Decreased serum adiponectin levels in patients with metastatic renal cell carcinoma

Background: Low levels of serum adiponectin are associated with increased risk and aggressiveness of obesity-related cancer. The purpose of the study reported here was to investigate the association between serum adiponectin levels and clinicopathological parameters of renal cell carcinoma. Methods: Preoperative serum total and high-molecular-weight (HMW) adiponectin levels were measured in 118 patients with renal cell carcinoma, and their association with clinicopathological parameters was analysed. Results: There were no statistically significant associations between total adiponectin and HMW adiponectin and pathological stage, regional lymph node involvement, histological grade, histological type (clear cell carcinoma versus other types) or presence of venous invasion. Total and HMW adiponectin levels in patients with metastasis, however, were significantly lower than in patients without metastasis (P = 0.044 for total adiponectin and P = 0.041 for HMW adiponectin). Low total and HMW adiponectin levels were significantly associated with metastasis in patients with a normal BMI (<25 kg/m(2)) (P = 0.034 for total adiponectin and P= 0.028 for HMW adiponectin) but not in overweight and obese patients (P = 0.652 for total adiponectin and P = 0.489 for HMW adiponectin). Multivariate logistic regression analysis showed that total adiponectin level was an independent predictor of metastasis of renal cell carcinoma in all patients (P= 0.024, 95% Cl = 1.031-1.560) and in patients with a normal BMI (P = 0.040, 95% Cl = 1.043-6.534). Conclusions: Serum total and HMW adiponectin levels were decreased in patients with metastatic renal cell carcinoma. Adiponectin might be a molecular link between obesity and the progression of renal cell carcinoma.