The modified IL-13 ligand includes a single point-mutation that confers 50-fold higher affinity to IL-13Rα2 in addition to a 5-fold lower affinity for IL-13Rα1/IL4Rα as compared to wild-type IL-13 [148], making this mutant superior for the GBM setting to provide minimal off-target effects. The gene discussed is IL13; the disease is glioblastoma.