dMMR has been widely known as microsatellite instability and used as a predictive biomarker for immunotherapy.58,59 Also in 1990s, women with familial mutations in genes BRCA1 and BRCA2 were found to be prone to breast cancer or ovarian cancer.60–62 Interestingly, familial mutations in BRCA1 exhibit a different cancer spectrum from BRCA2 mutations.63BRCA1 mutations are predominately implicated in breast and ovarian cancers,64 whereas BRCA2 mutations are predisposed to breast, prostate, pancreatic, melanoma and ovarian cancers (Table 3). Here, BRCA1 is linked to breast cancer.