Acquisition of Mixed Lineage Leukemia Rearrangement in a Chronic Myeloid Leukemia Patient While on Imatinib

Chronic myeloid leukemia (CML) is a clonal myeloproliferative disorder with a specific genetic abnormality, the Philadelphia chromosome (Ph) translocation t(9;22)(q34;q11) generating the BCR-ABL1 gene fusion. The role of the Philadelpia chromosome translocation t(9;22)(q34;q11) in CML development is well documented and early in the chronic phase of the disease it is the sole chromosome anomaly in the majority of patients with CML. By contrast, disruption of the mixed lineage leukemia gene located on 11q23 is a recurrent genomic change in acute leukemia and is particularly prevalent in secondary, acute myeloblastic leukaemia, arising following cytotoxic treatment.