IL21 and neoplasm: Antitumor effects have been demonstrated for fusion proteins composed of antibodies targeting different tumor-associated antigens (e.g., CEA, EDB, EDA, GD2, EGFR, FAP) and many cytokines of the common gamma chain receptor family (e.g., IL-2, IL-15, IL-15/IL15Rα, IL-21, IL-7) (25–32).