NT5E and neoplasm: As the end product of CD39-CD73 axis, adenosine mediates immunosuppression within the tumor microenvironment (TME) through triggering adenosine receptors on the membrane surface, including A1R (encoded by ADORA1), A2AR (encoded by ADORA2A), A2BR (encoded by ADORA2B), and A3R (encoded by ADORA3) (66).