JAK1 and acute lymphoblastic leukemia: We next compared efficacy of ruxolitinib or BBT594 in combination with AZD2014 in parental or ruxolitinib-“persistent” BaF/3 cells expressing the Ph-like B-ALL–associated JAK1 V658F mutation, the JAK2 R683G mutation, or co-expressing wild-type CRLF2 and the JAK2 R683S mutation, described previously [15, 17].