Mesquita KA, et al. - In this investigation, researchers ascertained if ERCC1-XPF deficiency would predict synthetic lethality to the PARP inhibitor Olaparib and platinum sensitivity in ovarian cancers. The protein expression of ERCC1, XPF and PARP1 were evaluated in tumors from a cohort of 331 patients treated at Nottingham University Hospitals and correlated with clinicopathological characteristics and survival. In univariate and multivariate analysis, low ERCC1 was significantly related to improved progression free survival (PFS) in patients with ovarian cancers. In platinum sensitive ovarian cancers, PARP inhibitor therapy improves PFS. Overall, the investigators concluded that low ERCC1 is not just a predictor of platinum sensitivity, but also a promising biomarker for synthetic lethality induced by Olaparib in ovarian cancers.