Influence of complex variant chromosomal translocations in chronic myeloid leukemia patients treated with tyrosine kinase inhibitors

Cytogenetic variants of the Philadelphia (Ph) chromosome can be observed in 5-8% of patients diagnosed with Chronic Myelogenous Leukemia (CML), and usually involve at least one chromosome other than 9 and 22. Despite the genetically heterogeneous nature of these alterations, available data indicate that CML patients displaying complex variant translocations (CVTs) do not exhibit a less favorable outcome as compared to individuals presenting conventional Ph-positive CML. Patients and methods. We report our experience with 10 CML patients carrying CVTs among 153 newly diagnosed cases followed at our Institution. Results and discussion. Unlike previously published reports, in our series only two CML patients exhibiting CVTs achieved an optimal response to tyrosine kinase inhibitors (TKI) treatment. The remaining eight patients obtained either a suboptimal response or failed drug therapy. Our data suggest that the presence of CVTs at diagnosis might confer an unfavorable clinical outcome, as these genetic alterations might be markers of genomic instability and indicate a higher likelihood of disease progression.