Renal cell carcinoma is derived from renal tubule, blastematous tubule or nephrogenic rest. Most common sporadic clear cell tumors have structural changes of the chromosomes, such as the cancer suppressor genes at 3p14, 3p21 or 3p25 (VHL gene). Cytogenetically, clear cell tumor (non papillary tumor) initially develops as a cancer, while papillary tumor progresses sequentially from atypical tubule to adenoma to carcinoma. Papillary tumors demonstrate numeric changes in the chromosomes. Renal cell carcinoma complicated with acquired renal cysts in dialysis patients tends to develop from papillary tumor. However, the exact mechanism inducing these genetic changes remains to be clarified.