TGFB1 and hepatocellular carcinoma: In HCC, TGF-β1, produced in neoplastic cells, would inhibit proliferation of tumor specific cytotoxic T lymphocytes (CTL) and natural killer (NK) cells and stimulate the growth of neoplastic cells, and also it promotes production of VEGF which triggers endothelial cell proliferation, angiogenesis, and tumor metastasis [38, 39].