The suppressive activity of TGF-β in antitumor CD8+ Teff cells can be performed either by specifically inhibiting the expression of perforin, granzymes A and B, Fas ligand, and IFN-γ in a Smad-dependent manner (150) or by indirect suppression through Treg-derived cell membrane–bound TGF-β (151) and via exclusion of CD8+ T cell infiltration to the tumor (152, 153). This evidence concerns the gene PRF1 and neoplasm.