biostudies-literatureHoppe MMCancer Research UKNational Research Foundation SingaporeNational Medical Research Councile13366https://www.ebi.ac.uk/biostudies/studies/S-EPMC8103098biostudies-literatureUnknown13(5)Early relapse after platinum chemotherapy in epithelial ovarian cancer (EOC) portends poor survival. A-priori identification of platinum resistance is therefore crucial to improve on standard first-line carboplatin-paclitaxel treatment. The DNA repair pathway homologous recombination (HR) repairs platinum-induced damage, and the HR recombinase RAD51 is overexpressed in cancer. We therefore designed a REMARK-compliant study of pre-treatment RAD51 expression in EOC, using fluorescent quantitative immunohistochemistry (qIHC) to overcome challenges in quantitation of protein expression in situ. In a discovery cohort (n = 284), RAD51-High tumours had shorter progression-free and overall survival compared to RAD51-Low cases in univariate and multivariate analyses. The association of RAD51 with rEMBO molecular medicineQuantitative imaging of RAD51 expression as a marker of platinum resistance in ovarian cancer.PMC8103098NMRC/TA/0052/2016NMRC/CIRG/1400/2014NMRC/CSA‐INV/0016/2017Jaynes PSedukhina ASLim SChoi HUpadhyayula SSPitt JJJeyasekharan ADLim DGZWardyn JDKarnezis AHuntsman DGPang BNKTan TZP S Yeong JScott CLChiu DSTan DSPTopp MDPatel NRLie SSato KHoppe MMKaye SBLeung SBrown RfalseQuantitative imaging of RAD51 expression as a marker of platinum resistance in ovarian cancer.Early relapse after platinum chemotherapy in epithelial ovarian cancer (EOC) portends poor survival. A-priori identification of platinum resistance is therefore crucial to improve on standard first-line carboplatin-paclitaxel treatment. The DNA repair pathway homologous recombination (HR) repairs platinum-induced damage, and the HR recombinase RAD51 is overexpressed in cancer. We therefore designed a REMARK-compliant study of pre-treatment RAD51 expression in EOC, using fluorescent quantitative immunohistochemistry (qIHC) to overcome challenges in quantitation of protein expression in situ. In a discovery cohort (n = 284), RAD51-High tumours had shorter progression-free and overall survival compared to RAD51-Low cases in univariate and multivariate analyses. The association of RAD51 with r2021-01-01T00:00:00Z2021 May2026-05-09T08:20:05.364Z2022-02-10T09:57:05.099ZS-EPMC81030983370947310.15252/emmm.202013366