Glioma cells express multiple immune-suppressive cytokines such as transforming growth factor-beta (TGF-β), IL-10, IL-4, IL-6, and IL-13, all of which interfere directly or indirectly with anti-glioma immune response (Debinski et al., 1999; Gomez and Kruse, 2006; Perng and Lim, 2015; Brown et al., 2016; Harshyne et al., 2016). Here, IL6 is linked to central nervous system cancer.