Impact of obesity and adiponectin signaling in patients with renal cell carcinoma: A potential mechanism for the obesity paradox.

449Background: Obesity increases the risk of renal cell carcinoma (RCC); however, obese patients experience longer survival than non-obese patients. The mechanism of this “obesity paradox” is unknown. We examined the impact of obesity, total adiponectin (AD) level, and intratumoral AD receptors expression on RCC aggressiveness and survival, and also investigated the mechanism underlying enhanced cancer aggressiveness in RCC cells with exogenous adiponectin stimulation. Methods: A total of 129 RCC patients treated with surgery were included in the analyses. Preoperative BMI, serum total adiponectin (AD) level, total AD secretion from perinephric adipose tissue, and intratumoral AD receptors mRNA and protein expression were analyzed. Caki-2 and 786- cells were used for in vitro functional analyses. Results: Overweight and obese patients had significantly lower grade cancers than normal patients in all patients and in those without metastasis (p = 0.003, and p = 0.027, respectively). Cancer-specific survival...