EPO induces a dose-dependent increase in viability and proliferation of Ba/F3 cells with wild-type and ▵SH2 but not with ▵ABD EPO R/ABL. Cells were cultured with 5 U/mL EPO, and the total number (A) and percentage (B) of viable cells was enumerated using 0.04% Trypan blue staining. (□) Wild-type; (◊) ▵ABD; (○) ▵SH2.