TGFB1 and nonpapillary renal cell carcinoma: Under hypoxic environment, HIF could initiate the expression of a large number of downstream regulatory factors, such as glucose transporter (GLUT), vascular endothelial growth factor (VEGF), transforming growth factor β (TGF-β) and epidermal growth factor (EGF), etc., thereby leading to unique highly active energy metabolism mode of ccRCC 30.