CD274 and nonpapillary renal cell carcinoma: However, the effect of selenium compounds on TGF-β1 in ccRCC is yet to be investigated either phenomenologically or mechanistically and the present study aimed to investigate whether TGF-β1, PD-L1, and VEGF are important therapeutic targets in ccRCC, and, if so, to also determine whether TGF-β1 is a specific, direct selenium target.