Bladder cancer is the 2^nd most common urological oncological disease in the worlds. Tumors can be muscle invasive and non-muscle invasive. Recently, tumor microenvironment (TME) became a focus of investigation in malignant tumors of the bladder. According to the currently available data, TME is a specific environment crating optimal conditions for carcinogenesis in the neoplastic lesion. The main parts of TME are extracellular matrix and stroma including vasculature, stromal, and immune cells. Additionally, TME includes cytokines, chemokines, and other compounds activating signal pathways necessary for tumor cells. Tumor-associated macrophages (TAMs) are being extensively studied as representatives of TME in solid tumors of varying locations. These macrophages can be classified into 2 phenotypes: M1 (pro-inflammatory and antitumor) and M2 (anti-inflammatory and protumor). The phenotypes perform different roles, and M2 macrophages regulate the most important processes of oncogenesis (invasion, proliferation, neoangiogenesis, etc.). In the context of bladder cancer, M2 macrophages are the most significant as they are the most numerous TAMs in TME.

Aim. To study the role of tumor-associated macrophages in development of bladder tumors, as well as prognostic value of these macrophages.

Neurofibromatosis type 1 is caused by a germline mutation in the NF1 gene encoding the tumor suppressor neurofibromin. Deficiency of this protein causes hyperactivation of Ras proto-oncogenes. This leads to the development of tumors. Ras proteins undergo prenylation, which is inhibited by inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme-A reductase. Therefore, statins can be proposed as anticancer drugs in the complex treatment of neurofibromatosis type 1. Clinical studies have proven the effectiveness of statins in the treatment of sporadic malignant neoplasms, in the pathogenesis of which mutations in the NF1 gene play an important role. Various pathways of the influence of these drugs on the development of tumors are described, including the activation of autophagy, ferroptosis, suppression of proliferation, stimulation of antitumor immunity, and effects on the microenvironment of neoplasms. Data on the effect of statins on the development and progression of neurofibromas in patients with neurofibromatosis type 1 are not presented in the scientific literature. However, it was found that statins enhance the effect of anticancer drugs, the use of which in monotherapy against malignant neoplasms associated with neurofibromatosis is ineffective. In this regard, despite the inefficiency of statins in cognitive disorders in patients with neurofibromatosis type 1, the introduction of these drugs into clinical practice in combination with other drugs could provide a pleiotropic effect, affect various links in the pathogenesis of the disease. 

Introduction. Liquid biopsy is considered as a minimally invasive method of molecular genetic analysis that can be used for early diagnosis, prognosis of disease development, monitoring of residual disease or treatment outcomes, and selection of optimal drug therapy schemes for a patient. Along with the development of tests based on the study of panels of oncologically significant genes or their regions, for various forms of genetically heterogeneous tumors a promising approach could be the use as an object of liquid biopsy of an individual spectrum of somatic mutations of a particular patient that can be detected on the basis of high-throughput sequencing of tumor tissue.

Aim. To determine the applicability of different methods for detecting single-nucleotide somatic mutations detected in tumor tissue of a particular patient in cDNA preparations from blood plasma obtained before surgical removal of the tumor and to evaluate the possibility of quantifying the proportion of the alternative variant in the total pool of cDNA. Materials and methods. We used normal and tumor tissue, as well as blood plasma samples from patients with hepatocellular carcinoma, and various methods for detecting single-nucleotide somatic mutations: real-time polymerase chain reaction (PCR) with intercalating dye or with TaqMan probes, droplet digital PCR and high-throughput sequencing of target amplicons.

Results. Using the example of a somatic mutation in the TLN1 gene detected in tumor tissue of a patient with hepatocellular carcinoma, methods were developed and tested, each of which allows specific detection of the mutant variant in small amounts (2 ng) of cDNA from the blood plasma of the same patient. The use of droplet PCR and target amplicon sequencing methods allowed us to quantify the proportion of the mutant variant in the total cDNA pool, which was 19.7 and 23.5 %, respectively.

Conclusion. Among the methods investigated, droplet digital PCR and targeted amplicon sequencing allow not only reliable detection of mutant variants in small amounts of cDNA, but also adequate quantification, which is particularly important for the development of ways to monitor tumor growth during treatment. The close values of the proportion of mutant variants in cDNA detected by these methods indicate the accuracy of quantitative analysis and the possibility of their use for cross-validation of the results obtained.

Introduction. In most patients with colorectal cancer (CRC), the tumor develops against the background of metabolically healthy obesity or metabolic syndrome (more than 60 % of patients), the key pathogenetic moment of which is developing hyperinsulinemia. Metabolic changes are also characteristic of patients with colon polyps (CP), which are currently considered as the most significant precancerous diseases. It has been shown that fractions of small extracellular vesicles (EVs) of adipocyte origin are specifically enriched in extracellular matrix proteins, including matrix metalloproteinases (MMPs), chaperones, and some metabolic enzymes involved in the synthesis of lipids and carbohydrates. This was the reason for choosing exosomal markers in our study. Comparison of protein expression on CD9- and FABP-4 positive vesicles will be useful to explain some clinical issues, such as the effectiveness of thermoradiotherapy or radiotherapy in obese CRC patients; for a more substantiated search for vesicular prognostic markers in obese cancer patients. However, taking into account the lack of data in the literature on the level of MMPs and HSPs expression in the composition of the total pool of EVs and in the composition of FABP4-positive EVs in patients with PTC and CRC patients, the aim of the work was formulated.

Aim. Study of the level of MMPs and heat shock proteins (HSPs) on CD9- and FABP4-positive EVs in patients with CP and CRC in relation to metabolic status.

Materials and methods. The study included 12 patients with CRC (T2-4N0-2M0; mean age 59.6 ± 1.6 years) who were treated at the Department of Abdominal Oncology of the Cancer Research Institute of the Tomsk National Research Medical Center from 2019 to 2021. The comparison group included 10 patients with CP. The level of proteins on the surface of CD9- and FABP4-positive EVs was studied using flow cytometry.

Results. MMP9-positive EVs were detected more often in CRC patients than in CP patients, however, MMP9+MMP2+TIMP-positive EVs were significantly more frequently detected in CP patients. Among the studied heat shock proteins, HSP60 was most often expressed on the surface of EVs, and HSP60-positive EVs were detected on the surface of CD9-positive exosomes in patients with PTC much more often than in CRC. In patients with CRC, compared with patients with СP, among FABP4-positive EVs, the proportion of triple-positive EVs and EVs with the MMP9+MMP2-TIMP1+ phenotype significantly increases, which in general may indicate overexpression of MMP9 and TIMP1 by adipocytes or marcrophages of adipose tissue in patients with CRC. Correlation analysis revealed multiple correlations of individual phenotypes of CD9-positive EVs in patients with CRC with body mass index and serum high density lipoprotein cholesterol levels, while the phenotypes of FABP4-positive EVs were associated mainly with triglyceride levels.

Conclusions. The phenotypes of CD9-positive and FABP4-positive circulating EVs are promising as predictors for clarifying cancer risk in patients with colon polyps, as well as in terms of explaining the effectiveness of the treatment of CRC patients with obesity or metabolic syndrome.

Introduction. It is known that the structural features of the Epstein-Barr virus (EBV) affect the manifestation of its biological properties. Based on differences in the sequences of the EBNA2, EBNA3A, -B, and -C genes, two types of the virus, EBV-1 and EBV-2, have been identified that have different ability to transform B cells in vitro and possibly playing certain role in the development of EBV-associated neoplasms.

Aim. To study the prevalence of EBV-1 and EBV-2 in two ethnic groups, Аdygeans and Slavs, as well as the contribution of EBV-associated tumors to the overall incidence of malignant neoplasms certain organs and tissues.

Materials and methods. DNA samples were extracted from 59 oral lavages of ethnic Аdygeans from Republic of Adygea and 40 such from oral cavity of ethnic Slavs of Moscow city. These samples were used for amplification of EBV DNA, determination of the concentration of viral DNA copies per 1 cell washout, as well as for amplification of EBV LMP1 followed by sequencing of the resulting gene samples and determination of their protein variant (LMP1).

Results. Studies have shown that among the representatives of the Аdygeans the 2^nd EBV type prevails, and among the Slavs, the 1^st one. Epstein-Barr virus isolates in representatives of the two ethnic groups also differed in the structure of LMP1. Among the Slavs, a set of its LMP1 variants (B95.8/A, China, Med- and NC) was identified. However, among the Adygeans, the only variant - B95.8 and its subtype - B95.8/A was identified. EBV-1, which prevails among the representatives of the Slavs and has the ability to transform B-cells, was projected onto a higher incidence of tumors of the pharynx, stomach, Hodgkin's and non-Hodgkin's lymphomas (where EBV-associated cases cam occur) in the population of Moscow than in the population of the Republic of Adygea. However, the differences between incidence rates for these neoplasms (with the exception for the stomach tumors) were not statistically significant (p >0.5). A higher and statistically significantly different incidence rate of stomach cancer in residents of Moscow city, compared with that in residents of the Republic of Adygea, in our opinion, is not due to EBV-1 type and/or LMP1 variants, but rather is associated with a genetic predisposition the population of Moscow city to this tumor.

Conclusion. The fact that two ethnic groups of Russia were found to be prevails by different types of EBV raises the question of their ethno-geographical association and their role in the induction of EBV-associated tumors. To resolve this issue additional studies in other geographical regions of Russia among representatives of different ethnic groups are required.

Introduction. Treatment of glioblastoma multiforme remains little effective due to the rapidly developing recurrence of the tumor, due to its high tumorigenic potential, resistance to chemoradiation therapy and increased dissemination of glioma stem cells. The identification of potential therapeutic targets, which make it possible to more effectively destroy glioma stem cells, becomes topical. In this regard, the study of ferroptosis (FP), which can cause the death of tumor cells with a highly malignant phenotype, is of great importance. However, FP and its regulatory pathways in the GSC are not fully understood. At present, it is also not clear how FP differs for glioma stem cells and glioblastoma differentiated cells.

Aim. To study the expression of ferroptosis signaling cascade determinants in CD133⁺ glioma stem cells and CD133^- glioblastoma differentiated cells using high resolution proteomic mass spectrometry.

Materials and methods. High-resolution proteomic mass spectrometry, cell technologies.

Results. In total, 1970 proteins were identified, 15 of which are associated with ferroptosis and are present in both cell populations. Upregulation of 12 FP determinants (ACSL1, ACSL3, COPZ1, FTH1, FTL, GPX1, GPX4, PCBP1, SLC3A2, TFRC, VDAC1, VDAC2) was found in CD133⁺ glioblastoma stem cells compared to CD133^- differential glioblastoma cells, 10 of which were more than 2-fold overexpressed.

Conclusion. Important regularities have been established in the expression of ferroptosis determinants and proteins controlling this process in glioma stem cells, which can be used in the development of new approaches to the detection of potential targets for the therapy of glioblastoma multiforme.

Introduction. The recurrence of diffuse large B-cell cell lymphoma in the central nervous system in the vast majority of cases is a fatal manifestation of the disease. The study of the lymphoma mutational profile can improve the accuracy of the prognosis of relapse in the central nervous system and justify the selection of patients for preventive treatment. Aim. To evaluate the mutational profile of cases of diffuse large B-cell cell lymphoma with central nervous system damage in relapse based on the results of our own experiment on high-performance sequencing.

Materials and methods. On the Illumina platform, full-exome sequencing of diagnostic samples of diffuse large B-cell cell lymphoma with relapses in the central nervous system was performed. A panel including more than 70 genes was analyzed.

Results. Four main groups of genetic events can be distinguished in the group of studied samples, namely: combined mutations in the NF-kB (MYD88, NOTCH1, CD79B, CARD11) and JAK-STAT (PIM1, STAT6) signaling pathways, as well as aberrations in the main oncosuppressor TP53 and chromatin remodeling system genes (ARID1A, KMT2D, EP300, SMARCA4). A recurrent mutation c. 794T>C, p.L265P MYD88 was detected in the study group. Among other findings, mutations in the CIITA and CD58 genes should be noted, which are important in avoiding tumor cells from immune surveillance.

Conclusion. Despite the apparent heterogeneity of the mutational profile of diffuse large B-cell cell lymphoma with relapses in the central nervous system, in most cases, tumor cells were characterized by genetic disorders leading to the production of a large number of pro-inflammatory cytokines by malignant lymphocytes, as well as aberrations that reduce immunogenicity and contribute to the avoidance of immune surveillance by the tumor.