BRCA2 and neoplasm: They found that 6TG was as efficient as the PARP inhibitor, AG014699, in selectively killing BRCA2-defective tumours in a xenograft model, and that 6TG also kills cisplatin-resistant or PARP inhibitor-resistant (PIR) BRCA2-defective cells.21 Although homologous recombination is reactivated in some PIR cells in response to PARP inhibitors, it is not fully restored for the repair of 6TG-induced lesions.