The development of the BCR/ABL tyrosine kinase inhibitor imatinib mesylate (Gleevec; formerly STI571) as the treatment of choice for chronic phase CML and its remarkable therapeutic effects suggest that blast crisis transition will be postponed for several years in the majority of CML patients (Deininger et al, 2005a; Roy et al, 2006). Here, BCR is linked to chronic myelogenous leukemia, BCR-ABL1 positive.