Biallelic EPCAM deletions induce tissue-specific DNA repair deficiency and cancer predisposition.

ABSTRACT: We report a case of Mismatch Repair Deficiency (MMRD) caused by germline homozygous EPCAM deletion leading to tissue-specific loss of MSH2. Through the use of patient-derived cells and organoid technologies, we performed stepwise in vitro differentiation of colonic and brain organoids from reprogrammed EPCAM^del iPSC derived from patient fibroblasts. Differentiation of iPSC to epithelial-colonic organoids exhibited continuous increased EPCAM expression and hypermethylation of the MSH2 promoter. This was associated with loss of MSH2 expression, increased mutational burden, MMRD signatures and MS-indel accumulation, the hallmarks of MMRD. In contrast, maturation into brain organoids and examination of blood and fibroblasts failed to show similar processes, preserving MMR proficienc

SUBMITTER: Forster VJ 

PROVIDER: S-EPMC10928233 | biostudies-literature | 2024 Mar

REPOSITORIES: biostudies-literature