CTLA4 and cancer: Antibodies and related molecules can enhance the immune response to cancer either through antagonism of immunosuppressive molecules, such as anti-CTLA-4 or PD-1 mAbs, through agonist activity, as previously described for mAbs targeting TNFRSF family members including GITR, OX40, CD40, and 4-1BB [41], or by depleting specific cell-types [42].