Investigation of the relation of leptin G-2548A and leptinr-Q223R gene variants with serum leptin and leptin receptor levels in ovarian cancer patients

Leptin is a hormone that is synthesized mainly in the adipocytes of the adipose tissue and released into blood. Thereupon, its serum levels increase is proportional to the magnitude of the individual`s adipose tissue. Although the effects of leptin on appetite and energy homeostasis have been known for many years, recent studies suggest that leptin is also associated with mechanisms such as migration, growth, invasion and angiogenesis, which play important roles in cancer development. On the other hand, ovarian cancer is one of the main causes of mortality among women all over the world and it is proposed that obesity may be a risk factor for ovarian cancer. Leptin G-2548A polymorphism in the promotor site of the leptin gene is directly related to increased leptin expression in the adipose tissue and its secretion. LeptinR-Q223R polymorphism in the region that encodes the extracellular domain of the leptin receptor gene causes disturbance in binding of leptin with its receptor and it has been suggested that this situation is related to increased levels of leptin in circulation. Recent epidemiological and molecular studies have suggested that these polymorphisms may be predisposed to cancers such as prostate, breast, and colorectal cancers. In our study, due to the data of the previous surveys on leptin, we aimed to assess the prevalence of Leptin G-2548A and LeptinR-Q223R polymorphisms, and the serum levels of leptin and soluble-leptin receptor in ovarian cancer patients by comparison with healthy controls, thus to assess their probable relationships with over-cancer. Our study group consisted of 61 ovarian cancer patients and 51 healthy women. Polymerase Chain Reaction (PCR), Restriction Fragment Length Polymorphism (RFLP) and Agarose Gel Electrophoresis methods were used to determine the polymorphisms of Leptin G-2548A and LeptinR-Q223R genes. Serum leptin and soluble-leptin receptor levels were measured by ELISA. In our study, no statistically significant difference was observed between the patient and the control groups when both polymorphisms were examined in terms of genotype and allelic distributions. Furthermore, no significant difference was found between leptin and soluble-leptin receptor levels according to genotype distribution. Although serum leptin levels of the patient group are significantly higher than those of the control group, it is proposed that the result may be due to the body mass indices of the patients being higher than those of the controls. We presume that further studies, carried out with larger patient and control groups, for determination of relationships between leptin G-2548A and LeptinR-Q223R gene variants, and the serum levels of leptin and soluble-leptin receptor with ovarian cancer will have more reliable results. Key words: Ovarian cancer, Leptin, Leptin receptor