ENTPD1 and neoplasm: This study was guided by our previous work demonstrating that the weakening of tumor hypoxia following supplemental oxygenation (respiratory hyperoxia, 60%) targets all downstream stages of the hypoxia-adenosinergic immunosuppressive pathway by decreasing levels of HIF1A, extracellular adenosine, CD39, CD73, and A2AR/A2BR (Figure 1A) (28, 29).