TGFB1 and cancer: In addition to its direct effect on cancer cells, increased TGF-β diminishes the infiltration of the cytotoxic T-lymphocytes (CTLs) and natural killer (NK) cells into the tumor microenvironment and promotes the expansion of suppressive immune cells, including T-regulatory (T-regs) cells and myeloid-derived suppressive cells (MDSC) [4,5].