Gastric cancer remains the fifth most common malignant neoplasm in the world and ranks fifth among the causes associated with cancer. The TNM system remains the gold standard for predictive stratification of patients with gastric cancer, but the search for new sensitive, specific and reproducible biomarkers to develop a personalized approach to the management of patients with gastric cancer does not lose its relevance. The phenomenon of tumor budding is a well-established independent prognostic factor in colorectal cancer. In 2017, the first guideline on the method of calculating tumor budding for colorectal cancer was published. Despite the promising potential of using tumor budding in gastric cancer this parameter is still not evaluated in everyday practice. This lection provides data on various methods of counting tumor budding in gastric carcinomas, describes the molecular mechanisms of interaction between tumor cells and the immune microenvironment, and summarizes the available data on the relationship of clinical and morphological characteristics of gastric cancer with the degree of tumor budding. The relationship between the degree of tumor budding and the prognostic characteristics of gastric cancer and the prospects for its use is also described.

To define the diagnostic value of eosinophilic cells for the detection of BRAF-mutated serous borderline ovarian tumors.

Gastric cancer (GC) is a heterogeneous tumor with various molecular changes. An active search for molecular markers is crucial to determine the effectiveness of drug treatment and prognosis of the disease. Several biomarkers have the greatest clinical significance: HER2, MSI / dMMR, PD-L1 (CPS), EBV and Claudin 18.

The development of drugs with the ability to increase differentiation and reduce tumor malignancy is one of the promising directions in the treatment of breast cancer (BC). As such, Human Leukemia Differentiation Factor (HLDF), a protein consisting of 54 amino acids and contributing to an increase in the degree of differentiation of invasive ductal breast carcinoma cells, can be used. The key disadvantage of the full-size HLDF is its rapid biodegradation. In this connection, the acetylamide form of the peptide (HLDF-6) was synthesized to protect against hydrolysis.

In 2021, a new type of tumor was defined according to the new WHO classification (high-grade astrocytoma with piloid features, HGAP). Morphological and neuroimaging differences of HGAP from pilocytic astrocytoma complicate diagnosis. Now, significant detection of this tumor is possible only using molecular genetic testing, in particular, methylation profile analysis.

Human papillomavirus type 16 (HPV16) belongs to viruses of the high-risk type and is associated by overexpression of E6 and E7 oncoproteins, which determine the oncogenic properties of the virus, such as immortalization and malignant transformation of proliferating epithelial cells. The biogenesis of redox-sensitive proteins E6 and E7 at the early stages of viral infection leads to blocking of the cell antioxidant defense system and ubiquintin-dependent degradation of p53 and Rb tumor suppressors. Maintaining high rates of tumor cell proliferation contributes to an increase in the level of reactive oxygen species (ROS) and a shift in the redox balance towards oxidative processes. Reduced glutathione (GSH) provides antioxidant protection to tumor cells through S-glutathionylation of thiol groups of redox-sensitive proteins, which leads to the appearance of multidrug-resistant forms of cancer. In this regard, drugs restoring redox balance and increasing susceptibility to antitumor therapy are of particular importance. We have established that, Bacillus pumilus RNase (binase) modulates the redox-dependent regulatory mechanisms that ensure tumor cell resistance to apoptosis in HPV-16-positive SiHa cells of cervical squamous cell carcinoma. Binase in nontoxic concentrations initiates a number of pre-apoptogenic changes, i.e., decreases ROS and reduced glutathione (GSH) levels, suppresses the expression of the E6 oncoprotein, activates the expression of the p53 tumor suppressor, and reduces the mitochondrial potential of tumor cells. Binase-induced disruption of the integrity of the mitochondrial membrane is a signal for activation of the mitochondrial apoptosis pathway.

Pancreatic Ductal AdenoCarcinoma (PDAC) is characterized by a poor prognosis and is poorly amenable to modern therapies. A range of cell cultures reflecting different degrees of tumor differentiation and malignancy can serve as a model of PDAC development. Highly differentiated cells with low malignancy are characterized by increased expression of the KLF5 gene. The KLF5 protein is a vivid representative of multifunctional transcription factors, and its involvement in a variety of cellular processes, particularly in the pathology of various cancers, has been demonstrated. We investigated the spatial organization of chromatin of the regulatory regions of the KLF5 gene using highly differentiated Capan2 PDAC cells with a high level of KLF5 expression and poorly differentiated MIA PaCa2 PDAC cells with a low level of expression of this gene by circular chromosome conformation capture (4C-seq). It was shown that the number and distribution of contacts of the KLF5 regulatory region with other chromatin regions are significantly different for these types of cells; the number of contacts is significantly higher for Capan2 cells. There is a correlation between the expression level of genes close to KLF5 and the intensity of their sequence contacts with the KLF5 regulatory region, indicating that their expression is coordinated, possibly within the transcriptional factory. Capan2 is characterized by a high level of contacts of the KLF5 regulatory region with the gene-free region containing a cluster of PDAC-associated single nucleotide polymorphisms (SNP/InDel). Thus, the total number of contacts of the promoter region of the KLF5 gene and the expression level of most of the surrounding KLF5 genes decrease as the grade of cell malignancy increases.

Dimethylarginine Dimethylaminohydrolase 1 (DDAH1) is an essential enzyme capable of degrading asymmetric dimethylarginine, which is an endogenous inhibitor of nitric oxide synthase. Increased expression of DDAH1 and subsequent increased NO production are associated with carcinogenesis. In particular, DDAH1 is involved in the creation of a vascular network by tumor cells, vasculogenic mimicry, which is closely associated with tumor progression and poor patient prognosis. This is the reason why DDAH1 may be a potential therapeutic target for the treatment of cancer.

Plexiform fibromyxoma (PFM) and gastroblastoma (GB) are rare gastric tumors with a specific MALAT1::GLI1 rearrangement, included in the conditional spectrum of neoplasms with alterations of the GLI1 gene. The article presents a clinical case of PFM in a 6-year-old girl and a literature review highlighting current data on the morphology, immunophenotype and molecular genetic characteristics of PFM and GB. Despite the common genetic anomaly, differences in the morphology and clinical course of these tumors indicate the need for further research to clarify their relationship and potential reclassification in the light of new data on tumors with GLI1 gene abnormalities. Integrating the accumulated knowledge about tumors with GLI1 gene alterations into diagnostic algorithms and therapeutic approaches will help improve the treatment outcomes of patients with these rare neoplasms.

Sinonasal papillomas are a group of benign, relatively rare tumors of the sinonasal tract with varying clinical courses. In the modern WHO classification, it is customary to distinguish three subtypes of sinonasal papillomas: the most common inverted type (ISP), oncocytic type (OSP) and exophytic type (ESP). Recently, the concept has emerged that the different types of sinonasal papillomas may not be variants of a single tumor, but rather separate tumors. Thus, OSP demonstrates KRAS mutations, and the pathogenesis of ISP is associated with EGFR mutations.

Despite the progress in understanding the pathogenesis of diffuse brainstem tumors, treatment of these neoplasms is usually empirical and conducted without morphological and molecular verification. Liquid biopsy is a minimally invasive technique providing data on tumor biology without standard biopsy. This method is based on analysis of cell-free nucleic acids (predominantly, extracellular DNA) in biological fluids with detection of specific mutations. Despite wide implementation in diagnosis and disease monitoring in extracranial malignancies, it is infrequently applied in neuro-oncology.

Pheochromocytoma (PHEO) currently is considered to be malignant due to metastatic potential. One of the most common familial forms of PHEO is multiple endocrine neoplasia syndrome (MEN) type 2. The penetrance of PHEO in MEN2 syndrome is up to 50% of cases. It may be one- or two-sided, but metastases occur extremely rare. The fact that in majority of cases of MEN2 syndrome the source of distant metastases is medullary thyroid carcinoma (MTC) complicates differential diagnosis in case of PHEO metastasis.Isolated cases of PHEO with metastases to the lymph nodes, lungs, liver, bones, brain in MEN2 patients were described. In the available literature, we have found a description of 31 cases of metastatic PHEO in MEN2 syndrome. The available data of those cases is presented as a table in the article.We present a description of a 40-year-old woman with MEN2A syndrome (mutation of the RET proto-oncogene p.Cys634Tyr), with a history of twice-performed surgical treatment of MTC, with daily crises of arterial hypertension accompanied by vegetative symptoms, with a giant bilateral PHEO (up to 200 m on the right and up to 150 mm on the left) with synchronous large metastasis (up to 50 mm) into the pubic bone with the destruction. The patient underwent several surgeries: bilateral adrenalectomy, then a bilateral revision of the neck, removal of the right upper and right lower parathyroid glands, residual thyroid tissue, then resection of the right pubic bone with a tumor.

Oncolytic viruses represent a promising class of immunotherapeutic agents for the treatment of malignant tumors. The proposed mechanism of action of various oncolytic viruses has initially been explained by the ability of such viruses to selectively lyse tumor cells without damaging healthy ones. Recently, there have emerged more studies determining the effect of the antiviral immunostimulating mechanisms on the effectiveness of treatment in cancer patients. Stimulation of innate immune cells by an oncolytic virus can initiate an adaptive antitumor immune response, yet at the same time, the antiviral mechanisms of the immune system can limit the spread of the virus, thereby reducing its effectiveness. Thus, the success of the clinical application of the oncolytic viruses directly depends on the three key components: tumor immunosuppression, antiviral responses, and antitumor immune responses. The review presents current data on the influence of pattern recognition receptors on the effectiveness of oncolytic viruses.

The purpose of this review was to analyze the most perspective methods for risk stratification of malignant transformation of pancreatic intraductal papillary mucinous neoplasms (IPMN). Advisability of humoral predictors (tumor markers, inflammatory markers, circulating leptin and branched-chain amino acids, etc.) is in identifying prognostic signs suitable for risk stratification of IPMN malignant transformation and, therefore, determining treatment strategy for a particular patient. According to data screening, the most advisable predictors of malignant transformation of neoplasms are carbohydrate antigen 19-9, carcinoembryonic antigen, neutrophil-to-lymphocyte ratio and high-grade dysplasia. At the same time, DNA sequencing, analysis of miRNA and telomere expression, as well as liquid biopsy have a high potential and require further research for routine clinical practice.

Ovarian cancer (OC) develops asymptomatically and escapes diagnosis until advanced stages, the feature contributing to a higher mortality rate. New prospects of OC diagnosis and treatment have been opened in studies of the gene regulation mechanisms that involve long noncoding RNAs (lncRNAs) and identification of the lncRNA genes that are inhibited via methylation of the promoter region. A set of 122 samples of primary OC tumors was examined by methylation specific real-time PCR to assess the methylation level of the lncRNA genes PLUT, SNHG1, SNHG6, SNHG12, and TINCR. A significant increase in their methylation levels was observed in OC (p < 0.001 by the nonparametric Mann-Whitney test). The methylation levels of SNHG6, SNHG12, and TINCR were found to correlate significantly (p < 0.05) with the stage of the tumor process, the histological grade, and metastasis. Downregulation of SNHG6, SNHG12, and TINCR was detected by real-time RT-qPCR, and a significant correlation between methylation and expression was demonstrated for SNHG6 and TINCR (rs < -0.5, p < 0.001). The respective lncRNA genes were assumed to provide potential epigenetic markers of OC.

The bony fish Danio rerio (zebrafish) has become one of the important vertebrate model organisms in biomedical cancer research and is used, among other things, for the development of anticancer drugs using xenotransplantation approaches. The ex utero development of zebrafish, optically transparent tissues in the first month of growth, and the immature adaptive immune system during this period greatly facilitate the manipulation of embryos. For highly aggressive cancers where patient survival may be expected to be only a few months, a zebrafish xenograft assay may be the only appropriate method as it requires only four to seven days. Thousands of embryos can be implanted with biopsy tissue from a patient to produce zebrafish xenografts and to use them to screen a large number of drugs and compounds automatically to develop an effective treatment regimen for a specific patient. This review examines the advantages and disadvantages of the zebrafish model in oncology research. The main focus is on the use of zebrafish xenografts to study metastasis and to create avatars in personalized medicine.

Today a global problem for humanity is represented by cancer, in particular gastric cancer, which is characterized by high mortality and aggressive course. In this regard, there is a search for new approaches to the diagnosis and therapy of gastric cancer, one of these areas is the study of the expression level of the intercellular adhesion molecule claudin-18.2 in tumor tissue and its use as a target molecule. In the case of various pathological processes, including tumors, the expression profile of claudin-18.2 changes, which indicates its possible role in the initiation and progression of cancer. The aim of this review is to systematize the data on claudin-18.2, its role in normal cell physiology and embryology, as well as in the development of pathological processes in the stomach, its relation to the clinical and morphological characteristics of gastric cancer and importance in biological therapy.

The molecular classification of endometrial cancer developed by The Cancer Genome Atlas project (TCGA, 2013) is currently actively used in gynecological oncology. According to it, endometrial carcinoma is divided into four molecular subtypes: POLE-mutated, MMR deficient (dMMR), TP53-aberrant and unspecified. Endometrial cancer samples belonging to the dMMR and POLE-mutant types are characterized by specific genetic profiles reflecting the hyper- and ultramutant phenotypes of the tumor. At the same time POLE-mutated endometrial carcinomas recur rarely and exhibit the excellent prognosis. Here we report the rare case of 65 y.o. female patient with endometrioid carcinoma sharing immunohistochemical and molecular features of TP53-aberrant, MMR deficient and POLE-mutated subtypes.

To study the features of protein expression of gene NDRG1 in primary breast cancer (BC) and to identify its relationship with regional metastasis.

Rhabdomyosarcomas (RMS) are one of the most common types of sarcomas in children and adolescents. The alveolar RMS subgroup is of particular interest because in some cases, the translocation of the PAX3 and FOXO1 genes is combined with an amplification of the corresponding hybrid gene. According to literature data, the frequency of the PAX3::FOXO1 translocation is 70-90% and the PAX7::FOXO1 translocation 10-30%.