Leukemia is a hematopoetic tissue tumor with a primary lesion of the bone marrow, where the morphological substrate is the blast cell. Chromosomal and molecular genetic aberrations play a major role in the acute leukemia pathogenesis, determing the morphological, immunological and clinical features of the disease. Our study was aimed to to analyze retrospectively the structure and frequency of chromosomal aberrations in children with initially diagnosed acute leukemia. Material and methods. Medical histories retrospective analysis of children charged to oncohematology department of the «Scientific Center of Pediatrics and Pediatric Surgery» in Almaty for the period 2015 - 2017 was carried out. 310 histories with primary diagnosed acute leukemia were studied. Results and discussion. Among 310 patients different chromosome aberrations were isolated in 158 patients (51%) during cytogenetic and molecular cytogenetic (in situ hybridization) studies of bone marrow blast cells. A normal karyotype was observed in 102 patients (33%). Conclusion. The lymphoblastic variant of acute leukemia was determined in 75.5%, that indicates its leading role in AL structure among the children of different ages. AML was determined in 22.6% of all OL cases. The most frequent chromosomal rearrangement in ALL patients was blast cell chromosome hyperdiploidy (10,6%) and t(12;21)(p13;q22)/ETV6-RUNX1,which was detected in 37 (16%) patients. The most frequent AML abberation was t (8;21) (q22;q22)/RUNX1-RUNX1T1, identified in 15 (21.4%) patients. Keywords: acute leukemia, bone marrow, blast cells, karyotype, chromosomal aberrations, cytogenetic study.

Teratoma is a germ cell tumor, which consists of derivatives of three germ layers and has various malignant potentials – from benign mature forms to immature embryonic forms with a somatic type of malignancy. Even the mature type of teratoma is biologically unpredictable providing for an ability to grow locally with invasion. Necessity for complete removal of tumors, wherever they are located, is explained by the fact that there is a risk of a possible development of growing teratoma syndrome or transformation into malignant tumors. This article describes the clinical case of growing teratoma syndrome of mediastinal localization in a teenager with Klinefelter syndrome, also as an example of the multidisciplinary approach of pediatric oncologists, surgeons, radiotherapists and pathomorphologists in decision-making for optimal treatment. The patients' parents gave their consent to the use of their child's data, including photographs, for research purposes and in publications.

Introduction: The relevance of research is conditioned by the study of the gene expression profile for the identification of molecular subgroups of non-Hodgkin B-cell lymphomas (NHBCLs) in haematology. Aim: The aim of this research was to study the gene expression profile with the identification of molecular subgroups in patients with NHBCLs for personalised treatment. Material and methods: This paper is aimed at analysing the frequency and role of expression of c-myc, B-cell lymphoma 2 (BCL 2) proteins and the Ki 67 proliferative index in patients with NHBCLs and conducting personalised therapy to improve the immediate effectiveness and immediate treatment results. Results and discussion: The paper presents the results of the use of high-dose polychemotherapy (PCT) in 9 patients out of 80 with NHBCL during co-expression of the c-myc, BCL 2 mutational gene and with high values of the Ki 67 proliferative index. High-dose chemotherapy (HDCT) was performed according to the R+HyperCVAD scheme (6 courses) and hematopoietic stem cell (HSC) autotransplantation improved the immediate effectiveness of therapy, with a complete remission rate of 80% and an event-free survival of 28 months. Conclusions: The study of molecular genetic characteristics in 80 patients with NHBCLs revealed co-expression of the c-myc and BCL 2 mutational gene in 9 out of 80 patients, and they differed in the aggressive course, ‘poor’ response to therapy, which predetermined the use of high-dose PCT with transplantation of autologous stem cells.