BC resulting from germline BRCAm (gBRCAm) has distinct clinical characteristics, increased sensitivity to poly(ADP-ribose) polymerase (PARP) inhibitors and DNA-damaging agents such as platinum-based chemotherapies [1, 4], and potentially decreased sensitivity to cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors [5]. This evidence concerns the gene CDK4 and breast cancer.