EPAS1 and nonpapillary renal cell carcinoma: Interestingly the TGFβRI was also found to be in a complex together with HIF1-α/HIF2-α in clear cell renal cell carcinoma (ccRCC)s in vitro, suggesting a role for TGFβRI in hypoxia [67], consistent with previous reports about a functional role of TGF-β in promoting angiogenesis [68,69,70].