[Expression of immune checkpoints PD-L1, CTLA4, LAG3 in the microenvironment of colon adenocarcinoma depending on MMR status]. / Ekspressiya immunnykh kontrol'nykh tochek PD-L1, CTLA4, LAG3 v mikrookruzhenii adenokartsinomy tolstoi kishki v zavisimosti ot MMR-statusa.

OBJECTIVE: Study of the features of expression of immune checkpoint proteins PD-L1, CTLA4 and LAG3 in the microenvironment of colon adenocarcinoma depending on MMR status. MATERIAL AND METHODS: The study group consisted of 32 patients with a morphologically confirmed diagnosis of colon cancer; all of them underwent surgical treatment in the form of hemicolonectomy or resection. The work assessed samples of tumor tissue obtained as a result of surgery, the study was carried out in 3 stages: morphological examination of histological slides of colon tumors at the light-optical level, immunohistochemistry examination of tumor samples to determine the dMMR/pMMR status of carcinoma using a panel of antibodies to proteins of the unpaired nucleotide repair system MLH1, MSH2, MSH6 and PMS2, multiplex analysis of PD-L1, CTLA4, LAG3, CD3+, CD8+, CD163+ markers using the Vectra 3.0.3 tissue scanning system (Perkin Elmer, USA). RESULTS: Significant differences in the expression of PD-L1, CTLA4, LAG3 in the area of the invasive tumor margin were revealed between the dMMR and pMMR groups of colon adenocarcinomas in patients comparable in clinical and morphological characteristics and treatment. In the group of tumors with dMMR status, an increase in the expression of all studied markers was noted. The number of CD3+ TILs was also significantly higher in the invasive margin of tumors with dMMR status. Similarly, in this group of colon carcinomas, a large number of CD163+ macrophages were noted both in the center and in the invasive margin zone. No statistically significant differences were found in the expression of immune checkpoints and the composition of TILs in the central zone of tumors with different MMR status. CONCLUSION: A study using multiplex immunohistochemical analysis showed that MMR-deficient colon adenocarcinomas are characterized by more pronounced immune infiltration and increased expression of immune checkpoints in microenvironmental cells, mainly in the area of invasive tumor growth. The data obtained may be important for understanding the mechanisms of immune-mediated control of tumor growth and the choice of immunotherapy tactics depending on MMR status.

[Assessment of HER2 status of carcinomas of various localizations]. / Opredelenie HER2-statusa kartsinom razlichnykh lokalizatsii.

A detailed description of the methodological aspects of the evaluation of HER2-status in carcinomas of such localizations as the mammary gland, pancreas, salivary glands, stomach, colon, endometrium, bladder, lungs is presented. Approaches and criteria for assessing HER2 status from methodological and clinical points of view are analyzed. The data are systematized in tables for use in practical diagnostic work.

[Atypical fibroxanthoma]. / Atipicheskaya fibroksantoma.

Atypical fibroxanthoma (AFX) is a rare skin tumor characterized by a combination of a «malignant¼ morphological features and non-aggressive clinical course. Diagnosing AFX is challenging due to histological «diversity¼ and heterogeneous immunophenotype. The presented review describes the history and evolution of AFX as a nosological form of cancer, its histogenetic origin, pathogenesis and biological potential. The clinical, morphological, immunohistochemical, molecular cytogenetic characteristics and histological subtypes of the tumor as well as differential diagnosis have been presented in detail.

Clinical and Morphological Features of Myocardial Infarction in Patients With a New Coronavirus Infection COVID-19.

Aim      To analyze fatal outcomes of myocardial infarction (MI) in patients after COVID-19.Material and methods  Data of pathoanatomical protocols and case histories of 612 patients managed in clinics of the Siberian State Medical University from 01.01.2020 through 31.12.2021 were studied. 68 (11%) of these patients were transferred to the clinics from respiratory hospitals for rehabilitation after the novel coronavirus infection. The main condition for hospitalization was a negative polymerase chain reaction (PCR) test for SARS-CoV-2 virus RNA. 544 (89%) of patients had no history of COVID-19. The incidence of MI was 14% (7/68) in patients after COVID-19 and 10% (74/544) in patients who have not had it. In pathoanatomical protocols and case histories of 81 patients diagnosed with MI, macroscopic and histological changes in the heart, pericardial cavity, coronary arteries, and laboratory results were evaluated. Statistical analysis was performed with a STATISTICA version 10.0 software package.Results The patients after COVID-19 had a lower percentage stenosis, more frequent coronary artery thrombosis, and a positive D-dimer. According to our data, MI emerged 10.0 (2.0; 21.0) days after admission to the hospital, had a larger area, always was transmural, and rapidly resulted in death; the time of necrotic changes in all cases did not exceed 24 h. Upon admission to the hospital, the PCR test for SARS-CoV-2 virus RNA was negative, and acute inflammatory changes were stopped at the previous stage of hospitalization.Conclusion      The risk of coronary thrombosis in patients after COVID-19 remains after the relief of acute inflammatory response and elimination of the infectious agent, thereby creating a risk of MI, that often leads to a fatal outcome.

[Lafora disease with a fatal outcome]. / Bolezn' Lafory s letal'nym iskhodom.

Lafora disease is a rare hereditary genetic pathology of the nervous system (a group of progressive myoclonic epilepsies). The distinctive morphological feature of this disease is the presence of specific abnormal structures - polyglucosane bodies («Lafora bodies¼) in the brain tissue, myocardium, liver, and epithelium of the sweat gland ducts. The article discusses the clinical data of the course of Lafora's disease in an 18-year-old patient with a fatal outcome and the results of a post-mortem examination. The diagnosis of Lafora disease was confirmed by genetic analysis data - the presence of a homozygous mutation in the 2nd exon of the EPM2A gene - laforin (chr6:146007412G>A, rs137852915). When analyzing literature, we did not find a description of Lafora's disease cases with a fatal outcome with the presentation of macroscopic examination data at autopsy, as well as the results of a pathohistological examination of altered organ tissues with the morphological manifestations specific for this pathology (Lafora bodies in the the brain, heart, sweat gland epithelium).

Molecular subtype conversion in CTCs as indicator of treatment adequacy associated with metastasis-free survival in breast cancer.

Molecular subtype of breast cancer has a great clinical significance and used as one of the major criteria for therapeutic strategy. Recently, for anticancer therapy, the trend for oncologists is the predominant determination of biomarkers in the existing foci of the disease. In the case of adjuvant therapy prescribed for distant metastases prevention, CTCs could be a suitable object for investigation. CTCs as one of the factors responsible for tumor metastatic potential could be more convenient and informative for evaluation of hormone receptors, Ki-67 and HER2 expression, which are determine molecular subtype in breast cancer patient. In our study, we aimed to investigate the molecular subtype discordance between the primary tumor and CTCs in breast cancer patients. We established conversion of molecular subtype in most of the cases. Namely, conversion was detected in 90% of untreated patients and in 82% of breast cancer patients treated by neoadjuvant chemotherapy. At the same time, molecular subtype conversions in patients treated by neoadjuvant chemotherapy were more diverse. Molecular subtype conversions resulted more often in the unfavorable variants in circulating tumor cells. We stratified all patients according to the adequacy of treatment against converted CTCs molecular subtype. Our study revealed that good response to neoadjuvant chemotherapy observed in case of adequate therapy, namely, when chemotherapy scheme was sufficient against CTCs. It turned out that patients with inadequate therapy were characterized by decreased simulated 5-year metastasis-free survival compared to patients who received appropriate therapy. Thus, detection of molecular subtype conversion in circulating tumor cells could be a perspective tool for optimization of antitumor therapy.

The Rarity of Metastasis to the Spleen - a Phenomenon with an Unknown Mechanism.

The review analyses the frequency of malignant tumors metastasizing to the spleen. The facts are presented of a higher frequency of metastasis to the spleen in the presence of multiple metastases to other organs and the extreme rarity of isolated metastases to the spleen. Despite the rarity of spleen metastases, their frequency varies depending on the nosological form of the malignancy. The data about clinical manifestations of spleen metastases and positive effects of splenectomy in these cases are presented. The hypotheses explaining the rarity of metastases to the spleen are analyzed. Emphasis is placed on the multiple immune functions of the spleen, including the development of immunogenesis and tolerance, and the possible role of these processes in inhibiting the development of spleen metastases. However, to date, there is no complete understanding of the mechanisms of spleen metastasis inhibition. The spleen is an area where antimetastatic microenvironment is naturally formed. Understanding of the mechanisms inhibiting the development of metastases in the spleen and underlying the failure of this function in cases where metastases do occur could arm oncologists with a new strategy to prevent metastasis to any organ. Targeted research in this field is required.

[Triple-negative breast cancer. Modern molecular genetic concepts and their clinical significance]. / Troinoi negativnyi rak molochnoi zhelezy. Sovremennye molekulyarno-geneticheskie predstavleniya i ikh klinicheskoe znachenie.

Triple negative breast cancer (BC) is a heterogeneous group of carcinomas that substantially differ in clinical, morphological, and molecular genetic characteristics, tumor response to chemotherapy, and prognosis. These features define triple negative BC today as a special clinical problem that has not yet been completely solved. The review is devoted to the description and systematization of the currently available literature data concerning molecular and genetic features and differences in a fairly significant group of breast carcinomas with a severe, aggressive course and an extremely poor prognosis. The review presents the existing molecular genetic classification of triple negative BC based on the results of studies conducted by M.D. Burstein (2015) and B.D. Lehmann (2016), which determines the presence of 4 tumor-specific subtypes: basal-like type (type 1 and type 2), mesenchymal, and luminal androgen receptor types. The paper reflects the main stages of transformation of the proposed classification over the past decade and an attempt has been make to describe the molecular characteristics of each subtype of these carcinomas.

[Current prerequisites for a molecular genetic classification of endometrial cancer]. / Sovremennye predposylki dlia molekuliarno-geneticheskoi klassifikatsii raka éndometriia.

The review analyzes current investigators' data on the introduction of an additional endometrial cancer classification based on the results of molecular and genetic studies. This necessity is dictated by clinical observations, according to which the genetic profile of the tumors may not correspond to their morphological structure, which considerably changes patient management tactics. The existing dualistic model of carcinogenesis makes it possible to identify and describe the characteristic molecular features of the tumors in terms of their histological structure. The review also analyzes the concept of 4 new endometrial cancer subgroups: ultramutated, hypermutated, copy-number low, and copy-number high (serous-like). It gives the results of investigations of the molecular and genetic characteristics of each subgroup. Particular attention is paid to the role of POLE gene mutations in the ultramutated subgroup. Different theories justifying a good prognosis in these patients are considered. The molecular characteristics of endometrial cancer versus tumors of other organs are compared. The potential benefits of introducing the new classification, which allow one to change approaches to stratifying the risk for this disease, are presented.

Intratumoral Morphological Heterogeneity of Breast Cancer As an Indicator of the Metastatic Potential and Tumor Chemosensitivity.

Breast cancer (BC) demonstrates considerable intratumoral morphological heterogeneity. The aim of this work was to evaluate the relationship among different morphological structures, the rate of metastasis, and efficacy of neoadjuvant chemotherapy (NAC) in NAC-treated (n = 427) and NAC-naïve (n = 249) BC patients. We also studied the involvement of an epithelial-mesenchymal transition (EMT) in the development of the intratumoral morphological heterogeneity of BC. We found a significant association between the intratumoral morphological heterogeneity and the rate of BC metastasis and response to NAC, which, in most cases, correlated with the presence of alveolar and trabecular structures. In particular, the rate of lymph node metastasis in tumors containing alveolar and trabecular structures was higher compared to that in tumors lacking such structures. NAC-treated patients with alveolar and trabecular structures had a high distant metastasis rate and a low metastasis-free survival rate. Furthermore, alveolar and trabecular structures were found to be associated with a lack of response to NAC. Interestingly, the association between alveolar structures and a high distant metastasis rate was found only in NAC-unresponsive patients, whereas the association between trabecular structures and an increased distant metastasis was revealed in responders. Alveolar structures were associated with chemoresistance only in patients with lymph node metastases, whereas trabecular structures were associated with chemoresistance only in patients without lymph node metastases. In general, increased intratumoral morphological diversity correlated with considerable chemoresistance and a high metastasis rate of BC. We found variable expressions of epithelial (EPCAM and CDH1) and mesenchymal (ITGA5, ITGB5, CDH2, CDH11, TGFb2, ZEB1, MMP2, DCN, MST1R) markers and, thus, different EMT manifestations in different morphological structures. Therefore, intratumoral morphological heterogeneity of BC may serve as an indicator of the metastatic potential and tumor chemosensitivity.

[Molecular biological predictors for kidney cancer].

The paper considers the data available in the modern literature on studies of potential molecular predictors for renal cell carcinoma (RCC). Investigations of cell death markers, namely; Bcl-2 as an inhibitor of apoptosis, are of interest. Its high expression correlates with a more favorable prognosis. Inactivation of Berclin 1 that is an authophagy indicator in intact tissues gives rise to t high risk for tumorigenesis. At the same time, high Beclin 1 expression in the tissue of the tumor itself results in the lower efficiency of performed chemotherapy. Excess annexin A2 in the tumor promotes the growth and invasion of cancer cells. Patients with tumor over-expression of SAM68 protein involved in cell proliferation have a lower overall survival rate. The lifespan of patients without distinct metastases survive significantly longer in the overexpression of epithelial cell adhesion molecule (EpCAM). High PD-L1 protein expression on the cell membrane is considered to be a potential marker of effective immunotherapy for RCC.

Cancer Invasion: Patterns and Mechanisms.

Cancer invasion and the ability of malignant tumor cells for directed migration and metastasis have remained a focus of research for many years. Numerous studies have confirmed the existence of two main patterns of cancer cell invasion: collective cell migration and individual cell migration, by which tumor cells overcome barriers of the extracellular matrix and spread into surrounding tissues. Each pattern of cell migration displays specific morphological features and the biochemical/molecular genetic mechanisms underlying cell migration. Two types of migrating tumor cells, mesenchymal (fibroblast-like) and amoeboid, are observed in each pattern of cancer cell invasion. This review describes the key differences between the variants of cancer cell migration, the role of epithelial-mesenchymal, collective-amoeboid, mesenchymal-amoeboid, and amoeboid- mesenchymal transitions, as well as the significance of different tumor factors and stromal molecules in tumor invasion. The data and facts collected are essential to the understanding of how the patterns of cancer cell invasion are related to cancer progression and therapy efficacy. Convincing evidence is provided that morphological manifestations of the invasion patterns are characterized by a variety of tissue (tumor) structures. The results of our own studies are presented to show the association of breast cancer progression with intratumoral morphological heterogeneity, which most likely reflects the types of cancer cell migration and results from different activities of cell adhesion molecules in tumor cells of distinct morphological structures.

The phenomenon of multi-drug resistance in the treatment of malignant tumors.

Multi-drug resistance (MDR) is a condition when there is broad cross-resistance of cells to various agents which are different in structure and effect. Modern perceptions on mechanisms of MDR development in malignant tumors have been considered, in particular, in tre-ating breast cancer. Physiological functions and contribution to MDR development of ABC-transporter protein families have been described. The role of activation of glutathione system enzymes and apoptosis-regulating proteins in MDR formation has been shown.

[Correlation of metastasis-free survival in patients with breast cancer and changes in the direction of expression of multidrug resistance genes during neoadjuvant chemotherapy].

Previously, we showed the association of neoadjuvant chemotherapy (NAC) response with changing the expression vector (increase or decrease) of multidrug resistance genes (MDR) in breast tumors during chemotherapy. The aim of the present study was to evaluate the relation between changes in the expression vector of MDR genes and distant metastasis-free survival. Patients (n = 120) with breast cancer (T1-4N0-3M0) treated by 2-4 cycles of NAC (CAX, FAC, and taxane regimes) and 4 cycles of adjuvant chemotherapy (FAC) were included. TaqMan-based quantitative reverse transcriptase PCR (qRT-PCR) was used to estimate the expression of the following MDR genes: ABCB1, ABCC1, ABCC2, ABCC5, ABCG1, ABCG2, GSTP1, and MVP--in biopsies before NAC and in tumor samples after chemotherapy. Comparing the corresponding expression levels allowed us to identify the vector of expression change during NAC. The results showed that 5-year distant metastasis-free survival was 73-78% in patients with a decrease in ABCB1, ABCC2, and ABCG1 expression. The up-regulation of these genes during NAC was related to a significant decrease (up to 50-55%) in metastasis-free survival (Kaplan-Meier analysis: log-rank p value = 0.006-0.03). The association of changing the expression vector of MDR genes with metastasis-free survival did not depend on tumor size, lymph node involvement, histological form, receptor status, molecular subtype, and others clinicopathological parameters of breast cancer. The obtained data suggest that changing the expression vector of MDR genes in breast tumors during NAC may be used as a new potential prognostic marker of breast cancer. An increase in tumor expression of ABCB1, ABCC2, and ABCG1 during chemotherapy is a factor of poor prognosis, whereas down-regulation of these genes--a favorable prognostic marker.

Intratumor heterogeneity: nature and biological significance.

Intratumor heterogeneity inherent in the majority of human cancers is a major obstacle for a highly efficient diagnosis and successful prognosis and treatment of these diseases. Being a result of clonal diversity within the same tumor, intratumor heterogeneity can be manifested in variability of genetic and epigenetic status, gene and protein expression, morphological structure, and other features of the tumor. It is most likely that the appearance of this diversity is a source for the adaptation of the tumor to changes in microenvironmental conditions and/or a tool for changing its malignant potential. In any case, both processes result in the appearance of cell clones with different undetermined sets of hallmarks. In this review, we describe the heterogeneity of molecular disorders in various human tumors and consider modern viewpoints of its development including genetic and non-genetic factors of heterogeneity origin and the role of cancer stem cells and clonal evolution. We also systematize data on the contribution of tumor diversity to progression of various tumors and the efficiency of their treatment. The main problems are indicated in the diagnosis and therapy of malignant tumors caused by intratumor heterogeneity and possible pathways for their solution. Moreover, we also suggest the key goals whose achievement promises to minimize the problem of intratumor heterogeneity and to identify new prognostic, predictive, and target markers for adequate and effective treatment of cancer.

[Epigenetic aspects of early lymphogenic metastasis in breast cancer].

Metastasizing is one of the key stages in tumor development. Understanding this process is necessary for effective diagnosis, therapy and prediction of clinical outcome. Some recent data suggest the possibility of metastatic phenotype cells appearance at the early stages of tumor evolution in contravention with generally accepted hypothesis of linear metastatic process development. In this study we have performed a comparative analysis of the array-based DNA methylation profile in biopsy samples of patients with benign breast disorders, breast cancer and lymphogenous metastases. In some cases the biopsy samples dated back to different stages of the same tumor. For the analysis the GoldenGate Methylation Cancer Panel I was used. The DNA methylation level in 1,505 CpG-sites was similar in samples from patients with benign breast disorders and lymphogenous metastases. Our data support the hypothesis of the early appearance of cell clones responsible for the tumor limphogenous dissemination. Epigenetic component apparently plays an important role in this process.

[Occult multicentric breast cancer].

The study included 92 patients with invasive ductal breast cancer (T2-4N0-2M0-1). In 38 cases, tumor growth was unicentric while histologically identifiable ones as multicentric in 44. Multicentricity mostly occurred in cases of macroscopically-identifiable nodes located in the central segments of the breast. Clinically-identifiable nodes of multicentric tumor growth measured more than 3 cm. Multicentric tumors were mostly grade III, featured lower expression of sex hormone receptors and positive Her2 status.

[Genetic and clinical and pathological characteristics of breast cancer in premenopausal and postmenopausal women].

This study involved 525 breast cancer (BC) patients of T2-4N0-2M0 stages at the age of 35 years and older. Significant differences in clinical and pathological characteristics between premenopausal and postmenopausal BC patients were found. Mostly marked differences were shown for positive lymph node correlation with distant metastasis, multicentric growth and local recurrence depending on menopause status. The prevalence of various morphological structures in primary tumors was appeared to be associated with different forms of tumor progression in pre- and postmenopausal women. We have studied polymorphisms in 15 genes involved in major cancer related pathways (apoptosis, interleukins, folate metabolism enzymes genes). We found that variant genotypes of MTHFR and DHFR genes were associated with an increased BC risk among premenopausal women while polymorphism in IL-18, p53 genes were associated with BC among postmenopausal women. These results demonstrate novel biological information, which points the different mechanisms contributed to breast cancer progression in premenopausal and postmenopausal women.

Carcinogenic effect of an antitumor drug etoposide in laboratory animals.

Intravenous injection of antitumor drug etoposide in the maximum tolerated dose was followed by the development of breast cancer in 38.1% female Wistar rats and 6.7% female outbred mice.