Effect of ABT-869 on proliferation and differentiation of normal human bone marrow progenitors and AML patient samples. (A) Methylcellulose-based colony assay was performed with normal human bone marrow cells treated with varying concentrations of ABT-869 and analyzed 14 days after treatment. The experiment is an average of 5 samples with triplicate platings. The inhibitor was not toxic to the bone marrow cells up to a concentration of 1 μM. (B) Methylcellulose-based colony assay performed on AML patient samples containing the FLT3-ITD gene. The experiment is an average of 2 patients with triplicate platings. (C) Methylcellulose-based colony assay performed on FLT3-ITD–negative AML patient samples. The experiment is an average of 5 samples with triplicate platings. All data are expressed as number of colonies ± SEM. All human samples were obtained through an approved protocol from the UCLA IRB and uphold the tenets of the Helsinki protocol.