Oxidative stress and antioxidant imbalance in endometrial carcinogenesis.

OBJECTIVE: To assess dynamic thiol-disulfide homeostasis as a biomarker of oxidative stress in patients with endometrial cancer and to evaluate its association with tumor grade and stage. METHODS: This prospective case-control study included 35 patients with histopathologically-confirmed endometrial cancer and 36 age-matched healthy controls. Venous blood samples were obtained after overnight fasting. Serum thiol-disulfide homeostasis parameters were measured using a fully-automated spectrophotometric method. Native thiol, total thiol, disulfide concentrations, and related ratios were analyzed. Tumor grade and International Federation of Gynecology and Obstetrics stage were recorded for all patients. RESULTS: Native thiol and total thiol levels were significantly lower in patients with endometrial cancer compared with healthy controls (both P < 0.001). Patients with grade 2 tumors exhibited significantly reduced native and total thiol levels compared with grade 1 patients and controls (P < 0.001). A significant inverse correlation was observed between tumor stage and thiol levels, with lower native and total thiol concentrations in stage IB compared with stage IA disease (R = -0.586, and R = -0.604, resp.; P < 0.001). Disulfide levels and thiol-disulfide ratios did not differ significantly between groups. CONCLUSION: Dynamic thiol-disulfide homeostasis is markedly impaired in endometrial cancer and is associated with tumor grade and stage. Reduced thiol levels reflect increased oxidative stress and diminished antioxidant capacity, suggesting that thiol-based redox parameters may serve as complementary biomarkers for disease severity and progression in endometrial cancer.