Ba/F3 cells expressing FLT3-WT, FLT3-ITD-W51, FLT3-ITD-NPOS, FLT3-W51-R602A, FLT3-W51-R602E, FLT3-W51-R602K, FLT3-W51-ΔR602, and FLT3-NPOS-ΔR623 seeded at a density of 4 × 10⁴ cells/mL in the absence or presence of different concentrations of PKC412 (0 to 100 nM) and counted after 72 hours. All cell lines were also cultured in the presence of IL-3 and 100 nM PKC412 to confirm nontoxicity of PKC412 to Ba/F3 cells. The IC₅₀ was calculated from 3 independent experiments (IC₅₀ is defined as the concentration of inhibitor required to induce a growth reduction of 50% compared to the cells grown in the absence of inhibitor).