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Cancer-associated fibroblasts (CAF), as the most important component of the tumor microenvironment, have been the subject of targeted study in recent years. There is increasing evidence of CAF heterogeneity and their different roles in tumor progression. However, there is no single marker identifying CAF, and there is also no understanding of the similarity of CAF markers in various tumors of the genitourinary system., Objective: To evaluate the response of CAF markers - FAP and PDGFR α+β in bladder cancer and prostate cancer., Material and Methods: An immunohistochemical study with antibodies to FAP and PDGFRα+β was conducted on material from 34 patients with prostate cancer and 44 patients with bladder cancer in order to identify statistical relationships with stage, morphological characteristics and survival, as well as to understand the applicability of the same markers for cancer of different localizations., Results: An increased FAP reaction was shown in prostate cancer with metastases ( p =0.0239), a significantly higher number of recurrences in the group with a high PDGFR a+β (3+) reaction ( p =0.0018); the presence of FAP reaction only in invasive bladder cancers ( p =0.0094) and bladder cancers with high grade dysplasia ( p =0.0000234), the absence of a relationship between the level of PDGFR a+β and clinical and morphological characteristics in bladder cancer., Conclusion: Our results confirm the heterogeneity of CAF in both bladder and prostate tumors and indicate that FAP is one of CAF subpopulation marker., Considering that FAP is expressed in a population of CAFs that lead to resistance to treatment with immune checkpoint inhibitors in melanoma, the FAP marker may also be diagnostically significant for tumors of the genitourinary system, especially given the fact that bladder tumors are treated with the BCG vaccine.

Background: More than 80% of pathologists suffer from various manifestations of disorders of the musculoskeletal system. The daily duties of pathologists include several hours of work at a microscope and a computer. Microscopes are often not optimized for ergonomics and do not allow the doctor to take the correct sitting position, most often working with a microscope requires leaning forward., Objective: To study the ergonomic properties of the workplace of a pathologist and develop specific practical recommendations for long-term work at a microscope., Material and Methods: The study included microscopes with an adjustable and non-adjustable angle of inclination of the tube and height-adjustable chairs. We identify following ergonomic parameters: pathologist height; angle of inclination of the back of the chair; angle of inclination of the microscope tube; angle of inclination of the neck; chair height. The study included 21 participants. Statistical processing and analysis were made using single-factor and multifactorial correlation analysis., Results: A strong positive linear correlation was identified ( r =0.80; p <0.05) between the height of test person and angle of inclination of the microscope tube. A strong positive linear correlation was established ( r =0.91; p <0.05) between the test person height and the angle of inclination of the neck for microscopes with non-adjustable 31°-angle of inclination of the tube. For microscopes with non-adjustable 45°-angle of inclination of the tube a strong polynomial correlation of the second degree ( r =0.85; p <0.05) was found. A moderate negative linear correlation was found between the height of the pathologist and his tilt angle neck with both adjustable and non-adjustable tube angle of the microscope., Conclusion: In this study for the first-time exact correlation dependencies between key ergonomic parameters of pathologist's workplace were evaluated. This study showed that only microscopes with an adjustable angle of inclination of the tube allow to achieve an optimal body position.

Objective: Assessment of the incidence of EBV-associated gastric adenocarcinomas in a sample of Russian patients, as well as clarification of the clinical and morphological characteristics and median survival of patients with EBV-associated gastric cancer., Material and Methods: We used samples of surgical material from 282 patients with a verified diagnosis of gastric cancer. Each sample was stained by in situ hybridization using primers for the Epstein-Barr virus-encoded small RNAs (EBER). The results obtained were compared with the main clinical and morphological characteristics of gastric cancer., Results: The detection rate of EBV-associated gastric adenocarcinoma in our sample was 9.57%. EBER-positive tumors much more often ( p =0.021) belong to the intermediate type according to the P. Lauren classification (66.67%) in comparison with EBER-negative tumors (38.82%). EBER-positive tumors significantly more often ( p =0.035) belong to high-grade tumors - 75.00% in comparison with EBER-negative tumors (52.13%). The overall median survival of all patients with EBER-positive tumors (53.5 months) was higher compared to the overall median survival of all patients with EBER-negative tumors - 36.5 months ( p =0.5379). The median survival of patients with EBER-positive stage III tumors (30.0 months) was also higher compared to that for patients with EBER-negative tumors - 20.0 months ( p =0.5622). It was found that a single EBER status is not a significant prognostic factor (HR=1.0143; CI: 0.9897-1.0196)., Conclusion: Separately taken EBER-status is not a significant independent prognostic factor and can be considered only in conjunction with the «classical» clinical and morphological characteristics, primarily with the stage of the tumor process, since it is they that determine the prognostic properties of the tumor.

Objective: Development of original methodological approaches to annotation and labeling of histological images in relation to the problem of automatic segmentation of the layers of the stomach wall., Material and Methods: Three image collections were used in the study: NCT-CRC-HE-100K, CRC-VAL-HE-7K, and part of the PATH-DT-MSU collection. The used part of the original PATH-DT-MSU collection contains 20 histological images obtained using a high performance digital scanning microscope., Each image is a fragment of the stomach wall, cut from the surgical material of gastric cancer and stained with hematoxylin and eosin. Images were obtained using a scanning microscope Leica Aperio AT2 (Leica Microsystems Inc., Germany), annotations were made using Aperio ImageScope 12.3.3 (Leica Microsystems Inc., Germany)., Results: A labeling system is proposed that includes 5 classes (tissue types): areas of gastric adenocarcinoma (TUM), unchanged areas of the lamina propria (LP), unchanged areas of the muscular lamina of the mucosa (MM), a class of underlying tissues (AT), including areas of the submucosa, own muscular layer of the stomach and subserous sections, image background (BG). The advantage of this marking technique is to ensure high efficiency of recognition of the muscularis lamina (MM) - a natural «line» separating the lamina propria of the mucous membrane and all other underlying layers of the stomach wall. The disadvantages of the technique include a small number of classes, which leads to insufficient detailing of automatic segmentation., Conclusion: In the course of the study, an original technique for labeling and annotating images was developed, including 5 classes (types of tissues). This technique is effective at the initial stages of teaching mathematical algorithms for the classification and segmentation of histological images. Further stages in the development of a real diagnostic algorithm to automatically determine the depth of invasion of gastric cancer require the correction and development of the presented method of marking and annotation.

Objective: To determine the level of E-cadherin expression in tumor emboli, to compare it with expression in a tumor, to determine the dependence of E-cadherin expression in tumor emboli on the clinical and morphological characteristics of gastric cancer., Material and Methods: We used samples of surgical material from 280 patients with a verified diagnosis of gastric cancer. E-cadherin expression was determined by immunohistochemical method. The results of the reactions were assessed semi-quantitatively and compared with the main clinical and morphological characteristics of gastric cancer (histological type according to the WHO classification 2019, histological type according to the classification of P. Lauren, clinical stage, depth of invasion (T), number of metastases in lymph nodes (N), presence or/absence of distant metastases (M), tumor localization in the stomach)., Results: Among 280 cases of cancer, emboli were detected only in 67 cases, used for further analysis. The rest of the samples were excluded from the analysis, since emboli did not get into the sections during the cutting of immunohistochemical preparations. The expression of E-cadherin in tumor emboli was significantly higher ( p <0.001) than in tumor tissue. At the same time, no cases identified where the level of E-cadherin decreased in emboli compared to the tumor. A significant increase in the expression of E-cadherin in tumor emboli compared to the primary tumor was noted for all histological types according to WHO 2019, for intermediate and diffuse types according to the P. Lauren classification ( p <0.001). Comparison of expression in emboli and tumors for neoplasms with different depths of invasion (T), different stages and different localizations did not reveal statistically significant differences. An increase in the expression of E-cadherin in emboli compared to tumors was characterized by a higher level of significance in the presence of metastases (N1, N2, N3a, N3b; p <0.001) than in the absence of metastases (N0; p =0.016)., Conclusion: The study revealed a statistically significant increase in the expression of E-cadherin in tumor emboli compared to the primary tumor, which is evidence of its important role in maintaining the integrity of emboli and tumor dissemination.

The Aim of the Study: Is to establish the relationship between the persistence of viral antigens of the Epstein-Barr virus (EBV) and the cellular composition of the immune microenvironment of tumor tissue and the mucous membrane of peritumoral area in gastric cancer., Material and Methods: We used samples of surgical material from 55 patients with a verified diagnosis of gastric cancer. The expression of CD4, CD8, CD68, CD1a and LMP-1 was assessed. The results were assessed by the morphometric method. We selected three fields of view (magnification x200) in tumor tissue and in peritumoral areas separately and counted an absolute number of cells with positive staining with further calculation of the average number of cells and the median., Results: LMP-1-negative tumors with LMP-1 expression in epithelium of peritumoral area were characterized by the highest density of CD4+ lymphocyte infiltration in the central part of the tumor; the highest density of CD8+ lymphocyte infiltration in the mucous membrane of peritumoral area ( p =0.0190); the highest density of infiltration by macrophages in the mucous membrane of peritumoral area ( p =0.2492); the highest density of infiltration by CD1a+ cells in the mucous membrane of peritumoral area ( p =0.1503). The highest density of infiltration with CD1a+ cells was characteristic for LMP-1-positive and LMP-1-negative tumors ( p =0.0813). The persistence of the LMP-1 viral antigen in the glandular epithelium of the peritumoral area in our sample does not have a statistically significant effect on the prognosis of the disease (RR=1.7718; p =0.0885) but there is a tendency towards a negative predictive value., Conclusion: High density of infiltration of glandular epithelium of peritumoral area with the expression of LMP-1 by CD4+ and CD8+ lymphocytes is most likely associated with the activation of the cellular immune response and may be one of the signs of the persistence of viral antigens. It was shown for the first time that the phenomenon of persistence of the LMP-1 viral antigen is characterized by a trend towards negative predictive value for patients with gastric cancer.

Introduction: Tumor budding was declared as independent prognostic factor for early cancer in 2016. Tumor-associated fibroblasts (CAFs) are one of the main components of tumor microenvironment. Plenty of different markers are used for detection of CAFs, including podoplanin (POD)., Objective: The aim of this study is to identify correlation between tumor budding, that indicates tumor invasive potential and is considered to be a negative prognostic factor, and CAFs near tumor buds using POD., Material and Methods: 43 cases of colon adenocarcinoma are included in the study. Double staining immunohistochemical technology with PCK and POD was used for detection of tumor budding and evaluation of POD expression near tumor buds., Results: Significant correlations are revealed between tumor budding and depth of tumor invasion ( p =0.023)/regional lymph node metastasis ( p =0.068), but between POD expression and depth of tumor invasion ( p =0.088) only a tendency of correlation is identified. These facts demonstrate critical prognostic value of tumor budding instead POD expression near tumor buds. It was found that intensity of POD expression near tumor buds is statistically analogous to POD expression in the invasive margin ( p =0.0016). That means it is not necessary to evaluate POD expression exactly near tumor buds. For the first time stronger POD expression near mucin complexes is reported. That, probably, will allow to use mucin complexes as alternative prognostic factor instead tumor budding, as tumor buds are absent in mucinous adenocarcinoma.

Carcinogenesis and tumor progression are not caused not only by malignant epithelial cells, but also by the tumor stroma around cancer stem cells which performs regulatory, nutritional and 'framework' functions. It is represented by mesenchymal cells of various types predominantly by cancer-associated fibroblasts (CAF). αSMA, FAP-1, desmin, podoplanin, neuron-glial antigen 2 (NG2), PDGFR-α and -β are used for CAF identification but there is no universal markers due to the plasticity of the cell population that underlies the subpopulation division CAF. CAF subpopulations are not described for many tumor types. Recently, evidence has accumulated that CAFs mediate many adverse processes in the tumor, including can support stromal inflammation and cause fibrosis. By forming a niche in cancer stem cells, CAFs mediate chemoresistance and the appearance of dormant metastases. The study of the role of CAF will allow not only to form a fundamentally new understanding of the mechanisms of carcinogenesis, but also to create new diagnostic and therapeutic targets for treating tumors.

EBV-associated gastric adenocarcinoma accounts for 10% of all gastric adenocarcinomas. The main known facts about the pathogenesis of EBV-associated gastric adenocarcinoma are presented. There are two main morphological types: gastric carcinoma with lymphoid stroma - GCLS (including lymphoepithelioma-like carcinoma; carcinoma with Crohn's disease-like lymphoid reaction; EBV-associated carcinoma with osteoclast-like giant cells) and conventional type adenocarcinoma. EBV-associated gastric adenocarcinomas predominantly express markers of gastric differentiation (MUC5AC, MUC6, CLDN-18) and a number of viral markers (EBER-1, EBNA-1 and BART mRNA). Three types of EBV latent cycle depending on the set of expressed viral transcripts are distinguished. It is believed that EBV-associated gastric adenocarcinoma is characterized by an intermediate position between latent cycles of types 1 and 2. The main method of virus identification is in situ hybridization with the detection of Epstein-Barr virus-encoded small RNAs (EBER-ISH).

Objective: To study the relationship of LMP-1 expression with the clinical and morphological characteristics of gastric cancer and to study LMP-1 expression in the glandular epithelium of the peritumoral tissue., Material and Methods: Samples of gastric cancer surgical material from 67 patients were included in this study. Primary mouse monoclonal antibodies to LMP-1 protein were used. LMP-1 expression was considered as positive if at least in one of the selected 10 fields of view (lens magn. ×40) ratio of the number of cells with LMP-1 expression to the total number of cells exceeded 10%., Results: Nine cases of LMP-1 positive tumors, 32 cases of LMP-1 negative tumors and 26 cases of LMP-1-negative tumors with LMP-1-expression in the epithelium of the peritumoral tissue were detected. Last group was described for the first time; 4 of these were intestinal type tumors, 19 tumors were 'intermediate' type and 3 tumors were diffuse type, the prevalence of 'intermediate' type tumors was statistically significant., Conclusion: LMP-1-negative tumors with LMP-1-expression in the epithelium of the peritumoral tissue were identified and described for the first time. This group was predominantly represented by tumors of an 'intermediate' histological type of gastric cancer. EBV antigens may have any direct oncogenic effects, or play the role of the background or the concomitant processes. No significant relationship was found between the LMP-1 expression and depth of invasion (T), lymph nodes metastasis (N), distant metastasis (M), clinical stages. This fact can be explained by the high heterogeneity of molecular and genetic properties of gastric cancer.