MSH6 and breast cancer: Cumulatively, germline mutations in BRIP1, RAD51C, and RAD51D account for ~ 2% of OC cases [25, 26], and they seem to be predominantly associated with the high risk of OC [18, 25–29], in contrast to mutations in other common genes (including BRCA1/2, TP53, PTEN, and the mismatch repair MSH2 and MSH6 genes), contributing also to breast cancer (BC).