CML primitive progenitors show a broad range of responsiveness to imatinib mesylate.

CML CD34⁺ cells exposed to imatinib mesylate for 96 hours were assayed for LTCIC frequency by limiting-dilution analysis. The progenitor frequency, normalized to the frequency of progenitors in the absence of imatinib mesylate, is shown for each sample at the indicated concentrations of the drug. The mean is indicated by a solid bar.