Objective:The obesity hormone,leptin,has been found to participate in the development and proliferation of normal and malignant tissues.The aim of this study was to evaluate the role of leptin in human colorectal cancer.Methods:Serum leptin levels were measured via ABC-ELLSA in 30 colorectal cancers and 24 normal controls.Leptin concentration in colorectal cancer was analyzed in terms of selected clinicopathological features and some oncogenes.Results:The mean concentration of leptin was significantly higher for colorectal cancers(3.54±1.46 ng/ml) than normal controls(2.27±0.99 ng/ml),no gender difference was observed in this study.Leptin expression in poorly differentiated tumors was obviously lower than those in moderately and well differentiated tumors.There were no statistically significant correlations between leptin and the serum CEA and CA199 in colorectal cancers(P>0.05),and between leptin and the expressions of K-RAS,P53,APC,DCC genes in tumor tissues(P>0.05).Conclusion:Leptin is overexpressed in human colorectal cancer,which is related to the differentiation degrees of the tumor.There is no correlation between leptin expression and changes of oncogenes in colorectal cancers. Objective: The obesity hormone, leptin, has been found participate in the development and proliferation of normal and malignant tissues. The aim of this study was to evaluate the role of leptin in human colorectal cancer. Methods: Serum leptin levels were measured via ABC -ELLSA in 30 colorectal cancers and 24 normal controls. Leptin concentration in colorectal cancer was analyzed in terms of selected clinicopathological features and some oncogenes. Results: The mean concentration of leptin was significantly higher for colorectal cancers (3.54 ± 1.46 ng / ml) than normal controls (2.27 ± 0.99 ng / ml), no gender difference was observed in this study. Leptin expression in poorly differentiated tumors was obviously lower than those in moderately and well differentiated tumors. There are no significant differences between leptin and the serum CEA and CA199 in colorectal cancers (P> 0.05), and between leptin and the expressions of K-RAS, P53, APC, DCC genes in tumor tissues in is overexpressed in human colorectal cancer, which is related to the differentiation degrees of the tumor. There is no correlation between leptin expression and changes of oncogenes in colorectal cancers.