Введение. Корректная оценка стадии и прогноза является основой успешного лечения любой опухоли. Цель — оценить роль ряда иммунологических параметров локального иммунитета при раке ободочной кишки (РОК) в зависимости от распространенности процесса и на основании полученных данных разработать комплексную модель для определения вероятности лимфогенного метастазирования опухоли. Материалы и методы. В работу включено 50 пациентов РОК: c поражением лимфатических узлов (N+) — 27 пациентов (54 %), без поражения (N0) — 23 пациента (46 %). Из ткани опухоли, перитуморальной зоны (1–3 см от опухоли), линии резекции (~10 см от опухоли) была получена клеточная суспензия для выявления основных субпопуляций лимфоцитов, а также определения экспрессии TLRs (2, 3, 4) на CD45+(лимфоцитах), CD45-EpCAM+ (эпителиальные клетки). Статистический анализ результатов исследования проводился с помощью программы STATISTICA 13.3. Результаты. В тканях опухоли у пациентов с N0 увеличено количество T-лимфоцитов, натуральных киллеров (NK). В перитуморальной зоне при N0 отмечено более низкое содержание CD19+, а при N+ — двойных позитивных лимфоцитов (ДП), NK (p < 0,05). Для тканей опухолей группы N0, в отличие от N+, характерно уменьшение количества опухолевых клеток, экспрессирующих TLR3. В перитуморальной зоне обеих групп отмечено разнонаправленное изменение количества клеток, которые экспрессируют TLR2: уменьшение — при N0, увеличение — при N+(p < 0,05). При анализе относительного количества лимфоцитов во фрагментах тканей первичных опухолей пациентов с N0 отмечено уменьшение относительного количества клеток, экспрессирующих TLR2, и увеличение экспрессирующих TLR3,4, а для пациентов N+ отмечено увеличение количества клеток, которые экспрессируют TLR4 в 2,5 раз (p < 0,05). С помощью метода логистической регрессии была разработана комплексная модель для определения вероятности лимфогенного метастазирования РОК. Индивидуальные значения пациентов подставляются в математическую модель и рассчитывается вероятность N+ (диагностическая чувствительность — 89,1 %, специфичность — 88,2 %). Выводы. Предложенная модель позволит прогнозировать распространенность процесса на предоперационном этапе у больных РОК, а также может стать одним из методов уточняющей диагностики в стадировании процесса.

Введение. Колоректальный рак по-прежнему занимает лидирующие позиции в структурах заболеваемости и смертности во всем мире, а процент пациентов резистентных к проводимой терапии остается достаточно высоким и требует поиска предиктивных маркеров эффективности для индивидуализации терапии. Неоангиогенез является причиной роста и прогрессирования злокачественных опухолей. Показана взаимосвязь между ангиогенезом, его регуляторными механизмами и изменениями в иммунной системе. Целью исследования было проанализировать особенности цитокинового профиля периферической крови пациентов с метастатическим колоректальным раком (мКРР), получавших терапию первой линии препаратом бевацизумаб в комбинации с химиотерапией до и после 4 курсов лечения. Материалы и методы. Методом мультиплексного анализа с использованием набора Bio-Plex Pro Human Immunotherapy 20-Plex Panel определяли концентрацию цитокинов в сыворотке крови 24 больных мКРР, проходивших лечение в отделении противоопухолевой лекарственной терапии ФГБУ «НМИЦ онкологии» Минздрава России, до и после 4 курсов терапии. Результаты. Проведение анти-VEGF терапии сопровождается разнонаправленным изменением содержания определяемых цитокинов: снижением IL-13, IL-6, IL-5 и GM-CSF и увеличением MIP-1α, IL-4, IL-8, IL-2, IFN-γ. Для IL-7, IL-10, IL-15, IL-17A, IL-18, IP-10, MCP-1, MIG, MIP-1β, RANTES, TNF-α изменений по сравнению с исходным уровнем не выявлено. В случае наличия положительного эффекта от терапии выявлено снижение концентрации IL-13, IL-5, IL-2, IL-10 как в случае полного ответа, так и при частичном ответе. Спектр цитокинов, содержание которых увеличивалось либо оставалось без изменения, был разнородным при различных вариантах ответа. Прогрессия заболевания характеризовалась увеличением содержания MIP-1α и IP-10, более выраженным снижением концентрации цитокинов, активирующих различные эффекторные механизмы иммунной защиты (GM-CSF, IL-6, IL-2, RANTES). Заключение. При проведении терапии мКРР с использованием анти-VEGF препаратов формируются определенные варианты цитокинового профиля, которые могут указывать на характер развивающихся процессов, что может быть использовано для оценки эффективности проводимого лечения.

e15502 Background: The purpose of this study was a comparative analysis of the expression of miRNAs in the tumor and circulating tumor cells (CTCs) in colon cancer (CC). Methods: Expression of seven miRNAs (hsa-let-7i-5p, hsa-miR-126-5p, hsa-miR-143-3p, hsa-miR-21-5p, hsa-miR-25-3p, hsa-miR-26a-5p, hsa-miR-92a-3p) were determined by real-time PCR in tumors of 200 patients with stage II-IV CC compared with normal colon tissue; levels of CTCs were determined by the CellSearch, and at CTC > 3, CTCs were isolated and the expression of the same miRNAs was studied in them. Results: Tumor tissues showed statistically significant (p < 0.0005) changes, compared to normal tissues, in the expression of hsa-let-7i-5p (increased by 4.2 times in stage IV), hsa-miR-126-5p (increased by 2.0; 2.1 and 2.9 times in stages II, III and IV, respectively), hsa-miR-143-3p (decreased by 3.3 times in stage IV), hsa-miR-21-5p (increased by 3.9 and 4.8 times in stages III and IV), hsa-miR-25-3p (increased by 3.2 times in stage IV), hsa-miR-26a-5p (decreased by 10.0; 5.0 and 6.7 times in stages II, III and IV, respectively) and hsa-miR-92a-3p (increased by 2.2; 5.1 and 9.5 times in stages II, III and IV, respectively). We observed changes in the expression of hsa-let-7i-5p (increased by 3.4 times), hsa-miR-143-3p (decreased by 3.4 times), hsa-miR-21-5p (increased by 3.2 times) and hsa-miR-92a-3p (increased by 4.3 times) in tumors of patients with stage IV disease, compared to stage II (p < 0.005). CTC expression of miRNAs hsa-miR-143-3p, hsa-miR-21-5p, hsa-miR-26a-5p in patients with lymph node metastases, compared to patients without metastases, was decreased by 2.5; 3.6; 5.0 times (p < 0.05) respectively, and expression of hsa-miR-92a-3p was elevated by 3.0 times (p < 0.05). In patients with liver metastases, CTC expression of hsa-miR-143-3p, hsa-miR-21-5p, hsa-miR-25-3p, hsa-miR-26a-5p was statistically significantly (p < 0.05) lower by 4.6; 5.5; 1.7; 5.3 times, respectively, compared to the CTC expression in patients without metastases, and expression of hsa-miR-126-5p and hsa-miR-92a-3p was higher by 2.6 and 5.0 times, respectively, compared to the CTC expression in patients without metastases (p < 0.05). CTC expression of hsa-miR-143-3p was 1.8 times lower (p < 0.05), and expression of hsa-miR-92a-3p was 1.7 times (p < 0.05) higher in patients with distant metastases, compared to patients with regional metastases. Conclusions: On the whole, the miRNA expression profile in the tumor and CTCs in CC were similar, although there were some differences. Tumor tissues in stage IV patients were characterized by overexpression of hsa-let-7i-5p, which is not typical for CTCs. The levels of the tumor suppressor hsa-miR-26a-5p were reduced in tumors of different stages to similar values, but differed in CTCs, which allows differentiation between non-metastatic CC and metastatic CRC.

e15503 Background: The purpose of this study was to analyze the effect of the CD44+ and CD133+ co-expression in cancer stem cells (CSCs) on lymphocytic microenvironment of colon cancer (CC). Methods: 200 CC patients received surgery as the first stage of treatment. The percentage of CSCs with the expression of CD44+ and/or CD133+ markers was studied in the tumor homogenates by flow cytometry, as well as some indicators of local immunity (CD3+, CD4+, CD8+, T regs (CD4+CD25+CD127dim), CD19+, PD-1, PD-L1, Th0, Tm, CD16/56+ and immunophenotypic characteristics of tumor cells (PD-L1, MHC-ABC). Results: Gradation depending on the absence or presence of co-expression of CSC markers on tumor cells allowed identification of 11 statistically significant differences out of 17 studied parameters of tumor cells and their lymphocytic microenvironment. Co-expression of CSC markers was accompanied by higher percentage of T regs (7.3±0.4 versus 5.3±0.5%), together with lower levels of CD4+ cells. At the same time, a higher content of the total number of T-lymphocytes was noted due to CD8+ with an increase in the percentage of memory T cells and a decline in naive T lymphocytes within this subpopulation. In addition, the co-expression of CSC markers was accompanied by a lower content of PD-L1 (34.3±3.0 vs. 42.9±2.5%) on lymphocytes and its higher content on tumor cells (10.6±1.5 vs. 4.1±0.8%), while the PD-1 expression on lymphocytes was higher (38.4±3.7 versus 22.3±2.9%). The presence of CD44+CD133+ CSCs was also accompanied by lower percentage of tumor cells expressing MHC class I (60.4±4.9 vs. 79.3±7.6%), which characterized the inhibition of recognition processes, and increased levels of CD8+, perhaps, should be considered as compensatory. Conclusions: The lymphocytic microenvironment of CC in the presence of CSCs with the CD44+CD133+ immunophenotype seems to be more immunosuppressive, according to the increase in the local content of T regs and the decrease in MHC-ABC expression. Higher expression of PD-L1 on tumor cells and PD-1 on lymphocytes allows activation of the PD-1/PD-L1 interaction, which enhances the immunosuppressive and growth-stimulating properties of the tumor microenvironment, but at the same time, makes tumor cells adequate targets for immunotherapy with immune checkpoint inhibitors.

e14027 Background: Circulating microRNAs (miRNAs) are currently being investigated as non-invasive diagnostic biomarkers in a wide range of tumors. However, there is still no sufficiently reliable siRNA signature for routine screening of patients with glial tumors of varying degrees of malignancy. Our study aimed to determine the level of microRNA pattern in the blood plasma of patients with glial tumors, which previously showed aberrant expression in tumors. Methods: Relative expression of twenty miRNAs (hsa-miR-3180, hsa-miR-3180-3p, hsa-miR-6782-5p, hsa-miR-182-5p, hsa-miR-133b, hsa-miR-670-3p, hsa-miR-342-3p, hsa-miR-454-3p, hsa-miR-1246, hsa-miR-433-3p, hsa-miR-195-5p, hsa-miR-29a-3p, hsa-miR -107, hsa-miR-21, hsa-miR-122, hsa-let-7c-5p, hsa-miR-125b-5p, hsa-miR-190b, hsa-miR-196a-3p, hsa-miR-16 -5p) was studied in the blood plasma of patients with glial tumors of various grades of malignancy (diffuse astrocytoma (DA, n=10), anaplastic astrocytoma (AA, n=10) and glioblastoma (GB, n=10)) and patients with menigioma (MEN, n=10) compared with a conditionally healthy group (CNTRL, n=10) by RT-PCR. Cycle thresholds were normalized to exogenous cel-miR-39-5p. Relative expression (RE) was calculated using the 2ΔΔCt method. Wilcoxon's t-test and Benjamini-Hochberg multiple comparison adjustment were used to assess differences. Results: As a result of evaluating the relative expression of the studied miRNAs between groups, differences were found for 9 miRNAs. P-values are listed in the Table. Conclusions: Thus, circulating miRNAs could potentially act as biomarkers for both gliomas and their subtypes and differentiate gliomas from meningiomas. The findings may provide new diagnostic strategies for gliomas. Significance levels of differences in the relative expression of miRNAs when comparing the studied groups with each other.[Table: see text]

e15500 Background: The immune response plays a key role in the oncogenesis of colorectal cancer. The heterogeneity of the tumor environment determines the need for immunogenetic profiling to identify associations with the implementation of tumor-specific immune responses in colorectal cancer. The purpose of our study was to describe the expression profiles of miRNAs and genes involved in the regulation of the immune response in colorectal cancer. Methods: The study included 18 patients (median age 66 years) diagnosed with colorectal cancer who were treated at the National Medical Research Centre for Oncology in 2018-2019. Total RNA was isolated using TRIzol (Thermo Fisher, USA) followed by treatment with DNase 1 (ThermoFisher, USA). Sequencing of RNA samples was performed using two approaches: AmpliSeq for Illumina Immune Response Panel (Illumina, USA) and TruSeq Small RNA Library Prep Kit -Set A (Illumina, USA) according to the manufacturer's instructions on a NextSeq 550 device (llumina, USA). Results: The study revealed 168 differentially expressed genes and 46 differentially expressed miRNAs (p < 0.05). 29 miRNA-mRNA pairs were identified. It has been established that the key signaling mechanism involved in the regulation of the tumor-specific immune response is chemokine signaling pathway (hsa04062). Expression of the CXCL1 and CXCL10 genes encoding the chemokines of the same name is increased in tumor cells (logFC = 1.51, p = 0.006 and logFC = 2.67, p < 0.001, respectively). At the same time, the level of hsa-miR-30a-5p and hsa-miR-99b-5p, which negatively regulate the expression of CXCL1 and CXCL10, is decreased (logFC = -2.26, p < 0.001 and logFC = -1.57, p < 0.001). Conclusions: Activation of expression CXCL1 and CXCL10 with simultaneous loss of negative regulators hsa-miR-30a-5p and hsa-miR-99b-5p was determined in colorectal tumors by NGS-sequencing, which seems promising for the development of personalized therapy, based on the immunogenetic features of colon tumors.

e15545 Background: For many years, colorectal cancer has been among the most frequently diagnosed cancers and one of the leading causes of cancer death. The effect of monoclonal antibodies on the immunological status remains relevant, since chemotherapy in combination with monoclonal antibodies (anti-EGFR, anti-VEGF) plays a key role in the treatment of patients with metastatic colorectal cancer. The purpose of this study was to reveal specific features of the cytokine profile of patients with metastatic colorectal cancer (mCRC) receiving bevacizumab in combination with chemotherapy before and after the treatment. Methods: The study included 15 patients with newly diagnosed mCRC receiving mFOLFOX6 chemotherapy combined with bevacizumab as the first-line treatment. Cytokine levels were determined in the blood serum (BS) by multiplex assay with the Bio-Plex Pro Human Immunotherapy 20-Plex Panel (GM-CSF, IFN-γ, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-13, IL-15, IL-17A, IL-18, IP-10, MCP-1, MIG, MIP-1α, MIP-1β, RANTES, TNF-α) (Bio-Rad, USA) before and after 4 cycles of the therapy. Results were evaluated using the Luminex 200 Analyzer (Bio-Rad, USA) with the Bio-Plex Manager Software. Results: Complete response to the therapy was registered in 5 (33.3%) patients, partial remission in 8 (53.3%) patients, progression in 13.3%. IL-6, IP-10, MIG, RANTES, and TNF-a were statistically significantly (p < 0.05) elevated in patients with complete response. IL-8 showed a tendency to decreasing after the therapy. Levels of IL-6, IL-8, IL-15, IL-17, and MIP-1a in patients with partial remission after the therapy reduced to zero values. An analysis of the cytokine profiles in patients with progression demonstrated a decrease of all the studied indices, except for elevated IL-15 and IL-17. Conclusions: Anti-VEGF agents together with chemotherapy changed the cytokine profiles in patients with mCRC. Probable mechanism may include the implementation of the antitumor response through the activation of some pro-inflammatory cytokines, since the complete response was accompanied by an increase in IL-6, IP-10, MIG, RANTES, TNF-a and a decrease in IL8.

e15613 Background: Colorectal cancer (CRC) is the third most commonly diagnosed cancer. More than 60% of all cases of CRC are colon cancer (CC). The role of individual units of the immune system in the development of this tumor is ambiguous. The purpose of this study was to characterize local populations and subpopulations of immunocompetent cells in colorectal cancer with different tumor locations. Methods: The study included 50 CC (adenocarcinoma) patients aged 35-86 years, women n = 26 (52%). Stage I tumors were registered in 4 patients (8%), stage II 25 (50%), stage III 21 (42%). 20 patients (40%) had right-sided CC (group 1), 9 (18%) left-sided CC (group 2), and 21 (42%) sigmoid CC (group 3). All patients received surgical treatment. Cell suspensions were obtained from tumor (TT) and peritumoral tissues (PT) (1-3 cm from the tumor), and then processed with an antibody panel in accordance with the manufacturer instructions (Becton Dickinson, USA) to identify the main populations and subpopulations of leukocytes and lymphocytes. The relative number of major populations and subpopulations of lymphocytes was determined on the BD FACSCanto flow cytometer. Results: A decrease in lymphocytic infiltration was noted left-sided tumors and sigmoid tumors compared to right-sided CC, by 46% and 51%, respectively. The percentage of CD3+ cells was almost the same regardless of the colon tumor location, and the number of main populations of T lymphocytes differed: in group 3, the content of CD4+ cells was 21% higher, and CD8+ cells were 22% lower compared with group 1, while group 2 had no differences. Group 2 differed in the tumor infiltration with both NK and NKT lymphocytes, which were higher by 25% and 22%, respectively, than in group 1. An increase in NK cells was noted in the sigmoid colon (group 3), and the relative number of NKT lymphocytes decreased. A common feature of TT in groups 2 and 3 was an increase in the content of B lymphocytes by 98% and 133%, respectively. PT of group 2 showed a decrease by 72%, 33%, 66%, and 46% in the relative number of lymphocytes, CD4+, NKT and B lymphocytes compared with group 1, together with an increased content of NK and CD8+ lymphocytes. PT in patients of group 3 had a decrease in the number of total and NK lymphocytes by 46% and 26%, respectively, and a significant increase by 85% in the content of CD8+ cells, with no changes in CD3+, CD4+ cells, B and NKT lymphocytes. Conclusions: The local immune status of CRC patients demonstrated a number of differences: right-sided tumors were characterized by a higher T-lymphocytic infiltration with the same tendency in the perifocal tissues, while left-sided and sigmoid tumors showed higher B-lymphocytic infiltration, which can help in the disease prognosis and choice of treatment strategy.

Purpose of the study. This work is devoted to the study of blood plasma miRNA patterns in blood plasma using high-throughput sequencing of the Omnibus Gene Expression base and the search for candidate miRNA molecules for the development of a minimally invasive diagnostic panel.Materials and methods. Basing on the open dataset of Omnibus Expression of the NCBI GSE150956 Gene, groups of samples with glioblastoma and conventionally healthy donors were formed. For each sample, information on the levels of miRNA expression was extracted. Determination of significant miRNAs using machine learning algorithms of the R 4.0.4 project. For significant miRNAs, target genes have been performed, an analysis of the improvement of functional characteristics and interactome analysis of target genes of miRNA were performed.Results. The study analyzed the data of 131 samples, where 35 samples with glioblastoma and 96 samples of the conditionally healthy group. Differential expression data were obtained for 945 miRNA. Two panels were obtained using machine learning methods, common miRNA – hsa-miR 3180, hsa-miR 3180-3p, hsa-miR 6782-5p, hsa-miR 182-5p, hsa-miR 133b and hsa-miR 670-3p. For significant miRNAs, information was obtained on experimentally confirmed target genes, a gene ontology demonstrating their participation in enzyme binding, participation in the regulation of primary cellular metabolic processes, and the development of glioblastomas and cancer in general.Conclusion. As a result of layer-by-layer filtering and application of machine learning algorithms, significant miRNAs were identified that are candidates for a diagnostic panel of a minimally invasive method of high-grade glial tumors.

e20520 Background: The aim of the study was an assessment of antitumor effect of 2-(6,8-dimethyl-5-nitro-4-chloroquinoline-2-yl)-5,6,7-trichloro-1,3-tropolone for subcutaneous xenografts of A-549 lung tumor cells in immunodeficient Balb/c Nude mice. Methods: 2-(6,8-dimethyl-5-nitro-4-chloroquinoline-2-yl)-5,6,7-trichloro-1,3-tropolone is a new compound in the series of 2-quinoline-2-yl-1,3-tropolone derivatives. The study included 50 immunodeficient Balb/c Nude mice divided into 5 groups depending on the dosage of the studied substance (0.0055; 0.055; 0.55 and 2.75 mg/g). The A-549 cells of lung cancer were used as the xenograft. Antitumor effect of tropolone was evaluated by the inhibition of tumor growth (ITG%) and the index of tumor growth (I). The experiment lasted for 36 days starting from the first administration of substances. Results: Indicators of the average tumor volume on day 36 of the experiment in experimental groups 1, 2, 3 and 4 and in the control group were 678.9; 952.3; 1746.4; 2150.8 and 2729.5 mm3, respectively. The indices of tumor growth in groups 1, 2, 3 and 4 were statistically significantly lower than in group 5 (controls) starting from days 15, 21, 21 and 24, respectively, and until the end of the experiment. Maximal differences between groups 1 and 5 were observed on days 33 and 36 – by 3.7 (p = 0.01) and 4.1 (p = 0.003) times, respectively. Antitumor effect of 2-(6,8-dimethyl-5-nitro-4-chloroquinoline-2-yl)-5,6,7-trichloro-1,3-tropolone demonstrated by the study could be associated with various mechanisms. For example, its closely related compound – hinoktiol, according to numerous studies, has a cytotoxic effect associated with stopping the cell cycle, induction of apoptosis, DNA damage, and autophagic death of tumor cells. Conclusions: The study demonstrated statistically significant differences in xenograft volumes between all experimental groups and the control group. 2.75 mg/g of mouse weight was the most effective dosage of the studied compound leading to a slow decrease in tumor growth rates and a decrease in the volumes of subcutaneous xenografts.

e20513 Background: Currently, an active search is underway for additional markers that predict the risk of tumor progression based on the epithelial-mesenchymal transition (EMT). Desmocollin 3 (DSC 3), a member of the Cadherin superfamily and a cell adhesion marker, is one of the markers for this transition. The aim of our study was to evaluate the expression of DSC 3 as a prognostic factor in different subtypes of non-small cell lung cancer. Methods: The study included 12 patients with squamous cell lung cancer and 8 patients with lung adenocarcinoma, aged 49 to 76 years. Immunohistochemical study was performed on sections from paraffin blocks of tumors using polyclonal rabbit antibodies to Desmocollin 3 (Invitrogen) at a dilution of 1:300 and the UltraVision Quanto Detection System HRP DAB. The expression of DSC 3 was semiquantitatively analyzed according to the percentage of cells and the intensity of staining: 0; 1+ (weak); 2+ (moderate); 3+ (high). Expression was considered positive if the score was ≥2. The Mann-Whitney U-test, Pearson's χ² distribution, and Spearman's correlation coefficient were used for statistical analysis of the results. Results: The predominance of patients with DSC3+ tumors was noted in the group with squamous cell carcinoma (64%), while the majority of patients with adenocarcinoma had DSC3- tumors (71%). However, Pearson's χ² was not statistically significant. Differences in DSC 3 expression values by 1.3 times were insignificant (p = 0.082): Me = 40 [0-80] in squamous cell carcinoma, Me = 30 [0-65] in adenocarcinoma. The correlation analysis between the expression of this marker and the survival rate of patients also had no statistical significance (rs = 0.061 for squamous cell carcinoma and rs = 0.196 for adenocarcinoma, p > 0.05). Conclusions: The immunohistochemical study revealed some specific features in the expression of DSC 3 in different subtypes of non-small cell lung cancer.

e20523 Background: The purpose of the study was to reveal the antitumor effect of 2-(6,8-dimethyl-5-nitro-4-chloroquinoline-2-yl)-5,6,7-trichloro-1,3-tropolone in subcutaneous PDX models of human non-small cell lung cancer (NSCLC). Methods: The studied tropolone was synthesized using a method of expanding the o-quinone cycle. Acute tropolone toxicity was evaluated by the survival and changes in the health status of female Balb/c Nude mice. Antitumor tropolone effects were studied in subcutaneous patient-derived xenograft (PDX) models of human squamous cell lung cancer in Balb/c Nude mice. The average volumes of tumor nodes and tumor growth inhibition (TGI%) rate were taken into account. Biochemical blood tests and histological analysis of the tumor material were performed in recipient mice. Results: An analysis of acute tropolone toxicity did not reveal the lethal dose. The maximal TGI, 73.5% for females and 74.4% for males, was observed on day 36 of the experiment in group 5 which received 2.75 mg/g tropolone. The average tumor volumes in females of this group were 431.3 mm3 on day 33 of the experiment, in males – 428.9 mm3 on day 30, and then the tumor volumes declined. Biochemical blood tests and histological analysis of the tumor material in recipient mice confirmed the tendency demonstrated during the analysis of the TGI dynamics, which in turn was the result of the dose-dependent antitumor effect of the studied tropolone. Conclusions: The research demonstrated the antitumor activity of 2-(6,8-dimethyl-5-nitro-4-chloroquinoline-2-yl)-5,6,7-trichloro-1,3-tropolone against subcutaneous PDX models of human NSCLC. The revealed tendencies can be used to search for effective modes of the compound application in clinical practice.

e19564 Background: Patients with non-Hodgkin's lymphomas (NHL) develop abnormalities in the structural and functional organization of the immune system leading to immune deficiency. Chemotherapy (CT) in patients after SARS-CoV infection is associated with a more severe disease course affecting the treatment results. The cytokine-producing activity (CPA) of blood cells is poorly studied, while it determines the effectiveness of antitumor and anti-infective functions of the immune system. The purpose of this study was to evaluate CPA of peripheral blood mononuclear cells in patients receiving treatment for NHL after COVID-19. Methods: The study included 8 patients with large B-cell NHL with PCR-confirmed COVID-19 infection in past medical history. All patients received from 3 to 4 chemotherapy cycles. K2EDTA blood samples obtained before and after 3-4 CT cycles were divided into 2 parts after dilution with a sterile nutrient medium solution: part 1, to assess spontaneous CPA; part 2, with addition of a sterile mitogen (phytohemagglutinin 4 μg, concanavalin A 4 μg, and lipopolysaccharide 2 μg) to assess stimulated CPA. The samples were incubated for 24 hours at 370C, and the levels of IL-1β, IL-6, IL-8, IL-10, IL-18, IL-4, IL-2, TNF- α, INF-ɣ, INF-α were determined in the obtained plasma. The stimulation coefficient (SC) was calculated as the ratio of stimulated CPA to spontaneous CPA. Results: 3-4 CT cycles in patients after COVID-19 was accompanied by an elevation of spontaneous CPA of the blood cells IL-6, INF-ɣ, TNF-α, IL-8, compared to the initial levels, by 678%, 127%, 64% and 57%, respectively. The ability of cells to spontaneous production of IL-10 and INF-α decreased by 30% and 100%. The mitogen-induced CPA of mononuclear cells in relation to IL-10, IL-6, IL-2, IL-1β and INF-α increased by 300%, 130%, 92%, 52% and 52%, respectively. Stimulated CPA in relation to INF-ɣ decreased by 21% compared to initial levels. As a result of the revealed CPA changes, SC in NHL patients after COVID-19 receiving CT increased, compared to the initial levels, by 465%, 92% and 48% respectively for IL-10, IL-2, IL-1β, as well as the appearing ability to INF-α production. SC for IL-6, INF-ɣ, TNF-α, and IL-8 decreased by 70%, 66%, 33% and 27% respectively. Conclusions: Certain features of spontaneous and mitogen-activated CPA of blood mononuclear cells were revealed in NHL patients after COVID-19, indicating a change in the functional activity of immune cells which could affect the development of the disease and the effectiveness of the therapy. The data obtained require additional studies and can be used to assess the condition of patients, as well as to predict the therapy efficacy.

e15501 Background: The purpose of this study was to demonstrate the importance of circulating tumor cells (CTCs) in the formation of immunosuppression in colon cancer. Methods: 200 patients with stage II-IV colon cancer underwent surgery as the first stage of treatment. Blood levels of CTCs were determined before surgery by flow cytometry using the CellSearch method (the sample was considered positive with CTCs > 3), as well as some indicators of innate immunity (NK cells, neutrophilic and monocytic phagocytosis). Results: Regardless of the stage, patients with CTCs had statistically significantly lower levels of NK lymphocytes (16.8±1.9 versus 22.3±1.8%, p≤0.05) compared with the absence of CTCs; on the contrary, levels of NKT cells in this group were higher than in the absence of CTCs (8.8±0.9 versus 5.0±1.0%, p≤0.05). The presence of CTCs was accompanied by higher levels of CD16dim56bright cells (13.1±3.2 versus 5.9±1.0% p≤0.05) with a lower content of CD16+56dim (82.5±3.6 versus 90.4±0.8%), and levels of perforin and granzyme were similar. The presence of CTCs was characterized by a higher percentage of phagocytic monocytes in the Phagotest test, as well as a higher percentage of monocytes and neutrophils capable of developing oxidative burst upon fMLF stimulation in the Phagoburst test (10.8±3.3 versus 3.2±1.5% and 5.1 ±0.8 vs. 2.0±1.1%, respectively; p≤0.05). A separate analysis of phagocytosis indicators by disease stages revealed that the presence of CTCs in patients was accompanied by stimulation of phagocytosis in local tumors and inhibition in advanced disease, however, in the latter case, the ability of granulocytes and monocytes to generate reactive oxygen species (ROS) was preserved and even increased. Conclusions: The presence of CTCs in patients with colon cancer is characterized by a redistribution of natural killer subpopulations with an increase in the blood levels of NKT cells, some of which have immunosuppressive activity, due to a decrease in NK cells, and an increase in CD16dim56bright and a decrease in CD16+56dim, apparently, indicates disturbance of their maturation. The established changes in the presence of CTCs indicate the inhibition of antitumor properties of the NK cell and phagocytic components of innate immunity in tumor cell circulation. The N-formylpeptide fMLF is known as a powerful neutrophil chemoattractant, stimulator of their migration and cytokine production, which plays a role in the development of inflammatory bowel diseases. The growth-promoting activity described for the similar antimicrobial protein LL-37 can be mediated through neutrophil migration and ROS production. Thus, the presence of CTCs has a negative impact on the parameters of NK cell and phagocytic components of innate cellular immunity in patients with colon cancer, which can serve as one of the strategies for survival and dissemination of the tumor.

e15509 Background: Intravasation and circulation of tumor cells involves active invasion of cells with an enhanced migration potential as a result of the epithelial-mesenchymal transition (EMT). The ZEB1 protein is one of the key regulators of this process. Our purpose was to evaluate the association between the amount of circulating tumor cells (CTCs) in the peripheral blood of patients with different stages of colorectal cancer and the expression of ZEB1 by tumor cells. Methods: The study included 299 patients (aged 42-86 years, mean age 64.2±1.7) with stage II-IV CRC T1-4N0-2M0-1; histologically verified G1-G3 adenocarcinoma in all patients. The numbers of CTCs were measured in the peripheral blood before surgery using the Veridex CellSearch system (Janssen). CTCs were registered taking into account morphological characteristics and expression of epithelial cell adhesion markers EpCAM, CD45, cytokeratins 8,18,19. The blood sample was evaluated according to the following criteria: 0 CTCs, 1-3 CTCs, and more than 3 CTCs. Tissues of surgically removed tumors were studied with IHC analysis using rabbit polyclonal anti-ZEB1 antibodies (Biorbyt Ltd.) diluted 1:200 and the Reveal Polyvalent HRP-DAB Detection System. The percentage and the intensity of staining were assessed: 0, 1+ weak, 2+ moderate, 3+ strong. ZEB1 expression was considered positive when staining was detected in more than 10% (cut-off) tumor cells with intensities of 2+ and 3+. Statistical analysis of results was performed in the Statistica 13.0 program (StatSoftInc., USA). Results: From 1 to 402 CTCs were determined in 62.9% cases (in 188 of 299 patients); CTCs were not registered in 37.1% cases (111 of 299). Positive ZEB1 expression was observed in 80.6% (241 of 299 patients), while the negative one was much more rare – 19.4% (58 of 299 patients). The rates of CTC detection significantly increased with the positive ZEB1+ expression, compared to the negative expression (75.1% vs. 12.1%). CTCs >3 were detected in the blood in 39.0% in ZEB1+ tumors, but not in ZEB1- tumors. 1-3 CTCs were observed 3 times more often in ZEB1+ tumors (36.1% vs. 12.1; p≤0.05). Conclusions: Statistically significant association was revealed between the epithelial-mesenchymal transition marker ZEB1 expression by tumor cells and the amount of CTCs in the peripheral blood (p < 0.001).

The aim is to conduct a cardiometric assessment of formation of acute and late toxic disorders in experimental animals with Guerin's carcinoma during carboplatin chemotherapy against the background of L-carnitine medication

e15510 Background: Tumor is a structure where malignant cells interact, among others, with cells of the adaptive and innate immune systems largely determining the tumor microenvironment. The role of TILs in the disease prognosis has been shown. The amount of CTCs is one of the factors that significantly affect the risk and rate of metastasis. The purpose of the study was to assess an association between TILs and CTCs in the peripheral blood of patients with various stages of colorectal cancer (CRC). Methods: The study included 299 patients (aged 42-86 years, mean age 64.2±1.7) with stage II-IV CRC T1-4N0-2M0-1. TILs were identified in tumor material after standard histological processing. Lymphocytes were counted per 100 epithelial cells in 5 fields of view at a magnification of x400; the result was expressed as a percentage ( < 5% weak, 5-30% moderate, >30% strong). The numbers of CTCs were measured in the peripheral blood using the Veridex CellSearch system (Janssen), taking into account the expression of epithelial cell adhesion markers EpCAM, cytokeratins 8,18,19 and absence of the CD45 expression. The blood sample was evaluated according to the following criteria: 0 CTCs, 1-3 CTCs, and more than 3 CTCs. Statistical analysis of results was performed in the Statistica 13.0 program (StatSoftInc., USA). Results: Weak lymphocytic infiltration was detected in 32.8%, moderate - in 48.1%, strong - in 19.1% of cases. CTCs were detected in 62.9% cases (in 188 of 299 patients). The percentages of patients with 1-3 CTCs and with >3 CTCs were equal - 50% (94 of 188). CTCs were not registered in 37.1% cases (111 of 299). The absence of CTCs was noted equally often in moderate and strong lymphocytic infiltration – 43.7% and 43.8%. The presence of tumor cells in the peripheral blood was most often detected in weak lymphocytic infiltration, being 1.4 times more frequent than in moderate and strong infiltration (76.5% vs. 56.3% and 56.2%) (p = 0.019, c 2 = 11.890). Conclusions: The study demonstrated a significant relationship between the level of CTCs and the intensity of lymphocytic infiltration in the tumor (p≤0.05), which can be used as a new prognostic approach.

3522 Background: Cancer stem cells (CSCs) capable of self-sustaining and multipotent differentiation are considered among the most important factors limiting treatment effectiveness. ALDH1 is a marker of colorectal cancer (CRC) CSCs; it is involved in cell differentiation and proliferation, determines resistance to alkylating chemotherapeutic agents, and also induces epithelial-mesenchymal transition (EMT), which increases the invasive and metastatic potential of tumors. The purpose of the study was to assess the association between the expression of the ALDH1 CSC marker in tissues of CRC of different stages and clinical and morphological factors of the disease prognosis. Methods: The study included 299 patients (aged 42-86 years, mean age 64.2±1.7) with stage II-IV CRC T1-4N0-2M0-1; histologically verified G1-G3 adenocarcinoma in all patients. Tissues of surgically removed tumors were studied with IHC analysis using mouse monoclonal anti-ALDH1 antibodies (clone B-5, Santa Cruz Biotechnology) diluted 1:1800 and the Reveal Polyvalent HRP-DAB Detection System. The percentage of cells positively stained for ALDH1 among all tumor cells was assessed. Statistical analysis was performed using the STATISTICA 13.0 program (StatSoftInc., USA). Results: Positive ALDH1+ expression was registered in 52.5% of all patients, negative expression – in 47.5%. Statistically significant association was observed between the ALDH1 expression and the CRC stage, since the ALDH1+ expression increased from stage II to stage IV (p = 0.003). The ALDH1 expression was statistically significantly associated with the depth of tumor invasion (p = 0.018) and the presence of distant metastases (p < 0.001). No significant relationship was observed between the ALDH1 expression and regional lymph node metastasis (p = 0.788). Statistically significant association was registered between the ALDH1 expression and the tumor grade (p < 0.001), perineural invasion (p = 0.010) and lymphocytic infiltration (p < 0.001). No significant relationship was observed between the tumor histological structure (p = 0.979), lymphovascular invasion (p = 0.772) and ALDH1 expression. Tumor site was not statistically significantly associated with ALDH1 expression (p = 0.349). Conclusions: The study demonstrated statistically significant association between the ALDH1 expression and clinical and morphological characteristics of CRC, determining invasive and metastatic potential of the tumor, and ALDH1 may be an independent prognostic factor and a new therapeutic target for the regulation of the progression process.

e16028 Background: Over the past 10 years, gastric cancer has been in the top five most common malignant tumors with a high mortality rate. Its poor prognosis is determined by the aggressive disease course with the development of distant metastases. Additional markers of tumor progression are required, and a special role in tumor progression is assigned to the epithelial-mesenchymal transition (EMT). E- and N-cadherins are among the key EMT regulators. Our purpose was to reveal possible prognostic value of EMT markers in different forms of gastric cancer. Methods: The study included patients (aged 30-80 years) with gastric cancer: control group (n = 20, 58.9±9.7 years) – non-metastatic gastric cancer T3-4аN0-3M0 (G2); main group (n = 20, 53.4±11.9 years) – gastric cancer T3-4аN0-3M1 (G2) with peritoneal metastases. IHC analysis was performed on sections from paraffin tumor blocks using mouse monoclonal antibodies to E-cadherin (SMP471, Diagnostic BioSystems) and N-cadherin (SP90, Spring Bioscience) diluted 1:30, and the Reveal Polyvalent HRP-DAB Detection System. Expression of E- and N-cadherins was analyzed semi-quantitatively according to the percentage of cells showing membrane positivity and the intensity of staining: 0 (from 0 to 10%); 1+ (from 11 to 30%); 2+ (from 31 to 70%); 3+ ( > 70%). Expression was considered positive in ≥2. Statistical analysis of results was performed in the Statistica 13.0 program (StatSoftInc., USA) using the Pearson's chi-square test and the Spearman's correlation. Results: Maximal staining for E-cadherin was observed in the control group (in 90%), staining for N-cadherin – in the main group (in 70%). Average expressions of E- and N-cadherins were: in controls – 34.5±4.5 and 24.1±5.7; in the main group – 24.6±5.8 and 28.3±4.3. The Pearson's test showed the statistically significant prevalence of patients with E-cadherin+ tumors in the control group (7.619, p = 0.006), and the prevalence of patients with N-cadherin+ tumors in the main group (4.912, p = 0.027). However, when considering the correlation between E-cadherin and N-cadherin in the groups, the Spearman's correlation was not statistically significant (rs = -0.342 in the control group and rs = -0.430 in the main group at p > 0.05). Conclusions: The study revealed only a tendency towards the loss of E-cadherin and increased expression of N-cadherin, which is often associated with a poor prognosis. However, a more extensive study is required to assess the possible prognostic value of these EMT markers in metastatic and non-metastatic gastric cancer.

Purpose of the study. This research was devoted to study of mRNA and miRNA expression patterns in glioglastomas using The Cancer Genome Atlas (TCGA) data, to search for genetic determinants that determine the prognosis of patient survival and to create of interaction networks for glioblastomas.Materials and methods. Based on the data of the open TCGA database groups of glioblastomas and conventionally normal brain tissue samples were formed. Survival gene and miRNA expression data were extracted for each sample. After the data stratification by groups the differential expression analysis and search the genes affecting patient survival was carried out. The enrichment analysis by functional affiliation and an interactome analysis were performed.Results. A total of 156 glioblastoma samples with mRNA sequencing data, 571 samples with microarray microRNA analysis data, and 15 control samples were analyzed. Networks of mRNA-miRNA interactions were built and expression profiles of genes and miRNAs characteristic of glioblastomas were developed. We have determined the genes which aberrant level is associated with survival and shown the pairwise DEG and DE of microRNA correlations.Conclusion. The microRNA-mRNA regulatory pairs identified for glioblastomas can stimulate the development of new therapeutic approaches based on subtype-specific regulatory mechanisms of oncogenesis.