TNFSF18 and neoplasm: Recent studies showed that both recombinant GITR ligand (GITR-L) or agonist anti-GITR antibody (DTA-1) treatment of tumor-bearing mice led to a loss of tumor-infiltrating Tregs due to either cell depletion, reduced intra-tumor infiltration, or intra-tumor down-regulation of the Foxp3 expression (Coe et al. 2010; Cohen et al. 2010; Hu et al. 2008).