TGFB1 and neoplasm: Treg cells also release immunosuppressive cytokines, such as the inhibitory cytokines IL-10 and TGF-β, which down-regulate the effector mechanisms of the anti-tumor immune response; moreover, they can also convert ATP to adenosine using CD39 and CD73, and secrete granzymes, which can directly kill T cells or APCs [45].