In addition, offering a Next Generation Sequencing (NGS)-based Multigene Panel Testing (MGPT) to BC and/or OC patients may significantly increase the detection rates of specific/recurrent and founder PVs in BC and/or OC predisposition genes beyond BRCA. PALB2, CHEK2, ATM, MUTYH, MSH2, and RAD51C have been shown to be the most frequently altered gene in BC and/or OC patients with negative test result for BRCA PVs [173–175]. This evidence concerns the gene ATM and breast cancer.