In addition, a higher frequency of TP53 mutations was found in the 17 BRCA1-associated breast cancers (n = 15, 88%) than in the 16 PALB2-associated breast cancers with bi-allelic inactivation (n = 3, 19%; P < 0.0001, Fisher’s exact test; Fig. 5a). This evidence concerns the gene BRCA1 and breast cancer.