USP21 and neoplasm: Considering the capacity of STING to sense cytosolic tumor-derived DNA in tumor-associated immune cells, as well as the ability of Treg cells to limit anticancer immunity and promote angiogenesis (Facciabene et al., 2012; Woo et al., 2015), these results together reinforce that targeting USP21 may offer promise for antitumor immunotherapies.