Cytotoxic response according to clinical status. (A) The results of the MTT assay for the 8 diagnostic samples versus the 5 relapsed samples exposed to 50 nM of either lestaurtinib (left) or 50 nM of the other 4 inhibitors averaged (right). Comparison was made using the Student 2-tailed t test. (B) Composite dose-response curves for 4 inhibitors (AC220, KW-2449, sorafenib, sunitinib) against low mutant ratio (Table 1; Samples 1-6, 8; thin dashed lines) and high mutant ratio (Table 1; Samples 7, 9-13; solid lines) FLT3/ITD samples. For each drug concentration, the percentage control for all samples was expressed as a mean value. Error bars, representing the SEMs, were all less than 3%, and were omitted for graph clarity. Comparison was made using the Student 2-tailed t test. (C) Composite dose-response curves for AC220 and lestaurtinib against low and high mutant ratio samples (as in panel B). For each drug concentration, the percentage control for all samples tested was expressed as a mean value, with error bars representing the SEMs. Comparison was made using the Student 2-tailed t test, with the arrow denoting a P value for AC220 low versus high allelic ratio samples.