Tregs inhibit tumor killing by CTLs through TGF-β-dependent cell contact (54), inhibit the production of memory CTLs via cytotoxic-T-lymphocyte-associated protein-4 (CTLA-4) (33), and induction of CTLs death via granzyme B and perforin-dependent manner (55). This evidence concerns the gene TGFB1 and neoplasm.