GPI and melanoma: Overexpression of ESAT-6-gpi and IL-21 antigens in CD133+CD44+ melanoma specific CSCs enhanced the levels of anti-ESAT-6 and interferon (IFN)-γ as well as increased cytotoxic activities of NK cells, splenocytes and complement dependent cytotoxicity leading to attenuation of melanoma growth and metastases [53] (Fig. 3).