To ensure reproducibility, all samples were performed and analyzed in duplicate. To obtain robust results, a cDNA from the KCL-22 cell line (DSMZ, Braunschweig, Germany), which has low hOCT1 mRNA expression, was used as an internal control for hOCT1 and GUS assessment. In addition, cDNA from the K562 cell line (DSMZ, Braunschweig, Germany) was used as an internal control BCR/ABL quantification.