THE COURSE OF CHRONIC LYMPHOCYTIC LEUKEMIA AFTER SARS-COV-2 VIRUS INFECTION. / ПЕРЕБІГ ХРОНІЧНОЇ ЛІМФОЦИТАРНОЇ ЛЕЙКЕМІЇ НА ТЛІ ІНФЕКЦІЇ ВІРУСОМ SARS-COV-2.

Objective - to investigate the course of B-cell chronic lymphocytic leukemia (CLL) in patients after SARS-CoV-2 virus infection taking into account anamnestic exposure to the ionizing radiation (IR).Methods. The study was performed in a group of 51 CLL patients who were admitted to the Department of Radiation hematology of the National Research Center for Radiation Medicine of NAMS of Ukraine, Kyiv, from January 2020 (the beginning of SARS-CoV-2 epidemic) to August 2023. The group included 19 (37.3 %) clean-up workers of the Chornobyl NPP accident, 15 (29.4 %) inhabitants of radionuclide contaminated areas and 17 (33.3 %) IR non-exposed patients. The diagnosis of CLL was based on clinical history, lymphocyte morphology, and immunophenotypic criteria. Statistical studies were performed using the SPSS software package, version 20.0.Results. The diagnosis of CLL was established for the first time in 14 patients, in seven of them, CLL was diagnosed after 2-17 months after SARS-CoV-2 infection. In contrast to patients who did not suffer from a coronavirus infection, they had pronounced lymphadenopathy, which in some cases was accompanied by hyperleukocytosis, and needed early treatment. Thirteen patients with a previously established CLL were diagnosed with COVID-19 by PCR test. In seven of them (53.8 %) starting treatment was needed, or CLL has progressed. Seven of 51 patients (13.5 %) were vaccinated against SARS-CoV-2. Then, four of them were diagnosed with SARS-CoV-2 infection, confirmed by a positive PCR test, and two patients had a relapse of CLL within 1-2 months after vaccination. Most of patients with signs of the influence of SARS-CoV-2 infection on CLL belonged to sufferers of the Chornobyl NPP accident Conclusions. The clinical features of CLL that developed after SARS-CoV-2 were characterized firstly. The negative impact of SARS-CoV-2 infection on previously established CLL was established. The question about vaccination of CLL patients remains debatable.

THE STRUCTURE OF THE INCIDENCE OF ONCOHEMATOLOGICAL DISEASES IN ECOLOGICALLY DISADVANTAGED REGIONS OF THE DNIPROPETROVSK REGION FOR THE PERIOD 2006-2017. / СТРУКТУРА ЗАХВОРЮВАНОСТІ НА ОНКОГЕМАТОЛОГІЧНІ ХВОРОБИ В ЕКОЛОГІЧНО НЕБЛАГОПОЛУЧНИХ РЕГІОНАХ ДНІПРОПЕТРОВСЬКОЇ ОБЛАСТІ ЗА ПЕРІОД 2006­2017 РОКІВ).

OBJECTIVE: to conduct a comparative analysis of the incidence of malignant oncohematological diseases structure among the population of the 4 most ecologically disadvantaged cities of the Dnipropetrovsk region, taking into account the possible influence of various adverse environmental factors (radiation and chemical pollution of air, water and soil) for the period 2006-2017. MATERIALS AND METHODS: 1948 cases of acute myeloblastic and lymphoblastic leukemia, chronic myeloid and lymphocytic leukemia in residents of 4 cities of the Dnipropetrovsk region were analyzed, taking into account the possible influence of adverse environmental factors (radiation, air pollution, etc.). We used clinical and hematological data per patient and statistic information on these diseasis incidence in the region. RESULTS: An analysis of the oncohematological patients incidence structure, namely: acute lymphoblastic (C91.0) and myeloblastic leukemia (C92.0), chronic lymphocytic (C91.1) and myeloid (C92.1) leukemia, over 12 years in environmentally disadvantaged cities of Dnipropetrovsk region have been conducted. A comparative analysis of the incidence of these diseases among the population of 4 cities of the Dnipropetrovsk region was carried out, taking into account the possible influence of adverse environmental factors (radiation, air pollution, etc.). An excess of the incidence rates of the above-mentioned oncohematological diseases for the period 2006-2017 was revealed in the cities of Dnipro, Kryvyi Rih, Kamianske and Zhovti Vody, where environmental factors significantly affect the increase in morbidity due to pollution mainly by radioactive and chemical substances.

ANALYSIS OF THE INFLUENCE OF PROLONGED IRRADIATION ON HEMATOPOIETIC PROGENITOR CELLS IN GEL DIFFUSION CHAMBERS USING MATHEMATICAL MODELLING. / ANALIZ VPLYVU PROLONGOVANOGO OPROMINENNIa NA GEMOPOETYChNI KLITYNY-POPEREDNYKY U GELEVYKh DYFUZIINYKh KAMERAKh ZA DOPOMOGOIu MATEMATYChNOGO MODELIuVANNIa.

OBJECTIVE: determining of the functional activity of mice bone marrow hematopoietic progenitor cells, cultivated in gel diffusion chambers, on the stages of hematopoiesis recovery after their prolonged irradiation in the lethal dose in a comparative aspect with the method of colony forming in spleen using mathematical model. MATERIALS AND METHODS: The method of cell cultivation in gel diffusion chambers, cytological methods, mathematical modeling, and statistical methods of research were used. Bone marrow samples extracted from the femur of mice irradiated with a total dose of 8 Gy with a power 0.0028 Gy/min were cultivated in diffusion chambers with semi solid agar in the abdominal cavity of CBA recipient mice. RESULTS: Comparative analysis of the colonyforming efficiency of progenitor cells (CFU) was carried out during cultivation in gel diffusion chambers in the process of hematopoiesis recovery for 30 days, as well as in the spleen of lethally irradiated animals, in accordance with the mathematical model. Analysis of colony forming kinetics in gel diffusion chambers after prolonged exposure to ionizing radiation indicated the biphasic nature of hematopoiesis recovery. Thus, in the first few days after the irradiation a drop in the number of CFU is observed compared to the control, which continues until the 9th day. Subsequently there is a sharp increase in the number of CFU in cell culture, which continues until the complete recovery of hematopoiesis. The obtained data, recalculated per mouse femur, correspond to the results of colony forming in the spleen of irradiated animals, described by K. S. Chertkov and taken as a basis while developing our mathematical model, as well as to its parameters, which describe the process of hematopoiesis recovery. CONCLUSIONS: Conformity of the indices obtained during the cultivation using the method of gel diffusion chambers of mice bone marrow prolongedly irradiated at a total dose of 8 Gy with a power 0.0028 Gy/min, to the results of colony forming in spleen of lethally irradiated mice, which were the basis for mathematical model development, is the evidence of the feasibility of using a mathematical model to assess the process of hematopoiesis recovery by progenitor cells of different maturation levels, and the experimental approach of CFU growing in gel diffusion chambers can be considered as an additional method of researching the hematopoiesis recovery along with the spleen colony method.

STEREOTYPED CASES IN UKRAINIAN COHORT OF CHRONIC LYMPHOCYTIC LEUKEMIA PATIENTS DEPENDING ON THE IONIZING RADIATION EXPOSURE. / STEREOTYPNI VYPADKY V UKRAÏNS'KII KOGORTI KhVORYKh NA KhRONIChNU LIMFOTsYTARNU LEIKEMIIu ZALEZhNO VID VPLYVU IONIZUIuChOGO VYPROMINIuVANNIa.

OBJECTIVE: to analyze the stereotyped subsets in cohort of Ukrainian chronic lymphocytic leukemia (CLL) patients in general and depending on the ionizing radiation (IR) exposure. METHODS: Analysis was performed in the groups of 118 CLL patients irradiated due to the Chornobyl NPP accident (95 clean-up workers, 17 inhabitants of radionuclide contaminated areas, and 6 evacuees) and 294 IR non-exposed patients. The IGHV (immunoglobulin heavy chain variable region) gene mutational status, mutations of NOTCH1, TP53 and SF3B1 genes were studied by polymerase chain reaction followed by direct sequencing. Associations between clinical and molecular data of patients were analyzed with the SPSS software package, version 20.0. RESULTS: The incidence of stereotyped CLL cases in Ukrainian cohort was high (50.5 %) and comparable in IR-exposed and non-exposed patients. The ratio of major and minor clusters as well as the frequency of individual clusters was comparable with reported data with some exceptions: a low incidence of subset #2; absence of subset #8; high frequency of minor subset #V4|J4.5.6|18|5. The distinctive features of IR-exposed CLL patients found were:1) comparable frequency of stereotyped cases among mutated and unmutated (UM) IGHV genes cases (p = 0.557);2) lack of differences IGHV gene repertoires among stereotyped and heterogeneous cases (p = 0.508); 3) «heterogeneity¼ of stereotyped cases: all identified stereotyped clusters, with the exception of cluster #1, consisted of one case. Stereotyped cases with expression of UM IGHV clan I genes (except IGHV1-69 gene) were more susceptible to the appearance of NOTCH1 mutations. Patients of cluster #4 were younger, tended to have a longer time-to-treatment period and overall survival (OS) compared to subset #2. Patients of cluster #2 are more likely to have autoimmune hemolytic anemia (AIHA) and SF3F1 mutations. IGHV3-21 expression was associated with worse OS in univariate and multivariate analysis. AIHA was more common in patients with UM IGHV4-59 and IGHV3-11 genes. CONCLUSIONS: The revealed differences in distribution of stereotyped CLL cases in Ukrainian cohort are most likely to reflect variations in the genetic background, environmental factors (including IR exposure), and their interactions in different geographic areas.

CHRONIC MYELOID LEUKEMIA COURSE IN PERSONS EXPOSED TO IONIZING RADIATION AS A RESULT OF THE CHORNOBYL ACCIDENT. / PEREBIG KhRONIChNOÏ MIIeLOÏDNOÏ LEIKEMIÏ U OSIB, IaKI ZAZNALY DIÏ IONIZUIuChOGO VYPROMINIuVANNIa VNASLIDOK ChORNOBYL'S'KOÏ AVARIÏ.

OBJECTIVE: Describe and characterize the peculiarities of the chronic myeloid leukemia (CML) course and responseto treatment in patients irradiated as a result of the Chornobyl nuclear power plant (ChNPP) accident based on theassessment of clinical-laboratory and clinical parameters. MATERIALS AND METHODS: The CML patients (n = 33) exposed to ionizing radiation as a result of the ChNPP accidentwere enrolled. The comparison group consisted of CML patients (n = 725) with no history of radiation exposure. Allpatients were in the chronic phase of the disease. Clinical, hematological and molecular genetic research methodswere applied. RESULTS: Patients exposed to ionizing radiation as a result of the ChNPP accident had no differences in CML manifestation, as well as in classical genetic markers at the onset of the disease compared with patients with no historyof radiation exposure. Reduction of tumor clone on imatinib therapy was significantly less effective in the patientsexposed to ionizing radiation than in cases of no history of radiation exposure. Cases of primary resistance were statistically significantly prevalent in the ChNPP accident consequences clean-up workers while in the residents ofradiologically contaminated areas a statistically significant increase in probability of loss of complete cytogeneticresponse (development of secondary resistance) to imatinib therapy was found. An association was found betweenthe radiation exposure and probability of loss of complete cytogenetic response to imatinib therapy in this group ofpatients. CONCLUSION: The radiation exposure in the history even many years before the onset of CML is an unfavorable exogenous factor responsible for the development of resistance to imatinib therapy.

Analysis of immunoglobulin heavy variable chain rearrangement in chronic lymphocytic leukemia patients among Chornobyl clean-up workers.

BACKGROUND: A number of epidemiological studies have shown an elevated radiation-associated risk for chronic lymphocytic leukemia (CLL). The aim of the paper was to analyze immunoglobulin heavy variable chain (IGHV) rearrangement and IGHV usage in CLL cases associated with ionizing radiation (IR) exposure. MATERIALS AND METHODS: Samples of 76 clean-up workers of Chornobyl Nuclear Power Plant accident of 1986 (the main group) and 194 non-exposed patients (the control group) were analyzed. Two groups of CLL patients were comparable by gender (all patients were male), age, and place of residence (rural or urban). RESULTS: Some features of IR-associated CLL cases as compared to CLL cases in patients without history of IR exposure were revealed. Among unmutated IGHV sequences, IGHV1 genes were less commonly used (29.4% vs 48.6%; p = 0.018), while the frequency of IGHD6 genes was higher (23.5% vs 10%; p = 0.029). The unmutated IGHV sequences did not use IGHD3-16 gene (0% vs 7.9%, p = 0.038). Mutated IGHV sequences were less frequently expressed IGHV3 genes (44% vs 68.5%; p = 0.037) due low representation of IGHV3-21 (4% vs 11.1%) and IGHV3-23 (0% vs 11.1%) genes; did not use IGHD3-22 gene (0% vs 18.5%, p = 0.025); and have signs of positive selection in the HCDR regions (Σ = 0.5029 ± 0.155 vs -0.0539 ± 0.14; p = 0.013). CONCLUSIONS: The revealed differences in IGHV gene usage and B-cell receptor structure in the main and the control groups of CLL patients indirectly indicate a change in the spectrum of antigens associated with CLL under IR exposure. The possible antigenic drivers associated with CLL associated with IR exposure are discussed.

THE INCIDENCE OF MULTIPLE MYELOMA IN THE DNIPROPETROVSK REGION. / ZAKhVORIuVANIST' NA MNOZhYNNU MIIeLOMU V DNIPROPETROVS'KIY̆ OBLASTI.

OBJECTIVE: To conduct a comparative analysis of the incidence of MM in the population of the Dnipropetrovsk region, taking into account the possible impact of various adverse environmental factors (air, water and soil con- tamination). MATERIALS AND METHODS: Epidemiological indicators of multiple myeloma (MM) morbidity in the 12-year observation period from 2006 to 2017 are analyzed in polluted and conventionally clean areas of the Dnipropetrovsk region. RESULTS: In assessing the dynamics of morbidity in MM for years 2006-2017 there was an increase in the incidence in 2011, 2015 and quite stable indicators for 2006-2010. The analysis of morbidity in the industrial cities of the region showed consistently high rates for the entire period of observation. A marked increase in the incidence rate in the Zhovti Vody (2007, 2012, 2016), Nikopol (2016), Novomoskovsk (2016), Marganets (2008, 2009 and 2017), Pokrov (2016, 2017) from 4.35 to 6.25 was noted. This may indicate a fluctuation in the incidence of MM in sepa- rate large cities of Dnipropetrovsk. The analysis of the dynamics of morbidity in the most polluted cities showed a clear increase in the number of cases in the MM in Zhovti Vody, which is characterized by radiation pollution. According to the average annual morbidity rate among cities of Dnipropetrovsk region, Pokrov takes the first place, the second - Zhovti Vody. CONCLUSIONS: The obtained data testify to the fluctuation in the incidence of MM in the Dnipropetrovsk region during the period 2006-2017 and the negative environmental factors clearly affect the growth of morbidity in large industrialized cities contaminated with radioactive and chemical substances.

THE SPECTRUM OF TP53, SF3B1, AND NOTCH1 MUTATIONS IN CHRONIC LYMPHOCYTIC LEUKEMIA PATIENTS EXPOSED TO IONIZING RADIATION DUE TO THE CHORNOBYL NPP ACCIDENT. / SPEKTR MUTATsII GENIV TP53, SF3B1 ta NOTCH1 U KhVORYKh NA KhRONIChNU LIMFOTsYTARNU LEIKEMIIu, IaKI ZAZNALY VPLYVU IONIZUIuChOGO VYPROMINENNIa VNASLIDOK AVARIÏ NA ChORNOBYL'S'KII AES.

OBJECTIVE: to analyze TP53, NOTCH1 and SF3B1 mutations in chronic lymphocytic leukemia (CLL) patients, sufferersof Chornobyl NPP accident to clarify the possible relationship between ionizing radiation (IR) and CLL. METHODS: Mutations of TP53, NOTCH1, and SF3B1 genes were studied by direct sequencing in the main group of 106 CLLpatients exposed to IR due to Chornobyl NPP accident and in the control group of 130 IR non-exposed CLL patients. RESULTS: We found TP53 and SF3B1 mutations with similar incidence in both groups - 11.3 % and 10.0 % in the maingroup, and 12.7 % and 11.5 % in the control group, respectively. In contrast, the frequency of NOTCH1 mutationswas lower in IR-exposed patients (6.7 % vs 17.7 %; p = 0.012). TP53 mutations were seen with equal frequency amongmutated (11.1 %) and unmutated (11.8 %) immunoglobulin heavy-chain variable gene (IGHV) cases in IR-exposedCLL patients, while the tendency to prevalence of TP53 mutations in unmutated compared with mutated IGHV caseswas found in the control group (14.1 % and 5.6 %, correspondingly; p = 0.178). In IR-exposed group SF3B1 muta-tions were combined with mutations in TP53 almost in half of detected cases. In opposite, in the control group therewas mutual exclusivity between SF3B1 and TP53 lesions (p = 0.001). Among IR-exposed CLL patients we found two dif-ferent cases with identical rare mutation of TP53 gene - c.665C>T substitution (Pro222Leu). This substitution is verylikely to represent inherited TP53 mutation, which may influence CLL development under IR exposure. CONCLUSION: Our preliminary data suggest that TP53 abnormalities are involved in CLL development in subjectsexposed at the Chornobyl accident and also a possible connection between inherited sensitivity to ionizing radia-tion caused by mutation in TP53, radiation and CLL development.

CASE OF DEVELOPMENT OF NON-HODGKIN'S MALIGNANT LYMPHOMA ON THE BACKGROUND OF CHRONIC MYELOID LEUKEMIA IN A PATIENT WHO SUFFERED OF THE CHORNOBYL ACCIDENT. / VYPADOK ROZVYTKU NEKhODZhKINS'KOÏ ZLOIaKISNOÏ LIMFOMY NA FONI KhRONIChNOÏ MIIeLOÏDNOÏ LEIKEMIÏ U PATsIIeNTKY, IaKA POSTRAZhDALA VNASLIDOK AVARIÏ NA ChAES.

In this paper, a clinical case of combination of chronic myeloid leukemia and T-lymphoblastic lymphoma is present-ed, which is currently a rather rare finding for a clinician. The diagnosis of T-lymphoblastic lymphoma is establishedafter 2 years from the verification of chronic myeloid leukemia. The course of diseases and approaches to treatmentare described.The pathogenetic relationship between myeloid and lymphoid diseases remains unclear and is likely to be the resultof several factors - radiation, chemical and, consequently, genetic disorders.

Analysis of the 3'UTR region of the NOTCH1 gene in chronic lymphocytic leukemia patients.

Deregulation of NOTCH1-signalling pathway is common in chronic lymphocytic leukemia (CLL). The most of studies are focused on detection of the hotspot c.7541_7542delCT NOTCH1 mutations in exon 34, while studies of mutations in the 3'UTR region are rare. The aims of work were to evaluate the frequencies of mutations in the 3'UTR region of the NOTCH1 gene (9:136,495553-136,495994) in Ukrainian CLL patients, the distribution of rs3124591 genotypes located in that area, and association of NOTCH1 mutations with structure of B-cell receptor. MATERIALS AND METHODS: Detection of mutations in the 3'UTR region of the NOTCH1 was performed by direct sequencing in 87 previously untreated CLL patients (from the total group of 237 CLL patients) with unmutated immunoglobulin heavy-chain variable (UM IGHV) genes and without mutations in hotspot regions of TP53, SF3B1, and exon 34 of NOTCH1 genes. RESULTS: Mutations in the 3'UTR region of the NOTCH1 were revealed in three of 87 CLL patients (3.4%). Two cases with non-coding mutations were related to subset #1 of stereotyped B-cell receptors, and one case belonged to stereotyped subset #28a. Analysis with inclusion of 30 UM IGHV cases with previously detected c.7544_7545delCT mutations revealed that the frequency of UM IGHV genes of I phylogenetic clan (except IGHV1-69) was significantly increased, and the frequency of UM IGHV3 and IGHV4 genes, on the contrary, was reduced in NOTCH1-mutated cases comparing with NOTCH1-unmutated cases (p = 0.002) and the general group (p = 0.013). SNP rs3124591 did not affect the risk of CLL and survival parameters of the patients. At the same time, differences were found in the frequency of IGHV gene usage and in the structure of HCDR3 in carriers of individual genotypes. CONCLUSION: The frequency of NOTCH1 mutations in 3'UTR region was low. Our findings confirmed current data on the association between the structure of the B-cell receptor and the appearance of NOTCH1 mutations. Some features of HCDR3 structure were identified in carriers of TT and CC genotypes of rs3124591.

Detection of NOTCH1 c.7541_7542delCT mutation in chronic lymphocytic leukemia using conventional and real-time polymerase chain reaction.

UNLABELLED: To evaluate real-time polymerase chain reaction (PCR) assay system for detection of NOTCH1 c.7541_754delCT mutation in chronic lymphocytic leukemia (CLL) patients. MATERIAL AND METHODS: A total of 325 CLL patients were included in the study. Screening for NOTCH1 c.7544_7545delCT was performed using conventional PCR-based amplification refractory mutation system (ARMS) method. All 33 samples harboring c.7544_7545delCT allele and 5 negative cases as control were submitted to real-time PCR. RESULTS: Specificity and sensitivity of two PCR techniques were comparable. NOTCH1 c.7544_7545delCT mutation was found by ARMS in 10.1% of CLL patients, which is consistent with the data of other studies. However, the results of ARMS PCR in a minority of cases (2.15%) were doubtful and required reinvestigation. Real-time PCR, being less time-consuming, showed advantage in the assessment of the amplification's specificity (using the melting curve analysis). It also allows the quantitative assessment of NOTCH1-mutated clone. CONCLUSION: NOTCH1 c.7544_7545delCT mutation resulting in removal of the C-terminal PEST domain, deregulation of NOTCH1-dependent signaling pathways, has negative influence on prognosis of CLL and efficiency of therapy with anti-CD20 monoclonal antibodies. Real-time PCR allows the fast and reliable detection of c.7544_7545delCT mutation and can be used for the screening of this molecular lesion in CLL patients.

The distribution of TP53 gene polymorphisms in chronic lymphocytic leukemia patients, sufferers of Chornobyl nuclear power plant accident.

Previous analyses in a cohort of Chornobyl cleanup workers revealed significantly increased radiation-related risk for all leukemia types, including chronic lymphocytic leukemia (CLL). Numerous investigations emphasized the significance of genetic susceptibility to the radiation carcinogenesis. The aim of the work was to study the distribution of TP53 single nucleotide polymorphisms (SNPs) in CLL patients exposed to ionizing radiation (IR) due to Chornobyl nuclear power plant accident and estimate their impact on disease development. MATERIALS AND METHODS: The TP53 exonic and intronic SNPs were analyzed in 236 CLL patients by polymerase chain reaction and direct sequencing. The main group included 106 IR exposed CLL patients and thecontrol group was composed of 130 IR non-exposed CLL patients. RESULTS: Nineteen TP53 SNPs were found in the observed CLL cohort. No significant differences were found between the main and the control groups, but increased frequencies of T/T rs12947788 + G/G rs12951053 homozygotes and rs146340390 C/T variants were found among IR-exposed CLL patients compared with healthy Europeans (data from the 1000 Genomes Project). Rare nucleotide substitution rs146340390 (c.665C>T) was found only in the main group. These features were primarily typical for the most affected group of IR-exposed patients, namely, cleanup workers engaged in emergency works in the 2nd quarter of 1986. CONCLUSION: These preliminary findings don't contradict the assumption on possible influence of IR on CLL development via the p53-dependent pathway. This article is a part of a Special Issue entitled "The Chornobyl Nuclear Accident: Thirty Years After".

Circulating hematopoietic progenitor cells in patients affected by Chornobyl accident.

High radiation sensitivity of stem cells and their ability to accumulate sublethal radiation damage provides the basis for investigation of hematopoietic progenitors using in vivo culture methodology. Unique samples of peripheral blood and bone marrow were derived from the patients affected by Chornobyl accident during liquidation campaign. AIM: To investigate functional activity of circulating hematopoietic progenitor cells from peripheral blood and bone marrow of cleanup workers in early and remote periods after the accident at Chornobyl nuclear power plant (CNPP). MATERIALS AND METHODS: The assessment of the functional activity of circulating hematopoietic progenitor cells was performed in samples of peripheral blood and bone marrow of 46 cleanup workers, who were treated in the National Scientific Center for Radiation Medicine of the Academy of Medical Sciences of Ukraine alongside with 35 non radiated patients, who served as a control. Work was performed by culturing peripheral blood and bone marrow mononuclear cells in the original gel diffusion capsules, implanted into the peritoneal cavity of CBA mice. RESULTS: It was shown that hematopoietic progenitor cells could be identified in the peripheral blood of liquidators of CNPP accident. At the same time the number of functionally active progenitor cells of the bone marrow was significantly decreased and during the next 10 years after the accident, counts of circulating progenitor cells in the peripheral blood as well as functionally active hematopoietic cells in bone marrow returned to normal levels. CONCLUSION: It was shown that hematopoietic progenitor cells are detected not only in the bone marrow but also in the peripheral blood of liquidators as a consequence of radiation exposure associated with CNPP accident. This article is a part of a Special Issue entitled "The Chornobyl Nuclear Accident: Thirty Years After".

Assessment of response to imatinib therapy in patients with chronic myeloid leukemia with e13a2 and e14a2 transcripts of BCR/ABL1 gene. / OTsINKA VIDPOVIDI NA TERAPIIu IMATYNIBOM U PATsIIeNTIV Z KhRONIChNOIu MIIeLOIDNOIu LEYKEMIIeIu Z E13A2 TA E14A2 TRANSKRYPTAMY GENA BCR/ABL1.

OBJECTIVE: Assess the influence of e13a2 and e14a2 transcripts of BCR/ABL1 gene on the efficiency of imatinib ther apy in patients with chronic myeloid leukemia. MATERIALS AND METHODS: We examined 508 patients with the chronic phase of chronic myeloid leukemia without radi ation in anamnesis as well as 13 patients with the similar diagnosis and with confirmed presence of radiation expo sure due to the Chornobyl Nuclear Power Plant accident. RESULTS: No significant differences in hematologic parameters, rate of additional chromosomal aberrations and f vari ant translocations were observed between patients with е13а2 and е14а2 transcript. Cumulative probability of com plete cytogenetic response did not differ in patients with е13а2 and е14а2 transcript and was 76 and 80 % respec tively (р = 0,981). Median of achieving a complete cytogenetic response was 20 months in both patient groups. Significantly more patients with e14a2 transcript compared to patients with e13a2 achieved major molecular response by 12 month of therapy (61.5 % versus 23.0 %, p = 0.016). The higher incidence of deep molecular response by 24 month of therapy was revealed in this group (38.7 % versus 6.25 %, p = 0.018). The overall survival and pro gression free survival rates were not statistically different between two groups with different transcripts. However, the rate of event free survival was statistically lower for the patients with e13a2 transcript compared to the ones with e14a2 transcript (51 % versus 62.0 %, p = 0.039). The number of primary resistant patients was 40 % regardless of the transcript expressed. A significant prevalence in incidence either of lost complete cytogenetic response or fail ure of the major molecular response was shown in patients with e13a2 transcript compared to patients with e14a2 transcripts (43.5 % versus 24.8 %, p = 0.015). CONCLUSION: Imatinib therapy is more effective for CML patients with e14a2 transcript compared to patients with e13a2 transcript expression. The transcript e13a2can be viewed as a adverse prognostic factor for imatinib therapy of chronic myeloid leukemia.

Functional activity of CD34-positive cells in chronic myeloid leukemia patients with different response to imatinib therapy.

INTRODUCTION: It is believed that the reason of the leukemic clone cell resistance to treatment with tyrosine kinase inhibitors during chronic myeloid leukemia (CML) is mutations in the genome of an early bone marrow progenitor cells that are CD34-positive. Such cells, regardless of treatment, acquire ability to proliferation and differentiation. This leads to the re-expansion of the CD34(+) cells. AIM: to determine the CD34 antigen expression in bone marrow and peripheral blood cells in CML patients with different response to imatinib therapy using the results of hematopoietic cells culturing and the data of flow cytometry. METHODS: Bone marrow aspirate from 39 patients who were treated with imatinib was studied with cytogenetic, flow cytometry and culture methods in vitro. RESULTS: In patients with an optimal response to imatinib therapy the number of colonies was 1.8 times lower than the number of those in the group of patients with a suboptimal response to therapy. In turn, in patients with failure of imatinib therapy the number of colonies was the highest and was 2.1 times higher than the patients with optimal response. The results of cytometric studies have shown that the number of CD34(+) cells in bone marrow was significantly higher compared to the number of CD34(+) cells in peripheral blood cells and increased with the acquisition of leukemic cells the resistance to imatinib. There was a direct correlation between the number of colonies and clusters in semisolid agar in vitro and the number of CD34(+) cells in the bone marrow of patients. CONCLUSIONS: The correlation between the number of CD34(+) cells and the number of cell aggregates in semisolid agar in vitro indicates the prognostic value of the method for determining CD34(+) cells in the patient bone marrow. The parallel increase of their number in the peripheral blood will allow developing express methods for the detection of individual patient response to imatinib therapy.

TP53 codon 72 single nucleotide polymorphism in chronic lymphocytic leukemia.

UNLABELLED: Defects in the tumor suppressor gene TP53 are known to be important in chronic lymphocytic leukemia (CLL) and TP53 inactivation is associated with a particularly aggressive form of the disease. The single nucleotide polymorphism in the TP53 gene at codon 72 (rs1042522), results in amino acid substitution influencing apoptotic potential of TP53 protein. The aim of the study was to evaluate the association of the TP53 codon 72 polymorphism and incidence of TP53 mutations in CLL patients. METHODS: 261 CLL samples were analyzed by polymerase chain reaction and direct sequencing for TP53 mutations and single nucleotide polymorphism. RESULTS: The 72Pro/Pro genotype was associated with an increased incidence of TP53 mutations in previously treated patients (OR = 2.503; 95% CI 1.142-5.487; р = 0.001). CONCLUSION: This study revealed that the TP53 codon 72 polymorphism may be used as a risk factor for incidence of TP53 mutations in CLL.

Gene polymorphisms of p53-mediated apoptosis in chronic lymphocytic leukemia patients: features of distribution depending on radiation factor in anamnesis. / Polimorfizmy geniv r53-oposeredkovanogo apoptozu u hvoryh na hronichnu limfocytarnu lejkemiju: osoblyvosti rozpodilu zalezhno vid radiacijnogo chynnyka v anamnezi.

Objective. To set of p53-mediated apoptosis gene polymorphisms (TP53 codon 72 Arg/Pro, р21 codon 31 Ser/Arg, MDM2 SNP309) for the occurrence of CLL in patients who were exposed to ionizing radiation (IR) from the Chornobyl accident. Methods. Polymorphisms of p53-mediated apoptosis were determined in 320 patients with CLL of B-cell origin: 107 irradiated by the Chornobyl accident patients, 213 patients with CLL who had no history of exposure to IR, 73 individuals without a cancer and hematologic diseases that were affected by the Chornobyl disaster and 72 residents of Kyiv without affecting by IR in anamnesis. Determination of polymorphisms of p53-mediated apoptosis was performed by polymerase chain reaction followed by restriction. Results. The distribution of genotypes in patients with CLL did not differ from controls, except for reduced the frequency of homozygotes Arg/Arg TP53 among patients with CLL (p = 0.01). Compared with non-irradiated CLL patients in the subgroup of patients affected by the accident, an increase in the frequency of polymorphic alleles of the gene р21 (p = 0.033) was found, especially in combination with Arg allels (genotypes Arg/Arg and Arg/Pro) of TP53 gene and genotype TT SNP309 of MDM2 gene (p = 0.009). Conclusion. Preliminary studies indicated the likely contribution of rs1801270 polymorphism of the gene р21 in the pathogenesis of CLL in patients who had been exposed to IR. The effects of SNPs rs1042522 of TP53 gene and SNP309 of MDM2 gene on the risk of CLL in the Chornobyl accident sufferers were not revealed.

The efficiency of tyrosine kinase inhibitor therapy in patients with chronic myeloid leukemia exposed to ionizing radiation due to the Chornobyl nuclear power plant accident. / Efektyvnist'' terapii' ingibitoramy tyrozynkinaz pacijentiv z hronichnoju mijeloi'dnoju lejkemijeju, jaki zaznaly vplyvu ionizujuchogo vyprominjuvannja vnaslidok avarii' na Chornobyl''s''kij AES.

Objective. To study the efficiency of tyrosine kinase inhibitors (TKI) therapy in patients with chronic myeloid leukemia (CML) exposed to ionizing radiation due to the Chornobyl NPP accident, based on the data of cytogenetic and molecular monitoring. Material and methods. 29 CML patients with confirmed radiation exposure due to Chornobyl NPP accident were examined. Of these, 20 patients were treated with imatinib; 103 patients with CML without radiation history treated with TKI were a comparison group. Cytogenetic and molecular genetic disturbances before and on the different stage of TKI therapy were analysed. Results. Additional chromosomal abnormalities as well as special pattern of BCR/ABL transcripts were not revealed in CML patients exposed to ionizing radiation. Complete cytogenetic response (CCR) was shown in 50 and 48.5 % of patients from study and comparison group, respectively. Major molecular response (MMR) was achieved in 20 % of patients with radiation exposure in anamnesis and in 27.6 % of patients from comparison group. The vast majority of CCR and MMR was reached in patients with the pretreatment term up to 6 months, when imatinib was used as a first line therapy. There were less cases of primary imatinib resistance in the same group of patients. In CML patients who had a history of radiation exposure, secondary resistance developed more frequently than in the comparison group and was 25 %. Conclusion. Laboratory monitoring based on the registration of CCR and MMR demonstrated high efficiency of TKI in the CML treatment of patients, exposed due to Chornobyl accident. Extension of pretreatment term leads to the loss of TKI therapy efficiency and increases the likelihood of primary resistance. CML patients exposed to ionizing radiation develop secondary resistence more often than CML patients without radiation exposure in anamnesis.

Determination of the optimal chemotherapy drugs pretreatment time through cultivation of hemopoietic cells in CML-patients treated with tyrosine kinase inhibitors.

BACKGROUND: Targeted therapy drugs, including imatinib, are used for inhibiting the marker oncoprotein of chronic myeloid leukemia - BCR-ABL tyrosine kinase. However, in some patients the drug resistance can emerge too rapidly and a previous treatment with chemotherapy drugs can lead to formation of resistance. AIM: To evaluate the influence of drugs that were used prior to the imatinib on the performance of the functional activity of bone marrow cells from chronic myeloid leukemia patients and their individual responses to therapy. METHODS: Bone marrow aspirate from 57 patients, who were getting busulfan (19 patients) or hydroxycarbamide (38 patients) prior to imatinib was studied with cytogenetic and tissue culture methods in vitro. RESULTS: Obtained data suggested that pretreatment with busulfan, regardless of duration, negatively affects the response to further therapy with imatinib. Instead, after using hydroxycarbamide as a previous therapy for six month, there was optimal response to imatinib. In those cases when duration of pretreatment with hydroxycarbamide was increased to a year or more, there was a suboptimal response and a resistance to imatinib therapy. In addition, there was a positive correlation between the number of cell aggregates (colonies and clusters) in semisolid agar and the duration of a prior treatment with hydroxycarbamide, if previous therapy did not exceed 20 months. With an increase of pretreatment terms to 21 months or more, such a correlation was not observed. CONCLUSIONS: These results suggest that chemotherapeutic agents (busulfan and hydroxycarbamide) may additionally contribute to the accumulation of mutations in the genome of leukemic cell clone affecting the behavior of these cells in vitro.

Multiple myeloma among Chornobyl accident clean-up workers - state and perspectives of analytical study.

UNLABELLED: The objective of the study was to analyze the Multiple Myeloma (MM) incidence in clean-up workers preparing the information background for consequent analytical study with a dose-dependent risk estimates. MATERIALS AND METHODS: The Cohort Database was linked to the Ukrainian National Cancer Registry to identify the MM cases in a cohort of 152 520 male clean-up workers. RESULTS: The 64 MM cases were identified in the studied Cohort for the 1987-2012 period. Fifty-eight of them were included to the preliminary incidence analysis accounting for the 10-years lag-period. According to the preliminary data analysis the MM incidence rate in studied clean-up workers Cohort did not exceed the corresponding rate in general population of Ukraine along the 21 years after the catastrophe. CONCLUSIONS: Standardized incidence ratio for the 2008-2012 period, that is 22-26 years after the accident, demonstrated the significant excess of MM incidence among male clean-up workers in comparison with general population of Ukraine of corresponding age and gender (SIR 1.61, 95% CI 1.01;2.21).