BRCA1 and breast cancer: Germline mutations affecting several DNA repair-related genes (eg, BRCA1, BRCA2, PALB2) have been associated with an increased BC risk, and these BCs often show genomic features of homologous recombination DNA repair deficiency (HRD) (14,16,17), including high large-scale state transitions (LSTs) scores, a dominant mutational signature 3, and long small deletion lengths.