BRCA1 and breast cancer: In a recent retrospective study involving the analysis of multigene panel testing of 708 MaBC patients, 97 patients (13.7%) have at least one pathogenic variant in breast cancer susceptibility gene, 11% tested positive for BRCA2, 4.1% for CHEK2, 1.5% for ATM, 1.3% for BRCA1, 0.6% for NF1, and 0.5% for PALB2 [42].