JAK1 and acute lymphoblastic leukemia: Genetically, ETP-ALL is heterogeneous, harboring mutations in pathways related to hematopoietic and lymphoid development (RUNX1, IKZF1, ETV6, GATA3, and EP300), Ras and cytokine receptor signaling (NRAS, IL7R, KRAS, JAK1, JAK3, NF1, and PTPN11), and epigenetic regulators (EZH2, SUZ12, EED, and SETD2) [13].