JAK2 and acute lymphoblastic leukemia: Exposing the primary BCP-ALL leukemic cells (either hiCRLF2 or loCRLF2) to these treatments (Supplementary Table 2) and comparing phosphoprotein levels to the TSLP-stimulated condition, we found that the JAKi, ruxolitinib, decreased the TSLP-induced STAT5 activation in hiCRLF2 samples but the response was heterogeneous (p=0.3338) as patients #1, #2 (both JAK2 altered) and patient #6 demonstrated a strong pSTAT5 inhibition with ruxolitinib.