CD200 and neoplasm: However, tumors have developed many different strategies to escape immune surveillance, such as loss of tumor antigen expression, expression of Fas ligand (Fas-L) or CD200 that can induce apoptosis of activated T cells, and immunosuppressive cytokine secretion, such as IL-10 or TGF-β, Or production of regulatory T cells, and downregulation or loss of MHC70.