Among the non-BRCA1/2 genes, our study confirmed a significantly increased risk association between mBC and PTVs in the BC predisposition genes PALB2, CHEK2, and ATM. This finding may be considered in mBC risk prediction models such as BOADICEA (Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm) [33]. Here, PALB2 is linked to breast cancer.