{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,22]],"date-time":"2026-06-22T06:47:04Z","timestamp":1782110824649,"version":"3.54.5"},"reference-count":45,"publisher":"Oxford University Press (OUP)","issue":"6","license":[{"start":{"date-parts":[[2026,6,1]],"date-time":"2026-06-01T00:00:00Z","timestamp":1780272000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/pages\/standard-publication-reuse-rights"}],"funder":[{"name":"Health Commission of Hubei Province Scientific Research Project","award":["WJ2019H124"],"award-info":[{"award-number":["WJ2019H124"]}]},{"name":"2020 Jingjian\u00b7 Tongshu Microsatellite Instability Research Fund Project","award":["JJTS2020-017"],"award-info":[{"award-number":["JJTS2020-017"]}]},{"name":"Research Projects of Biomedical Center of Hubei Cancer Hospital","award":["2022SWZX24"],"award-info":[{"award-number":["2022SWZX24"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,6,4]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Objectives<\/jats:title>\n                    <jats:p>The expression of mismatch repair (MMR) proteins does not follow a simple \u201cintact\u201d or \u201closs\u201d pattern. Rather, \u201cnonclassic loss\u201d patterns can be presented.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>We retrospectively collected data on 569 patients with colorectal cancer. According to the MMR protein expression patterns of intact expression (pattern A), complete absence (pattern B), regional\/patchy loss of 10% or more tumor cells (pattern C), and positive signals of 10% or more tumor cells weaker than control cells (pattern D), the patients were divided into 3 groups: MMR proficiency (all 3 MMR proteins were pattern A), classic MMR deficiency (proteins exhibiting pattern B), and nonclassic possible MMR deficiency (regardless of the presence or absence of pattern B, with at least 1 protein exhibiting pattern C or D).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Patients with both complete and nonclassic loss patterns had microsatellite instability high status (17\/17 [100.00%]); 64.71% (11\/17) had MLH1\/PMS2 co-complete loss combined with MSH6 regional loss. Microdissection of the MSH6 loss region and next-generation sequencing detection were performed, and pathogenic mutations were found in 6 patients (6\/7 [85.71%]), 83.33% of whom had somatic mutations in the MSH6 gene. Among the 26 patients with only a nonclassic loss pattern, 8 (30.77%) had microsatellite instability high status, of whom 7 (26.92%) had MMR gene mutations and 3.85% probably had pathogenic germline heterozygous mutations.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Microsatellite instability high status (30.77%) and Lynch syndrome (3.85%) can occur in patients with only nonclassic loss of MMR proteins (without the B pattern). It is necessary to deepen our understanding of nonclassical MMR expression patterns to avoid missing patients with microsatellite instability high status and Lynch syndrome.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1093\/ajcp\/aqag070","type":"journal-article","created":{"date-parts":[[2026,6,1]],"date-time":"2026-06-01T11:23:05Z","timestamp":1780312985000},"source":"Crossref","is-referenced-by-count":0,"title":["Mismatch repair protein \u201cnonclassic expression loss\u201d pattern in colorectal cancer: an important staining pattern that is not well understood"],"prefix":"10.1093","volume":"165","author":[{"given":"Jinchuan","family":"Yu","sequence":"first","affiliation":[{"name":"Department of Pathology, Hubei Cancer Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan, Hubei,","place":["China"]},{"name":"Department of Surgical Pathology, Women's Hospital, School of Medicine, Zhejiang University , Hangzhou, Zhejiang,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xuexue","family":"Xiao","sequence":"additional","affiliation":[{"name":"Department of Pathology, Hubei Cancer Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan, Hubei,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Weiying","family":"He","sequence":"additional","affiliation":[{"name":"Department of Pathology, Hubei Cancer Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan, Hubei,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yanan","family":"Yang","sequence":"additional","affiliation":[{"name":"Department of Pathology, Hubei Cancer Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan, Hubei,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1984-8445","authenticated-orcid":false,"given":"Junqiu","family":"Yue","sequence":"additional","affiliation":[{"name":"Department of Pathology, Hubei Cancer Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan, Hubei,","place":["China"]},{"name":"Laboratory of Molecular Pathology, Hubei Provincial Clinical Research Center for Colorectal Cancer , Wuhan, Hubei,","place":["China"]},{"name":"Wuhan Clinical Research Center for Colorectal Cancer , Wuhan, Hubei,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2026,6,22]]},"reference":[{"key":"2026062201515292800_aqag070-B1","doi-asserted-by":"publisher","first-page":"1506","DOI":"10.1158\/1078-0432.Ccr-11-1469","article-title":"Molecular pathways: microsatellite instability in colorectal cancer: prognostic, 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