IK6 enhances the activation of STAT5 in CD34⁺ CML cells. (A) Phosphoprotein analysis of CD34⁺ cells from 2- to 4-week cultures initiated with IK6- or control-transduced CD34⁺ cells shown individually for 4 CP-CML and 2 normal BM samples except for the STAT1 analysis, which was performed on 3 CP-CML and 1 normal BM sample. Values shown for each protein are the mean ± SEM of the ratios of the median fluorescent intensity values obtained for the IK6- compared with control-transduced cells in 3 replicate experiments. P values were generated by comparing the effects of IK6 on CP-CML vs normal BM cells. (B) Representative flow cytometry histograms taken from one of the CML experiments shown in panel A. (C) Comparison of transcript differences in IK6- and control-transduced CD34⁺ cells harvested from 2- to 4-week cultures for 5 CP-CML and 2 normal BM samples. Values shown are the mean ± SEM of the ratios of normalized transcript levels in the progeny of IK6- as compared with control-transduced cells obtained from 3 to 5 replicate cultures (with the exception of one of the normal BM samples where only 1 replicate could be set up). P values were generated by comparing the effects of IK6 on CP-CML vs normal BM cells. ***P < .001, **P < .01, *P < .05. NBM, normal bone marrow.