients.
Methods:
To determine the effects of chemoradiation on resected esophageal adenocarcinomas, we examined the immune microenvironment pre- and post-chemoradiation using immunohistochemistry, quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), and functional analysis of tumor-infiltrating lymphocytes. Additionally, to assess the duration and dependency of radiation-induced PD-L1 upregulation, a surgical rat reflux model of esophageal adenocarcinoma is used. First, tumor-bearing animals were dosed with single-fraction 13Gy or 16Gy radiation to determine safety, dose correlation, and PD-L1 upregulation using qRT-PCR post-radiation. Next, longitudinal PD-L1 expression levels within individual animals were determined using serial endoscopic biopsies at baseline, 1, 5, and 9 weeks post 16Gy radiation.
Results:
The majority of cancers displayed enhanced interferon γ and activated CD8+ T lymphocytes at the tumor stroma interface. These tumors also demonstrated enhanced upregulation of PD-L1 and multiple other immune checkpoints including TIM3, GITR, IDO1, LAG3, OX40, and KIR. The animal model results indicated PD-L1 upregulation is dose-dependent and transiently elevated post radiation exposure.
Conclusions:
Collectively, these findings provide insights into the evolving immune landscape after chemoradiation and have significant implications for neoadjuvant trial designs that will combine radiotherapy with immune checkpoint inhibitors.
