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The development of omics technologies and sequencing has significantly expanded the understanding of the role of microorganisms that inhabit various human organs and collectively make up its microbiota in the development of cancer. The extensive literature of recent years devoted to various aspects of the participation of the microbiota in carcinogenesis substantiates the relevance of analyzing the impact of its features on the processes of carcinogenesis in various human organs.Purpose of the study. Analysis of literature data on the key issues of the relationship between the human microbiome and the risk of cancer and explore possible prospects for its use in the diagnosis, therapy and prevention of cancer.Materials and methods. A literature search was carried out in the databases NCBI MedLine (PubMed), Scopus, Web of Science, based on an extended list of keywords that included all the localizations of malignant neoplasms (MNs) considered in the review. Original studies, meta-analyses, randomized controlled trials, and reviews published in recent years were used.Results. Recent studies using omics technologies have shown significant differences in the composition of microbial communities of healthy and tumor tissues and have made it possible to characterize the potential tumor microbiota in some types of cancer. The microbiota present in the various organs of the human body forms a network through which it interacts via migration or by forming metabolic axes between organs. Dysbiosis plays an important role in carcinogenesis, and its presence in one organ can negatively affect the condition of other distant organs and contribute to the development of pathological conditions in them.Conclusion. Numerous studies conducted over the past decade have revealed a complex relationship between microorganisms, tumors, and the host, reflecting the diverse effects of the microbiota on various organ- specific types of MNs. Gastrointestinal tract tumors, as well as sites outside it with significant bacterial associations, have been identified for a better understanding of the multifaceted mechanisms by which the microbiota influences cancer. The data obtained so far complement the emerging possibilities of using the microbiota in clinical practice, which represents a new approach to the prevention and treatment of malignant neoplasms.

Purpose of the study. Analysis of the molecular and biological features of synovial sarcoma (SS), as well as its tissue microenvironment according to modern research.Materials and methods. The analysis of literature sources was carried out mainly in the databases «Istina» and «PubMed», publication date limitations were set up from 2019 to 2023. The following keywords for the search were used: «synovial sarcoma», «chromosomal aberrations», «carcinogenesis».Results. Understanding the molecular mechanisms and signaling pathways in the development of SS may lead to the development of more effective treatment strategies. The importance of further research in this area cannot be overestimated, as it can provide new data to create innovative approaches aimed at improving the prognosis and quality of patients’ lives. Chromosomal aberrations, such as translocations and deletions, can lead to the activation of oncogenes or inactivation of tumor suppressor genes, which, in turn, contributes to the malignant transformation of cells. Epigenetic changes such as DNA methylation and histone modifications also play an important role in the regulation of genes related to the growth and survival of tumor cells. Disorders in these processes can contribute to tumor progression by altering the expression of key genes involved in the cell cycle, apoptosis, and angiogenesis. Additionally, part of the review is devoted to the interaction of atypical cells against the background of chromosomal aberrations and epigenetic changes with the SS microenvironment. These factors may have a certain effect on the growth and progression of synovial sarcoma. In addition, the review discusses various aspects of the diagnosis of SS using modern molecular genetic methods. Examples of successful use of targeted therapy and immunotherapy are given, which open up new prospects in the treatment of this disease.Conclusion. The importance of molecular biological and molecular genetic analysis of SS for the possibility of an interdisciplinary approach in the study and treatment of this aggressive malignant tumor has been revealed.

The basis for the prevention of cancer is the correction of initial epigenetic disorders in the cell, i.e. implementation of pathological genome reversion. Convincing evidence has accumulated to support the potential antitumor activity of compounds derived from cruciferous vegetables of the genus Brassicaceae. Indole-3-carbinol and 3,3'-diindolylmethane (DIM) have been investigated for their use as chemopreventive agents. DIM is formed in the acidic environment of the stomach as a result of dimerization of indole-3-carbinol monomers. Currently, it is impossible to identify a specific vector of influence of DIM at the molecular level. In this review, we summarize the pleiotropic effects of DIM aimed at correcting reversible epigenetic changes in tumor cells. Emphasis will be placed on the major cellular and molecular events that are effectively modulated by DIM. The main profile of DIM competencies concerns the management of intracellular signal transmission and correction of initial molecular genetic changes at the level of key participants in signaling pathways (NF-κB/Wnt/Akt/mTOR) leading to the development of cancer. The ability of DIM to differentially modulate tumor cell apoptosis has been observed in preclinical studies. It has been suggested that using DIM it is possible to increase the effectiveness of chemotherapeutic compounds with different molecular targets, thereby increasing chemosensitization. DIM has entered phase III clinical trials, with preliminary results confirming its promise both as a stand-alone drug and in combination with other components of anticancer therapy. Establishing the range of epigenetic control of DIM molecular and genetic changes in various cancers will allow optimization of therapeutic epigenetics approaches.

The intestinal microbiota, having enormous metabolic potential, makes a significant contribution to the physiological and pathological processes of humans and animals and is currently considered as an important factor in the pathogenesis of cancer. The aim of this study is to determine changes in the quantitative and qualitative composition of the intestinal microbiota in Wistar rats during chemical induction of breast cancer (BC). Material and methods. The work was performed on female Wistar rats (n = 40) aged 3 months, weighing 200–210 g, using cultural methods for studying fecal microbiota in intact rats (1 group) on the 1st, 14th, 35th days and in rats with induction of breast cancer and and in rats, whereby N-methyl-N-nitrosourea was administered to induce breast cancer (2 group) on the 1st (before injection of N-methyl-N-nitrosourea), 14th, 35th days after injection of N-methyl-N-nitrosourea. Results and discussion. In all experimental animals, representatives characteristic of the intestinal normobiota of warm-blooded animals predominated, namely: Bifidobacterium spp., Lactobacillus spp., Escherichia coli with pronounced enzymatic properties, Enterococcus spp., Clostridium spp. In addition, Staphylococcus spp., yeast-like fungi of the genus Candida and mold. Escherichia coli with reduced enzymatic activity was also detected. It was established that the isolated bacteria belonged to 3 types, 4 classes, 5 orders, 6 families, 6 genera of the bacterial domain. Also, 2 genera of fungi belonging to the order Saccharomycetales were isolated. The most significant changes in the composition of the intestinal microbiota were noted in rats with chemically induced breast cancer on the 35th day tumor induction: the appearance of pathogenic microflora in the intestine was revealed.

It is known that chronic social stress leads to immunity disorders in humans and experimental animals. It has been shown that the effect of stress is also manifested in changes in the level of expression of genes involved in the functioning of various physiological systems in the brain of mice, in particular, in the hypothalamus. It was noted that in stressed animals, genes involved in the processes of carcinogenesis and apoptosis change their expression, and in animals without signs of developing a malignant process, but under conditions conducive to tumor growth. In this regard, we used the RNA-seq method to study the expression of cytokine response genes in the hypothalamus of male mice under the influence of chronic social stress caused by repeated experience of defeats in intermale confrontations, compared with control individuals. Multidirectional changes in the expression of cytokine genes, their receptors and genes performing a regulatory function were detected (IL17d, IL18, IL33, Csf1r, Csf2ra, IL11ra1, IL13ra1, IL2ra, IL3ra, IL5ra, Lifr, Cish, IL4i1, Irf1, Irf5, Irf9, Jak2, Socs3, Stat3, Tgfb1, Tlr3). Thus, it has been shown that changes in the cytokine response in the brain under the influence of stress occur at the level of changes in gene expression. In this case, we should not talk about the activation of the system or a decrease in its activity, but about the disruption of its functioning. Next, we analyzed the correlations between the level of expression of genes of the cytokine system and the main genes of carcinogenesis and apoptosis that we studied earlier (Akt1, Bag6, Foxp4, Mapk3, Mapk8, Nol3, Pdcd10, Xiap). The Akt1, Jak2, Stat3 genes were identified, for which the maximum number of correlations was found, moreover, negative correlations were most characteristic of Jak2, and positive correlations were most characteristic of Stat3 and Akt1. In addition, protein-protein interactions between genes of carcinogenesis and apoptosis and genes of the cytokine system were analyzed using the String database in mice under chronic social stress. It was confirmed the key role of these genes in the development of dysfunction of cytokines in the brain.

Background. In oncology, of particular interest is the study of the T-cell receptor excision circles (TREC) and the κ-deletion B-cell receptor excision circles (KREC), which are extrachromosomal DNA structures. In many malignancies, the effectiveness of immune checkpoint inhibitors depends on the mutational load of the tumor, which correlates with the formation of specific antitumor immunity. Quantitative indicators of recombination excision circles reflect the occurrence of a different repertoire of T-cell receptors, an integral component in the formation of specific immunity. Understanding the change in quantitative values of TREC and KREC in cancer patients can improve the selection of patients for immunotherapy. Aim. To determine quantitative indicators of TREC and KREC for immunological evaluation of patients with malignancies. Materials and methods. The study included 55 healthy individuals and 180 patients with malignancies. Among healthy individuals, 49.1% (27/55) were males and 50.9% (28/55) females. Among patients with malignancies, 20.5% (37/180) were males and 79.5% (143/180) females. The median age in healthy individuals was 36 years [Q1–Q3: 26–58]. The median age in the group of patients with malignancies was 57 years [Q1–Q3: 47.5–67]. Results. In the general population of healthy individuals, the median TREC level was 60.1 [Q1-Q3: 31.3-188.9] and the median KREC level was 256 [Q1-Q3: 149.8-353]. In the general population of patients with malignancies, the median TREC rate was 4.6 [Q1-Q3: 0.9-17.3] and the median KREC was 111.9 [Q1-Q3: 29.3-339.28]. According to the results of the study, we noted statistically significant differences in TREC and KREC indices between all patients with malignancies and healthy individuals (p0.001, p=0.001). Analysis of TREC and KREC indices in patients with malignancies of various localizations (breast cancer, ovarian cancer, lung cancer, colorectal cancer, skin melanoma, lymphomas) in comparison with healthy individuals statistically significant differences in TREC level were noted (p=0.001, p0.001). When analyzing the KREC level in the studied groups, statistically significant differences in patients with ovarian malignancies (p0.001), lymphoma (p0.001), colorectal cancer (p=0.001) and melanoma (p=0.039) in comparison with healthy individuals were obtained. When comparing groups pairwise, it was found that TREC level in patients with malignancies in the age group of 25–44 years was significantly higher than in the age group of 45–60 years (p=0.03); TREC level in the age group of 25–44 years was significantly higher than in the age group of persons over 60 years (p0.001); TREC level in the age group of 45–60 years was significantly higher than in the age group over 60 years (p0.001). Statistically significant differences of KREC level in the studied patients with malignancies depending on the age group were not established (p=0.16), there were no age differences of groups by KREC level. Conclusion. The results demonstrate a significant decrease in TREC and KREC levels in patients with malignancies compared to healthy individuals. The study of TREC and KREC excision circles in peripheral blood is one of the promising approaches for the immunological evaluation of cancer patients.

INTRODUCTION. The development of malignant neoplasms is associated with changes in the expression of small non-coding RNAs (miRNAs). This emphasises the need for research into the development of miRNA-targeted inhibitors as a promising approach to cancer treatment.AIM. This study aimed to compare current strategies for suppressing the functional activity of tumour-associated miRNAs based on the use of therapeutic nucleic acids and to determine the application potential of these strategies.DISCUSSION. This study analysed known oligonucleotide-based miRNA inhibitors with different mechanisms of action. Based on their mechanism of action, miRNA-targeted inhibitors can be classified into two groups. The first group of miRNA-targeted inhibitors exhibits an indirect inhibitory effect, either by blocking functional connections between miRNAs and specific mRNA targets through the use of miRNA-masking oligonucleotides or by introducing mutations into miRNA genes and disrupting gene biosynthesis processes through the use of the CRISPR/Cas system. Despite their relatively high biological potential, these strategies are mostly used as search tools to study miRNA functional roles and molecular interactions in carcinogenesis. The second group of oligonucleotide constructs interacts with miRNA targets directly, which leads to steric blocking or degradation of oncogenic microRNAs. These miRNA-binding oligonucleotide constructs come in a variety of structural variants, including miRNA sponges, RNA zippers, antisense oligonucleotides, and miRNases, which demonstrate high therapeutic potential in vitro and in vivo.CONCLUSION. The described analysis of the biological properties, therapeutic potential, and key advantages of the developed miRNA-targeted oligonucleotide constructs helps outline the areas for their potential practical application in cancer treatment.

Alzheimer’s disease affects an average of 5 % of the population with a significant increase in prevalence with age, suggesting that the same mechanisms that underlie aging may influence this pathology. Investigation of these mechanisms is promising for effective methods of treatment and prevention of the disease. Possible participants in these mechanisms are transposons, which serve as drivers of epigenetic regulation, since they form species-specific distributions of non-coding RNA genes in genomes in evolution. Study of miRNA involvement in Alzheimer’s disease pathogenesis is relevant, since the associations of protein-coding genes (APOE4, ABCA7, BIN1, CLU, CR1, PICALM, TREM2) with the disease revealed as a result of GWAS make it difficult to explain its complex pathogenesis. Specific expression changes of many genes were found in different brain parts of Alzheimer’s patients, which may be due to global regulatory changes under the influence of transposons. Experimental and clinical studies have shown pathological activation of retroelements in Alzheimer’s disease. Our analysis of scientific literature in accordance with MDTE DB revealed 28 miRNAs derived from transposons (17 from LINE, 5 from SINE, 4 from HERV, 2 from DNA transposons), the expression of which specifically changes in this disease (decreases in 17 and increases in 11 microRNA). Expression of 13 out of 28 miRNAs (miR-151a, -192, -211, -28, -31, -320c, -335, -340, -378a, -511, -576, -708, -885) also changes with aging and cancer development, which indicates the presence of possible common pathogenetic mechanisms. Most of these miRNAs originated from LINE retroelements, the pathological activation of which is associated with aging, carcinogenesis, and Alzheimer’s disease, which supports the hypothesis that these three processes are based on the primary dysregulation of transposons that serve as drivers of epigenetic regulation of gene expression in ontogeny.

Markers for identification of ER+/PR breast cancer (BC) risks and conversion of ER+/ER+ to ER-/PR- tumors are necessary for effective prevention and therapy of BC by the selective ER – modificators. Purpose – To reveal the proposed associations of gene polymorphisms of ESR1 and ESR2 and antiidiotypic antibodies to estradiol (IgG2-E2) with ER+/PR+ BC risk and conversion of ER+/PR+ to ER-/PR- tumors and to study the interrelations between gene variants of ESR and IgG2-E2 in healthy women and BC patients. Polymorphic loci of ESR1 (rs2234693) and ESR2 (rs4986938) were studied by the real time PCR in 370 healthy women and 1169 BC patients. Tumor tissues ER and PR were detected by the standard immunohistochemical methods. Serum IgG2-E2 were studied using non-competitive enzyme immuno-assay. TT, TC and CC genotypes of ESR1 were revealed with the equal frequency in healthy women and BC patients I stage. Homozygotes GG of ESR2 were detected rarely, but AA frequently in BC patients with ER+/PR+ tumors at the I stage, than in healthy women женщин (44.0% and 14.2% vs 52.7 and 8.4%, respectively; p=0.005). The low levels of IgG2-ES were revealed more rarely but high levels more frequently in BC patients with ER+/PR+ tumors at the I stage, that in healthy donors (39.8% and 60.2% vs 58.0% and 42.0%, respectively; p=0.0002). Decreasing of ER+/PR+ tumors proportion and corresponding increasing of ER-/PR- tumors from I stage to II–IV stages (71.7% to 58.9% and 13.9% to 23.1%; p=0.006) were revealed in TC heterozygotes of ESR1 only. The same conversion of ER+/PR+ tumors to ER-/PR- were detected in GG homozygotes of ESR2 (p=0.004). There have been the similar ER/PR transformation in BC patients with high IgG2-E2 levels (74.7% to 57.6% and 11.3%, to 25.0%, respectively, p

It has been proven that 98 % of the human genome is transcribed. The main part of resulting molecules after their processing function as various RNA molecules, among which the best known are long noncoding RNA (lncRNA) and microRNA. There are 126,000 lncRNA genes in humans that regulate transcription, translation, histone modifications, heterochromatin formation, splicing, microRNA expression and formation, and matrix RNA (mRNA) post-transcriptional modifications. An important property of lncRNAs is their mutual and self-regulation by peptides formed during their translation, which also affect the expression of protein-coding genes. This property may be due to origin of lncRNAs from transposable elements and is a conservative evolutionary characteristic of lncRNA, as one of properties in formation of new genes for variability and adaptation. The role of lncRNAs originating from retroelements and microRNAs formed during their processing in the specific regulation of genes involved in carcinogenesis has been proven. The peptides formed during lncRNA translation can be used as universal tools for targeted therapy of malignant neoplasms. Analysis of the scientific literature made it possible to describe 21 lncRNAs that are translated to form peptides involved in specific tumors pathogenesis. Since the ability of lncRNA to self-regulate by products of its own translation, which is characteristic of all lncRNAs, is also a property of transposable elements, it is promising to study transposons and their relationship with lncRNAs for designing new therapeutic models.

The main aim of the study is to analyze modern knowledge on endocrine disruptors, non-genotoxic carcinogens, contributing significantly to the total level of contamination of the biosphere by anthropogenic blastomogens.Material and Methods. For the review preparation, we analyzed articles on molecular mechanisms of the effects of endocrine disruptors, available at biomedical literature databases sciVerse scopus, pubmed, Web of science, Rsci. The review cited 65 recent publications, 21 of them being published over the past three years, 3 papers being the official documents on hazards associated with the use of endocrine disruptors, and 10 papers presenting a background to separate endocrine disruptors into the group of compounds with specific functional activity.Results. The role of endocrine disruptors involves the development of the tumors of reproductive organs. They may reveal the properties of strong agonists or antagonists disrupting the hormonal balance by inhibition of the synthesis of natural hormones, their secretion, transport, metabolism, binding or degradation. In addition, they activate alternative proliferation signaling pathways by activating g-proteincoupled receptors, estrogen-bound eRRγ or/and β-adrenergic receptors. The main mechanism of action of endocrine disruptors is the induction of epigenetic modifications, in particular, methylation/demethylation of cpg dNa islands, histone modifications and changes in expression of non-coding RNa. since the effects of endocrine disruptors are nonlinear, they can be caused by concentrations corresponding to the real content in the biosphere and detected in the umbilical blood and breast milk. In addition, they contribute to the metabolic activation of the procarcinogens, the main component of air pollution, by activation of the cytochrome p450 isoforms.Conclusion. Endocrine disruptors can underlie the development of tumors of hormone-dependent organs both at direct and transplacental exposure.

The review presents data on studies of the role of mycoplasmas as infectious agents in carcinogenesis, as well as their participation in cancer drug therapy and the impact on the outcome of treatment. Mycoplasmas are of particular interest because they have unique abilities to readily attach to and enter eukaryotic cells, modulate their functional state, and induce chronic inflammation while evading the host’s immune system. The review will highlight the data confirming the increased colonization of tumor tissue by mycoplasmas compared to healthy ones, describe the molecular mechanisms by which mycoplasmas activate the expression of oncogenes and growth factors, inactivate tumor suppressors, promote NF-κB-dependent migration of cancer cells and modulate apoptosis, which results in abnormal growth and transformation of host cells. The review also presents data on the effectiveness of anticancer drugs in mycoplasmal infections.

The incidence and mortality of malignant neoplasms of non-reproductive organs both carcinomas and sarcomas in men is one and a half times higher than in women. This is based on genetic differences, which are superimposed by patterns of epigenetic regulation of the expression of sex chromosome genes that determine sex differences in the processes of tissue differentiation, which, in turn, mediates the formation of the hormonal status of the body. Compared to the Y chromosome, the mammalian X chromosome contains several dozen times more genes encoding major regulators of proliferation, metabolism, immunity, and tumor growth inhibitors, as well as X-linked microRNAs affecting transcription factors and cross-regulation by other non-coding RNAs. This results in a female or male gene expression profile that accounts for phenotypic differences. This peculiarity, along with the fact that in female cells on the second inactivatedX chromosome epigenetic repression of the most important genes is reversed and, accordingly, their expression level is doubled, may largely explain the sex disparity in carcinogenesis. The influence of sex hormones and disparity in the expression of antitumor immunity contribute significantly to this difference. A detailed study of the mechanisms underlying sex dimorphism in carcinogenesis will be an essential contribution to fundamental oncology and to the practice of diagnosis, prognosis and personalized treatment of malignances with regard to their gender-specific course. These studies are especially relevant in relation to insufficiently studied soft tissue sarcomas, the ratio of the frequencies of which in men and women varies greatly depending on the histological subtype of the tumor.

Background. Imbalance of aminothiol metabolism is a potential risk factor for malignant transformation of cells and caner development, including breast cancer, which is the most commonly diagnosed cancer in the world. The purpose of the study was to summarize the available data on the characteristics of thiol metabolism as one of the factors contributing to the progression of breast cancer. Material and Methods. Data were searched from 1999 to 2022 using the Web of Science, Scopus, MedLine, The Cochrane Library, PubMed databases, which made it possible to assess the role of thiol-dependent metabolic disturbances in the regulation of tissue redox balance in breast cancer genesis. Results. The review considers the results of both our own data and international studies on breast cancer, which suggest that an imbalance of thiol compounds necessary to maintain a moderately reducing cellular environment that counteracts oxidative stress during cellular metabolism and detoxifcation under conditions of tumor progression can provoke reprogramming of the leading links of antiblastoma resistance, contributing to cancer progression. Conclusion. A more detailed study of the mechanisms of aminothiol metabolism in breast cancer emphasizes their particular importance for stabilizing the cellular genome and providing antitoxic protection of the cell, as well as understanding the important role of thiols as a coordination center in redox signaling. Disturbances at any stage of thiol metabolism can play an etiological role in oncogenetic pathologies, while the role of thiols as signaling molecules and the regulation of their metabolism should not be generalized for the entire group of diseases. Determination of serum markers of the redox state in patients with breast cancer, especially during antitumor therapy, can serve for an objective assessment of the effectiveness of treatment and the adaptive capabilities of the body, as well as predicting tumor growth and optimizing the program for screening and preventing cancer.

Introduction. Head and neck squamous cell carcinoma is the 6th most common malignant tumor. It is characterized by immune response evasion and drug resistance. To stimulate antitumor immune response, antibodies against such cell cycle checkpoints as programmed cell death 1 (pD-1) and programmed death-ligand 1 (pD-L1) are used. However, effectiveness of monotherapy with these checkpoint inhibitors turned out to be low, and combinations with other antitumor drugs have high risk of adverse events.Aim. To determine the most practical ways to influence epigenetic factors in treatment of head and neck squamous cell carcinoma.Materials and methods. Scientific literature published between 2011 and 2022 and indexed in the eLIBRARY, Scopus, woS, NCBI databases (398 articles, of which 76 were used) was analyzed.Results. prospects of development of epigenetic stimulation of expression of retroelements located in tumor genomes through inhibition of DNA methyltransferases, deacetylases and histone methyltransferases were considered. when retroelements are activated, their transcripts form double-stranded RNA stimulating T killers and interferon response (virus mimicry). for DNA methyltransferase inhibitors, restoration of tumor suppressor genes which are hypermethylated in squamous cell carcinoma is also observed. However, retroelement activation is a driver mechanism of carcinogenesis, and their nonspecific expression can lead to tumor progression and formation of secondary tumors. Therefore, in the virus mimicry method it is practical to use as targets microRNA complementary to retroelements which recruit epigenetic factors to their loci (RNA-directed DNA methylation), as well as antisense oligonucleotides against oncogenic microRNA associated with retroelements. These approaches allow to inhibit retroelements participating in carcinogenesis. Nonspecific method of retrotransposon activity suppression is being developed in antitumor therapy, but data show successful application of only reverse transcriptase inhibitors preventing insertions and progression of genomic instability. we have performed analysis of scientific literature on transposable elements-derived microRNA associated with head and neck squamous cell carcinoma. As a result, 31 microRNAs were identified, derived from: LINE: miR-1249, -151a, -211, -2355, -28, -31, -3144, -374a, -374b, -421, -450b, -511, -576, -577, -582, -708, -769, -887, -95; HERv: miR-1269a, -1911, -3200, -495; non-autonomous SINE: miR-335, -342, -378a, -3934, -487b; DNA transposons: miR-224, -584, -652. These microRNAs can serve as the basis for epigenetic therapy of head and neck squamous cell carcinoma.

Hormonal-induced changes in the breast occur due to both endogenous and exogenous sex hormones. For two decades, the safety of hormonal contraceptives (HC) in terms of their effect on breast tissue has been discussed in the literature. The pleiotropic effect of the components in the combined HC, on the one hand, prevents unwanted pregnancy; on the other hand, they help to maintain good health of women of childbearing age due to a wide range of non-contraceptive effects (eliminating hyperandrogenism manifestations, reducing the pain severity during menstruation and the menstrual blood loss, the risk of recurrence of functional ovarian cysts, oncoprotective effect due to reducing the risk of ovarian, endometrial, colorectal, pancreatic, and lung cancer). However, according to epidemiological studies, in addition to the beneficial effects, there are risks that require further study, including the controversial impact of HC on the oncogenesis and progression of breast cancer. In addition, some young women with breast cancer experience induced menopause after antitumor treatment. However, amenorrhea is not a marker for complete disabling of ovarian function, and pregnancy is associated with a risk of disease recurrence or progression. Therefore, in each case, it is necessary to determine the need for an effective and safe method of contraception.

Cancers are one of the leading causes of mortality in the world. Cellular and physiological mechanisms of cancer development remain not well defined. In vivo models are an attractive approach for understanding of cancer origin and progression. This review presents current state of experimental in vivo systems including syngeneic models, patient-derived xenografts (PDX), cell line-derived xenografts (CDX) and various animals – humanized and genetically engineered models (GEM). These models provide opportunities for developing patients’ avatars, lifetime visualization of tumor migration and invasion at the organism level, and the evaluation of new therapeutic methods aimed at primary tumors, metastases, and cancer prevention. We also discuss the problems of choosing the optimal model and potential solutions for their overcoming.

Malignant neoplasms cells are characterized by clonal evolution that is resistant to the applied antitumor drug and evasion from the effects of the immune system. Therefore, a promising direction in modern oncology is the stimulation of the immune response against neoplasms. This method can be used in combination with other anticancer drugs and alone. Tumor cells produce CTLA4 (CTLA4 — cytotoxic T-lymphocyte protein 4) and PD-1 (programmed cell death) checkpoints that inhibit the activity of T-lymphocytes and their production of antitumor cytokines. The clinic uses antibodies against CTLA4, PD-1 and PD-L1, monotherapy with which increases the effectiveness of the chemotherapy used, but significantly aggravates the development of adverse reactions, which limits their use. Monotherapy with anti-PD/PD-L1 showed low efficacy and also a high risk of pulmonary, hepatic, and thyroid complications. In this regard, it is necessary to develop new methods of tumor immunotherapy. The most promising in this regard is the method of viral mimicry, when double-stranded RNA formed from transcripts of retroelements serve as a trigger for the production of interferon and activation of T-killers. For artificial activation of retroelements, inhibitors of DNA methyltransferases, deacetylases, and histone methyltransferases are used. Since retroelements are located in gene introns, viral mimicry can be used in spliceosomal targeted therapy. Transposons serve as drivers of carcinogenesis, therefore, in addition to their artificial activation, oncology uses methods for silencing retroelements using reverse transcriptase inhibitors. The use of non-specific methyltransferases and inhibitors of histone demethylases for this can lead to suppression of the expression of other genes, with possible side effects. Therefore, this technique is the most promising with the use of guides that direct histone modification enzymes to the loci of the location of retroelement genes in the genome. Guides can also be used to activate the most significant retroelements in the development of the immune antitumor response and exclude the expression of elements involved in the initiation and maintenance of carcinogenesis. MicroRNAs, long non-coding RNAs, and antisense oligonucleotides can be used as guides.

Purpose. The aim of the review is to analyze the modern data on the molecular mechanisms of stomach and intestinal carcinogenesis, which can be the basis for managing of malignant stomach and intestine neoplasms mortality risks’ reduction. Materials and methods. The review includes data from foreign and domestic studies published in the electronic bibliographic databases PubMed, Cyberleninka, Elibrary over the past 10 years. Results. It is given the analysis of Wnt and β-catenin gene family role in the pathogenesis of stomach and colon malignant tumors and the carcinogenic potential of Helicobacter pylori in gastric cancer, as well as the driver bacteria contributing to the development of colon cancer. Conclusion. Stomach cancer and colon cancer are heterogeneous diseases with diverse molecular and histological subtypes, having both similarities and differences in the patterns of cancer promotion. Progress in transparency genesis of these diseases is associated with an understanding of cytotoxic and genotoxic effects, oxidative stress and chronic inflammation mechanisms.

Breast cancer (BC) is the leading cause of morbidity and mortality of malignant neoplasms in women worldwide. In spite of a large number of studies devoted to the etiopathogenesis of this group of malignant tumors, many questions concerning specific mechanisms of their origin and development are still unresearched. Based on numerous studies in recent years, in addition to traditional risk factors (such as hereditary factors, hormonal disorders, environmental factors, etc.), foreign and Russian authors have identified a new risk factor for BC development - the sphere of molecular disorders affecting circadian rhythms and circadian genes, as well as metabolic and regulatory intracellular pathways regulated by them. It has been shown that the balance between oncogenes and suppressor genes and processes such as neoangiogenesis, metastasis and antitumor immune response depend on the functioning of the circadian rhythm system. One of the key metabolites in the circadian rhythm regulation system is melatonin, which physiological effects extend not only to the central nervous system, but also to peripheral tissue cells. The study of the relationship between circadian rhythm disturbances, melatonin secretion and malignant tumors is one of the important tasks of modern oncology. In the present review the following aspects of this problem are considered in detail: relationships between circadian rhythms, melatonin and BC; molecular mechanisms of melatonin antitumor action in BC; therapeutic potential of melatonin in prevention and treatment of malignant breast tumors as a direct antitumor agent, a component of accompanying treatment, and as a radiosensitizer and radioprotector for radiotherapy. The purpose of this review is to investigate the problem of the relationship between the circadian rhythm system, melatonin and molecular mechanisms of development and progression of breast malignancies, as well as the therapeutic potential of melatonin in their prevention and treatment. The review is based on the study of relevant and reliable scientific articles, reviews, meta-analyses, systematic reviews, and clinical trials published in Scopus, PubMed, Web of Science and in peer-reviewed Russian journals mainly during the last 5 years.

Fusobacterium nucleatum is a component of the oral microflora, and in clinical practice it is associated primarily with periodontal diseases. Since 2011, the scientific community has confirmed the association of F. nucleatum with colorectal cancer (CRC) by seeding it from tumor tissue samples. Research has led to the discovery of mechanisms by which this bacterium may contribute to the development, metastasis of CRC and chemoresistance. With the help of its adhesion proteins (FadA and Fap2) F. nucleatum specifically attaches to colorectal carcinoma cells. Following invasion, F. nucleatum induces inflammation, activates β-catenin signaling, and creates a favorable microenvironment for tumor growth and development. Recently, the role of F. nucleatum in other types of oncological pathology, such as oral cavity cancer, head and neck cancer, gastric cancer, esophageal cancer, pancreatic cancer, cervical cancer and breast cancer, has been confirmed. Understanding the mechanisms of association of F. nucleatum with oncological diseases will help to find new approaches in the treatment, prevention and diagnosis of cancer. Thus, further studies of the correlation between F. nucleatum and carcinogenesis are needed, using a multidisciplinary approach and physicians from other specialties.

The review presents information on the role of hepatitis B virus (Hepadnaviridae: Orthohepadnavirus: Hepatitis B virus) (HBV) X gene and the protein it encodes (X protein) in the pathogenesis of viral hepatitis B. The evolution of HBV from primordial to the modern version of hepadnaviruses (Hepadnaviridae), is outlined as a process that began about 407 million years ago and continues to the present. The results of scientific works of foreign researchers on the variety of the influence of X protein on the infectious process and its role in the mechanisms of carcinogenesis are summarized. The differences in the effect of the X protein on the course of the disease in patients of different ethnic groups with regard to HBV genotypes are described. The significance of determining the genetic variability of X gene as a fundamental characteristic of the virus that has significance for the assessment of risks of hepatocellular carcinoma (HCC) spread among the population of the Russian Federation is discussed.

An interaction between decreasing host anti-infective defense due to long-term invasion with Opisthorchis felineus in the hepatobiliary system, duct bile colonization by microflora and revealing the endogenous mutagenesis (carcinogenesis) factor in bile — secondary bile acids — is considered in the article. The role of organism genotype in pathogen-related immune response to Opisthorchis felineus trematode and helminth development in the hepatobiliary system has been shown. The role of dysregulated mechanisms of tissue homeostasis in induction of compensatory chronic homeostatic proliferation and somatic cell oncogenesis is discussed. The study results evidence that disturbed functioning of regulatory T cells, inhibition of the NK cell effector function and very high functional activity of memory B cells are of great importance in imbalanced host immunobiological reactivity, caused by chronic opistorchis invasion. Decreased host anti-infective protection causes intrahepatic bile duct infection with different bacterial species. Presence of secondary bile acids in hepatobiliary system was associated with biliary bacterial strains inhabiting intestinal tract: Proteus vulgaris, Proteus mirabilis, Citrobacter freundii, Bacteroides alcaligues faecalis, Clostridium, Streptococcus faecalis, Еscherichia coli — gut microflora agents. Participation of microbiota in bile acid biotransformation immediately in the duct bile has been confirmed in experiments in vitro. Experimental methods on Drosophila melanogaster and Salmonella typhimurium strains: TA100, TA98 allowed to find out that bile from chronic opistorchiasis patients exerts higher mutagenic activity compared to control groups. Mutational events in somatic and bacterial cells depend on the presence of secondary bile acids (deoxycholic, lithocholic) in duct bile, as well as the level of total bile acid concentration. The study data confirm the concept by Professor A.A. Shain about the presence of endogenous risk factor for developing primary cholangiocellular liver cancer such as secondary bile acids in the bile of chronic opistorchiasis patients. A concept of cholangiocarcinogenesis, based on mutational events, is added up with disturbance of generative cycle in tissue cells and their differentiation due to decreased chalone factor activity, as well as sensitivity threshold to it. Level of investigation and understanding of mechanisms underlying cholangiocarcinogenesis during chronic opisthorchis invasion will allow to develop pathogenetic approaches to correct homeostasis regulation and prevention of cholangiocarcinomas.

Analysis of scientific literature data has revealed several ways in which retrotransposons, when activated, are involved in carcinogenesis. First, retroelements can encode oncogenic proteins. For example, the Np9 protein is translated from HERV-K endogenous retrovirus transcript. Second, retroelements are used as alternative promoters of protooncogenes. Accordingly, their activation contributes to the enhanced expression of oncogenes (e.g. CSF1R, IRF5, MET, RAB3IP, CHRM3). Third, retroelements are located in the introns of some genes, and upon their activation, they form chimeric transcripts, such as LTR2-FABP7, LTR-ALK, LTR-ERBB4, LINE1-MET, which have pronounced oncogenic activity. Fourth, retroelements are transposed into tumor suppressor genes (e.g. APC, NF1, MSH2, PTEN, RB1, TSC2, STK11, VHL) and inactivate them, which is associated with the presence of hot spots of insertional mutagenesis in them. As a result, the growth of tumors and the survival of their cells are stimulated. It is important to note that protein products of tumor suppressor genes, such as TP53, RB1, VHL, BRCA1, ATM, are characterized by the ability to inhibit the activity of retroelements. Accordingly, when even one oncosuppressive gene is inactivated, a kind of "vicious circle" can be triggered when the control of expression of retroelements is weakened. The latter, in turn, inactivate other tumor suppressors containing hot spots of insertional mutagenesis. This stimulates new pathways of carcinogenesis and the production of oncogenes associated with transposons. Thus, it is possible to explain in a new way the mechanisms of tumor formation in hereditary tumor syndromes. This is due to the fact that the weakening of the function of an oncosuppressor in a germinal heterozygous mutation may be sufficient to trigger a vicious circle involving retroelements, oncogenes and other oncosuppressors. Similar mechanisms are likely for sporadic malignant tumors. However, the initiating event in them can be the direct activation of transposons under the influence of stressors, chemical and physical carcinogens. In addition to the events described, activation of retroelements causes genomic instability, which contributes to complex genomic rearrangements often observed in malignant tumors. MicroRNAs and long noncoding RNAs, the sources of which are retroelements, also play an important role in the evolution of tumors. Their study is promising for the development of targeted therapy for neoplasms.

Genomic instability caused by activated retroelements plays an important role in the development of malignant neoplasms. Activated retroelements cause enhanced expression of oncogenes containing transposon sequences in their promoters and introns. Oncosuppressor genes contain hot spots of insertional mutagenesis, therefore retroelements cause their inactivation. As a result, genomic instability increases during the development of tumors, since oncosuppressors normally silence retrotransposons. Accordingly, inactivation of the oncosuppressor causes increased expression of retroelements.The study objective is to describe the role of retrotransposons on the development of hereditary tumor syndromes, which will allow a new look at the classical concepts of carcinogenesis. The data we have described allow us to consider in a new way the Knudson’s two-hit hypothesis in hereditary tumor syndromes, since the germinal inactivation of 1 allele of the oncosuppressor gene promotes the development of malignant tumors due to an increase in the activity of transposons. The consequence of the developed instability in the tumor is the inactivation of the second allele of the oncosuppressor gene, which contributes to clonal evolution and the progression of carcinogenesis.

Nanomaterials become more widespread in the different areas of human life, forming the new technosphere philosophy, in particular, new approaches for development and usage of these materials in everyday life, manufacture, medicine etc.The physicochemical characteristics of nanomaterials differ significantly from the corresponding indicators of aggregate materials and at least some of them are highly reactive and / or highly catalytic. This suggests their aggressiveness towards biological systems, including involvement in carcinogenesis. The review considers the areas of use of modern nanomaterials, with special attention paid to the description of medicine production using nanotechnologies, an analysis of the mechanisms of action of a number of nanomaterials already recognized as carcinogenic, and also presents the available experimental and mechanistic data obtained from the study of the carcinogenic / procarcinogenic effects of various groups of nanomaterials currently not classified as carcinogenic to humans.Preparing the review, information bases of biomedical literature were analysed: Scopus (307), PubMed (461), Web of Science (268), eLibrary.ru (190) were used. To obtain full-text documents, the electronic resources of PubMed Central (PMC), Science Direct, Research Gate, Sci-Hub and eLibrary.ru databases were used.

For all tumors, regardless of type and tissue, there are a number of common features. These include high proliferative activity, disturbances in the mechanisms of apoptosis and "invisibility" for the cells of the immune system. At the basis of all these disorders lies a malfunction in the interaction between signaling proteins inside the cell, due to a violation of the expression of genes responsible for their synthesis. The aim of the review is to study the molecular biological mechanisms of carcinogenesis, characteristics and features of tumor cells that affect the development of the disease, progression, drug resistance and clinical results and the possibilities of targeted therapy of oncological diseases. Material and methods. The search for literature sources was carried out using PubMed, CyberLeninka, eLibrary, Google Scholar databases; the search depth was 15 years. Results. Recent works have shown the evolution of views on the classification of tumors from the point of view of the mechanisms of damage to the processes of cellular regulation and histogenesis, as well as the development of the modern theory of carcinogenesis, ideas about the mechanisms of development of tumor diseases and the prospects of modern therapies. Conclusion. The study of molecular biological mechanisms of carcinogenesis, characteristics and features of tumor cells is not only fundamental, but also of applied importance in order to predict the development of the disease, progression, drug resistance, clinical results and the possibilities of targeted therapy.

Currently, the role of human papillomavirus (HPV) in carcinogenesis is well known: more than 90 % of HPV-positive oropharyngeal squamous cell carcinomas are caused by HPV type 16 (HPV-16). HPV E6 and E7 oncoproteins play a significant role in the development of this tumor. The E6- mediated degradation of suppressor protein p53 results in G2/M-phase checkpoint dysregulation and inhibition of apoptosis. HPV oncoprotein E7 binds to pRb, promoting its degradation and the release of E2F transcription factor. Diagnostic assays for HPV detection include immunohistochemical staining for p16, polymerase chain reaction, in situ hybridization, and next-generation sequencing. Immunohistochemical examination (determination of p16 protein expression) is an economical and very specific way to detect a viral infection. Patients with HPV-positive oropharyngeal squamous cell carcinoma demonstrate significantly better response to treatment and overall survival rates than those with HPV-negative oropharyngeal squamous cell carcinoma. Despite the fact that five-year overall survival rate in patients with HPV-positive oropharyngeal squamous cell carcinoma after treatment exceeds 80 %, some patients have poor survival. Unfortunately, currently available methods of risk stratification still do not endure their timely identification. Further research is needed to address these problems.

Purpose of the study: to review in vivo studies on the relationship and role of various molecular genetic components of the circadian rhythm system in the initiation and development of malignant neoplasms. in contrast to clinical and epidemiological studies, animal models, including transgenic animal models, can model various changes and disturbances in the activity of clock genes and track the results of these changes.Material and Methods. the review includes data from studies carried out over the past 10 years in animal models, studying the mechanisms and effects of disturbances in the system of circadian rhythms related to the formation and development of tumors. the data sources for the review were the Medline, embase and scopus databases.Results. analysis of the literature has shown that interference with the work of the «biological clock» by changing the light cycle, disrupting the expression of clock genes and other manipulations is a factor predisposing to the development of tumors. in tumors of various types, the expression of clock genes is often mismatched, and it is unclear at what stage of their formation this occurs. in addition, the development of tumors disrupts the circadian homeostasis of the body. there are three key areas of research aimed at studying the role of circadian rhythms in tumor development: disturbance of circadian rhythms as a carcinogenic factor, disturbances in the clock gene system in a tumor, disturbances in the clock gene system of the whole organism, provoked by tumor development.Conclusion. the results of studies on animal models demonstrate that the relationship between the disturbance of circadian rhythms and the tumor process is complex since the causal relationship has not yet been studied. in this regard, the prospect of targeted pharmacological correction of circadian rhythms in clinical practice in cancer patients does not seem to be the nearest one.

Article presents current data on the contribution of the human microbiota to the development of oncological conditions, microbial impact on cell transformation, influence on chemotherapy outcome. Brief description of the methods used for studying microbiota in carcinogenesis as well as prospects of creating non-invasive diagnostic tools is given.

Aim. A study of atrophic gastritis severity and rate in patients with gastric polyps (GP).Materials and methods. The study enrolled 61 patients with hyperplastic (HGP) and 41 — with adenomatous GP (AGP). All patients had 24-h gastric pH-metry, control of the pepsinogen I, II and gastrin-17 levels, in addition to a general clinical, endoscopic, histological examination and testing for Helicobacter pylori.Results. GP patients had benign manifestations prevailed with epigastric heaviness and overflow, and a scarce history of H. pylori testing at no control of rendered eradication therapy. A symptomatic proton pump inhibitor treatment in GP was either prescribed or voluntary. Focal atrophic gastritis in endoscopy was revealed in 12 (19.7 %) HGP and 16 (39.0 %) AGP patients, diffused atrophic gastritis — in 49 (80.3 %) HGP and 25 (60.9 %) AGP patients. Low-grade chronic gastritis in histology prevailed in HGP, moderate — in AGP, and severe — in 21.9 % cases. Moderate (27.9 %) to severe (65.6 %) atrophy of gastric mucosa was registered in HGP, with 53.7 and 39.0 % respective AGP cases. Polyp dysplasia was detected in 20 % HGP and 75.6 % AGP cases. Pepsinogen I H. pylori-positive were 52.5 % HGP and 70.7 % AGP cases.Conclusion. A largely similar aetiopathogenesis of gastric polyps and chronic atrophic gastritis warrants the H. pylori diagnosis and a more detailed patient control for chronic gastritis grading and staging, functional insufficiency of gastric mucosa and the severity of hyperplastic and dysplastic change. The H. pylori eradication, in contrast to anti-secretory therapy, allows the containment of chronic gastritis and is a critical measure in gastric cancer prevention.

Introduction. Neurofibromatosis type 1 (NF1) is the most common hereditary tumor syndrome (frequency of its occurrence in the world is 1 : 3000 of the population). The main clinical manifestations of the disease are multiple café-au-lait macules on the skin and neurofibromas, skeletal abnormalities and cognitive deficits. The disease is based on mutations in the oncosuppressor gene NF1. This disease is characterized by significant clinical polymorphism of manifestations, even among members of the same family. No geno-phenotypic correlations were found for NF1. Therefore, it is assumed that modifier genes are the cause of the varying expressiveness of the disease. Materials and methods. Clinical-epidemiological and molecular-genetic research of patients with NF1 in the Republic of Bashkortostan (RB) was carried out. Sequencing was used to search for intragenic mutations in 57 exons of the NF1 gene. Microsatellite analysis was used to detect the deletion of the entire gene.Results. The frequency of occurrence of NF1 in RB was 1 : 10153 of the population. Analysis of the clinical manifestations of NF1 in RB patients showed a lower incidence of brain cysts in patients born in mixed marriages, which indicates the protective role of mestization. In patients with NF1 who inherited the disease from the mother, a more frequent development of skeletal anomalies and facial dysmorphism was determined. We identified 1 deletion of the entire NF1 gene in 1 patient and 14 intragenic mutations (c.205-1G>C, с.1278G>A, c.1369_1370insGGGTC, с.1570G>A, с.1973_1974delTC, c.2806A>T, с.2991-1G>C, c.3158C>G, с.3526_3528delAGA, с.3826delC, с.4514+5G>A, с.4537С>Т, c.5758_5761delTTGA, с.6792С>A) in 20 patients with NF1. We determined the random distribution of the types of mutations and did not reveal the specific features of the NF1 clinic depending on the type of mutations.Conclusions. The protective role of crossbreeding in relation to brain cysts, as well as the predominance of skeletal anomalies in patients with NF1 inheritance from the mother, indicate the role of modifier genes in the pathogenesis of the disease. The identified mutations in the NF1 gene will allow us to perform prenatal prevention of NF1 in RB patients.

Causes and mechanisms of cancer development are currently one of the urgent problems of medicine. The main variant for today is the mutation theory. Identification of the system of gene mutations, including in mitochondria, leading to this or that type of tumors, made it possible to develop a personalized, so-called targeting, the therapy of malignant tumors.

Gastric cancer is currently one of the most prevalent malignancies worldwide with a high mortality rate. Helicobacter pylori (H. pylori) infection significantly contributes to the onset and progression of gastric cancer mainly due to the induction of chronic inflammatory responses. The pathogenicity of H. pylori is associated with a vast number of virulence factors among which cytotoxin-associated gene A (CagA) plays a crucial role. We conducted a literature review of PubMed, Web of Science, and Scopus on September 1st, 2021. There were no limits regarding the year and the language of publication. Articles included in this review concerned human and animal studies. The following search string was applied during the search: (gastric cancer) AND (epithelial-mesenchymal transition) AND (Helicobacter pylori) AND (cytotoxin-associated gene A). The final analysis included 135 articles independently reviewed by the authors. H. pylori CagA-positive strains seem to be more virulent compared to the CagA-negative strains. CagA pathogenicity includes the increased secretion of pro-inflammatory cytokines, induction of cancer stem cell-like properties, apoptosis prevention, or overactivation of particular oncogenic pathways. H. pylori might induce epithelial-mesenchymal transition (EMT) via numerous pathways, among which CagA-related pathogenicity is considered to be of high significance. Mechanisms associated with CagA action are involved in the maintenance of chronic H. pylori infection, subsequent EMT induction, and further onset and progression of gastric cancer. Because of a huge number of H. pylori strains with different virulence mechanisms, the clinical outcome of patients is also associated with the particular type of strain that infected a patient.

Despite significant advances in the diagnosis and treatment of oncopathology, the main epidemic indicators have a negative trend.Based on the above, a very relevant topic is the development of experimental models of carcinogenesis. The importance of scientific work in this area is increasing because in experimental conditions it is better to test new methods, diagnostics and treatment. Thus, it becomes possible to study the peculiarities of the pathogenesis of any tumor at different stages.The purpose of the work – to study and demonstrate the strengths and weaknesses of the main experimental models of carcinogenesis for further selection of the most appropriate.Results The main directions of carcinogenesis modeling are presented in the article. Initially, the problem was justified. The next step is described in chronological order of using the models.Of course, the achievements of clinical and experimental oncology played an important role in the emergence of models. Thus, the first model was the effect of physical and chemical carcinogens on a laboratory animal. The latest achievement of experimental oncology is the use of stem cells in combination with genetic engineering.No less important is the fact of comparing experimental models. We present the strengths and weaknesses of all these models.Conclusions1. To date, there are a large number of experimental models of carcinogenesis.2. When planning a study, you need to calculate all the goals to be achieved and select the appropriate model.3. The most effective and common model for ascites ovarian tumor is the transplantation of atypical cells to laboratory animals.

Introduction:One of the main characteristics of cancer is uncontrolled cell proliferation as well as loss of cells adhesion in the case of metastases. Cadherins and catenins are the molecules responsible for cell-to-cell interaction. Together, they form a complex called ECCU (E-cadherin/catenin complex) which maintains the proper tissue structure. However, an impairment in its functioning can result in many adverse health effects, such as cancer promotion. Purpose: To evaluate the potential role of ECCU complex in carcinogenesis. Materials and methods: We performed the database research using PubMed, Springer Link and ResearchGate and we made review and meta-analysis of relevant studies. We searched for studies analyzing the relationship between ECCU complex and carcinomas development. Results: ECCU takes part in many cell processes and pathways, such as Wnt/Wingless‐signaling pathway or EMT/MET processes. It interacts with various molecules, for instance p27 protein or transcription factors. Aberrations in the expression of ECCU components is related to carcinoma promotion, shorter survival rate of patients and poor differentiation of the tumor. Conclusions: A role of the ECCU complex is complicated, however there is a clear correlation between loss of cell adhesion and carcinoma promotion and progression. The complex can be a possible target of anti-cancer therapy in the future; it is also under investigations as a marker of the disease, however it is questionable.

Background: Barrett's esophagus (BE) is a precan-cerous disease of the esophagus. The risk of adenocarcinoma in BE patients increases with the extension of segment length and with the presence of dysplasia. Columnar-lined esophagus (CLE) devoid goblet cells is also associated with dysplasia and adenocarcinoma, however, with a lower risk. Aim: To perform clinical and morphological analysis of patients with BE with goblet cells and CLE devoid goblet cells on the presence or absence of dysplasia. Materials and methods: This prospective clinical morphological study included 78 patients with columnar-lined esophagus at EGDS, among them 20 patients with a long segment, 58 patients with a short segment. Biopsy specimens from the CLE area of the distal part of the esophagus were stained by hematoxylin and eosin and standard PAS-reaction with Alcian blue. Histological examination showed BE with goblet cells in 49 patients and CLE devoid goblet cells in 29 patients. In those with BE, the morphometric analysis of the goblet cells density was performed and the number of the affected crypts was counted in dysplastic fragments. Results: In the short segment group, the male to female ratio was ~ 1:1.1, and CLE devoid goblet cells was found in 53% of cases (27/58 patients), and BE with goblet cells in 57% of cases (31/58 patients). In the long segment group, the male to female ratio was ~ 2.3:1, along with predominance of BE with goblet cells cases (18/20 patients, 90%) and high density of goblet cells (11/18 patients, 61%). The rates of goblet cells detection increased with the extension of the segment length (p < 0.05). The relative goblet cells density in the patients with the long BE segment was also significantly higher than in the short segment group (p < 0.001). Advanced inflammatory infiltration was found in 22 of 58 (38%) cases with the short segment and in 13 of 20 patients with the long one (65%, p = 0.012). The rates of erosion in the long segment group were 1.62-fold higher and ulcerations 3.87-fold higher (p = 0.014). Esophageal dysplasia was identified in 10 of 20 cases (50%) with the long segment and in 2 of 58 cases (3.4%) with the short segment. In 10 of 12 cases (83.3%) dysplasia was multifocal and involved from 2 to 10 crypts (in total, up to 25 crypts). Conclusion: The long segment of metaplasia was associated with higher rates of active chronic esophagitis, higher presence of goblet cells and their higher density. Dysplasia was found in 10 patients with three and more risk factors of progression (male gender, long segment, hiatal hernia, etc.). In most cases, the biopsy samples showed multiple foci of dysplasia.

Aim. To analyze and systematize the available information on pathogenetic mechanisms of hormonal carcinogenesis. Materials and methods. The review includes data from foreign articles published in PubMed and Medline and national works posted on elibrary.ru over the past 20 years. Results. Currently, the term estrogen is often used in the context of hormonal carcinogenesis. According to most researchers, it should not fit into the narrow framework of receptor-mediated proliferation induced by estrogens in target tissues. The concept of estrobiome as a combination of all mechanisms providing the realization of estrogen effects should include not only hormones and native receptors themselves, but also the enzymes involved in their synthesis, estrogen metabolites, intestinal microbiota, as well as genetic and epigenetic factors. Conclusions. When analyzing cancer risk, it is necessary to comprehensively assess contributing factors and hormonal-metabolic preconditions for neoplastic process.

This article is devoted to the most common bone tissue tumor among children — Ewing's sarcoma. The epidemiological data, most frequent afflicted zones of bones, clinical signs, diagnostics and treatment methods are analysed. The main focus is on the molecular genetic mechanisms of carcinogenesis initiation.

One of the most outstanding scientific achievements in the thrombolysis is the development and administration of fibrinolysin - the first Soviet drug that lyses blood clots. Intracoronary administration of fibrinolysin reduced the mortality of patients with myocardial infarction by almost 20%. For his work in this field Yevgeny Chazov was awarded the Lenin Prize in 1982. Over the next decades, under his leadership, the Cardiology Center established scientific and clinical laboratories that created new generations of drugs based on fibrinolytics for treating patients with myocardial infarction, restoration of blood flow in ischemic tissue, and also studying the mechanisms of remodeling of blood vessels involving the fibrinolysis system. It have been found new mechanisms of regulation of the navigation of blood vessels and nerves growth, tumor growth and its metastasis with the participation of the fibrinolysis system proteins. The review reports the role of the fibrinolysis system in the thrombolysis, blood vessels growth and remodeling, neurogenesis, carcinogenesis and fibrosis. The article is dedicated to the 90th anniversary of academician E.I. Chazov.

This review is devoted to assessing the prevalence of human papillomavirus (HPV) in head and neck tumors (HNC). HPV is recognized as the etiological factor of cervical cancer, but it may be involved in other tumors progression. Of the 28 studies presented, 6 studies showed a low incidence of HPV in HNC tissue (1.6—6.2 %).Most often, HPV was detected in Singapore (90.6 %), Japan (100 %) and France (94.7 %). Most often found 16 types of virus (82 %) and 18 types (43 %). Low-grade HPV type 11 was most often observed in the Russian Federation (19 %). The frequency of occurrence of HPV in HNC varies, which raises the question about impact HPV and co-infection in HNC progression. It makes further research in this area relevant and promising.

Summary Introduction and objective: Cancer arises from genetic and epigenetic changes in the cell. Indication of the direct causes of cancer is no doubt very difficult, because the process of carcinogenesis is a multi-level and multi-stage. Knowledge of existing threats to health is a determinant in making everyday decisions that are crucial in minimizing the risk for precancerous and cancerous. Featured Review article is only an outline of selected factors participate in the induction of neoplastic process. Its aim is to present the concept and the process of carcinogenesis, and to discuss the participation of selected factors in the induction of neoplastic lesions. Description of knowledge: Preiniciation is a period in which the carcinogenic effect on normal cells. Initiation is related to the appearance of the first permanent changes in the genetic material of the cell. The promotion is the stage in which the diseased cells grow and multiply. However, in the progression of metastasis occurs it. Factors that are surrounded by human impact on the integrity of the genetic material. Many of them have been scientifically proven effect mutogenne and carcinogenic. Conclusions:The effects of interactions of carcinogens accumulate in different time intervals. Carcinogens interact with DNA, causing deterioration or change in its structure. They can also cause changes in gene expression. Carcinogenic for a human body may be the same ingredients, food products and substances in food preservatives. Some viruses can be oncogenic due to the integration of the viral genome into the host genome in the vicinity of proto-oncogenes. Exposure to heavy metals and their metabolites contribute to DNA damage.

Introduction and objective: Free radicals (ROS), affect the course of each step of the process of carcinogenesis. Antioxidants that interact with ROS inactivates them, resulting in a positive effect both in preventing and inhibiting the progression of cancer. Vitamins such as A, C, E and D have anticancer properties. The article gives an overview of the problems of comp contribution of each vitamin in the chemoprevention of cancer. Its purpose is to present some antioxidants for its potential anti-tumor and to provide modifications to their effect on the carcinogenesis process. Description of knowledge: Vitamin A inhibits inter alia, lipid peroxidation and influences the growth and differentiation of epithelial cells to prevent neoplastic transformation. Vitamin E inhibits inter alia, angiogenesis, growth and proliferation of diseased cells. It also has the ability to stop the cell cycle. It prevents the formation of carcinogenic nitrosamines. Vitamin D inhibitor of vascular endothelial growth factor, and factors stimulating cell proliferation. Suppressive affects COX-2 enzyme. Increases the synthesis of E-cadherin. Vitamin C contributes to the proper functioning of the immune system by stimulating the activity of B and T lymphocytes is an electron donor for protecting cell components against oxidation. Stimulates cells to produce hyaluronidase inhibitor. Induces the synthesis of proteins p73 and MLH1. Conclusions: Imbalance redox system can lead to neoplastic transformation. Taking antioxidant supplements is associated with the risk of delivering them in too large a dose. Consequently, there is a support of the oxidation processes. The best way to protect against cancer and support cancer therapy is to provide antioxidants in their natural form, ie in the form of fresh vegetables and fruits.

The review analyzes literature data and the results of our own research on the role of reactive nitrogen species (NO, NO2, N2O3) in the initiation and progression of tumors. The possibility of modulating the activity of inducible NO synthase by the biologically active components of plant products and their effect on carcinogenesis is analyzed. Possible mechanisms of the ambiguous action of NO and its metabolic products in the mechanisms of carcinogenesis are discussed. The generalization and analysis of these data allowed us to formulate some principles for the use of substances that modulate the activity of inducible NO synthase and affect the formation of NO and its metabolic products in inhibiting carcinogenesis.

Proteins of the superfamily of small guanosine triphosphate hydrolase (GTPase) perform various functions: from the control of cell proliferation to the regulation of vesicular transport. The superfamily of small GTPase Ras includes more than 150 proteins, devided to 5 major families (Arf, Ran, Rho, Ras and Rab), and plays an important role in carcinogenesis. Compared to the other families, the Rab family was investigated by relatively small number studies, which does not equally reflect their role in malignant transformation processes. In our review we have focused on both the subfamily Rab3 and its poorly investigated member Rab3B. Recent findings allow to consider Rab3B not only as a promising diagnostic or prognostic marker for several types of neoplasms, but also is a potential target for antitumor therapy. Our analysis of publicly available transcriptional databases revealed that kidney, lung and liver cancer patients with low Rab3B gene expression demonstrate a better overall five-year survival.

The multifunctional urokinase-type plasminogen activator system (uPA-system) includes serine proteinase — uPA or urokinase, its receptor (uPAR) and two inhibitors (PAI-1 and PAI-2). The review discusses the structural features and involvement of the system components in the development of life-threatening processes including carcinogenesis, inflammation, neurogenesis and fibrinolysis, in regulation of which the destruction of extracellular matrix (ECM), cell mobility and signaling inside and outside the cell play a decisive role. uPA triggers the processes by activating the plasminogen and its convertion into plasmin involved in the activation of matrix metalloproteinases (MMPs) in addition to the regulation of fibrinolysis. MMPs can hydrolyze all the major ECM components and therefore play a key role in invasion, metastasis, and cell mobility. MMPs activates a cassette of biologically active regulatory molecules and release them from ECM. uPAR, PAI-1 and PAI-2 are responsible for regulation of the uPA activity. In addition, being a signaling receptor, uPAR along with MMPs lead to the stimulation of a number of signaling pathways that are associated with the regulation of proliferation, apoptosis, adhesion, growth and migration of cells contributing to tumor progression, inflammation, chemotaxis, and angiogenesis. Effective participation of the uPA system components in ECM destruction and regulation of intracellular and extracellular signaling pathways demonstrates that the system significantly contributes to the regulation of various physiological and pathological processes.

Previous studies reported some associations between class A antibodies specific for benzo[a]pyrene (IgA-Bp), estradiol (IgA-Es) and progesterone (IgA-Pg) and breast cancer (BC) in women like as with lung cancer (LC) in men. It was suggested that IgA-Bp and IgA-Es may stimulate tumor initiation and promotion, whereas IgA-Pg may inhibit the in vivo human carcinogenesis.The purpose of this study was to identify the suggested associations of such immunological imbalance with BC and LC in postmenopausal women.The serum A-class antibodies specific to benzo[a]pyrene, estradiol and progesterone (IgA-Bp, IgA-Es, IgA- Pg) were studied in 335 healthy women, 824 breast cancer (BC) patients and 127 cases of lung cancer (LC) by means of non-competitive solid phase immunoassay. The following results were obtained: Increased ratio of IgA-Bp and IgA-Es amounts exceeding the IgA-Pg levels was associated with a higher risk of breast cancer (OR = 2.8 and 2.4 respectively, p < 0.0001), and higher risk of LC (OR = 2.9 and 2.8, respectively, p < 0.0001). Conversely, the OR values decreased to 0.3-0.4 for BC and LC if IgA-Pg levels were higher than IgA-Bp and IgA-Es levels (p < 0.0001). These findings confirm the hypothesis that IgA-Bp and IgA-Es are capable to stimulate, and IgA-Pg, to inhibit the BC and LC occurrence n postmenopausal women. The balance between IgA-Bp and IgA-Es, on the one hand, and IgA-Pg, on the other hand, is much more important than individual contents of these antibodies.In conclusion, the phenomenon of “immunological interference” is revealed, i.e., the mutual enhancement of IgA-Bp and IgA-Es effects, thus, probably, stimulating the initial and subsequent events of carcinogenesis initiation and promotion, with a weak anticancer effect of IgA-Pg, and by weakening the mutual procarcinogenic effects of IgA-Bp and IgA-Es by the marked effect of IgA-Pg.

Oral cancer is an aggressive and rapidly progressive disease. The oral cavity is home to over 700 species of microorganisms that regulate metabolism, immune function, and health. There are three types of mechanisms by which bacteria may participate in carcinogenesis. First, bacteria cause chronic inflammation, which stimulates the production of cytokines, including interleukins, interferons, and tumor necrosis factor. Second, bacteria can interact directly with host cells by secreting toxins or by binding to membrane receptors. Finally, the production of metabolites by bacteria may also contribute to carcinogenesis. The importance of the bacteria level and composition in the transition of oral precancerous lesions to cancer has been demonstrated. The relationships of changes in microbiome composition with smoking, inflammation in healthy individuals, as well as with the development of oral cancer in patients, have been studied.

Breast cancer is considered a major and common health problem in both developing and developed countries. The etiology of breast cancer, the most frequent malignancy diagnosed in women in the western world, has remained unidentified. Chemicals as the organophosphorous pesticide malathion have been used to control a wide range of sucking and chewing pests of field crops, and are involved in the etiology of breast cancers. The association between breast cancer initiation and prolonged exposure to estrogen suggests that this hormone may also have an etiologic role in such a process. However, the key factors behind the initiation of breast cancer remain to be elucidated. The effect of environmental substances, such as malathion and estrogen was analyzed in an experimental rat mammary gland model. Different cytoplasmic proteins are key in the transformation of a normal cell to a malignant tumor cell and among these are the Ras super family and Ras homologous A (Rho-A). Both types of proteins were greater in animals treated with malathion than those with estrogens. E-Cadherins constitute a large family of cell surface proteins.Results showed greater expression of E-Cadherin and vimentin than c-Ha-ras and Rho-A in rats treated by estrogens. In breast cancer, analysis using immunohistochemical markers is an essential component of routine pathological examinations, and plays an important role in the management of the disease by providing diagnostic and prognostic strategies.The aim of the present study was to identify markers that can be used as a prognostic tool for breast cancer patients.

Significant progress in understanding the mechanisms of carcinogenesis is associated with the discovery of tumor suppressor genes (or antioncogenes). It is known that in the human population, the number of normally functioning suppressor genes varies in different individuals at birth. The aim of the study was to assess the probability of cancer development in an individual with a different initial number of undamaged normally functioning antioncogenes. On the basis of the probabilistic mathematical model of carcinogenesis, the most probable age of cancer development depending on the number of intact antioncogenes was assessed. As a result of the studies, the probability of cancer development depending on the age of the patient is estimated. The dependence of the probability of cancer development in an individual on the number of undamaged antioncogenes is also investigated. The analysis of the significance of the number of tumor suppressor genes, the damage of which may be the cause of initiation of cell malignancy, has been carried out.