The introduction of imatinib mesylate as treatment of chronic myelogenous leukemia has saved many patients, but the success of therapy is hampered by resistance and possible non-destruction of the malignant clone. This article describes the cytogenetic responses and abnormal cytogenetic patterns involving the ABL and BCR genes detected by FISH in patients who use exclusively imatinib. The results showed that other alterations involving the BCR and ABL genes do not seem to be related to resistance to the drug as they occur in low frequencies and can not be associated to the cytogenetic response or to the time of treatment. Moreover, the response to imatinib seems to be individual and unpredictable, independent of the time of treatment and of its initiation after diagnosis.
Chronic myelogenous leukemia; imatinib; FISH
