HIF1A and cancer: The role of TGF-β in upregulating the expression of CD73 on cancer cells has been well-documented (Regateiro et al., 2013), and its effects on the expression of CD73/CD39 on myeloid-derived suppressor cells were shown to occur by phosphorylation and activation of mTOR and HIF-1α, respectively (Li et al., 2017).