There is indeed considerable evidence to support a role for Th2 cytokines in protecting against gliomas, including from animal model studies demonstrating roles for IL-4 and activated eosinophils in glioma suppression [71,72] and overexpression of IL-4 driving rejection, or regression, of glioma in rats [73,74]; as well as multiple associations made between glioma risk, progression, and polymorphisms in IL-4R and IL-13 genes [75,76,77]. This evidence concerns the gene IL4R and central nervous system cancer.