TGFB1 and nonpapillary renal cell carcinoma: miRs and HIFs are upregulated in cancer cells, regardless of normoxic or hypoxic conditions, and directly or indirectly regulate the expression of several target genes, including transforming growth factor-beta (TGF-β); the nuclear factor-erythroid factor 2-related factor 2 (Nrf2), which regulates the expression of programmed death-ligand 1 (PD-L1); and vascular endothelial growth factor-A (VEGF-A) in clear cell renal cell carcinoma (ccRCC) tumors with and without sarcomatoid differentiation [8,9,10,11].