The incidence of atypical patterns of rearrangement and molecular-cytogenetic response to tyrosine kinase inhibitor therapy in newly diagnosed cases with chronic myeloid leukemia (CML).

BACKGROUND

To analyze the frequency of atypical fluorescence hybridization signal patterns and estimate the complete cytogenetic response (CCyR) and major molecular response (MMR) during 12 months of tyrosine kinase inhibitor therapy in patients with newly diagnosed chronic myeloid leukemia.

METHODS

The study included bone marrow and peripheral blood samples from 122 patients with newly diagnosed chronic myeloid leukemia. Detection of the - fusion gene () was performed using fluorescence hybridization with a dual-color dual-fusion translocation probe, and MMR analysis was performed using the real-time quantitative polymerase chain reaction method.

RESULTS

Variant translocation was determined in 10 samples and a deletion on the derivative chromosome 9 (del/der(9)) was found in 20 samples. The rates of CCyR and MMR were similar between patients with reciprocal translocation, variant translocation, deletion of derivative , or fusion gene. The Kaplan-Meier test did not show any significant differences in the rates of CCyR and MMR among those groups of patients.

CONCLUSION

The frequencies of variant translocation and del/der(9) in the present study agree with the results of other studies performed worldwide. No differences were observed in the rates of CCyR and MMR between patients with atypical patterns and reciprocal translocation.