Aberrant expression and possible involvement of the leptin receptor in endometrial cancer

Objective. Leptin and its receptor are the key players in the regulation of energy balance and body weight control. However, their roles in gynecological malignancies are mostly unclear. In this study, we analyzed the expression and possible involvement of leptin and the leptin receptor in the pathogenesis of endometrial cancer. Methods. Radioimmunoassay was performed to analyze the serum leptin levels in the endometrial cancer patients, while RT-PCR, immunoblotting, and immunohistochemistry techniques were applied to study the expression of leptin receptor in the endometrioid-type endometrial cancer tissues. Furthermore, BrdU labeling followed by immunofluoreseent analysis was used to analyze the effect of leptin receptor overexpression on endometrial cancer cell proliferation. Results. Serum leptin levels are elevated in endometrial cancer patients, but show no significant difference to those of normal controls when normalized by body mass index. On the other hand, lower expression levels of leptin receptor short form (Ob-Ra) were observed in most endometrial cancer tissues, especially in the poorly differentiated ones, and the forced expression of Ob-Ra in RL95-2 endometrial cancer cells prevented them from entering the S-phase. Conclusion. In summary, our data demonstrates for the first time that the leptin receptor is aberrantly expressed in endometrial cancer tissues and is possibly involved in the pathogenesis of endometrial cancer. (C) 2004 Elsevier Inc. All rights reserved.