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Chronic myelogenous leukemia (CML) accounts for 15-20% of adult leukemias but is very rare in children (2%). Fewer than 10% of CML patients are younger than 20 years. CML is a myeloproliferative disorder characterized by the presence of the Philadelphia chromosome or the BCR-ABL fusion oncogene. The objective of this paper is to present the monitoring of imatinib therapy in two children with CML by the BCR-ABL fusion gene expression assessment from peripheral blood with quantitative real-time polymerase chain reaction (PCR) method. The 18 and six months follow-up of the patients included clinical examination, routine laboratory tests, bone marrow aspirate investigation including cytogenetic tests and the major BCR-ABL fusion gene expression measurement with qRT-PCR method from the peripheral blood. Patient No. 1 diagnosed with chronic phase CML showed excellent adherence to daily 400 mg imatinib treatment and achieved complete hematologic (CHR) and cytogenetic response (CCR) by three months and major molecular response (MMR) by 12 months, with lack of side effects due to imatinib. Patient No. 2 experienced severe hematologic toxicity, which necessitated temporary withdrawal of the drug. Transient non-compliance together with imatinib dose reduction has driven to treatment failure. In this case, mutational analysis is warranted. BCR-ABL fusion gene expression level measurement from peripheral blood with qRT-PCR method is an excellent tool in the follow-up of CML patients.
What tyrosine kinase, involved in a Philadelphia- chromosome positive chronic myelogenous leukemia, is the target of Imatinib (Gleevec)?