ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: During the treatment of CML; Quantitative, real-time PCR (RQ-PCR) for the determination of BCR/ABL1 transcripts level on the international scale, to be performed every 3 months until an MMR has been achieved, then every 3 to 6 months and/or CBA of the bone marrow cell metaphases (at least 20 banded metaphases), to be performed at 3, 6 and 12 months until a CCyR has been achieved, then every 12 months.