Most renal cancers are clear cell adenocarcinoma. The classification is based on the tumor size, the renal vein and lymph node involvement, and metastases. Renal cancer originates from the proximal convoluted tubule. The murine Renca tumor and the Wistar-Lewis rat renal adenocarcinoma are experimental models which well reproduce the evolution of the human renal cell carcinoma. They allow the study of the effect of chemotherapeutic agents, of lymphokines and of transfected cytokines. However, experimental models have limited value.