The in vitro effects of lestaurtinib and PKC412 on FLT3 phosphorylation in primary AML mononuclear cells. (A) Western blot images showing in vitro inhibition of FLT3 phosphorylation by lestaurtinib and PKC412 in a representative patient sample (case M-6, with FLT3 ITD mutation). Percentages refer to percentage FLT3 phosphorylation relative to untreated control as determined by densitometric analysis of blot images. (B) Dot plots showing the range of individual patient IC₅₀ values for in vitro inhibition of FLT3 phosphorylation by lestaurtinib and PKC412. The 12 cases are grouped according to FLT3 mutation status, with the median values indicated. P values refer to comparison of ITD and WT groups using the Student t test. (C) Mean FLT3-inhibitory and MTS-derived cytotoxic dose responses of cells from 12 patients to lestaurtinib and PKC412. Cases are divided according to the presence or absence of a FLT3 activating mutation. Error bars refer to the SEM.