JAK1 and acute lymphoblastic leukemia: These lesions target genes encoding lymphoid transcriptions factors (e.g., IKZF1, PAX5, EBF1 in BCP-ALL and, e.g., RUNX1, ETV6, GATA3 in T-ALL), controlling cell-cycle regulation (CDKN2A/CDKN2B, RB1), apoptosis (ETV6, ERG) or intracellular signaling pathways, e.g., via mutations in JAK1, JAK3, STAT5B, KRAS, NF1, AKT1, PTEN or PTPN2 [199,200,201].