The effect of MMR deficiency on DFS was evaluated via Cox proportional hazard ratios; epigenetic loss of MLH1 was independently associated with worse DFS in early-stage EC after controlling for GOG99 and PORTEC risk classification (HR 2.75; 95% CI 1.69-4.48; p=≤0.001). The gene discussed is MLH1; the disease is mismatch repair cancer syndrome 1.