EPAS1 and renal cell carcinoma: As the above analysis excluded the possibility of direct regulation of HOOK1 by HIF‐1α or HIF‐2α, we then turned our attention to E2F3, which was previously reported been regulated by VHL.[18, 19] Western blotting confirmed that E2F3 were significantly downregulated in RCC cells with ectopic VHL transfection (Figure S3A, Supporting Information).