BRCA1 and ovarian cancer: Finally, mutations of the breast cancer type 1 and 2 susceptibility (BRCA1/2) genes, that are associated with familial breast cancer and ovarian cancer, were documented to be involved in immune dysfunction (337, 338).The observation of increased expression of PD-L1 in BRCA1/2-mutated ovarian cancer implies a possible role of BRCA1/2 for PD-L1 regulation, although the underlying mechanism remains to be explored (319, 338, 339).