JAK2 and acute lymphoblastic leukemia: Overall, activation of kinases or cytokine receptor signaling pathways was identified in 191 patients with Ph‐like ALL (Figure 2), including ABL‐class fusions (45/191, 23.6%; ABL1, ABL2, CSF1R, and PDGFRB), CRLF2 positive (52/191, 27.2%; rearrangement or high‐expression), EPOR or JAK2 rearrangement (41/191, 21.5%), JAK‐STAT pathway mutations (22/191, 11.5%; IL7R, SH2B3, JAK1, JAK3, and FLT3), Ras pathway mutations only (17/191, 8.9%; KRAS, NRAS, PTPN11, and NF1), p‐CRKL or p‐STAT5 high‐expression only (14/191, 7.3%).