Fetal gut cell-like differentiation in esophageal adenocarcinoma - rare tumor subtype with therapeutically relevant claudin-6 positivity and SWI/SNF gene alteration

Fetal gut cell-like differentiation in esophageal adenocarcinoma - rare tumor subtype with therapeutically relevant claudin-6 positivity and SWI/SNF gene alteration | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Fetal gut cell-like differentiation in esophageal adenocarcinoma - rare tumor subtype with therapeutically relevant claudin-6 positivity and SWI/SNF gene alteration Max Kraemer, Thomas Zander, Hakan Alakus, Reinhard Buettner, Adrian Georg Simon, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3356259/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 12 You are reading this latest preprint version Abstract Esophageal adenocarcinoma (EAC) is one of the deadliest tumor entities worldwide, with a 5-year survival rate of less than 25%. Unlike other tumor entities, personalized therapy options are rare, partly due to the lack of knowledge about specific subgroups. In this publication, we demonstrate a subgroup of patients with EAC in a large screening cohort of 826 patients, characterized by specific morphological and immunohistochemical features. This subgroup represents approximately 0.7% (6/826) of the total cohort. Morphological features of this subgroup show a striking clear cytoplasm of the tumour cells and the parallel existence of rare growth patterns like yolk sac-like differentiation and enteroblastic differentiation. Immunohistochemistry reveals expression of the fetal gut cell-like proteins Sal-like protein 4 (SALL4), claudin-6, and glypican 3. Interestingly, we find a correlation with alterations of SWI/SNF-complex associated genes, which are supposed to serve as tumor suppressor genes in various tumour entities. Our results suggest a possible implication of rare tumour subtypes in the WHO classification for EACs according to the classification for gastric cancer. Furthermore, claudin-6 positive tumors show promising efficacy of CAR T cell therapies in clinical studies. This represents a personalized therapeutic option for this tumor subtype. Biological sciences/Cancer/Cancer screening Biological sciences/Cancer/Tumour biomarkers Biological sciences/Cancer/Gastrointestinal cancer Biological sciences/Cancer/Gastrointestinal cancer/Oesophageal cancer Biological sciences/Cancer/Cancer therapy Biological sciences/Cancer/Cancer therapy/Drug development Biological sciences/Cancer/Cancer therapy/Targeted therapies Fetal-gut SALL4 claudin-6 glypican 3 SMARCA2-loss esophageal adenocarcinoma clear cell adenocarcinoma Figures Figure 1 Figure 2 Introduction Esophageal cancer is the 10th most common cancer worldwide in 2020 with 604.100 reported cases and has a five-year survival of less than 25% [ 1 , 2 ]. While the incidence of esophageal adenocarcinoma (EAC) is expected to increase within the upcoming years there is a simultaneous decrease of squamous cell carcinoma (ESCC) [ 1 ]. Although the focus of clinical research is shifting towards chemotherapy-free regimens, chemotherapy remains the backbone of EAC therapy in advanced tumor stages. Therefore, the identification of subgroups that can benefit from targeted and possibly less toxic treatment regimens is an important component of current research. While the WHO classification of 2019 includes rare tumor entities for gastric carcinoma, such a classification does not exist for esophageal cancer [ 3 ]. These rare tumor entities include hepatoid adenocarcinomas as well as other alpha-fetoprotein (AFP)-producing tumours such as enteroblastic-differentiated adenocarcinomas and yolk-sac tumor-like carcinomas. More than one of these histological subtypes often coexist [ 3 ]. Adenocarcinoma with enteroblastic differentiation show a tubulopapillary growth pattern and the carcinoma cells have a strikingly clear cytoplasm. Overall, the histology resembles that of a fetal intestine and fetal intestinal surface markers such as Sal-like protein 4 (SALL4), claudin-6, and glypican 3 are expressed at increased levels. Furthermore, an AFP expression may be present, although this is not mandatory [ 3 ]. There is limited clinical data available on gastric adenocarcinoma with enteroblastic differentiation. The largest study by Murakami et al. includes 29 patients and presents the morphological, immunohistochemical and clinical characteristics of this rare tumor entity [ 4 ]. In their patient cohort, there is a trend towards an aggressive tumor biology with a high rate of lymphatic and haematogenous metastasis [ 4 ]. Despite the prognostic significance of enteroblastic differentiation, the question arises whether this histological feature could even have therapeutic implications. Currently, e.g. targeted therapy options exist for solid tumours with claudin-6 expression, being evaluated in an open phase 1/2 trial (trial no.: BNT211-01). Until now, nearly nothing is known about similar morphological features in esophageal cancer. Does this rare (gastral) tumor subtype also exist in the esophagus? If so, how common is it and what are the characteristics of these tumors in the esophagus? In this publication, we describe for the first time an enteroblastic differentiation with fetal gut cell-like surface markers in a group of patients with esophageal adenocarcinoma (EAC), analyse patients’ and tumor characteristics and discuss potential implications for clinical practice. Material and methods Patients and tumour samples: For screening our patient cohort for enteroblastic differentiation, we used the formalin-fixed and paraffin embedded samples from 826 patients with EACs. All patients underwent primary surgical resection or resection after neoadjuvant therapy between 1999–2017 at the Department of General, Visceral and Cancer Surgery, University of Cologne, Germany. The standard surgical procedures were laparotomic or laparoscopic gastrolysis and right transthoracic en-bloc esophagectomy, with intrathoracic esophagogastrostomy, including two-field lymphadenectomy of mediastinal and abdominal lymph nodes, transhiatal extended distal esophagectomy with intrathoracic or cervical anastomosis as described previously [ 5 ]. Preoperative chemoradiation (5-Fluouracil/cisplatin or carboplatin/paclitaxel + 40 Gy) or chemotherapy were administered in case of tumour stage ≥ c3. For the screening procedure, we constructed a tissue microarray (TMA), as previously described [ 6 ]. In brief, for this TMA, we randomly punched out one tissue core from each tumour and transferred it into a TMA recipient block. Four µm sections of the resulting TMA blocks were transferred to an adhesive coated slide system (Instrumedics Inc., Hackensack, NJ) for immunohistochemistry (IHC). The study protocol was in accordance with the ethical guidelines of the 1964 Declaration of Helsinki and its later amendments as reflected by the approval of the institution’s human research review committee (Ethics Committee of the Medical Faculty of University of Cologne: registration no.13–091; Ethics-No.: 21-1146). All patients gave written informed consent to the use of their tumour specimen and their data for research and publication. Immunohistochemistry IHC was performed on the TMA slides and for positively screened cases on large-scale slides. The following antibodies were used for IHC studies: a mouse monoclonal antibody (clone 6E3; dilution 1:400; Cell Marque) for SALL4, a mouse monoclonal antibody (clone A-4; dilution 1:50; Santa Cruz/RUO) for claudin-6, a mouse monoclonal antibody (clone 1G12; dilution 1:50; Cell Marque/CE) for glypican 3, a mouse monoclonal antibody (clone A4; dilution 1:6000; Dako/CE) for cytokeratin 7 (CK7), a rabbit monoclonal antibody (clone D9E8B; dilution 1:50; Cellsignal/RUO) for SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily A member 2 (SMARCA2), a mouse monoclonal antibody (clone EPNCIR111A; dilution 1:300; abcam) for SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily A member 4, a rabbit monoclonal antibody (clone : EPR13501 dilution 1:1000; abcam) for AT-rich interactive domain-containing protein 1A (ARID1A), a monoclonal antibody (clone poly; dilution 1:1600; Dako/CE) for AFP. All immunohistochemical stainings were performed using the BOND-MAX-stainer (Leica Biosystems, Germany) according to the protocol of the manufacturer. The evaluation of immunohistochemical expression was assessed manually by two pathologists (A.Q. and A.G.S). Strategy of evaluation We initially performed a screening for the expression of SALL4 and glypican 3 on the TMA. If at least one of the surface markers was detectable on more than 50% of the tumor cells, we analysed the case on a large-scale slide (whole tumor block). If the impression from the TMA that more than 50% of the tumor cells were positive for at least one of the two proteins (SALL4 or glypican 3) was confirmed on the large-scale slide, claudin-6 was additionally determined on whole tumor blocks. Cases showing an expression of at least two of the three surface markers claudin-6, SALL4 or glypican 3 on whole tumor slides were considered for further analysis. Following that, immunohistochemical stainings for CK7, SMARCA2, SMARCA4, ARID1A, and AFP were performed on the positively screened cases. Results Clinicopathological findings The screening procedure identified 6 out of 826 patients (0.7%) who were positive for at least two out of the three markers SALL4, glypican3, or claudin-6. Five out of the six patients were male, average age at diagnosis was 63.5 (46–72). The clinicopathological findings are summarized in Table 1 . Table 1 Baseline characteristics of the screening patient cohort EAC total cohort (n = 826) non-enteroblastic (n = 820; 99.0%) enteroblastic (n = 6; 0.7%) n (%) n (%) Sex Male 717 (87.4) 5 (83.3) Female 103 (12.6) 1 (16.7) Median age (range) 64.0 (28–92) 63.5 (46–72) (y)pT pT1 152 (18.5) 0 (0) pT2 151 (18.4) 1 (25.0) pT3 489 (59.6) 4 (50.0) pT4 28 (3.5) 1 (25.0) (y)pN pN0 333 (40.6) 0 (0) pN+ 487 (59.4) 6 (100.0) Neoadjuvant treatment Yes 518 (63.2) 5 (83.3) No 302 (36.8) 1 (16.7) Histological features All tumours showed parts with carcinoma cells with a strikingly clear cytoplasm. Very different tumor growth patterns were found. Only in one case the characteristics of enteroblastic differentiation were observed focally. In the remaining cases, tubulo-papillary or solid or garland-shaped growth patterns were detected, which suggested a yolk sac-like differentiation. These different growth patterns also occurred within the same tumor (Fig. 1 ). Immunohistological staining The results of the performed immunohistological staining are summarized in Table 2 . Regarding the markers of enteroblastic differentiation, all patients showed a claudin-6 and glypican 3 on at least 70% of the carcinoma cells (Fig. 2 a and 2 b). The SALL4 expression was heterogeneous, with three patients showing expression on at least 80% of the carcinoma cells (Fig. 2 c). If positive, glypican 3, SALL4 and claudin-6 were ubiquitously expressed in the carcinoma cells throughout different growth patterns. Furthermore, all tumours showed marked reduced expression or absence of CK7 (Fig. 2 d), various expression of AFP (Fig. 2 e) and a low developed desmoplastic stromal reaction. Additionally, all tumours exhibited an alteration of at least one SWI/SNF marker, mostly a SMARCA2 loss (Fig. 2 f). Table 2 Immunohistological Staining results of the positively screened patient cohort Case 1 2 3 4 5 6 Sex M M M F M M Age 46 63 66 72 66 68 CK7 2% 0% 5% 15% 0% 5% SMARCA4 100% 100% 100% 100% 100% 100% ARID1a 0% 100% 100% 100% 100% 100% SMARCA2 0% 0% 10% 0% 10% 15% AFP 2% 10% 0% 10% 90% 0% Claudin-6 85% 100% 80% 100% 70% 90% Glypican 3 70% 100% 80% 100% 85% 80% SALL4 15% 80% 5% 100% 40% 10% Discussion In this retrospective analysis of 826 patients with esophageal adenocarcinomas (EAC), we can identify a subgroup of patients characterized by the expression of fetal gut-like surface markers (glypican 3, SALL4, claudin-6). These patients exhibit not only immunohistochemical peculiarities but also morphological characteristics like a strikingly clear cytoplasm and loss or marked reduced CK7 expression. So far, there have only been case reports for this phenotype in EAC, making us the first to demonstrate these morphological and immunohistochemical characteristics in a group of patients within a large and representative patient cohort [ 7 – 9 ] With a frequency of 0.7%, we find the above-described characteristics only in a small portion of patients. In the WHO classification 2019 for gastric carcinomas, the frequency of AFP-producing carcinomas, including adenocarcinomas with enteroblastic differentiation, is estimated to be 0.3-2% [ 3 ]. The observed frequency in our patient cohort of EACs seems to be comparable to this. Despite this rareness, we know from other tumor entities like non-small cell lung cancer (NSCLC) that the identification of small sub-entities (like ROS1 altered NSCLC) can have a significant impact on the treatment concepts for the concerned patients [ 10 ]. In terms of therapeutic relevance, the consistent expression of claudin-6 in the identified subgroup could lead to such implications. Claudin-6 is a tight junction protein and is expressed to varying degrees in different tumor entities. For example, testis cancer shows increased expression in over 90% of tumor samples, while the rate in gastric carcinoma is around 3% [ 11 ]. Claudin-6 is the target protein for new therapeutic approaches, as for example a Chimeric Antigen Receptor T-Cell Therapy (CAR-T-cell therapy), which is currently being investigated in an early phase study by BioNTech (trial no. BNT-211-01). This therapy offers patients with solid tumours and a claudin-6 expression on > 50% of the tumor cells a new therapeutic option after the failure of approved therapy lines. Therefore, for EAC, it seems reasonable that in the presence of an enteroblastic differentiation or a population with strikingly clear tumour cell cytoplasm in the haematoxylin and eosin staining or and loss/marked reduced CK7 expression on tumor cells, pathologists should consider the presence of fetal gut-like proteins and perform corresponding staining. Hereby, a subgroup of patients could significantly benefit from new therapeutic approaches. Interestingly, we find a loss of SMARCA2 expression simultaneously to the expression of fetal-gut like surface markers in all patients. One patient additionally showed a loss of ARID1A expression. SMARCA2 and ARID1A are subunits of the SWI/SNF chromatin-remodelling complex, which is altered in up to 25% of all tumour entities [ 12 ]. In EAC, TCGA data describe SWI/SNF alteration across all subunits in approximately 20%, loss of function alterations of SMARCA2 in 4% and ARID1A in 8% [ 13 , 14 ]. At protein level, Schallenberg et al. report a loss of SMARCA2 expression in 9.9% and ARID1A in 10.4% in EAC [ 15 ]. However, an underlying oncogenic mechanism of SWI/SNF alteration remains unclear. Currently, an increased prevalence of genetic instability resulting from impaired DNA repair mechanisms, lineage-specific, epigenetic modifications and an association with distinct, oncogenic signalling pathways are being discussed [ 16 – 21 ]. Various early phase clinical trials are currently investigating the therapeutic potential of the suspected effects of SWI/SNF alterations, for example, by using poly(ADP-ribose)-polymerase (PARP) inhibitors in order to address impaired DNA repair mechanisms or Enhancer of zeste homolog 2 (EZH2) inhibitors to modulate certain epigenetic signatures [ 12 ]. Furthermore, there is evidence for a particular role of the SWI/SNF complex in the differentiation of pluripotent embryonic stem cells [ 22 , 23 ]. In this context, the embryonic SWI/SNF complex prevents further differentiation of the stem cells by modifying the regulatory elements of the master pluripotency factors Octamer binding transcription factor 4 (Oct4), SRY-Box Transcription Factor 2 (Sox2), and Nanog [ 23 ]. The composition of the embryonic SWI/SNF complex is characterized by the absence of the ATPase SMARCA2, which is fully compensated by SMARCA4 expression [ 22 , 24 ]. The identified six patients with expression of fetal gut-like surface markers all show an alteration of SMARCA2 and, with the exception of one patient, a strong, preserved SMARCA4 expression. This constellation may also indicate the “fetal nature” (so called stem cell-derived differentiation) of the tumor cells. However, it remains unclear to what extent the differentiation stage of tumor cells has clinical relevance. Therefore, for now, rather the distinct characteristics of fetal differentiation, such as the expression of claudin-6 or abnormalities in the SWI/SNF complex, may potentially serve as targets for future therapeutic concepts. Conclusion In conclusion, in our analysis, we identified a small subgroup of patients with EAC who exhibit morphological and immunohistochemical features of a fetal-gut like differentiation. Due to the limited number of cases, the clinical characteristics of these patients are still unknown, and the 2019 WHO classification does not separately list this subgroup of esophageal carcinoma. However, increased attention to the described features in routine diagnostics may help identify more patients with this phenotype and contribute to further characterization. There is already today a therapeutic relevance for this subtype, suggesting that it could have significant importance in the future. Declarations Data availability: The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request. Author contributions: M.K. and A.Q. conceived and designed the study; T.Z., H.A., W.S., C.J.B., enrolled the patients and collected the clinical data, while AQ, R.B. and A.G.S. performed the pathological analysis; M.K., T.Z. and A.Q. interpreted the data. All authors were involved in writing the paper, critically revised the manuscript for important intellectual content approved the submitted version. Competing interests: The authors declare no competing interests. References Arnold, M., Laversanne, M., Brown L.M., Devesa, S.S., and Bray, F., Predicting the Future Burden of Esophageal Cancer by Histological Subtype: International Trends in Incidence up to 2030. Am J Gastroenterol, 2017. 112 (8): p. 1247-1255. 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Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 26 Mar, 2024 Reviews received at journal 11 Mar, 2024 Reviewers agreed at journal 05 Mar, 2024 Reviewers agreed at journal 03 Jan, 2024 Reviewers agreed at journal 07 Dec, 2023 Reviews received at journal 07 Dec, 2023 Reviewers agreed at journal 01 Dec, 2023 Reviewers invited by journal 26 Sep, 2023 Editor assigned by journal 26 Sep, 2023 Editor invited by journal 22 Sep, 2023 Submission checks completed at journal 22 Sep, 2023 First submitted to journal 14 Sep, 2023 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-3356259","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":235466376,"identity":"f4e775f1-adee-4709-8843-75aa68113021","order_by":0,"name":"Max Kraemer","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA+ElEQVRIie3PsYrCMBzH8X8IxKXg2i53TyCkCJmKzxIpdLpNcHFQl3ap3KpwD+HU6YZIoV2CtwYcbJdODn0DTbkbTe14Q75LyPAhvwDYbP80tPk7KxBAAbC+k2EE01+ChhPiDiKTRFJ0+J69TZJds3IkTMejbVzBMjASJiOOjk04ZbJkF0cB89JTQuEcmYkIBaoEnmcqIhenvQdUzWMXxbmZ/NQbTdbr7NqQhdNCQK91R+5movQrR5FzpgjB3TCqUEdED2n4aS9KP5MR9r70971UD+PnsGfYh1+nYvXOygK1twL8z1FeuO1yZiRdTzbwXmCz2Wy2Vz0ATxtZ8zyHOC4AAAAASUVORK5CYII=","orcid":"","institution":"University of Cologne, Gastrointestinal Cancer Group Cologne GCGC","correspondingAuthor":true,"prefix":"","firstName":"Max","middleName":"","lastName":"Kraemer","suffix":""},{"id":235466377,"identity":"a2283751-5f71-40a4-a947-30e0bf5b07d9","order_by":1,"name":"Thomas Zander","email":"","orcid":"","institution":"University of Cologne, Gastrointestinal Cancer Group Cologne GCGC","correspondingAuthor":false,"prefix":"","firstName":"Thomas","middleName":"","lastName":"Zander","suffix":""},{"id":235466378,"identity":"02fa1b23-14bb-4393-b8e5-fb6324333594","order_by":2,"name":"Hakan Alakus","email":"","orcid":"","institution":"Department of General, Visceral, Cancer and Transplantation Surgery, University Hospital Cologne, Cologne (Germany)","correspondingAuthor":false,"prefix":"","firstName":"Hakan","middleName":"","lastName":"Alakus","suffix":""},{"id":235466379,"identity":"82cacae3-b22d-4188-af28-d62d0472ca31","order_by":3,"name":"Reinhard Buettner","email":"","orcid":"","institution":"Faculty of Medicine and University Hospital of Cologne, Institute of Pathology, University of Cologne, Cologne, Germany","correspondingAuthor":false,"prefix":"","firstName":"Reinhard","middleName":"","lastName":"Buettner","suffix":""},{"id":235466380,"identity":"eb849c04-eefe-4fa8-b36a-74297dd7adf8","order_by":4,"name":"Adrian Georg Simon","email":"","orcid":"","institution":"Faculty of Medicine and University Hospital of Cologne, Institute of Pathology, University of Cologne, Cologne, Germany","correspondingAuthor":false,"prefix":"","firstName":"Adrian","middleName":"Georg","lastName":"Simon","suffix":""},{"id":235466381,"identity":"3b985698-60ae-4c9a-b30d-9d522c5e7ec2","order_by":5,"name":"Wolfgang Schroeder","email":"","orcid":"","institution":"Department of General, Visceral, Cancer and Transplantation Surgery, University Hospital Cologne, Cologne (Germany)","correspondingAuthor":false,"prefix":"","firstName":"Wolfgang","middleName":"","lastName":"Schroeder","suffix":""},{"id":235466382,"identity":"524c87b1-e0cd-4c49-8d39-692236e23e01","order_by":6,"name":"Christiane J. Bruns","email":"","orcid":"","institution":"Department of General, Visceral, Cancer and Transplantation Surgery, University Hospital Cologne, Cologne (Germany)","correspondingAuthor":false,"prefix":"","firstName":"Christiane","middleName":"J.","lastName":"Bruns","suffix":""},{"id":235466383,"identity":"2145651f-05e5-4e38-a776-9309ca6ba64c","order_by":7,"name":"Alexander Quaas","email":"","orcid":"","institution":"Faculty of Medicine and University Hospital of Cologne, Institute of Pathology, University of Cologne, Cologne, Germany","correspondingAuthor":false,"prefix":"","firstName":"Alexander","middleName":"","lastName":"Quaas","suffix":""}],"badges":[],"createdAt":"2023-09-14 17:29:22","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-3356259/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-3356259/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":43843506,"identity":"c3661af7-165a-4789-91b0-0cb9fac4e48d","added_by":"auto","created_at":"2023-09-28 15:49:54","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":284904,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eHE-morphology of different tumor growth patterns (different growth patterns can co-exist within the same tumor): 1a) enteroblastic, 1b) papillary, 1c) solid clear cell, 1d) garland “yolk-sac”-like\u003c/em\u003e\u003c/p\u003e","description":"","filename":"Figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3356259/v1/8a3b5b48968d776fa07490a8.jpg"},{"id":43843508,"identity":"efb8da67-930a-42c4-b33f-4502dc255267","added_by":"auto","created_at":"2023-09-28 15:49:55","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":250587,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eImmunohistochemistry in esophageal adenocarcinoma with expression of fetal-gut like surface markers; 2a) Claudin-6 expression on tumour cells, 2b) glypican 3 expression on tumor cells, 2c) SALL4 expression on tumor cells, 2d) CK7 loss of the tumour cells, 2e) AFP expression on tumour cells (lymph node metastasis), 2f) SMARCA2 loss of tumour cells (tumor nuclei in pale blue without expression of SMARCA2 protein and co-existing lymphocytes and other stroma cells within the tumor show preserved SMARCA2 expression)\u003c/em\u003e\u003c/p\u003e","description":"","filename":"Figure2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3356259/v1/c709025d7542e1d0b8df03db.jpg"},{"id":43844303,"identity":"74e3f5ed-17e7-4ffe-866a-126d99b14768","added_by":"auto","created_at":"2023-09-28 15:57:55","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":552723,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3356259/v1/0180de10-a439-4eec-928a-8d9863910243.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Fetal gut cell-like differentiation in esophageal adenocarcinoma - rare tumor subtype with therapeutically relevant claudin-6 positivity and SWI/SNF gene alteration","fulltext":[{"header":"Introduction","content":"\u003cp\u003eEsophageal cancer is the 10th most common cancer worldwide in 2020 with 604.100 reported cases and has a five-year survival of less than 25% [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. While the incidence of esophageal adenocarcinoma (EAC) is expected to increase within the upcoming years there is a simultaneous decrease of squamous cell carcinoma (ESCC) [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Although the focus of clinical research is shifting towards chemotherapy-free regimens, chemotherapy remains the backbone of EAC therapy in advanced tumor stages. Therefore, the identification of subgroups that can benefit from targeted and possibly less toxic treatment regimens is an important component of current research.\u003c/p\u003e \u003cp\u003eWhile the WHO classification of 2019 includes rare tumor entities for gastric carcinoma, such a classification does not exist for esophageal cancer [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. These rare tumor entities include hepatoid adenocarcinomas as well as other alpha-fetoprotein (AFP)-producing tumours such as enteroblastic-differentiated adenocarcinomas and yolk-sac tumor-like carcinomas. More than one of these histological subtypes often coexist [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAdenocarcinoma with enteroblastic differentiation show a tubulopapillary growth pattern and the carcinoma cells have a strikingly clear cytoplasm. Overall, the histology resembles that of a fetal intestine and fetal intestinal surface markers such as Sal-like protein 4 (SALL4), claudin-6, and glypican 3 are expressed at increased levels. Furthermore, an AFP expression may be present, although this is not mandatory [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. There is limited clinical data available on gastric adenocarcinoma with enteroblastic differentiation. The largest study by Murakami et al. includes 29 patients and presents the morphological, immunohistochemical and clinical characteristics of this rare tumor entity [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. In their patient cohort, there is a trend towards an aggressive tumor biology with a high rate of lymphatic and haematogenous metastasis [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Despite the prognostic significance of enteroblastic differentiation, the question arises whether this histological feature could even have therapeutic implications. Currently, e.g. targeted therapy options exist for solid tumours with claudin-6 expression, being evaluated in an open phase 1/2 trial (trial no.: BNT211-01).\u003c/p\u003e \u003cp\u003eUntil now, nearly nothing is known about similar morphological features in esophageal cancer. Does this rare (gastral) tumor subtype also exist in the esophagus? If so, how common is it and what are the characteristics of these tumors in the esophagus? In this publication, we describe for the first time an enteroblastic differentiation with fetal gut cell-like surface markers in a group of patients with esophageal adenocarcinoma (EAC), analyse patients\u0026rsquo; and tumor characteristics and discuss potential implications for clinical practice.\u003c/p\u003e"},{"header":"Material and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003ePatients and tumour samples:\u003c/h2\u003e \u003cp\u003eFor screening our patient cohort for enteroblastic differentiation, we used the formalin-fixed and paraffin embedded samples from 826 patients with EACs. All patients underwent primary surgical resection or resection after neoadjuvant therapy between 1999\u0026ndash;2017 at the Department of General, Visceral and Cancer Surgery, University of Cologne, Germany. The standard surgical procedures were laparotomic or laparoscopic gastrolysis and right transthoracic en-bloc esophagectomy, with intrathoracic esophagogastrostomy, including two-field lymphadenectomy of mediastinal and abdominal lymph nodes, transhiatal extended distal esophagectomy with intrathoracic or cervical anastomosis as described previously [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Preoperative chemoradiation (5-Fluouracil/cisplatin or carboplatin/paclitaxel\u0026thinsp;+\u0026thinsp;40 Gy) or chemotherapy were administered in case of tumour stage\u0026thinsp;\u0026ge;\u0026thinsp;c3.\u003c/p\u003e \u003cp\u003eFor the screening procedure, we constructed a tissue microarray (TMA), as previously described [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. In brief, for this TMA, we randomly punched out one tissue core from each tumour and transferred it into a TMA recipient block. Four \u0026micro;m sections of the resulting TMA blocks were transferred to an adhesive coated slide system (Instrumedics Inc., Hackensack, NJ) for immunohistochemistry (IHC).\u003c/p\u003e \u003cp\u003e The study protocol was in accordance with the ethical guidelines of the 1964 Declaration of Helsinki and its later amendments as reflected by the approval of the institution\u0026rsquo;s human research review committee (Ethics Committee of the Medical Faculty of University of Cologne: registration no.13\u0026ndash;091; Ethics-No.: 21-1146). All patients gave written informed consent to the use of their tumour specimen and their data for research and publication.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eImmunohistochemistry\u003c/h2\u003e \u003cp\u003eIHC was performed on the TMA slides and for positively screened cases on large-scale slides. The following antibodies were used for IHC studies: a mouse monoclonal antibody (clone 6E3; dilution 1:400; Cell Marque) for SALL4, a mouse monoclonal antibody (clone A-4; dilution 1:50; Santa Cruz/RUO) for claudin-6, a mouse monoclonal antibody (clone 1G12; dilution 1:50; Cell Marque/CE) for glypican 3, a mouse monoclonal antibody (clone A4; dilution 1:6000; Dako/CE) for cytokeratin 7 (CK7), a rabbit monoclonal antibody (clone D9E8B; dilution 1:50; Cellsignal/RUO) for SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily A member 2 (SMARCA2), a mouse monoclonal antibody (clone EPNCIR111A; dilution 1:300; abcam) for SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily A member 4, a rabbit monoclonal antibody (clone : EPR13501 dilution 1:1000; abcam) for AT-rich interactive domain-containing protein 1A (ARID1A), a monoclonal antibody (clone poly; dilution 1:1600; Dako/CE) for AFP. All immunohistochemical stainings were performed using the BOND-MAX-stainer (Leica Biosystems, Germany) according to the protocol of the manufacturer. The evaluation of immunohistochemical expression was assessed manually by two pathologists (A.Q. and A.G.S).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eStrategy of evaluation\u003c/h2\u003e \u003cp\u003eWe initially performed a screening for the expression of SALL4 and glypican 3 on the TMA. If at least one of the surface markers was detectable on more than 50% of the tumor cells, we analysed the case on a large-scale slide (whole tumor block). If the impression from the TMA that more than 50% of the tumor cells were positive for at least one of the two proteins (SALL4 or glypican 3) was confirmed on the large-scale slide, claudin-6 was additionally determined on whole tumor blocks.\u003c/p\u003e \u003cp\u003eCases showing an expression of at least two of the three surface markers claudin-6, SALL4 or glypican 3 on whole tumor slides were considered for further analysis. Following that, immunohistochemical stainings for CK7, SMARCA2, SMARCA4, ARID1A, and AFP were performed on the positively screened cases.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eClinicopathological findings\u003c/h2\u003e \u003cp\u003eThe screening procedure identified 6 out of 826 patients (0.7%) who were positive for at least two out of the three markers SALL4, glypican3, or claudin-6. Five out of the six patients were male, average age at diagnosis was 63.5 (46\u0026ndash;72). The clinicopathological findings are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u003cem\u003eBaseline characteristics of the screening patient cohort\u003c/em\u003e\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003eEAC total cohort (n\u0026thinsp;=\u0026thinsp;826)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003enon-enteroblastic\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;820; 99.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eenteroblastic\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;6; 0.7%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003en (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003en (%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSex\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e717 (87.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5 (83.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e103 (12.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (16.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMedian age (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e64.0 (28\u0026ndash;92)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e63.5 (46\u0026ndash;72)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e(y)pT\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003epT1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e152 (18.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003epT2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e151 (18.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (25.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003epT3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e489 (59.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4 (50.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003epT4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e28 (3.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (25.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e(y)pN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003epN0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e333 (40.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003epN+\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e487 (59.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6 (100.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNeoadjuvant treatment\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e518 (63.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5 (83.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e302 (36.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (16.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eHistological features\u003c/h2\u003e \u003cp\u003eAll tumours showed parts with carcinoma cells with a strikingly clear cytoplasm. Very different tumor growth patterns were found. Only in one case the characteristics of enteroblastic differentiation were observed focally. In the remaining cases, tubulo-papillary or solid or garland-shaped growth patterns were detected, which suggested a yolk sac-like differentiation. These different growth patterns also occurred within the same tumor (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eImmunohistological staining\u003c/h2\u003e \u003cp\u003eThe results of the performed immunohistological staining are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. Regarding the markers of enteroblastic differentiation, all patients showed a claudin-6 and glypican 3 on at least 70% of the carcinoma cells (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb). The SALL4 expression was heterogeneous, with three patients showing expression on at least 80% of the carcinoma cells (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ec). If positive, glypican 3, SALL4 and claudin-6 were ubiquitously expressed in the carcinoma cells throughout different growth patterns. Furthermore, all tumours showed marked reduced expression or absence of CK7 (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ed), various expression of AFP (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ee) and a low developed desmoplastic stromal reaction. Additionally, all tumours exhibited an alteration of at least one SWI/SNF marker, mostly a SMARCA2 loss (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ef).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u003cem\u003eImmunohistological Staining results of the positively screened patient cohort\u003c/em\u003e\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCase\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSex\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e66\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e66\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e68\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCK7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e15%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e5%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSMARCA4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e100%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e100%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e100%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e100%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e100%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e100%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eARID1a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e100%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e100%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e100%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e100%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e100%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSMARCA2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e10%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e15%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAFP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e10%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e90%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eClaudin-6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e85%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e100%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e80%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e100%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e70%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e90%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGlypican 3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e70%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e100%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e80%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e100%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e85%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e80%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSALL4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e80%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e100%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e40%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e10%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn this retrospective analysis of 826 patients with esophageal adenocarcinomas (EAC), we can identify a subgroup of patients characterized by the expression of fetal gut-like surface markers (glypican 3, SALL4, claudin-6). These patients exhibit not only immunohistochemical peculiarities but also morphological characteristics like a strikingly clear cytoplasm and loss or marked reduced CK7 expression. So far, there have only been case reports for this phenotype in EAC, making us the first to demonstrate these morphological and immunohistochemical characteristics in a group of patients within a large and representative patient cohort [\u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eWith a frequency of 0.7%, we find the above-described characteristics only in a small portion of patients. In the WHO classification 2019 for gastric carcinomas, the frequency of AFP-producing carcinomas, including adenocarcinomas with enteroblastic differentiation, is estimated to be 0.3-2% [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. The observed frequency in our patient cohort of EACs seems to be comparable to this. Despite this rareness, we know from other tumor entities like non-small cell lung cancer (NSCLC) that the identification of small sub-entities (like ROS1 altered NSCLC) can have a significant impact on the treatment concepts for the concerned patients [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn terms of therapeutic relevance, the consistent expression of claudin-6 in the identified subgroup could lead to such implications. Claudin-6 is a tight junction protein and is expressed to varying degrees in different tumor entities. For example, testis cancer shows increased expression in over 90% of tumor samples, while the rate in gastric carcinoma is around 3% [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Claudin-6 is the target protein for new therapeutic approaches, as for example a Chimeric Antigen Receptor T-Cell Therapy (CAR-T-cell therapy), which is currently being investigated in an early phase study by BioNTech (trial no. BNT-211-01). This therapy offers patients with solid tumours and a claudin-6 expression on \u0026gt;\u0026thinsp;50% of the tumor cells a new therapeutic option after the failure of approved therapy lines. Therefore, for EAC, it seems reasonable that in the presence of an enteroblastic differentiation or a population with strikingly clear tumour cell cytoplasm in the haematoxylin and eosin staining or and loss/marked reduced CK7 expression on tumor cells, pathologists should consider the presence of fetal gut-like proteins and perform corresponding staining. Hereby, a subgroup of patients could significantly benefit from new therapeutic approaches.\u003c/p\u003e \u003cp\u003eInterestingly, we find a loss of SMARCA2 expression simultaneously to the expression of fetal-gut like surface markers in all patients. One patient additionally showed a loss of ARID1A expression. SMARCA2 and ARID1A are subunits of the SWI/SNF chromatin-remodelling complex, which is altered in up to 25% of all tumour entities [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. In EAC, TCGA data describe SWI/SNF alteration across all subunits in approximately 20%, loss of function alterations of SMARCA2 in 4% and ARID1A in 8% [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. At protein level, Schallenberg et al. report a loss of SMARCA2 expression in 9.9% and ARID1A in 10.4% in EAC [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. However, an underlying oncogenic mechanism of SWI/SNF alteration remains unclear. Currently, an increased prevalence of genetic instability resulting from impaired DNA repair mechanisms, lineage-specific, epigenetic modifications and an association with distinct, oncogenic signalling pathways are being discussed [\u003cspan additionalcitationids=\"CR17 CR18 CR19 CR20\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Various early phase clinical trials are currently investigating the therapeutic potential of the suspected effects of SWI/SNF alterations, for example, by using poly(ADP-ribose)-polymerase (PARP) inhibitors in order to address impaired DNA repair mechanisms or Enhancer of zeste homolog 2 (EZH2) inhibitors to modulate certain epigenetic signatures [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eFurthermore, there is evidence for a particular role of the SWI/SNF complex in the differentiation of pluripotent embryonic stem cells [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. In this context, the embryonic SWI/SNF complex prevents further differentiation of the stem cells by modifying the regulatory elements of the master pluripotency factors Octamer binding transcription factor 4 (Oct4), SRY-Box Transcription Factor 2 (Sox2), and Nanog [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. The composition of the embryonic SWI/SNF complex is characterized by the absence of the ATPase SMARCA2, which is fully compensated by SMARCA4 expression [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. The identified six patients with expression of fetal gut-like surface markers all show an alteration of SMARCA2 and, with the exception of one patient, a strong, preserved SMARCA4 expression. This constellation may also indicate the \u0026ldquo;fetal nature\u0026rdquo; (so called stem cell-derived differentiation) of the tumor cells. However, it remains unclear to what extent the differentiation stage of tumor cells has clinical relevance. Therefore, for now, rather the distinct characteristics of fetal differentiation, such as the expression of claudin-6 or abnormalities in the SWI/SNF complex, may potentially serve as targets for future therapeutic concepts.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn conclusion, in our analysis, we identified a small subgroup of patients with EAC who exhibit morphological and immunohistochemical features of a fetal-gut like differentiation. Due to the limited number of cases, the clinical characteristics of these patients are still unknown, and the 2019 WHO classification does not separately list this subgroup of esophageal carcinoma. However, increased attention to the described features in routine diagnostics may help identify more patients with this phenotype and contribute to further characterization. There is already today a therapeutic relevance for this subtype, suggesting that it could have significant importance in the future.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eData availability:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eM.K. and A.Q. conceived and designed the study; T.Z., H.A., W.S., C.J.B., enrolled the patients and collected the clinical data, while AQ, R.B. and A.G.S. performed the pathological analysis; M.K., T.Z. and A.Q. interpreted the data. All authors were involved in writing the paper, critically revised the manuscript for important intellectual content approved the submitted version.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eArnold, M., Laversanne, M., Brown L.M., Devesa, S.S., and Bray, F., \u003cem\u003ePredicting the Future Burden of Esophageal Cancer by Histological Subtype: International Trends in Incidence up to 2030.\u003c/em\u003e Am J Gastroenterol, 2017. \u003cstrong\u003e112\u003c/strong\u003e(8): p. 1247-1255.\u003c/li\u003e\n\u003cli\u003eSung, H., et al., \u003cem\u003eGlobal Cancer Statistics 2020: GLOBOCAN Estimates of Incidence and Mortality Worldwide for 36 Cancers in 185 Countries.\u003c/em\u003e CA Cancer J Clin, 2021. \u003cstrong\u003e71\u003c/strong\u003e(3): p. 209-249.\u003c/li\u003e\n\u003cli\u003eNagtegaal, I.D., et al., \u003cem\u003eThe 2019 WHO classification of tumours of the digestive system.\u003c/em\u003e Histopathology, 2020. \u003cstrong\u003e76\u003c/strong\u003e(2): p. 182-188.\u003c/li\u003e\n\u003cli\u003eMurakami, T., et al., \u003cem\u003eClinicopathologic and immunohistochemical characteristics of gastric adenocarcinoma with enteroblastic differentiation: a study of 29 cases.\u003c/em\u003e Gastric Cancer, 2016. \u003cstrong\u003e19\u003c/strong\u003e(2): p. 498-507.\u003c/li\u003e\n\u003cli\u003eHolscher, A.H., Schneider, P.M., Gutschow, C., and Schroeder, W., \u003cem\u003eLaparoscopic ischemic conditioning of the stomach for esophageal replacement.\u003c/em\u003e Ann Surg, 2007. \u003cstrong\u003e245\u003c/strong\u003e(2): p. 241-6.\u003c/li\u003e\n\u003cli\u003eGebauer, F., et al., \u003cem\u003eLymphocyte activation gene-3 (LAG3) mRNA and protein expression on tumour infiltrating lymphocytes (TILs) in oesophageal adenocarcinoma.\u003c/em\u003e J Cancer Res Clin Oncol, 2020. \u003cstrong\u003e146\u003c/strong\u003e(9): p. 2319-2327.\u003c/li\u003e\n\u003cli\u003eGushima, R., Narita, R., Shono, T., Hideaki, N., Takashi, Y., and Sasaki, Y., \u003cem\u003eEsophageal adenocarcinoma with enteroblastic differentiation arising in ectopic gastric mucosa in the cervical esophagus: a case report and literature review.\u003c/em\u003e J Gastrointestin Liver Dis, 2017. \u003cstrong\u003e26\u003c/strong\u003e(2): p. 193-197.\u003c/li\u003e\n\u003cli\u003eSugawara, K., et al., \u003cem\u003eCombined tubular adenocarcinoma, neuroendocrine carcinoma and adenocarcinoma with enteroblastic differentiation arising in Barrett esophagus.\u003c/em\u003e Clin J Gastroenterol, 2023.\u003c/li\u003e\n\u003cli\u003eShore, K.T., Phelps, K.C., Balani, J., and Mitschell, J.M., \u003cem\u003eAlpha-Fetoprotein-Producing Esophageal Adenocarcinoma With Enteroblastic, Yolk Sac Tumor-Like, and Hepatoid Carcinoma Differentiation: A Rare Case and Literature Review.\u003c/em\u003e Int J Surg Pathol, 2023. \u003cstrong\u003e31\u003c/strong\u003e(5): p. 884-889.\u003c/li\u003e\n\u003cli\u003eKorpanty, G.J., Graham, D.M., Vincent, M.D., and Leighl, N.B., \u003cem\u003eBiomarkers That Currently Affect Clinical Practice in Lung Cancer: EGFR, ALK, MET, ROS-1, and KRAS.\u003c/em\u003e Front Oncol, 2014. \u003cstrong\u003e4\u003c/strong\u003e: p. 204.\u003c/li\u003e\n\u003cli\u003eSimon, A.G., et al., \u003cem\u003eThe tight junction protein claudin 6 is a potential target for patient-individualized treatment in esophageal and gastric adenocarcinoma and is associated with poor prognosis.\u003c/em\u003e J Transl Med, 2023. \u003cstrong\u003e21\u003c/strong\u003e(1): p. 552.\u003c/li\u003e\n\u003cli\u003eMittal, P. and C.W.M. 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\u003cstrong\u003e8\u003c/strong\u003e: p. 626383.\u003c/li\u003e\n\u003cli\u003eToto, P.C., Puri, P.L., and Albini, S., \u003cem\u003eSWI/SNF-directed stem cell lineage specification: dynamic composition regulates specific stages of skeletal myogenesis.\u003c/em\u003e Cell Mol Life Sci, 2016. \u003cstrong\u003e73\u003c/strong\u003e(20): p. 3887-96.\u003c/li\u003e\n\u003cli\u003eHo, L., et al., \u003cem\u003eAn embryonic stem cell chromatin remodeling complex, esBAF, is essential for embryonic stem cell self-renewal and pluripotency.\u003c/em\u003e Proc Natl Acad Sci U S A, 2009. \u003cstrong\u003e106\u003c/strong\u003e(13): p. 5181-6.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Fetal-gut, SALL4, claudin-6, glypican 3, SMARCA2-loss, esophageal adenocarcinoma, clear cell adenocarcinoma","lastPublishedDoi":"10.21203/rs.3.rs-3356259/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3356259/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eEsophageal adenocarcinoma (EAC) is one of the deadliest tumor entities worldwide, with a 5-year survival rate of less than 25%. Unlike other tumor entities, personalized therapy options are rare, partly due to the lack of knowledge about specific subgroups. In this publication, we demonstrate a subgroup of patients with EAC in a large screening cohort of 826 patients, characterized by specific morphological and immunohistochemical features. This subgroup represents approximately 0.7% (6/826) of the total cohort. Morphological features of this subgroup show a striking clear cytoplasm of the tumour cells and the parallel existence of rare growth patterns like yolk sac-like differentiation and enteroblastic differentiation. Immunohistochemistry reveals expression of the fetal gut cell-like proteins Sal-like protein 4 (SALL4), claudin-6, and glypican 3. Interestingly, we find a correlation with alterations of SWI/SNF-complex associated genes, which are supposed to serve as tumor suppressor genes in various tumour entities. Our results suggest a possible implication of rare tumour subtypes in the WHO classification for EACs according to the classification for gastric cancer. Furthermore, claudin-6 positive tumors show promising efficacy of CAR T cell therapies in clinical studies. This represents a personalized therapeutic option for this tumor subtype.\u003c/p\u003e","manuscriptTitle":"Fetal gut cell-like differentiation in esophageal adenocarcinoma - rare tumor subtype with therapeutically relevant claudin-6 positivity and SWI/SNF gene alteration","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2023-09-28 15:49:50","doi":"10.21203/rs.3.rs-3356259/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-03-26T10:32:21+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-03-11T06:15:19+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"ed61e042-d6f4-4344-8e9e-34723922fa04","date":"2024-03-06T04:03:10+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"cba64233-203b-4652-9b74-1e9e1a9d2f19","date":"2024-01-03T13:48:15+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"d14caa11-3332-427f-aa31-b6ebd57ead39","date":"2023-12-07T17:31:27+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2023-12-07T12:00:54+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"58844aa1-a06b-4f38-899f-6a718dedf525","date":"2023-12-01T10:05:25+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2023-09-26T16:00:29+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2023-09-26T13:26:15+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2023-09-23T03:05:03+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2023-09-23T03:02:04+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2023-09-14T17:24:24+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"eb03b61a-852d-458a-bf43-cf5b376fc202","owner":[],"postedDate":"September 28th, 2023","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":24947552,"name":"Biological sciences/Cancer/Cancer screening"},{"id":24947553,"name":"Biological sciences/Cancer/Tumour biomarkers"},{"id":24947554,"name":"Biological sciences/Cancer/Gastrointestinal cancer"},{"id":24947555,"name":"Biological sciences/Cancer/Gastrointestinal cancer/Oesophageal cancer"},{"id":24947556,"name":"Biological sciences/Cancer/Cancer therapy"},{"id":24947557,"name":"Biological sciences/Cancer/Cancer therapy/Drug development"},{"id":24947558,"name":"Biological sciences/Cancer/Cancer therapy/Targeted therapies"}],"tags":[],"updatedAt":"2024-06-05T07:44:09+00:00","versionOfRecord":[],"versionCreatedAt":"2023-09-28 15:49:50","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-3356259","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3356259","identity":"rs-3356259","version":["v1"]},"buildId":"J0_U0BvcaRcwD8yVFaRlm","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}