Introduction. Acute myeloid leukemias (AML) are characterized by different clinical courses and different sensitivity to therapy. Taking into consideration their significant prevalence, an intensive search for new prognostic criteria is conducted that may determine individual prognosis and define the most appropriate treatment approach for patients with MLL. 

Aim of the study was to detect diagnostic and prognostic significance of translocation t(8;21)(q22;q22) and corresponding RUNX1/RUNX1T1 (AML1/ETO) chimeric gene in AML with maturation (AML M2). 

Materials and methods. Cytogenetic investigations of peripheral blood (PB) and/or bone marrow (BM) cells from 29 patients with AML M2 (range: 27-85 years, 19 males and 10 females) were performed. The method of conventional cytogenetics (GTG) and fluorescence in situ hybridization (FISH) were used. Cytogenetic methods were performed using standard techniques and karyotypes were described according to the International System for Human Cytogenetic Nomenclature (ISCN, 2020). 

Results. Cytogenetic abnormalities of various kinds were found, namely t(8;21)(q22;q22), RUNX1/RUNX1T1 gene, -Y, 3q21q26 rearrangements, del(9)(q22), monosomal karyotype and others, in 55 % of patients with AML M2. Some genetic abnormalities (RUNX1/RUNX1T1 fusion gene) were detected by molecular genetic method (FISH). Translocation t(8;21)(q22;q22) and/or RUNX1/RUNX1T1 gene was found in 9 (31 %) patients with AML M2. The type of AL was confirmed according to the WHO classification (2016, 2022) in 48 % of patients. Taking into consideration the identified cytogenetic abnormalities AML M2 patients were classified into three prognostic groups: the group of patients with adverse prognosis factors (17 %) (3q21q26 rearrangements, complex karyotype (≥ 3 abnormalities)), the intermediate prognostic group without significant cytogenetic markers (52 %) (rare or atypical abnormalities, normal karyotype) and the group of patients with favorable prognostic markers (31 %) (t(8;21)(q22;q22), RUNX1/RUNX1T1 gene). The difference in survival rates between AML M2 patients in the first and second groups, and the first and third groups, was statistically significant (p < 0.05). Confirmed that prognostically favorable t(8;21)(q22;q22) and RUNX1/RUNX1T1 gene in AML M2 are more often observed in young people, whereas unfavorable prognostic markers – in older people. 

Conclusions. Chromosomal abnormalities of various kinds were found in 55 % patients with AML M2. Taking into consideration the identified abnormalities patients were classified into three cytogenetic prognostic groups: the group of patients with adverse prognosis factors, the intermediate prognostic group and the group of patients with favorable prognostic markers. The difference in survival rates between patients in the first and second groups, and the first and third groups, was statistically significant. The frequency of t(8;21)(q22;q22) and/or RUNX1/RUNX1T1 gene was 31 %. Cytogenetic investigations should be included in the standard examination of patients with AML for diagnosis, prognosis and selection of the optimal treatment strategy. Besides the analysis of differential banding pattern chromosomes for AML patients it is necessary to apply molecular genetic studies.

Keywords: acute myeloid leukemia; karyotype; cytogenetic abnormalities; diagnosis; prognosis.