BRCA1 and cancer: Biallelic loss of HRR genes, especially BRCA1, BRCA2, RAD51D, RAD51 C, and PPP2R2 A was linked to higher HRD scores in BRCA-associated cancers, while BARD1, RAD51D, RAD54L, BRCA1, and MRE11 were associated with elevated HRD scores in in other cancer types (non-BRCA cancers).