STAT5 is necessary for cytokine rescue. (A) Immunoblot of MV4;11 cells treated with indicated drugs for 2 hours. (B) Percent apoptosis by Annexin-V staining of MV4;11 cells treated for 72 hours with indicated drugs ± GM-CSF (n = 3). (C) Immunoblot of MV4;11 cells nucleofected with indicated siRNA. (D) Percent apoptosis by Annexin-V staining of MV4;11 cells nucleofected with control or STAT5A/B siRNA and treated with crenolanib ± GM-CSF for 72 hours (n = 3). Error bars represent SEM. **P < .01; ****P < .0001. C, control; Rapa, rapamycin 100 nM; S, STAT5A/B; Tram, trametinib 10 nM.