The Role of Molecular Genetic Translocations in the Initial Response to the Treatment under the ALLIC BFM 2009 Program in Children Patients with Acute Lymphoblastic Leukemia

Abstract

The correlation analysis between the number of blast cells in bone marrow and peripheral blood was performed, and the dependence of blast percentage on the presence of molecular genetic translocations (AF4/MLL, BCR/ABL1, TEL/AML, E2A/PBX1) in patients with acute lymphoblastic leukemia (ALL) under the conditions of ALLIC-BFM 2009 cytostatic therapy was researched. The purpose of the study was to establish a relationship between the number of blast cells in bone marrow and peripheral blood depending on the presence of molecular genetic translocations for early detection of induction treatment by ALLIC BFM 2009. Materials and methods. The survey group consisted of 105 children aged 12 months to 16 years (median age was 6 years). Among those surveyed were 62 boys (59.0%) and 43 girls (41.0%). All patients were diagnosed with acute lymphoblastic leukemia. Results and discussion. Correlation analysis revealed a high degree of correlation between the number of blast cells in the bone marrow and peripheral blood, as the correlation coefficient (r) is 0.87. It is shown that the increase in the number of blast cells depends on the presence of chromosomal translocations. The highest number of blasts was observed in patients with BCR/ABL1 and E2A/PBX1 translocations, in whom the content of blasts in bone marrow was 97 and 96%, respectively, and in peripheral blood - 67 and 73%, respectively. It was found that treatment under the ALLIC BFM 2009 program leads to a decrease in the number of blast cells in the bone marrow and blood with minimal values on the 33rd day of treatment. It has been shown that the highest levels of blast cells during chemotherapy are observed in patients with chromosomal translocations BCR/ABL1 and E2A/PBX1. In patients with AF4/MLL translocation, the efficacy of therapy was the highest because no blast cells in the bone marrow were visualized on day 33 of treatment. The study of the primary response of patients with acute lymphoblastic leukemia to induction treatment according to the ALLIC BFM 2009 program revealed the dependence of the level of blast cells of bone marrow and blood on the type of chromosomal aberration. Patients with BCR/ABL1 and E2A/PBX1 have the highest resistance to chemotherapy with molecular genetic translocations, and patients with AF4/MLL and TEL/AML have the lowest resistance, as evidenced by the presence and absence of blast cells in the peripheral blood, respectively. Conclusion. Establishing the relationship between cytogenetic and molecular genetic features of the tumour clone will help determine the degree of malignancy of the process, as well as the risk group for the course of the disease. Determining the dependence of acute leukemia on molecular genetic translocations will make it possible to further modify the treatment program