CCND1 and renal cell carcinoma: HIF-2 was shown to be necessary and sufficient to maintain tumor growth in VHL-deficient RCC cells.31, 32 HIF-2 was shown to control cellular proliferation through modulation of c-Myc activity and cyclin D1 in RCC cells.30, 54 In addition, new mechanisms for HIF-2 were described in digestive system cancer.