NT5E and cancer: Extracellular adenosine generated by cancer cells can recruit tumor-associated macrophages (TAMs), which their endonucleotiase activity, in collaboration with CD73 expression on other cells of the tumor microenvironment, further contributes (e.g., suppressing antitumor CD4+ T cell proliferation) to extracellular adenosine-mediated immunosuppression in tumors (116).