PARP1 and breast cancer: With PARP inhibitors approved for germline BRCA mutation (gBRCAm) carriers in the metastatic setting and recently approved for early-stage disease, it is worth considering how the efficacy of PARP inhibitors might be improved and how the population of patients with breast cancer who could benefit from PARP inhibitors could expand beyond gBRCAm carriers (the term mutation will be used to indicate pathogenic or likely pathogenic gene variants).