Consistent with a previous report using a xenograft model of CRLF2-rearranged B-ALL, JQ1 provided a survival advantage to mice transplanted with syngeneic CRLF2/JAK2 mutant B-ALLs (Ott et al. 2012); however, this effect was augmented through coadministration of JAK2i ruxolitinib, which together demonstrated potent repression of c-Myc and induction of apoptosis in vitro. This evidence concerns the gene JAK2 and precursor B-cell acute lymphoblastic leukemia.