The first diagnostic HR deficiency mutational signature (HRD score) was recently approved to direct PARP inhibitor therapy in ovarian cancer cases without BRCA1/2 mutations based on data showing that patients with high HR deficiency associated mutational signatures without canonical HR gene mutations (BRCA1, BRCA2, etc.)benefited from PARP inhibitor therapy11. This evidence concerns the gene BRCA1 and ovarian cancer.