[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-372120-105":59,"doc-detail-372120-en":134},{"code":4,"msg":5,"data":6},0,"success",[7,13,18,23,28,33,38,43,48,51,55],{"id":8,"doc_module":4,"doc_module_name":9,"category_name":10,"show_sort_weight":11,"slug":12},1,"Document","Story & Novel",90,"story-novel",{"id":14,"doc_module":4,"doc_module_name":9,"category_name":15,"show_sort_weight":16,"slug":17},2,"Literature",80,"literature",{"id":19,"doc_module":4,"doc_module_name":9,"category_name":20,"show_sort_weight":21,"slug":22},4,"Exam",70,"exam",{"id":24,"doc_module":4,"doc_module_name":9,"category_name":25,"show_sort_weight":26,"slug":27},5,"Comic",60,"comic",{"id":29,"doc_module":4,"doc_module_name":9,"category_name":30,"show_sort_weight":31,"slug":32},6,"Technology",50,"technology",{"id":34,"doc_module":4,"doc_module_name":9,"category_name":35,"show_sort_weight":36,"slug":37},7,"Healthcare",40,"healthcare",{"id":39,"doc_module":4,"doc_module_name":9,"category_name":40,"show_sort_weight":41,"slug":42},8,"Research & Report",30,"research-report",{"id":44,"doc_module":4,"doc_module_name":9,"category_name":45,"show_sort_weight":46,"slug":47},9,"Religion & Spirituality",20,"religion-spirituality",{"id":46,"doc_module":4,"doc_module_name":9,"category_name":49,"show_sort_weight":46,"slug":50},"World Cup","world-cup",{"id":52,"doc_module":4,"doc_module_name":9,"category_name":53,"show_sort_weight":52,"slug":54},10,"Lifestyle","lifestyle",{"id":56,"doc_module":4,"doc_module_name":9,"category_name":57,"show_sort_weight":24,"slug":58},19,"General","general",{"code":4,"msg":60,"data":61},"ok",{"site_id":62,"language":63,"slug":64,"title":65,"keywords":66,"description":67,"schema_data":68,"social_meta":127,"head_meta":129,"extra_data":131,"updated_unix":133},105,"en","lynch-syndrome-screening-in-colorectal-and-endometrial-cancers-in-iceland","Lynch syndrome screening in colorectal and endometrial cancers in Iceland","","Screening for Lynch syndrome (LS) using mismatch repair (MMR) protein immunohistochemistry (IHC) was introduced in Iceland in 2017 for all newly diagnosed colorectal (CRC) and endometrial cancer (EC) patients. This study evaluates screening accuracy in 2020–2022 and compares performance with 2017–2019. CRC and EC cases were identified from the Icelandic Cancer Registry, and results were cross-matched with deCODE genotyping to estimate sensitivity, specificity, and predictive values. In 2020–2022, IHC showed 70% sensitivity and 88% specificity, with PPV 8.4% and NPV 99.4%, and missing LS cases were consistent with sporadic disease. MSH6 and PMS2 deficiency strongly predicts LS in Iceland.",{"@graph":69,"@context":126},[70,84,105],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":35,"@type":76,"position":81},"https://docshare.wps.com/document/healthcare/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/lynch-syndrome-screening-in-colorectal-and-endometrial-cancers-in-iceland/372120/",{"url":83,"name":65,"@type":85,"image":86,"author":91,"headline":65,"publisher":94,"fileFormat":97,"inLanguage":63,"description":67,"dateModified":98,"datePublished":99,"encodingFormat":97,"isAccessibleForFree":100,"interactionStatistic":101},"DigitalDocument",{"url":87,"@type":88,"width":89,"height":90},"https://docshare.wps.com/thumbnails/lynch-syndrome-screening-in-colorectal-and-endometrial-cancers-in-iceland/372120.png","ImageObject",300,407,{"name":92,"@type":93},"Eliana","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","application/pdf","2026-10-30","2026-09-23",true,{"@type":102,"interactionType":103,"userInteractionCount":44},"InteractionCounter",{"@type":104},"ViewAction",{"@type":106,"mainEntity":107},"FAQPage",[108,114,118,122],{"name":109,"@type":110,"acceptedAnswer":111},"What was the purpose of Lynch syndrome screening in Iceland starting in 2017?","Question",{"text":112,"@type":113},"Universal LS screening was implemented for all newly diagnosed colorectal and endometrial cancer patients using MMR protein immunohistochemistry (IHC). The study assesses its accuracy in 2020–2022 and compares it with 2017–2019.","Answer",{"name":115,"@type":110,"acceptedAnswer":116},"How were patients included and how was screening performance measured?",{"text":117,"@type":113},"All CRC and EC patients diagnosed in 2020–2022 were included from the Icelandic Cancer Registry. Screening outcomes were crossmatched with deCODE genotyping data to calculate sensitivity and specificity for LS detection.",{"name":119,"@type":110,"acceptedAnswer":120},"What were the key diagnostic performance results for IHC screening?",{"text":121,"@type":113},"For 2020–2022, IHC sensitivity was 70% and specificity was 88%. The positive predictive value was 8.4% and the negative predictive value was 99.4%.",{"name":123,"@type":110,"acceptedAnswer":124},"Were any Lynch syndrome cases missed by the MMR IHC screening?",{"text":125,"@type":113},"Three LS cases were missed with MMR IHC (one MSH6 and two PMS2 carriers). The interpretation notes that these patients may have had sporadic cancers unrelated to LS carrier status.","https://schema.org",{"og:url":83,"og:type":128,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":130,"canonical":83},"index,follow",{"doc_id":132,"site_id":62},372120,1790717245,{"code":4,"msg":5,"data":135},{"doc_id":132,"user_id":136,"nickname":92,"user_avatar":137,"doc_module":4,"category_id":34,"category_name":35,"doc_title":65,"doc_description":67,"doc_content":138,"file_id":139,"file_url":140,"file_type":141,"file_size":142,"view_count":44,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":81,"language":143,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":144,"faqs":145,"seo_title":146,"seo_description":67,"update_tm":147,"read_time":39},4398048949847,"https://ap-avatar.wpscdn.com/avatar/400002536579ef2da7f?_k=1778318612642679267","SHORT REPORT  \nLynch syndrome screening in colorectal and endometrial cancers in Iceland  \nKatla R. Kluversa, Thordur Tryggvasonb, Vigdis Stefansdottirc, Jon G. Jonassona,b, Petur Snaebjornssona,d and Sigurdis Haraldsdottira,e  \na Faculty of Medicine, University of Iceland, Reykjavik, Iceland; bDepartment of Pathology, Landspitali University Hospital, Reykjavik, Iceland; c Department of Genetics and Molecular Medicine, Landspitali University Hospital, Reykjavik, Iceland; dDepartment of Pathology, Netherlands Cancer Institute, Amsterdam, the Netherlands; e Department of Oncology, Landspitali University Hospital, Reykjavik, Iceland  \nABSTRACT  \nBackground and purpose: Screening for Lynch syndrome (LS) with mismatch repair (MMR) protein immunohistochemistry (IHC) in all patients with newly diagnosed colorectal (CRC) and endometrial cancer (EC) was implemented in Iceland in 2017. The aim of the study is to assess the accuracy of screening in 2020– 2022 and compare it to 2017–2019 when screening was initiated.  \nPatients/materials and methods: All patients diagnosed with CRC and EC according to the Icelandic Cancer Registry in 2020–2022 were included. Screening results were crossmatched with a genotyping database from deCODE to calculate sensitivity and specificity for LS detection.  \nResults: In 2020–2022, 429 of 522 (82%) diagnosed CRCs were stained and 90 of 106 (85%) ECs, compared to 74% of CRCs and 82% of ECs in 2017–2019. The screening protocol was followed in 90% of cases for CRCs and 95% of cases for ECs compared to 89% and 68% during 2017–2019. The sensitivity of IHC as a screening method for LS was 70% and specificity 88% with a positive and negative predictive value of 8.4% and 99.4%, respectively.  \nInterpretation: Three LS cases were missed with MMR IHC (1 MSH6 and 2 PMS2 carriers), it is possible these patients had sporadic cancers unrelated to their LS carrier status. MSH6 and PMS2 deficiency strongly predicts LS in Iceland.  \nARTICLE HISTORY  \nReceived 7 September 2024 Accepted 16 January 2025 Published 31 January 2025  \nKEYWORDS  \nLynch syndrome; mismatch repair deficiency; MMR;  \nimmunohistochemistry; founder variant; cancer genetics  \nIntroduction  \nLynch syndrome (LS) is a hereditary cancer syndrome caused by pathogenic germline variants in one of the four mismatch repair (MMR) genes: MLH1, MSH2, MSH6, PMS2 or EPCAM [1]. LS is the most common hereditary cause of colorectal cancer (CRC) and increases the lifetime risk of multiple cancer types, most notably colorectal and endometrial cancer (EC) [2] . LS has a documented population prevalence from 1:370 to 1:2000 [3] and has been reported to be as high as 1:226 in the Icelandic population [4] . This is in part because of a high prevalence of MSH6 and PMS2 founder variants in Iceland [4] . A hallmark of LS tumors is MMR deficiency (dMMR) with absent staining of corresponding MMR proteins on immunohistochemistry (IHC) on tumor tissue, which can be used as a screening method for LS [1] . Up to 15% of all diagnosed CRCs and 20% of all ECs are MMR deficient, but only about 2–3% of CRCs and ECs carry LS [1, 5] .  \nScreening for LS with MMR IHC in all newly diagnosed CRCsand ECs was implemented universally in Iceland in 2017. We previously published results on the efficacy of IHC screening for LS in 2017–2019 where screening accurately identified 89% of LS cases [6] . The aim of this study is to assess the efficacy of  \nscreening in 2020–2022 and compare to 2017–2019 when screening was initiated.  \nAll patients diagnosed with CRC or EC in 2020–2022 were included in this retrospective cohort study. The Icelandic Cancer Registry captures all cancer diagnoses in the country and has an accuracy of 99.15%[7] . All tumor MMR IHC and clinical genetic testing is performed centrally at Landspitali University Hospital; clinical genetic testing is performed with Illumina TruSight Hereditary Cancer Panel. deCODE Genetics have collected extensive genotyping information on the Iceland","cbCaic6BTWiMmFKl","https://ap.wps.com/l/cbCaic6BTWiMmFKl","pdf",147355,"English","# Abstract\n## Background and purpose\n## Patients/materials and methods\n## Results\n## Interpretation\n# Introduction\n## Lynch syndrome and mismatch repair\n## Universal screening in Iceland\n# Methods and study design\n## Case inclusion and data linkage\n## Screening protocol criteria\n# Results and discussion\n## Case numbers and staining rates\n## MMR-deficient proportions and referral performance","[{\"question\":\"What was the purpose of Lynch syndrome screening in Iceland starting in 2017?\",\"answer\":\"Universal LS screening was implemented for all newly diagnosed colorectal and endometrial cancer patients using MMR protein immunohistochemistry (IHC). The study assesses its accuracy in 2020–2022 and compares it with 2017–2019.\"},{\"question\":\"How were patients included and how was screening performance measured?\",\"answer\":\"All CRC and EC patients diagnosed in 2020–2022 were included from the Icelandic Cancer Registry. Screening outcomes were crossmatched with deCODE genotyping data to calculate sensitivity and specificity for LS detection.\"},{\"question\":\"What were the key diagnostic performance results for IHC screening?\",\"answer\":\"For 2020–2022, IHC sensitivity was 70% and specificity was 88%. The positive predictive value was 8.4% and the negative predictive value was 99.4%.\"},{\"question\":\"Were any Lynch syndrome cases missed by the MMR IHC screening?\",\"answer\":\"Three LS cases were missed with MMR IHC (one MSH6 and two PMS2 carriers). The interpretation notes that these patients may have had sporadic cancers unrelated to LS carrier status.\"}]","Lynch syndrome screening in colorectal and endometrial cancers in Iceland | PDF",1790193752]