Objective: To investigate the change of Philadelphia chromosome-positive clone with secondary chromosomal aberrations after imatinib mesylate (IM) treatment in patients with chronic myeloid leukemia (CML) and its relation with prognosis.
Methods: 37 cases of CML in accelerated phase and blastic phase were collected and chromosome specimens of bone marrow cells were prepared by with 24-hour culture. G-banding technique was used for karyotyping.
Results: The major secondary chromosomal aberrations were double Ph, +8, and i (17q); the minor ones were -Y, chromosome 17 abnormalities other than i (17q) and inv (3q). The percentage of Philadelphia chromosome-positive clone with secondary chromosomal aberrations showed the following 4 types of change; amplification, no change, decrease and complete remission after treatment with IM. 2 of the 24 cases in CML in accelerated phase gained complete cytogenetic response (CCyR) and 2 of the 13 in blastic phase did so. The groups with amplification and no change showed significantly shorter overall survival and progression free survival than the groups with decrease and complete remission.
Conclusion: The percentage of Philadelphia chromosome-positive clone with secondary chromosomal aberrations may drop in some CML patients after IM treatment and the patients may gain CCyR with accompanied prolonged survival.