TGFA and nonpapillary renal cell carcinoma: Moreover, we found other genes known to be involved in vasculature development and angiogenesis to be upregulated in ccRCC, comprising neuropilin 1 (NRP1), apolipoprotein L domain containing 1 (APOLD1), endothelin 1 (EDN1), notch 4 (NOTCH4), transforming growth factor, alpha (TGFA) and angiopoietin-related proteins (ANGPT2, ANGPTL4).