TGFB1 and neoplasm: Cytokine production by T cells can also contribute to immunosuppression, as ablation of tumor growth factor β1 (TGF-β1) in T cells (not Treg) enhanced tumor T cell cytotoxic activity in mice, inhibiting tumor growth and metastases, and suggesting that tumor immunosurveillance escape is dependent on TGF-β1 production by conventional T cells (52).