CML) is a clonal hematopoietic disorder caused by the reciprocal translocation between chromosome 9 and 22. As a result of this translocation, a novel fusion gene, BCR-ABL, is created on Philadelphia (Ph) chromosome, and the constitutive activity of the BCR-ABL protein tyrosine kinase plays a critical role in the disease pathogenesis. Imatinib mesylate, a selective BCR-ABL tyrosine kinase inhibitor