ENTPD1 and neoplasm: In another study, it was demonstrated that most of the intra-tumor CD4+Foxp3+ Treg cells have a Helios+, CTLA-4+, and CD39+ phenotype, but 30% of CD4+Foxp3− cells also expressed markers associated with regulatory functions, including CD25, LAG-3, and latency-associated peptide (LAP) (Figure 2B).