Efficacy of ruxolitinib in xenograft models of Ph-like ALL. Genetic lesions are indicated to the left of each row. (A) Peripheral blast count (PBC) over time in JAK-mutated (JAK_m) or wild-type (JAK_wt) and CRLF2-rearranged (CRLF2_R) or nonrearranged (CRLF2_NR) ALL xenografts. Graphed are means and SDs with PBC × 10³ per microliter on the vertical axis and weeks of treatment on the horizontal axis; n indicated in panel B. (B) Splenic blast count (SBC) at sacrifice. Means and SDs are graphed with the vertical axis representing absolute SBC × 10⁶; n for each arm indicated above bar. (C) Levels of phosphorylated STAT5 (pSTAT5) by immunoblot. Xenografts were treated with ruxolitinib (rux) or vehicle (veh) for 72 hours, spleens were harvested, and protein lysates subjected to immunoblot for pSTAT5, total STAT5, and actin.