Correlation Of Serum Leptin/Adiponectin Expression With Colorectal Cancer

ObjectiveObesity has been shown in epidemiologic studies to be associated with an increased risk of colorectal cancer.Leptin,the product of ob gene,are raised in obese individuals,much effort has been directed at elucidating the possible role of leptin in cancer development.On the other hand,the insulin resistance is related to the incidence of many tumors,including colorectal cancer,and levels of adiponectin are inversely associated with insulin resistance and obesity,then adiponectin may be one carcinogenic factor for colorectal cancer.The aim of the present study was to evaluate the correlation of leptin and adiponectin expression with favorable clinicopathologic phenotype in colorectal cancer,then search for the possible pathway of leptin and adiponectin participate in colorectal carcinogenesis though the correlation analysis with the mutation oncogenes.MethodsSerum leptin and adiponectin levels were measured via ABC-ELLSA in 30 colorectal cancers and 24 normal controls,which were correlated with selected clincopathological features in colorectal cancer.RT-PCR was used to quantitative analysis the expression of K-ras,p53,APC and DCC genes in tumor samples,data were analyzed with the expression of leptin and adiponectin.Results1 Mean concentrations of leptin were significantly higher for colorectal cancers(3.54±1.23ng/mL)than normal controls(2.27±1.01 ng/mL)(p＜0.05),no gender difference was observed in this study.2 Leptin expression in poorly differentiated tumors were obviously lower than those in moderately and well differentiated tumors(p＜0.05),but did not reveal significant difference for tumor locations and TNM stages(p＞0.05).3 The levels of leptin were higher in APC oncogene positive expression compared with negative expression(p＜0.05),and the intensity of APC oncogene increased with the higher levels of leptin(p＜0.05).There were no statistically significant correlations between leptin with the expression of K-ras,p53,and DCC genes in tumors(p＞0.05).4 The levels of adiponectin were significantly lower for colorectal cancers (especially in males)(13.08±7.99μg/ml)than normal controls(21.92±8.76μg/ml) (p＜0.01).5 With the tumor TNM stages increased,the levels of adiponectin showed decreasing tendency gradually,and no significant difference for tumor locations and histological types(p＞0.05).6 The levels of adiponectin were higher in K-ras oncogene positive expression compared with negative expression(p＜0.05),but there were no statistically significant correlations between adiponectin with the expression of K-ras in tumors (p＞0.05).The levels of adiponectin were lower in APC oncogene positive expression compared with negative expression(p＜0.05),and the intensity of APC oncogene increased with the lower levels of adiponectin.There were no statistically significant correlations between adiponectin with the expression of p53 and DCC genes in tumors(p＞0.05).Conclusion1 Leptin was overexpressed in human colorectal cancer,which affected by the differentiation degree of tumors,gender difference did not change the results.There were significant correlations between the levels of leptin and the expression of APC oncogene in colorectal cancer.2 Low levels adiponectin in human serum were observed in colorectal cancer, and with the tumor TNM stages increased,the levels of adiponectin decreased tendency gradually.There were significant correlations between the levels of adiponectin and the expression of APC oncogene in colorectal cancer too.