PARP1 and ovarian cancer: Cells with defects in genes required for repair of DNA double-strand breaks (DSBs) via the homologous recombination repair (HRR) pathway are exquisitely sensitive to PARP inhibitors,1,2 and the PARP inhibitors olaparib, rucaparib and niraparib have been approved for use in patients with BRCA-deficient breast and/or ovarian cancers, while talazoparib and veliparib are in clinical trials.3–6