Agonistic antibodies that are directed against costimulatory molecules, such as 4-1BB (CD137), OX40 (CD134), CD27, glucocorticoid-induced tumour necrosis factor receptor (TNFR) family-related gene (GITR), ICOS, and CD28 have been developed for use as cancer therapies. The gene discussed is TNFRSF9; the disease is cancer.