IL21 and neoplasm: α-GalCer-activated NKT cells are capable of producing high levels of cytokines (including IFN-γ and IL-21), anti-tumor effector and cytotoxic molecules (perforin and granzymes), and elicit direct tumor lysing properties (76–78), which assists to alleviate immunosuppression and enhances DC maturation, leading to improved anti-tumor T cell immunity (79–81).