IL9 and acute lymphoblastic leukemia: Ksionda and colleagues reported that overexpression of the Ras Guanyl exchange factor (GEF) RasGRP1 (Ras guanine nucleotide-releasing protein 1) in T-ALL cells makes them highly sensitive to IL-9, which is, therefore, able to strongly stimulate the Ras-mediated signaling pathways, enhancing leukemic cell proliferation and survival [45] (Figure 1).