VHL and neoplasm: Kaelin et al. identified a complex formed by von Hippel-Lindau (VHL) tumor suppressor protein (pVHL) with Cullin2 (CUL2), Elongin B, and Elongin C.15 Among these factors, VHL protein has a negative regulatory effect on HIF,16 and the absence of VHL prohibits HIF degradation and promotes tumor initiation.17 Accumulating evidence has clarified the regulatory role of HIF.