JAK1 and acute lymphoblastic leukemia: Recurrent activating mutations detected in kinase-coding genes or kinase regulators involve the PI3K-AKT axis (AKT1, PIK3CD, and PIK3R1), the JAK-STAT (IL7R, JAK1, and JAK3 which is mutated in about 16% of T-ALL cases6), or the Ras signaling pathways (PTPN11, NF1, N-RAS, and K-RAS), while in some early T cell precursor (ETP)-ALL cases, Fms-like tyrosine kinase (FLT3) mutations and/or overexpression are found7.