Mechanistically, Tregs express inhibitory molecules, including cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), inducible T-cell costimulator (ICOS), glucocorticoid-induced TNFR-related protein (GITR), and OX40, both in tumors and tumor-draining lymph nodes. This evidence concerns the gene ICOS and neoplasm.