NT5E and neoplasm: The ectoenzymes CD39 (which hydrolyzes Adenosine Triphosphate (ATP)/Adenosine Diphosphate (ADP) to Adenosine Monophosphate (AMP)) and CD73 (which dephosphorylates AMP to ADO) are highly expressed on the surface of tumor cells, cancer-associated fibroblasts (CAFs), and regulatory immune cells [48].