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.

IMMUNOPHENOTYPE OF LEUKEMIC CELLS IN CHRONIC LYMPHOCYTIC LEUKEMIA PATIENTS WITH NOTCH1 AND SF3B1 GENE MUTATIONS.

BACKGROUND: The typical chronic lymphocytic leukemia (CLL) immunophenotype is vital for diagnosis, but the expression of some antigens varies and has prognostic value. There are data that reduced CD20 expression is associated with NOTCH1 and SF3B1 gene mutations. AIM: To determine a high-risk group of CLL patients for prediction of unfavorable NOTCH1 and SF3B1 gene mutations based on immunophenotyping of leukemic cells. MATERIALS AND METHODS: Flow cytometric and molecular-genetic analysis (mutations of NOTCH1, SF3B1, and TP53 genes using the polymerase chain reaction followed by direct sequencing) was performed in a group of 86 previously untreated CLL patients. RESULTS: The immunophenotype of leukemic cells of all examined patients met the criteria of CLL diagnosis. NOTCH1 gene mutations were found in 21 patients (24.4%), and SF3B1 gene mutations - in 7 patients (8.1%). There were no TP53 gene mutations among the examined patients. A decreased number of CD20+CD5+ cells and a downward trend in the relative index of mean fluorescence intensity (iMFI) of CD20+ cells were found in patients with NOTCH1 and SF3B1 gene mutations. Based on the iMFI level (higher and/or lower than 3.0) and the number of CD20+CD5+ cells among all B-cells (higher and/or lower than 50%), we distinguished CLL cases with low and relatively high levels of CD20 antigen expression. Using ROC analysis and the parameter of low CD20 antigen expression, we could predict the presence of NOTCH1 and SF3B1 gene mutations in 73.3 ± 0.06% of patients (p = 0.001). The risk of NOTCH1 and SF3B1 gene mutations in cases with low CD20 antigen expression was 6.96 (95% CI = 2.53-19.18; p = 0.0001). The revealed regularities were statistically significant for patients in whom the diagnosis was established in all Binet - Rai stages except A0-AI. CONCLUSION: Our data confirmed a reduced CD20 expression in CLL patients with NOTCH1 and SF3B1 mutations. In addition, an approach was proposed to identify high-risk CLL patients for prediction of such mutations: previously untreated CLL patients at advanced Binet - Rai stages (BII, CIII, CIV) with a reduced number of double-positive CD20+CD5+ cells in peripheral blood and/or low iMFI of CD20+ cells.

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.

EXPRESSION OF IMMUNOGLOBULIN SEQUENCES HOMOLOGOUS TO ANTI-SARS-CoV-2 ANTIBODIES AND HIV IN CHRONIC LYMPHOCYTIC LEUKEMIA CASES.

BACKGROUND: Identification of epitopes recognized by leukemic B cells could provide insights into the molecular mechanisms of B cell transformation in chronic lymphocytic leukemia (CLL). The aim of this paper was to compare nucleotide sequences of immunoglobulin heavy chain variable region (IGHV) genes in CLL with known sequences directed against antigens of different origins available in public databases. MATERIALS AND METHODS: Analysis was performed in the groups of 412 unselected CLL patients with productive IGHV gene using polymerase chain reaction followed by direct sequencing. RESULTS: Homology between CLL Ig sequences and antibodies directed against autoantigens was found in 12 patients (2.9%), homology between CLL Ig sequences and antiviral antibodies - in 35 patients (8.5%). Most of these sequences belonged to stereotypical clusters. Among the sequences that have homology to antiviral antibodies, the most prevalent were cases homologous with antibodies against HIV (14 cases, 3.4%) and SARS-CoV-2 antigens (10 cases, 2.4%). None of the patients in our cohort was HIV-infected and the study was conducted before the emergence of SARS-CoV-2 virus. CONCLUSIONS: Suggestions could be made about the possible impact of past infection of SARS-CoV-2 virus on the pathogenesis of CLL. In particular, an increase in the proportion of CLL cases with the expression of some stereotyped BCR and/or an increase of CLL risk in the long-term period after SARS-CoV-2 virus infection is not excluded. This assumption needs to be verified by epidemiological data.

Association of lipoprotein lipase expression with TP53 gene polymorphisms in chronic lymphocytic leukemia cells.

BACKGROUND: Expression of lipoprotein lipase (LPL) correlates with unmutated (UM) status of the variable region of the heavy chain of immunoglobulin (IGHV) genes, but the expression level of LPL in UM chronic lymphocytic leukemia (CLL) cases varies significantly. AIM: To study the association of LPL expression with the genetic variants of the TP53 gene since both genes are involved in lipid metabolism. MATERIALS AND METHODS: Expression of LPL mRNA was measured in peripheral blood mononuclears of 45 CLL patients with UM IGHV genes by real-time quantitative reverse transcription polymerase chain reaction. Mutational status of IGHV genes and TP53 genotyping (rs1042522, rs1642785, rs17883323, rs2909430, rs145153611, rs113530090, rs12947788, rs12951053, and rs17878362) were performed by polymerase chain reaction amplification followed by direct sequencing. RESULTS: Observed CLL patients were divided on groups with low (11.17 ± 2.66) and high (275.48 ± 39.37) LPL expression. In CLL patients with UM IGHV genes and low LPL expression we found an increased frequency of rs1042522 G (p = 0.0036), rs1642785 C (p = 0.0001), and rs17878362A2 alleles (p = 0.0091). The possible functional significance of these changes is discussed. CONCLUSION: Some polymorphic variants of TP53 may be genetic modifiers for LPL expression level in CLL leukemic B-cells. Further research is required in a larger cohort to confirm these findings.

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.

MYC copy number and mRNA expression in chronic lymphocytic leukemia patients exposed to ionizing radiation due to the Chornobyl NPP accident.

Some clinical and biological features indicating an unfavorable course of the disease were found in ionizing radiation (IR) - related chronic lymphocytic leukemia (CLL) patients. The MYC proto-oncogene is considered to contribute to CLL pathogenesis. Increased MYC copy number is associated with poor prognosis in CLL. AIM: To investigate the frequency of MYC gene copy number amplification in IR-exposed CLL patients and relate the findings to the MYC mRNA levels, the presence of unfavourable prognosis mutations (TP53, SF3B1, NOTCH1), and patient`s outcome. MATERIALS AND METHODS: The analysis of MYC copy number was carried out by real-time quantitative polymerase chain reaction (PCR) in 70 IR-exposed CLL patients. The MYC mRNA expression was measured by real-time quantitative reverse transcription PCR. RESULTS: Increased MYC gene copy number was present in 5.7% of cases. There was a statistically significant association between increased MYC copy number and increased MYC mRNA (p < 0.014). Additionally, somatic deletion in MYC locus was found in one patient. Most of patients (80%) with detected MYC aberrations were previously untreated, suggesting that these lesions might occur early in the course of the disease. The MYC aberrations were found mutually exclusive with high risk TP53 and SF3B1 mutations, while one case was identified, where MYC amplification and NOTCH1 mutation coincided simultaneously. Regarding clinical outcome, the MYC aberrations were associated with a shorter time to first treatment (3 vs 25 months, p = 0.008) as well as reduced overall survival (60 vs 139 months). CONCLUSION: Our data suggest that MYC aberrations might be an early event in IR-related CLL and contribute to aggressive disease development in the absence of high risk TP53 and SF3B1 mutations.

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.

Analysis of LPL gene expression in patients with chronic lymphocytic leukemia.

AIM: The IGHV mutational status is one of the most important markers for chronic lymphocytic leukemia (CLL) prognostication. Lipoprotein lipase (LPL) gene expression was found to correlate with IGHV status and was suggested as its surrogate marker. Recent data reported that LPL expression might be influenced by pivotal signalling pathways in CLL. This study aimed to assess LPL gene expression in relation to key immunogenetic and molecular markers of CLL, including IGHV mutational status, B-cell receptor (BCR) stereotypy, TP53, NOTCH1, and SF3B1 gene mutations. Materials and Methods: Expression of LPL mRNA was measured in peripheral blood mononuclear cells of 73 CLL patients by real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR). IGHV, NOTCH1, TP53, and SF3B1 gene mutation analysis was performed by PCR amplification and direct sequencing. RESULTS: 44 of 73 (60%) CLL cases were categorized as LPL-positive based on the cut-off value established by ROC (receiver operating characteristic) curve analysis. LPL expression was significantly associated with IGHV mutation status (r = 0.684; p < 0.0001) and tended to correlate with presence of NOTCH1 gene mutations (p = 0.113). BCR stereotyped cases showed higher LPL expression values in comparison to unstereotyped cases in the LPL-positive group of patients (p = 0.041). LPL expression was associated with a shorter overall survival in the entire СLL group (median 107 vs 143, p = 0.048) as well as in Binet A patients, albeit with borderline significance (median 139 vs not reached, p = 0.086). CONCLUSION: LPL expression was found to be closely correlated with IGHV gene mutational status and overall survival, proving LPL as prognostic marker in CLL. Our results also indicate a possible relationship between aberrant expression of LPL and BCR- and NOTCH1-dependent signalling pathways.

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.

Buccal mucosa micronuclei counts in relation to exposure to low dose-rate radiation from the Chornobyl nuclear accident and other medical and occupational radiation exposures.

BACKGROUND: Ionizing radiation is a well-known carcinogen. Chromosome aberrations, and in particular micronuclei represent an early biological predictor of cancer risk. There are well-documented associations of micronuclei with ionizing radiation dose in some radiation-exposed groups, although not all. That associations are not seen in all radiation-exposed groups may be because cells with micronuclei will not generally pass through mitosis, so that radiation-induced micronuclei decay, generally within a few years after exposure. METHODS: Buccal samples from a group of 111 male workers in Ukraine exposed to ionizing radiation during the cleanup activities at the Chornobyl nuclear power plant were studied. Samples were taken between 12 and 18 years after their last radiation exposure from the Chornobyl cleanup. The frequency of binucleated micronuclei was analyzed in relation to estimated bone marrow dose from the cleanup activities along with a number of environmental/occupational risk factors using Poisson regression adjusted for overdispersion. RESULTS: Among the 105 persons without a previous cancer diagnosis, the mean Chornobyl-related dose was 59.5 mSv (range 0-748.4 mSv). There was a borderline significant increase in micronuclei frequency among those reporting work as an industrial radiographer compared with all others, with a relative risk of 6.19 (95% CI 0.90, 31.08, 2-sided p = 0.0729), although this was based on a single person. There was a borderline significant positive radiation dose response for micronuclei frequency with increase in micronuclei per 1000 scored cells per Gy of 3.03 (95% CI -0.78, 7.65, 2-sided p = 0.1170), and a borderline significant reduction of excess relative MN prevalence with increasing time since last exposure (p = 0.0949). There was a significant (p = 0.0388) reduction in MN prevalence associated with bone X-ray exposure, but no significant trend (p = 0.3845) of MN prevalence with numbers of bone X-ray procedures. CONCLUSIONS: There are indications of increasing trends of micronuclei prevalence with Chornobyl-cleanup-associated dose, and indications of reduction in radiation-associated excess prevalence of micronuclei with time after exposure. There are also indications of substantially increased micronuclei associated with work as an industrial radiographer. This analysis adds to the understanding of the long-term effects of low-dose radiation exposures on relevant cellular structures and methods appropriate for long-term radiation biodosimetry.

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".

Incidence of multiple myeloma among cleanup workers of the Chornobyl accident and their survival.

The study presents the updated data on the multiple myeloma (MM) incidence in Ukrainian cleanup workers after the Chornobyl accident and their survival. The epidemiological analysis is based on the extended follow-up period to identify new MM cases for higher statistical power and to collect additional data on the disease course and outcome for the survival analysis. The objective of the study was to analyze the MM incidence and survival in Chornobyl cleanup workers in 1996-2013 in comparison with the national MM statistical data. MATERIALS AND METHODS: A study cohort consisted of 152,520 male cleanup workers resided in one of 6 regions of Ukraine or Kyiv city and registered in the Ukrainian State Chornobyl Registry (SChR). The Cohort Database was linked to the Ukrainian National Cancer Registry (NCR) Database to identify MM cases and to analyze MM incidence in 1996-2013. Standardized incidence ratios (SIR) for MM over the period 1996-2013 were calculated as compared to the general population of Ukraine. A 10-year lag period (when incident cases are not considered radiation-related) was applied. One-year and 5-year cause-specific survival of MM cases were calculated as percentage of those who were alive correspondingly for 1 or 5 years after diagnosis among overall diagnosed. By the moment, the 5-year survival rate either for the sub-period 2008-2013 or for the whole study period 1996-2013 cannot be determined. Vital status data were updated according to the recent SChR and NCR information. RESULTS: 75 MM cases diagnosed in 1986-2013 were identified in the studied cohort. 69 of them were included to the incidence analysis considering a 10-year lag period. While the incidence over 15 years after the accident did not differ significantly from the corresponding rate in general population of Ukraine, a tendency to increase was seen in the period from 16 to 21 years after the accident, and significantly increased SIR estimate was revealed for 2008-2013 (SIR 1.86, 95% confidence interval (CI) 1.27-2.44). The highest incidence was detected in 2008-2013 among cohort members diagnosed over the age of 50 years mostly due to the significant excess among those aged 60-69 (SIR 2.46, 95% CI 1.32-3.59). Survival rates in cleanup workers were shown to be higher than in the general population of Ukraine (73.9% and up to 65.0%, respectively). CONCLUSIONS: SIR for the 2008-2013 period, 22-27 years after the accident, demonstrated the significant excess of MM incidence among male cleanup workers. Survival of MM cases is higher in cleanup workers in comparison with that in general population. This article is a part of a Special Issue entitled "The Chornobyl Nuclear Accident: Thirty Years After".