PDCD1 and neoplasm: Adenosine which is hydrolyzed from AMP by the extracellular domain of CD73 present on tumor cells has also been implicated in apoptosis of T cells and suppression of their activation and effector function[89].The combination of anti-PD1 or anti-CTLA-4 mab with anti-CD73mab has been shown to have impressive therapeutic activity and increases survival in a murine model.