David et al. showed that hypoxia can induce the high expression of ENTPD2 in cancer cells of HCC, leading to an increase in extracellular 5'-AMP (5'-Adenosine Monophosphate), which could promote the maintenance of myeloid-derived suppressor cells (MDSCs) by inhibiting the differentiation of MDSCs. The gene discussed is ENTPD2; the disease is hepatocellular carcinoma.