Analogous measurements were performed in 23 patients with IMA naïve de novo CML. Similarly, a large distribution of expression was seen from individual groups of cells (Fig. 1) . Total hOCT1 mRNA expression in PB LEU was again significantly influenced by the PMNC hOCT1 mRNA expression and PMNC percentage. The large variability in the percentage of PMNC from total LEU in patients with IMA naïve de novo CML (median: 75%; range: 33-93%) is, therefore, an important factor in the marked variability seen in hOCT1 mRNA expression in total LEU at the time of CML diagnosis. In addition, the hOCT1 mRNA expression from each analyzed group of cells was always significantly lower in IMA naïve de novo CML patients compared to healthy volunteers (Fig. 1 ). This suggested that CML cells have an additional effect on the observed hOCT1 mRNA expression level.