CD8A and colorectal carcinoma: The TGF-β may have inhibitory effects on T-helper1 phenotype differentiation, CD8 T-cell activity, IL-2 expression, and natural cell killer proliferation and function and increased the percentage of immunosuppressive M2 macrophages and myeloid-derived suppressor cells (MDSC).114 The TGF-β pathway is active starting from the earlier phases of CRC carcinogenesis and is even more prominent in the CRC hepatic metastases.