When only exonic mutations were analysed in the whole-genome sequenced breast cancers from WSI, BRCA1- and BRCA2-deficient breast cancers remained associated with higher mutation burden with medians being 2.2 and 2.1 fold higher, respectively, compared to BRCA-proficient breast cancers (P = 3.5 x 10−11 and 7.4 x 10−6, respectively; S3 Fig). Here, BRCA1 is linked to breast carcinoma.