IL13RA1 and glioblastoma: Although mRNA for three chains of IL-13 receptor are expressed at different levels in GBM samples, we did not find any correlation between the expression of IL-13Rα2 and of IL-13Rα1 (Fig. 4a) mRNA, nor any correlation between the expression of IL-13Rα2 and of IL-4Rα mRNA (Fig. 4b).