VHL and nonpapillary renal cell carcinoma: Epidermal growth factor receptor (EGFR), epidermal growth factor (EGF), vascular endothelial growth factor A (VEGFA), von Hippel–Lindau tumor suppressor (VHL), vascular endothelial growth factor B (VEGFB), and hypoxia-inducible factor 1 alpha (HIF-1α) are genes that have been proved by a large number of studies to exert crucial functions in ccRCC.