VEGFA and nonpapillary renal cell carcinoma: The HIFα/HIFβ heterodimer activates the transcription of downstream hypoxia-driven genes, including VEGF and platelet-derived growth factor-beta (PDGF-β), as well as EPO, which explains the high vascularity and the paraneoplastic erythrocytosis that are often associated with ccRCC [32] (Figure 1).