No significant differences in the frequency of PIK3CA and TP53 mutations, the two genes most frequently mutated in breast cancer,19 were detected between the 24 PALB2 and the 683 ER−/HER2− and ER+non-BRCA1/2/PALB2-associated breast cancers (Fig. 4a). Here, BRCA1 is linked to breast carcinoma.