Adenosine, produced by Cluster of Differentiation 39 (CD39) and Cluster of Differentiation (CD73) in the tumor microenvironment as an extrinsic immunosuppressive mechanism, binds to the Adenosine A1 Receptor, Adenosine A2A Receptor, Adenosine A2B Receptor and Adenosine A3 Receptor receptors, thereby inhibiting T cell activity and promoting Treg accumulation. The gene discussed is NT5E; the disease is neoplasm.