Associations Between The Breast Cancer And Serum Levels Of Adiponectin And Leptin

BackgroundBreast cancer has become one of the major tumors which threaten women’ health seriously all over the world, and its incidence rate now is living in the first of malignant tumors of females worldwide. At present, there are about1.38million new cases of breast cancer each year in the world, and the number of deaths with breast cancer each year is about460,000. In recent years, incidence of breast cancer in China increased significantly. For example, the incidence rate of breast cancer in Beijing and Shanghai were45/100000and54.9/10million, published by the Chinese CDC in2007,with increases of23%and31%in10years respectively. Since prevention is the key of reducing the incidence of breast cancer, it is very important to define the high-risk groups and make an effective chemical intervention. Many studies have shown that obesity is an important risk factor of breast cancer, but the mechanism that obesity affects the breast cancer is inconclusive. Researchers have proposed that adiponectin and leptin which are secreted by adipose tissue can improve insulin sensitivity and may therefore mediate the association between obesity and breast cancer. Presently there has been research for this problem at home and abroad, but the conclusions of those researches are the association between breast cancer and separate low adiponectin level or high leptin level. There is no research focused on the relationship between breast cancer and the adiponectin/leptin ratio. In addition, domestic researches of adiponectin or leptin are admitted local hospital diagnosed breast cancer cases as case group. The different living environment and large age span will inevitably produce a certain amount of bias, which needs to be corrected by a survey based on population. Therefore a study based on an epidemiological survey is needed to investigate the association between the breast cancer and serum levels of adiponectin and leptin.ObjectiveThis study is aimed to investigate the association between the breast cancer and adiponectin, leptin and adiponectin/leptin ratio, to explore the potential indicators for risk evaluation of breast cancer, and to provide some guideline for further study of defining high-risk groups and providing some effective chemical intervention.MethodsThe pre-study, an epidemiological survey, has investigated122058women in Shandong, Hebei, Jiangsu and Tianjin, and gained123cases newly histological diagnosed in2years. After informed consent and discounted the cases refused to collect blood specimens,43cases of123breast cancer patients were enrolled. Then in the ratio of1:1,43women who attended the physical check up but without evidence of breast cancer were included as control group, with the pairing standard of same communities and same ages(±3years). Serum levels of adiponectin and leptin were tested by enzyme-linked immunosorbent assay (ELISA) for final statistical analysis, such as X2test and Conditional Logistic Regression Analysis.Results1. Univariate analysis showed that compared to control group, serum levels of leptin in breast cancer patients were increased (8.35±5.57μg/mL vs5.31±3.39μ g/mL, P=0.007), while serum levels of adiponectin(4.54±2.60μg/mL vs6.48±4.66μ g/mL, P=0.017) and the adiponectin/leptin ratio (0.76±0.59vs1.84±1.81, P=0.000) were decreased.2. The serum adiponectin levels of premenopausal women were significantly lower than the postmenopausal women (4.43±3.45μg/mL vs6.45±4.02μg/mL, P=0.015), while the serum adiponectin levels of pre-menopausal breast cancer patients were significantly lower than the post-menopausal breast cancer patients (3.35±1.55μg/mL vs5.90±2.92μg/mL, P=0.001).3. After multivariate analysis, breast cancer risk was not associated with serum levels of adiponectin or leptin, but the adiponectin/leptin ratio was found to be significantly correlated to breast cancer(OR=6.33,95%CI:1.87～21.40,p=0.003), and its relevance is more effective than adiponectin or leptin alone.Conclusions1. Population-based data showed that, breast cancer group have higher serum leptin levels, lower serum adiponectin levels and lower adiponectin/leptin ratio than the control group.2. The serum levels of breast cancer patients are lower, and the serum levels of pre-menopausal breast cancer patients are especially lower, suggesting that the estrogen levels may have an interaction with serum adiponectin levels and affect breast cancer together.3. Correlation of adiponectin, leptin and breast cancer is not statistically significant, suggesting that the separate adiponectin or leptin is not suitable to be used to evaluate breast cancer risk. But the adiponectin/leptin ratio, combination of adiponectin and leptin, was significantly correlated to breast cancer risk, suggesting that adiponectin/leptin ratio may be a potential indicator to evaluate the risk of breast cancer, worthy of our further study.