Role of adiponectin and leptin in non-diabetic, non-obese patients with endometrial cancer

Objective: To clarify the roles of adiponectin and leptin in endometrial cancer, this study examined serum concentrations of adiponectin and leptin, intra-tumor expression of two adiponectin receptors (AdipoR-1 and AdipoR-2) and the leptin receptor (ObR), and analyzed their relationship to clinicopathological parameters in non-diabetic, non-obese patients with endometrial cancer. Materials and Methods: Samples were obtained from 50 patients with endometrial cancer with fasting blood glucose levels < 120 mg/dl and body mass indices < 30. Serum concentrations of adiponectin, high-molecular weight (HMW) adiponectin, and leptin were measured by immunoassays. Expression of AdipoR-1, AdipoR-2, and ObR in tumor tissue was examined by immunohistochemical staining. Results: In endometrial cancer, serum concentrations of adiponectin were higher in patients with G1 or G2 tumors and in patients without lymphovascular space involvement. In 32 patients with AdipoR-1-positive tumors, serum concentrations of adiponectin, HMW adiponectin, and leptin did not differ by any pathological parameter. In contrast, in 18 patients with AdipoR-1-negative tumors, serum adiponectin concentrations were higher in patients with G1 or G2 tumors and in patients without lymphovascular space involvement. High histological grade, positive peritoneal cytology, lymphovascular space involvement, negative AdipoR-1 expression, and lower serum adiponectin levels were associated with poor disease-free survival by univariate regression analysis. In patients with AdipoR-1-negative tumors, disease-free survival was shorter in cases with serum adiponectin concentrations < 11 mu g/ml. Conclusion: Decreased serum adiponectin concentrations combined with the absence of AdipoR-1 expression in tumors are associated with high-grade tumor, lymphovascular space involvement, and poor prognosis in patients with endometrial cancer.