IL2 and cancer: The Treg cells hinder immunosurveillance in cancers by suppressing APCs via CTLA-4 engagement, depleting interleukin-2 (IL-2) that is needed for the expansion effector T-cells and producing immunosuppressive cytokines such as transforming growth factor-beta (TGF-β), interleukin-10 (IL-10), and interleukin-35 (IL-35) [70].