SLC47A1 and chronic myelogenous leukemia, BCR-ABL1 positive: In a first step, we thus measured mRNA expression levels of the potential imatinib transporters in PBMCs of healthy volunteers as well as in the immortalized CML cell line K562, derived from a BCR-ABL-positive CML patient in blast crisis.25 In both cell types mRNA for OCT1 (1/ΔCt= 0.07 and 0.07, NS), OCT2 (0.08 and 0.07, NS), and MATE1 (0.09 and 0.07, NS) in PBMC and K562 cells, respectively, were expressed at similar levels (Figure 1c).