Reijnen C, et al. - In this retrospective multicenter cohort study including patients with stage IB/II, grade 3 endometrioid endometrial cancer (EEC), researchers assessed whether mismatch repair (MMR) status can serve as a predictor for response to adjuvant radiotherapy. They examined 128 patients, with MMR-deficient EECs were present in 57 of them (43.0%). Findings revealed that patients with MMR-deficient EECs experienced an improved survival in relation to adjuvant radiotherapy. For the selection of candidates for whom adjuvant radiotherapy would be most beneficial, MMR status can be used as a predictive biomarker.