Gene expression profiling of chronic myeloid leukemia with variant t(9;22) reveals a different signature from cases with classic translocation.

Background: The t(9;22)(q34;q11) generating the BCR/ABL1 fusion gene represents the cytogenetic hallmark of chronic myeloid leukemia (CML). About 5-10% of CML cases show variant translocations with the involvement of other chromosomes in addition to chromosomes 9 and 22. The molecular bases of biological differences between CML patients with classic and variant t(9;22) have never been clarified.Findings: In this study, we performed gene expression microarray analysis to compare CML patients bearing variant rearrangements and those with classic t(9;22)(q34;q11). We identified 59 differentially expressed genes significantly associated with the two analyzed groups. The role of specific candidate genes such as TRIB1 (tribbles homolog 1), PTK2B (protein tyrosine kinase 2 beta), and C5AR1 (complement component 5a receptor 1) is discussed.Conclusions: Our results reveal that in CML cases with variant t(9;22) there is an enhancement of the MAPK pathway deregulation and show that kinases are a common target of molecular alterations in hematological disorders.