Renal cell carcinoma (RCC),originating from the renal tubular epithelium,is a malignant tumor accounting for 80％-90％ of renal malignancies.The most common histopathological type of RCC is clear cell carcinoma,followed by papillary RCC and chromophobe RCC,and then the rare type such as collecting ductal carcinoma.In China,the incidence of renal cancer is second next to bladder cancer in the urinary system.