The discovery of synthetic lethality between BRCA mutations and PARP inhibitors ranks has led to major advances in the treatment of BRCA-mutated cancers. Mutations in BRCA1 and BRCA2 can leave cells with a deficiency in homologous repair (HR). And that deficiency can make them vulnerable to PARP inhibitors, which block alternate DNA repair pathways, as well as platinum-based treatment, which induces DNA mutations that BRCA-deficient cells are unable to cope with.