Loss of switch/sucrose non‐fermenting complex protein expression in undifferentiated gastrointestinal and pancreatic carcinomas

• DOI: 10.1111/his.14096
• Publication Date: 2020-05-16T06:57:20Z
• Authors: Basile Tessier‐Cl...; David F Schaeffer; Julinor Bacani; Celia E Marginean; Steve Kalloger; Martin Köbel; Cheng‐Han Lee
• Keywords: SMARCA4; SMARCB1; ARID1A; MSH6; MSH2

Undifferentiated carcinoma refers to an epithelial malignancy that lacks morphological evidence of differentiation. Recent studies have implicated the loss constitutively expressed switch/sucrose non-fermenting (SWI/SNF) complex subunits in undifferentiated carcinomas gastrointestinal tract and other sites. In this study we examine expression SWI/SNF mismatch repair (MMR) proteins a series from pancreas.We searched pathology databases four Canadian health centres for primary pancreatic resection specimens. Upon review 31 cases, 19 were confirmed be (eight colonic, six gastric, three pancreatic, one appendiceal duodenal). Immunohistochemical analysis SMARCA4, SMARCA2, SMARCB1, ARID1A, ARID1B, MSH2, MSH6, MLH1 PMS2 was performed on whole sections. Five (26%) showed core (two SMARCB1 two concurrent ARID1A ARID1B). or ARID1A/ARID1B-deficient consistently exhibited sheet-like growth pattern, with cellular discohesion rhabdoid morphology. Nine 17 tested MMR-deficient by immunohistochemistry. comparison, none 12 poorly differentiated originally diagnosed as ARID1B.Undifferentiated gastrointestinal/pancreatic show frequent proteins. The these components may contribute arrest differentiation, resulting histology aggressive clinical behaviour.