Kawakami et al. indicate that expression of DLK1 was lost in primary renal cell carcinoma (RCC) compared to adjacent normal kidney tissue in the Japanese and show tumor growth to be blocked by restoration of DLK1 compared to control cells suggesting that DLK1 has tumor suppressor activity in RCCs in vitro and in vivo31. This evidence concerns the gene DLK1 and renal cell carcinoma.