For example, studies suggest that ccRCC is closely associated with tumor suppressor von-Hippel Lindau (VHL) gene mutations that lead to stabilization of hypoxia inducible factors (HIF-1α and HIF-2α, also known as HIF1A and EPAS1) in both sporadic and familial forms [5, 6]. This evidence concerns the gene VHL and nonpapillary renal cell carcinoma.