This may reflect an increased expression of A2AR on Treg cells, which are known to express high levels of CD39 and PD-1 in the tumor microenvironment35–38, particularly given CD4+GFP+CD39+ cells were enriched for CD25+ cells relative to CD4+GFP+CD39− counterparts (Fig. 3G). This evidence concerns the gene ENTPD1 and neoplasm.