The incidence of atypical patterns of BCR-ABL1 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 in situ 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 breakpoint cluster region—Abelson fusion gene (BCR-ABL1) was performed using fluorescence in situ 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 BCR, or ABL1-BCR 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.

Biological features and outcome of biphenotypic acute leukemia: a case series

Biphenotypic acute leukemia [BAL] is a distinct entity that is immunophenotypically defined by the European Group for the Immunological Classification of Leukemia [EGIL] scoring system and accounts for less than 5% of all acute leukemia cases. Since it is a rare and heterogeneous form of acute leukemia with an allegedly poor outcome, there is no consensus on the best treatment approach in these patients. Our objective was to analyze the biological features and outcome of patients diagnosed with BAL in our institution. Using the EGIL system, we identified 21 cases [3.9%] of BAL from 535 newly diagnosed acute leukemia patients in an 11-year period. There were ten cases of myeloid+B-lymphoid leukemia, eight cases of myeloid+T-lymphoid, one case of B+T-lymphoid and two cases of trilineage [myeloid+B+T-lymphoid leukemia]. The complete remission [CR] rate with high-dose chemotherapy was 72% and overall survival at 5 years was 21%. Patients that received acute lymphoblastic leukemia-oriented chemotherapy had a higher CR rate compared with those who received acute myeloid leukemia-oriented chemotherapy [100% vs. 60%, P=.007]. The white blood cell count at diagnosis was found to have statistically significant impact on survival. Despite the progress in the treatment of acute leukemia, the prognosis of BAL remains poor and treatment protocols devised explicitly for this entity should be investigated in prospective collaborative studies