The gold standard for the treatment of chronic myeloid leukaemia (CML) is Imatinib, the first tyrosine inhibitor (TKI) of BCR-ABL. Imatinib specifically targets the BCR-ABL tyrosine kinase encoded by the BCR-ABL fusion gene, the molecular hallmark of CML. Regular monitoring of BCR-ABL transcript levels by quantitative RT-PCR is of key importance for the assessment of treatment response to imatinib.