Pathogenic germline variants in patients with early-onset colorectal cancer according to phenotype.

Pathogenic germline variants in patients with early-onset colorectal cancer according to phenotype. | 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 Brief Communication Pathogenic germline variants in patients with early-onset colorectal cancer according to phenotype. Patrick Benusiglio, Antoine Dardenne, Marion Dhooge, Noemie Basset, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5002627/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 17 Mar, 2025 Read the published version in European Journal of Human Genetics → Version 1 posted 9 You are reading this latest preprint version Abstract We assessed retrospectively the prevalence of pathogenic germline variants (PGVs) in 271 French adult patients diagnosed with colorectal cancer (CRC) before age 41, stratified by phenotype. APC, BMPR1A, CDH1, EPCAM, MLH1, MSH2, MSH3, MSH6, MUTYH, POLE, POLD1, PTEN, PMS2, SMAD4, and STK11 were analysed. Overall, 21.4% of cases carried a PGV. A high prevalence was observed in Mismatch Repair-deficient (MMRd) CRC (59.7%, MMR genes) and CRC associated with polyposis (48%, APC , biallelic MUTYH and MSH3 , POLE ). In contrast, MMR-proficient, non-polyposis cases only had a 1.7% prevalence. The only gene involved in this third group was POLE , and two out of three cases had either two synchronous CRC or a CRC family history. PGV prevalence is dependent on CRC phenotype, questioning the need for systematic germline testing in early-onset cases. A more targeted approach, focusing on MMRd CRC, or CRC associated with polyposis, might be warranted. Health sciences/Diseases/Cancer/Cancer genetics Health sciences/Risk factors Figures Figure 1 Figure 2 Introduction The latest American National Comprehensive Cancer Network (NCCN) guidelines (2023) recommend germline genetic testing for all patients with colorectal cancer (CRC) diagnosed before the age of 50 years 1 . According to French recommendations, all patients below the age of 41 years are to be referred for germline testing 2 . European Society for Medical Oncology (ESMO) guidelines are more conservative, as they only advise testing in the presence of a Mismatch Repair-deficient (MMRd) CRC, in patients with polyposis, or above a certain predisposition probability threshold based on prediction models 3 . Of note, ESMO guidelines were published as far back as 2019, versus 2023 for the NCCN and French ones. The NCCN and French guidelines seem supported by recent studies showing an overall pathogenic or likely pathogenic germline variant (PGV) prevalence of about 20% among patients with early-onset CRC 4 , 5 . We made the hypothesis that prevalence was actually phenotype-dependent, and that characteristics such as Mismatch Repair proficiency or absence of polyposis could obviate the need for germline testing. We tested it by conducting a retrospective study of PGV prevalence among a large series of French CRC cases diagnosed < 41 years, grouped by phenotype. Our aim was to guide future practice, i.e., confirm systematic germline testing of early-onset cases, or allow for more conservative case selection. Material and Methods We explored all cases with CRC diagnosed <41 years, referred to the adult Cancer Genetics clinics of two large Paris University Hospitals, Saint-Antoine and Cochin, between 2013 and 2023 (Saint-Antoine) and 2018 and 2023 (Cochin), and in whom germline panel testing had been performed (see below). All cases had signed a consent form for testing, and agreed to the possibility of further research based on collected data. They, or their next of kin whenever possible, were also informed of this retrospective study with a possibility to opt out. French law did not require ethics committee approval given the retrospective nature of the study. We assigned cases to the following groups, based on CRC phenotype and associated polyps: -Group 1. MMRd CRC as determined by immunohistochemistry -Group 2. Polyposis, i.e., history of ≥10 colorectal polyps regardless of histology -Group 3. MMR proficient (MMRp) CRC with no or fewer than 10 polyps Germline testing consisted of a panel of gastrointestinal cancer susceptibility gene that included APC, BMPR1A, CDH1, EPCAM, MLH1, MSH2, MSH3, MSH6, MUTYH, POLE, POLD1, PTEN, PMS2, SMAD4, and STK11 . Libraries were prepared according to the Kapa sample preparation protocol (Kapa Biosystems®). They were pooled and captured using the SeqCap EZ Choice Library (Roche/NimbleGen, Madison, WI) according to the manufacturer’s protocol and sequenced using an Illumina Platform (Illumina, San Diego, CA). PGV were confirmed by Sanger sequencing and MLPA (for copy number variation). Results We included 271 cases. One hundred and forty-four were female, 127 were male. Mean age at diagnosis was 33 years (range 17-40). Fifty-eight cases carried a PGV, the overall PGV detection rate was thus 21.4% (58/271) (figure 1). Group 1 (MMRd CRC) A PGV was identified in 43/72 cases (59.7%). The genes involved were MLH1 (n=23), MSH2 (n=17), MSH6 (n=1), and PMS2 (n=2) (figure 2). Group 2 (CRC and polyposis) A PGV was identified in 12/25 cases (48%). Among the twelve carriers, six carried an APC PGV, and three MUTYH biallelic PGV. One case carried MSH3 biallelicPGV, one a POLE PGV, and one a BMPR1A PGV (figure 2). Regarding CRC-associated polyps, their number and type matched the susceptibility syndrome. All but one APC cases had >100 adenomatous polyps, while the remaining case had a “large number” of such lesions (number not specified). Biallelic MUTYH and MSH3 cases had between 16 and 50 adenomatous polyps. The POLE case had a “large number” (not specified further) of adenomatous polyps. The BMPR1A case had 30 polyps, most of them juvenile. Group 3 (MMRp, non-polyposis CRC) A PGV was identified in 3/174 cases (1.7%). The only gene involved in this group was POLE (figure 2). One case had two synchronous CRC aged 31 years. Another one had three 1 st - or 2 nd degree relatives with CRC before the age of 50 years. The remaining case had no other manifestation, personal or family history suggestive of POLE- associated susceptibility to CRC. Discussion We report an overall PGV prevalence of 21% (58/271) among adult patients with CRC diagnosed <41 years. Prevalence was high in cases with either MMRd CRC (group 1) or CRC associated with polyposis (group 2): 59.7% and 48%, respectively. However, among MMRp CRC patients without associated polyposis (group 3), only 1.7% (n=3) carried a PGV. Importantly, one of them had two synchronous CRC, and another a strong family history of CRC. These observations show that PGV prevalence differs greatly by phenotype. In the absence of MMRd or polyposis, it is very low, even more so when patients with a single isolated CRC and negative family history are considered. In this context, one wonders whether systematic germline testing is really justified. Available resources are a major determinant. State-funded and social security-based might recommend germline testing only when specific criteria are met. Our overall results are concordant with the literature. Coughlin et al. reported a PGV prevalence of 17-26% in CRC cases <40 years tested at a commercial laboratory 4 . In another study, among 130 unselected CRC patients diagnosed <50 years, twenty-five carried a PGV (19%) 5 . The strength of our study was to divide our cases in three groups, and therefore to assess PGV according to specific features (MMR status, associated polyposis). Of note, we did not report CHEK2 PGV or the APC I1307K variant, as recent data suggest either no association with CRC or an association that too weak to be clinically relevant 6,7 . Lynch syndrome was identified in 59.7% of cases with MMRd CRC. The remainder likely had either two somatic events in their tumor, or carried a structural variant missed by NGS 8–10 . Complementary investigations are ongoing on a case-by-case basis. In conclusion, overall PGV prevalence is high in adult patients with CRC diagnosed before the age of 41 years. However, this observation does not apply to MMRp CRC without associated polyposis, and these cases likely should not be offered systematic germline testing. Phenotypic features should be taken into account during genetic counseling and for testing decision. Declarations Data availability statement Data are available on reasonable request from European Union researchers, and pending a data transfer agreement between institutions. Author contributions Genetic counseling, patient management: AD, MD, JM, SF, JN, PRB. Data collection and interpretation: AD, MD, JM, SF, PRB. Genetic analyses: NB, AC, FC. Manuscript writing: PRB Final approval of manuscript: all authors Funding No funding was received for this study. Ethical approval In France, ethics committee approval is not required for retrospective studies such as this one. However, and in accordance with French law, all participants were sent an information note with the possibility to opt out. Competing interests PRB has received honoraria from AstraZeneca, MSD and BMS, and funding support from Astrazeneca (unrelated to the present study). References NCCN Guidelines Genetic/Familial High-Risk Assessment: Colorectal version 2.2023. Published online October 2023. Accessed July 18, 2024. https://www.nccn.org/professionals/physician_gls/pdf/genetics_colon.pdf Lecomte T, Tougeron D, Chautard R, et al. Non-metastatic colon cancer: French Intergroup Clinical Practice Guidelines for diagnosis, treatments, and follow-up (TNCD, SNFGE, FFCD, GERCOR, UNICANCER, SFCD, SFED, SFRO, ACHBT, SFP, AFEF, and SFR). Dig Liver Dis . 2024;56(5):756-769. doi:10.1016/j.dld.2024.01.208 Stjepanovic N, Moreira L, Carneiro F, et al. Hereditary gastrointestinal cancers: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up†. Ann Oncol . 2019;30(10):1558-1571. doi:10.1093/annonc/mdz233 Coughlin SE, Heald B, Clark DF, et al. Multigene Panel Testing Yields High Rates of Clinically Actionable Variants Among Patients With Colorectal Cancer. JCO Precis Oncol . 2022;6:e2200517. doi:10.1200/PO.22.00517 You YN, Moskowitz JB, Chang GJ, et al. Germline Cancer Risk Profiles of Patients With Young-Onset Colorectal Cancer: Findings From a Prospective Universal Germline Testing and Telegenetics Program. Dis Colon Rectum . 2023;66(4):531. doi:10.1097/DCR.0000000000002347 Valle L, Katz LH, Latchford A, et al. Position statement of the International Society for Gastrointestinal Hereditary Tumours (InSiGHT) on APC I1307K and cancer risk. J Med Genet . 2023;60(11):1035-1043. doi:10.1136/jmg-2022-108984 Mundt E, Mabey B, Rainville I, et al. Breast and colorectal cancer risks among over 6,000 CHEK2 pathogenic variant carriers: A comparison of missense versus truncating variants. Cancer Genet . 2023;278-279:84-90. doi:10.1016/j.cancergen.2023.10.002 Pope BJ, Clendenning M, Rosty C, et al. Germline and Tumor Sequencing as a Diagnostic Tool To Resolve Suspected Lynch Syndrome. J Mol Diagn JMD . 2021;23(3):358-371. doi:10.1016/j.jmoldx.2020.12.003 Te Paske IB, Mensenkamp AR, Neveling K, et al. Noncoding Aberrations in Mismatch Repair Genes Underlie a Substantial Part of the Missing Heritability in Lynch Syndrome. Gastroenterology . 2022;163(6):1691-1694.e7. doi:10.1053/j.gastro.2022.08.041 Bjørnstad PM, Aaløkken R, Åsheim J, et al. A 39 kb structural variant causing Lynch Syndrome detected by optical genome mapping and nanopore sequencing. Eur J Hum Genet . 2024;32(5):513-520. doi:10.1038/s41431-023-01494-7 Additional Declarations There is no duality of interest Cite Share Download PDF Status: Published Journal Publication published 17 Mar, 2025 Read the published version in European Journal of Human Genetics → Version 1 posted Editorial decision: revise 17 Oct, 2024 Review # 2 received at journal 11 Oct, 2024 Review # 1 received at journal 26 Sep, 2024 Reviewer # 2 agreed at journal 25 Sep, 2024 Reviewer # 1 agreed at journal 24 Sep, 2024 Reviewers invited by journal 20 Sep, 2024 Submission checks completed at journal 13 Sep, 2024 Editor assigned by journal 30 Aug, 2024 First submitted to journal 30 Aug, 2024 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. 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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-5002627","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Brief Communication","associatedPublications":[],"authors":[{"id":356942458,"identity":"830657e0-e5f4-45a1-9a6c-b82a4010de54","order_by":0,"name":"Patrick Benusiglio","email":"data:image/png;base64,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","orcid":"https://orcid.org/0000-0003-1003-1997","institution":"Hôpital Pitié-Salpêtrière, AP-HP, Sorbonne Université","correspondingAuthor":true,"prefix":"","firstName":"Patrick","middleName":"","lastName":"Benusiglio","suffix":""},{"id":356942459,"identity":"8bfdbbeb-0e79-49ec-b65c-2d000b02d6c6","order_by":1,"name":"Antoine Dardenne","email":"","orcid":"","institution":"APHP Sorbonne Université, INSERM, Hôpital Pitié-Salpêtrière","correspondingAuthor":false,"prefix":"","firstName":"Antoine","middleName":"","lastName":"Dardenne","suffix":""},{"id":356942460,"identity":"cbd44f46-2308-42c7-8070-caa703423bc2","order_by":2,"name":"Marion Dhooge","email":"","orcid":"https://orcid.org/0000-0002-7279-5549","institution":"Hôpital Cochin","correspondingAuthor":false,"prefix":"","firstName":"Marion","middleName":"","lastName":"Dhooge","suffix":""},{"id":356942461,"identity":"e49e9ea0-d84b-4aec-973c-e7fb75f40eb0","order_by":3,"name":"Noemie Basset","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Noemie","middleName":"","lastName":"Basset","suffix":""},{"id":356942462,"identity":"acd71466-2e40-49a2-ab15-df6b8a919c06","order_by":4,"name":"Albain Chansavang","email":"","orcid":"https://orcid.org/0000-0002-9835-2156","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Albain","middleName":"","lastName":"Chansavang","suffix":""},{"id":356942463,"identity":"c106fffb-9b69-470f-9a44-206b0f1d2bc8","order_by":5,"name":"Julie Metras","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Julie","middleName":"","lastName":"Metras","suffix":""},{"id":356942464,"identity":"f84000cf-27c8-4abf-9e54-a96ca6cdd756","order_by":6,"name":"Solenne Farelly","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Solenne","middleName":"","lastName":"Farelly","suffix":""},{"id":356942465,"identity":"67ebc66b-451d-42ed-aa35-a5865c4be818","order_by":7,"name":"Florence Coulet","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Florence","middleName":"","lastName":"Coulet","suffix":""}],"badges":[],"createdAt":"2024-08-30 09:11:09","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5002627/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5002627/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41431-025-01808-x","type":"published","date":"2025-03-17T04:00:00+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":66066611,"identity":"7e461c08-0251-4c55-bb56-5b50ddbca873","added_by":"auto","created_at":"2024-10-07 11:24:48","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":21223,"visible":true,"origin":"","legend":"\u003cp\u003eStudy flowchart with pathogenic germline variant detection rates. We defined polyposis as the presence of \u0026gt;10 polyps regardless of type. \u0026nbsp;CRC, colorectal cancer; MMRd, mismatch repair deficient; PGV, pathogenic germline variant.\u003c/p\u003e","description":"","filename":"Figure1earlyonsetCCR411.png","url":"https://assets-eu.researchsquare.com/files/rs-5002627/v1/317bbf98414c6bfb6cdd4779.png"},{"id":66066608,"identity":"7ef8cba2-3657-4294-a854-f2c7d02124c9","added_by":"auto","created_at":"2024-10-07 11:24:47","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":31335,"visible":true,"origin":"","legend":"\u003cp\u003ePathogenic germline variants identified in cases, according to group.\u003c/p\u003e","description":"","filename":"Figure2earlyonsetCCR411.png","url":"https://assets-eu.researchsquare.com/files/rs-5002627/v1/b4ee1b3f5f88d414e7d8299b.png"},{"id":78729164,"identity":"c0465012-725f-46f3-bd49-b38844e5880f","added_by":"auto","created_at":"2025-03-18 07:08:16","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":439713,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5002627/v1/56df3fa4-7e15-45b8-b834-0d761522bf20.pdf"}],"financialInterests":"There is no duality of interest","formattedTitle":"Pathogenic germline variants in patients with early-onset colorectal cancer according to phenotype.","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe latest American National Comprehensive Cancer Network (NCCN) guidelines (2023) recommend germline genetic testing for all patients with colorectal cancer (CRC) diagnosed before the age of 50 years \u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e. According to French recommendations, all patients below the age of 41 years are to be referred for germline testing \u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e. European Society for Medical Oncology (ESMO) guidelines are more conservative, as they only advise testing in the presence of a Mismatch Repair-deficient (MMRd) CRC, in patients with polyposis, or above a certain predisposition probability threshold based on prediction models \u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. Of note, ESMO guidelines were published as far back as 2019, versus 2023 for the NCCN and French ones.\u003c/p\u003e \u003cp\u003eThe NCCN and French guidelines seem supported by recent studies showing an overall pathogenic or likely pathogenic germline variant (PGV) prevalence of about 20% among patients with early-onset CRC \u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e,\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eWe made the hypothesis that prevalence was actually phenotype-dependent, and that characteristics such as Mismatch Repair proficiency or absence of polyposis could obviate the need for germline testing.\u003c/p\u003e \u003cp\u003eWe tested it by conducting a retrospective study of PGV prevalence among a large series of French CRC cases diagnosed\u0026thinsp;\u0026lt;\u0026thinsp;41 years, grouped by phenotype. Our aim was to guide future practice, i.e., confirm systematic germline testing of early-onset cases, or allow for more conservative case selection.\u003c/p\u003e"},{"header":"Material and Methods","content":"\u003cp\u003eWe explored all cases with CRC diagnosed \u0026lt;41 years, referred to the adult Cancer Genetics clinics of two large Paris University Hospitals, Saint-Antoine and Cochin, between 2013 and 2023 (Saint-Antoine) and 2018 and 2023 (Cochin), and in whom germline panel testing had been performed (see below). All cases had signed a consent form for testing, and agreed to the possibility of further research based on collected data. They, or their next of kin whenever possible, were also informed of this retrospective study with a possibility to opt out. French law did not require ethics committee approval given the retrospective nature of the study.\u003c/p\u003e\n\u003cp\u003eWe assigned cases to the following groups, based on CRC phenotype and associated polyps:\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e-Group 1. MMRd CRC as determined by immunohistochemistry\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e-Group 2. Polyposis, i.e., history of\u0026nbsp;≥10 colorectal polyps regardless of histology\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e-Group 3. MMR proficient (MMRp) CRC with no or fewer than 10 polyps\u003c/p\u003e\n\u003cp\u003eGermline testing consisted of a panel of gastrointestinal cancer susceptibility gene that included \u003cem\u003eAPC, BMPR1A, CDH1, EPCAM, MLH1, MSH2, MSH3, MSH6, MUTYH, POLE, POLD1, PTEN, PMS2, SMAD4, and STK11\u003c/em\u003e. Libraries were prepared according to the Kapa sample preparation protocol (Kapa Biosystems®). They were pooled and captured using the SeqCap EZ Choice Library (Roche/NimbleGen, Madison, WI) according to the manufacturer’s protocol and sequenced using an Illumina Platform (Illumina, San Diego, CA). PGV were confirmed by Sanger sequencing and MLPA (for copy number variation).\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eWe included 271 cases. One hundred and forty-four were female, 127 were male. Mean age at diagnosis was 33 years (range 17-40). Fifty-eight cases carried a PGV, the overall PGV detection rate was thus 21.4% (58/271) (figure 1).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eGroup 1 (MMRd CRC)\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eA PGV was identified in 43/72 cases (59.7%). The genes involved were \u003cem\u003eMLH1\u003c/em\u003e (n=23), \u003cem\u003eMSH2\u0026nbsp;\u003c/em\u003e(n=17), \u003cem\u003eMSH6\u0026nbsp;\u003c/em\u003e(n=1), and \u003cem\u003ePMS2\u0026nbsp;\u003c/em\u003e(n=2) (figure 2).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eGroup 2 (CRC and polyposis)\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eA PGV was identified in 12/25 cases (48%). \u0026nbsp;Among the twelve carriers, six carried an \u003cem\u003eAPC\u0026nbsp;\u003c/em\u003ePGV, and three \u003cem\u003eMUTYH\u0026nbsp;\u003c/em\u003ebiallelic PGV. One case carried \u003cem\u003eMSH3\u0026nbsp;\u003c/em\u003ebiallelicPGV, one a \u003cem\u003ePOLE\u0026nbsp;\u003c/em\u003ePGV, and one a \u003cem\u003eBMPR1A\u0026nbsp;\u003c/em\u003ePGV (figure 2). Regarding CRC-associated polyps, their number and type matched the susceptibility syndrome. All but one \u003cem\u003eAPC\u0026nbsp;\u003c/em\u003ecases had \u0026gt;100 adenomatous polyps, while the remaining case had a “large number” of such lesions (number not specified). Biallelic \u003cem\u003eMUTYH\u0026nbsp;\u003c/em\u003eand \u003cem\u003eMSH3\u0026nbsp;\u003c/em\u003ecases had between 16 and 50 adenomatous polyps. The \u003cem\u003ePOLE\u0026nbsp;\u003c/em\u003ecase had a “large number” (not specified further) of adenomatous polyps. The \u003cem\u003eBMPR1A\u0026nbsp;\u003c/em\u003ecase had 30 polyps, most of them juvenile.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eGroup 3 (MMRp, non-polyposis CRC)\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eA PGV was identified in 3/174 cases (1.7%). The only gene involved in this group was \u003cem\u003ePOLE\u0026nbsp;\u003c/em\u003e(figure 2). One case had two synchronous CRC aged 31 years. Another one had three 1\u003csup\u003est\u003c/sup\u003e- or 2\u003csup\u003end\u003c/sup\u003e degree relatives with CRC before the age of 50 years. The remaining case had no other manifestation, personal or family history suggestive of \u003cem\u003ePOLE-\u003c/em\u003eassociated susceptibility to CRC.\u0026nbsp;\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eWe report an overall PGV prevalence of 21% (58/271) among adult patients with CRC diagnosed \u0026lt;41 years. Prevalence was high in cases with either MMRd CRC (group 1) or CRC associated with polyposis (group 2): 59.7% and 48%, respectively. However, among MMRp CRC patients without associated polyposis (group 3), only 1.7% (n=3) carried a PGV. Importantly, one of them had two synchronous CRC, and another a strong family history of CRC.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThese observations show that PGV prevalence differs greatly by phenotype. In the absence of MMRd or polyposis, it is very low, even more so when patients with a single isolated CRC and negative family history are considered. In this context, one wonders whether systematic germline testing is really justified. Available resources are a major determinant. State-funded and social security-based might recommend germline testing only when specific criteria are met.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eOur overall results are concordant with the literature. Coughlin \u003cem\u003eet al.\u0026nbsp;\u003c/em\u003ereported a PGV prevalence of 17-26% in CRC cases \u0026lt;40 years tested at a commercial laboratory\u0026nbsp;\u003csup\u003e4\u003c/sup\u003e. In another study, among 130 unselected CRC \u0026nbsp;patients diagnosed \u0026lt;50 years, twenty-five carried a PGV (19%)\u0026nbsp;\u003csup\u003e5\u003c/sup\u003e.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe strength of our study was to divide our cases in three groups, and therefore to assess PGV according to specific features (MMR status, associated polyposis).\u003c/p\u003e\n\u003cp\u003eOf note, we did not report \u003cem\u003eCHEK2\u003c/em\u003e PGV or the \u003cem\u003eAPC\u0026nbsp;\u003c/em\u003eI1307K variant, as recent data suggest either no association with CRC or an association that too weak to be clinically relevant\u0026nbsp;\u003csup\u003e6,7\u003c/sup\u003e.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eLynch syndrome was identified in 59.7% of cases with MMRd CRC. The remainder likely had either two somatic events in their tumor, or carried a structural variant missed by NGS\u0026nbsp;\u003csup\u003e8–10\u003c/sup\u003e . Complementary investigations are ongoing on a case-by-case basis.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn conclusion, overall PGV prevalence is high in adult patients with CRC diagnosed before the age of 41 years. However, this observation does not apply to MMRp CRC without associated polyposis, and these cases likely should not be offered systematic germline testing. Phenotypic features should be taken into account during genetic counseling and for testing decision.\u0026nbsp;\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eData availability statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData are available on reasonable request from European Union researchers, and pending a data transfer agreement between institutions.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eGenetic counseling, patient management: AD, MD, JM, SF, JN, PRB.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eData collection and interpretation: AD, MD, JM, SF, PRB.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eGenetic analyses: NB, AC, FC.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eManuscript writing: PRB\u003c/p\u003e\n\u003cp\u003eFinal approval of manuscript: all authors\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo funding was received for this study.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical approval\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn France, ethics committee approval is not required for retrospective studies such as this one. However, and in accordance with French law, all participants were sent an information note with the possibility to opt out.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePRB has received honoraria from AstraZeneca, MSD and BMS, and funding support from Astrazeneca (unrelated to the present study).\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eNCCN Guidelines Genetic/Familial High-Risk Assessment: Colorectal version 2.2023. Published online October 2023. Accessed July 18, 2024. https://www.nccn.org/professionals/physician_gls/pdf/genetics_colon.pdf\u003c/li\u003e\n\u003cli\u003eLecomte T, Tougeron D, Chautard R, et al. Non-metastatic colon cancer: French Intergroup Clinical Practice Guidelines for diagnosis, treatments, and follow-up (TNCD, SNFGE, FFCD, GERCOR, UNICANCER, SFCD, SFED, SFRO, ACHBT, SFP, AFEF, and SFR). \u003cem\u003eDig Liver Dis\u003c/em\u003e. 2024;56(5):756-769. doi:10.1016/j.dld.2024.01.208\u003c/li\u003e\n\u003cli\u003eStjepanovic N, Moreira L, Carneiro F, et al. Hereditary gastrointestinal cancers: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up\u0026dagger;. \u003cem\u003eAnn Oncol\u003c/em\u003e. 2019;30(10):1558-1571. doi:10.1093/annonc/mdz233\u003c/li\u003e\n\u003cli\u003eCoughlin SE, Heald B, Clark DF, et al. Multigene Panel Testing Yields High Rates of Clinically Actionable Variants Among Patients With Colorectal Cancer. \u003cem\u003eJCO Precis Oncol\u003c/em\u003e. 2022;6:e2200517. doi:10.1200/PO.22.00517\u003c/li\u003e\n\u003cli\u003eYou YN, Moskowitz JB, Chang GJ, et al. Germline Cancer Risk Profiles of Patients With Young-Onset Colorectal Cancer: Findings From a Prospective Universal Germline Testing and Telegenetics Program. \u003cem\u003eDis Colon Rectum\u003c/em\u003e. 2023;66(4):531. doi:10.1097/DCR.0000000000002347\u003c/li\u003e\n\u003cli\u003eValle L, Katz LH, Latchford A, et al. Position statement of the International Society for Gastrointestinal Hereditary Tumours (InSiGHT) on APC I1307K and cancer risk. \u003cem\u003eJ Med Genet\u003c/em\u003e. 2023;60(11):1035-1043. doi:10.1136/jmg-2022-108984\u003c/li\u003e\n\u003cli\u003eMundt E, Mabey B, Rainville I, et al. Breast and colorectal cancer risks among over 6,000 \u003cem\u003eCHEK2\u003c/em\u003e pathogenic variant carriers: A comparison of missense versus truncating variants. \u003cem\u003eCancer Genet\u003c/em\u003e. 2023;278-279:84-90. doi:10.1016/j.cancergen.2023.10.002\u003c/li\u003e\n\u003cli\u003ePope BJ, Clendenning M, Rosty C, et al. Germline and Tumor Sequencing as a Diagnostic Tool To Resolve Suspected Lynch Syndrome. \u003cem\u003eJ Mol Diagn JMD\u003c/em\u003e. 2021;23(3):358-371. doi:10.1016/j.jmoldx.2020.12.003\u003c/li\u003e\n\u003cli\u003eTe Paske IB, Mensenkamp AR, Neveling K, et al. Noncoding Aberrations in Mismatch Repair Genes Underlie a Substantial Part of the Missing Heritability in Lynch Syndrome. \u003cem\u003eGastroenterology\u003c/em\u003e. 2022;163(6):1691-1694.e7. doi:10.1053/j.gastro.2022.08.041\u003c/li\u003e\n\u003cli\u003eBj\u0026oslash;rnstad PM, Aal\u0026oslash;kken R, \u0026Aring;sheim J, et al. A 39 kb structural variant causing Lynch Syndrome detected by optical genome mapping and nanopore sequencing. \u003cem\u003eEur J Hum Genet\u003c/em\u003e. 2024;32(5):513-520. doi:10.1038/s41431-023-01494-7\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"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":"european-journal-of-human-genetics","isNatureJournal":false,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"ejhg","sideBox":"Learn more about [European Journal of Human Genetics](http://www.nature.com/ejhg/)","snPcode":"41431","submissionUrl":"https://mts-ejhg.nature.com/cgi-bin/main.plex","title":"European Journal of Human Genetics","twitterHandle":"@ejhg_journal","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-5002627/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5002627/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eWe assessed retrospectively the prevalence of pathogenic germline variants (PGVs) in 271 French adult patients diagnosed with colorectal cancer (CRC) before age 41, stratified by phenotype. \u003cem\u003eAPC, BMPR1A, CDH1, EPCAM, MLH1, MSH2, MSH3, MSH6, MUTYH, POLE, POLD1, PTEN, PMS2, SMAD4,\u003c/em\u003e and \u003cem\u003eSTK11\u003c/em\u003ewere analysed. Overall, 21.4% of cases carried a PGV. A high prevalence was observed in Mismatch Repair-deficient (MMRd) CRC (59.7%, \u003cem\u003eMMR\u003c/em\u003e genes) and CRC associated with polyposis (48%, \u003cem\u003eAPC\u003c/em\u003e, biallelic \u003cem\u003eMUTYH\u003c/em\u003e and \u003cem\u003eMSH3\u003c/em\u003e, \u003cem\u003ePOLE\u003c/em\u003e). In contrast, MMR-proficient, non-polyposis cases only had a 1.7% prevalence. The only gene involved in this third group was \u003cem\u003ePOLE\u003c/em\u003e, and two out of three cases had either two synchronous CRC or a CRC family history. PGV prevalence is dependent on CRC phenotype, questioning the need for systematic germline testing in early-onset cases. A more targeted approach, focusing on MMRd CRC, or CRC associated with polyposis, might be warranted.\u003c/p\u003e","manuscriptTitle":"Pathogenic germline variants in patients with early-onset colorectal cancer according to phenotype.","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-10-07 11:23:58","doi":"10.21203/rs.3.rs-5002627/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"revise","date":"2024-10-17T08:40:41+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"This content is not available.","date":"2024-10-11T13:10:13+00:00","index":2,"fulltext":"This content is not available."},{"type":"editorInvitedReview","content":"This content is not available.","date":"2024-09-26T17:54:22+00:00","index":1,"fulltext":"This content is not available."},{"type":"reviewerAgreed","content":"This content is not available.","date":"2024-09-25T06:52:55+00:00","index":2,"fulltext":"This content is not available."},{"type":"reviewerAgreed","content":"This content is not available.","date":"2024-09-24T23:21:53+00:00","index":1,"fulltext":"This content is not available."},{"type":"reviewersInvited","content":"","date":"2024-09-20T15:53:43+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-09-13T09:44:13+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-08-30T09:09:25+00:00","index":"","fulltext":""},{"type":"submitted","content":"European Journal of Human Genetics","date":"2024-08-30T09:09:25+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"european-journal-of-human-genetics","isNatureJournal":false,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"ejhg","sideBox":"Learn more about [European Journal of Human Genetics](http://www.nature.com/ejhg/)","snPcode":"41431","submissionUrl":"https://mts-ejhg.nature.com/cgi-bin/main.plex","title":"European Journal of Human Genetics","twitterHandle":"@ejhg_journal","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"232be0f2-d859-4537-bfae-76a325936674","owner":[],"postedDate":"October 7th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":37969073,"name":"Health sciences/Diseases/Cancer/Cancer genetics"},{"id":37969074,"name":"Health sciences/Risk factors"}],"tags":[],"updatedAt":"2025-03-18T07:08:10+00:00","versionOfRecord":{"articleIdentity":"rs-5002627","link":"https://doi.org/10.1038/s41431-025-01808-x","journal":{"identity":"european-journal-of-human-genetics","isVorOnly":false,"title":"European Journal of Human Genetics"},"publishedOn":"2025-03-17 04:00:00","publishedOnDateReadable":"March 17th, 2025"},"versionCreatedAt":"2024-10-07 11:23:58","video":"","vorDoi":"10.1038/s41431-025-01808-x","vorDoiUrl":"https://doi.org/10.1038/s41431-025-01808-x","workflowStages":[]},"version":"v1","identity":"rs-5002627","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5002627","identity":"rs-5002627","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}