In the tumor microenvironment, cells release extracellular ATP (eATP) through pannexin channels, which can bind to P2X and P2Y receptors or can be hydrolyzed to ADP or AMP by ectonucleoside triphosphate diphosphohydrolase (also known as NTPDase or CD39) and converted into adenosine by 5′-nucleotidase enzymes (also known as ecto-5′-nucleotidase, 5-NT, or CD73) [6,7]. Here, ENTPD1 is linked to neoplasm.