ENTPD1 and malignant tumor of neck: In contrast to the established role of CD39+ Treg in suppressive tumor microenvironments (including colorectal, pancreatic, head, and neck cancer) (30, 31, 35), we found a trend toward increased CD39− Treg within the Treg compartment in BM and PB of NDMM patients compared to MGUS patients (34).