Similarly, GFP+ splenocytes harvested from moribund ruxolitinib-treated Eμ-Crlf2/Jak2R683G B-ALL recipient mice retained GFP expression and showed Jak2Y1007/1008 hyperphosphorylation and a sustained loss of pStat5Y694 (Fig. 3K, M3–M6). This evidence concerns the gene CRLF2 and acute lymphoblastic leukemia.