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Following the discovery of circulating tumor cells (CTCs) in the peripheral blood of cancer patients, CTCs were initially postulated to hold promise as a valuable prognostic tool through liquid biopsy. However, a decade and a half of accumulated data have revealed significant complexities in the investigation of CTCs. A challenging aspect lies in the reduced expression or complete loss of key epithelial markers during the epithelial-mesenchymal transition (EMT). This likely hampers the identification of a pathogenetically significant subset of CTCs. Nevertheless, there is a growing body of evidence regarding the prognostic value of such molecules as CD24 expressing in the primary breast tumor. Herewith, the exact relevance of CD24 expression on CTCs remains unclear. We used two epithelial markers (EpCAM and cytokeratin 7/8) to assess the count of CTCs in 57 breast cancer patients, both with (M0 mts ) and without metastasis (M0) during the follow-up period, as well as in M1 breast cancer patients. However, the investigation of these epithelial markers proved ineffective in identifying cell population expressing different combinations of EpCAM and cytokeratin 7/8 with prognostic significance for breast cancer metastases. Surprisingly, we found CD24+ circulating cells (CCs) in peripheral blood of breast cancer patients which have no epithelial markers (EpCAM and cytokeratin 7/8) but was strongly associated with distant metastasis. Namely, the count of CD45-EpCAM-CK7/8-CD24+ N-cadherin-CCs was elevated in both groups of patients, those with existing metastasis and those who developed metastases during the follow-up period. Simultaneously, an elevation in these cell counts beyond the established threshold of 218.3 cells per 1 mL of blood in patients prior to any treatment predicted a 12-fold risk of metastases, along with a threefold decrease in distant metastasis-free survival over a 90-month follow-up period. The origin of CD45-EpCAM-CK7/8-CD24+ N-cadherin-CCs remains unclear. In our opinion their existence can be explained by two most probable hypotheses. These cells could exhibit a terminal EMT phenotype, or it might be immature cells originating from the bone marrow. Nonetheless, if this hypothesis holds true, it's worth noting that the mentioned CCs do not align with any of the recognized stages of monocyte or neutrophil maturation, primarily due to the presence of CD45 expression in the myeloid cells. The results suggest the presence in the peripheral blood of patients with metastasis (both during the follow-up period and prior to inclusion in the study) of a cell population with a currently unspecified origin, possibly arising from both myeloid and tumor sources, as confirmed by the presence of aneuploidy., (© 2024. The Author(s).)

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.

A case of organ-preserving treatment of prostate stromal tumor with an uncertain malignancy potential is presented in the article. The patient underwent laparoscopic resection of the prostate neoplasm. Mesenchymal prostate tumors are rare. Their diagnosis is difficult due to the lack of experience of both pathologists and urologists. Mesenchymal neoplasms include prostate stromal tumors of uncertain malignant potential. Due to the rare occurrence of these tumors and the difficulties of its diagnosis, there is no recommended treatment algorithm. Taking into account the anatomical location of the tumor, the patient underwent enucleoresection without removing the entire prostate. The control examination, including pelvic MRI, was carried out after 3 months. There were no signs of disease progression. The presented clinical case of prostate preservation during resection of a prostate stromal tumor of uncertain malignancy potential demonstrates a possibility of organ-preserving procedures in such a rare disease. However, due to a small number of publications and a short follow-up period, these tumors require further study and evaluation of long-term results.

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., (© 2022. The Author(s).)

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., (© 2022. Springer Science+Business Media, LLC, part of Springer Nature.)

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.

Crosstalk between the estrogen receptors and the receptor tyrosine kinases, including vascular endothelial growth factor receptor type II (VEGFR2), is a key mechanism in breast cancer resistance to antiestrogen therapy with tamoxifen. A high level of VEGFR2 expression in a tumor serves as a marker of tamoxifen resistance. The tamoxifen efficacy prognostic value of functional polymorphisms in the VEGFR2/KDR gene has not been established. Using qRT-PCR, we detected the rs2071559 and the rs2305948 variants and the levels of KDR gene expression in 122 breast tumor tissue samples from cohorts of patients with progression (distant metastases or relapse) and patients with no progression during tamoxifen therapy. The expression levels of VEGFR2 protein were analyzed by immunohistochemistry. The frequency of heterozygous and mutant genotypes of the rs2305948 SNP was significantly higher in patients without progression than in the cohort with progression. KDR rs2305948 was associated with high survival rates in breast cancer patients. A correlation between the mRNA of the ESR1 and KDR genes in patients without progression was detected. The results indicate the prognostic value of rs2305948 and its potential contribution to the tumor phenotype sensitive to tamoxifen.

Intravasation is a key step in cancer metastasis during which tumor cells penetrate the vessel wall and enter circulation, thereby becoming circulating tumor cells and potential metastatic seeds. Understanding the molecular mechanisms of intravasation is critically important for the development of therapeutic strategies to prevent metastasis. In this article, we review current data on the mechanisms of cancer cell intravasation into the blood and lymphatic vessels. The entry of mature thymocytes into the circulation and of dendritic cells into the regional lymph nodes is considered as example of intravasation under physiologically normal conditions. Intravasation in a pathophysiological state is illustrated by the reverse transendothelial migration of leukocytes into the bloodstream from the sites of inflammation mediated by the sphingosine 1-phosphate interaction with its receptors. Intravasation involves both invasion-dependent and independent mechanisms. In particular, mesenchymal and amoeboid cell invasion, as well as neoangiogenesis and vascular remodeling, are discussed to play a significant role in the entry of tumor cells to the circulation. Special attention is given to the contribution of macrophages to the intravasation via the CSF1/EGF (colony stimulating factor 1/epidermal growth factor) paracrine signaling pathway and the TMEM (tumor microenvironment of metastasis)-mediated mechanisms. Other mechanisms including intravasation of tumor cell clusters surrounded by the vessel wall elements, cooperative intravasation (entry of non-invasive tumor cells to the circulation following invasive tumor cells), and intravasation associated with the vasculogenic mimicry (formation of vascular channels by tumor cells) are also discussed. Novel intravasation-specific mechanisms that have not yet been described in the literature are suggested. The importance of targeted therapeutic strategies to prevent cancer intravasation is emphasized.

Aim: To identify gene expression profiles involved in drug resistance of different morphological structures (tubular, alveolar, solid, trabecular, and discrete) presented in breast cancer., Material and Methods: Ten patients with luminal breast cancer have been included. A laser microdissection-assisted microarrays and qRT-PCR were used to perform whole-transcriptome profiling of different morphological structures, to select differentially expressed drug response genes, and to validate their expression., Results: We found 27 differentially expressed genes (p < 0.05) encoding drug uptake (SLC1A3, SLC23A2, etc.) and efflux (ABCC1, ABCG1, etc.) transporters, drug targets (TOP2A, TYMS, and Tubb3), and proteins that are involved in drug detoxification (NAT1 and ALDH1B1), cell cycle progression (CCND1, AKT1, etc.), apoptosis (CASP3, TXN2, etc.), and DNA repair (BRCA1 and USP11). Each type of structures showed an individual gene expression profile related to resistance and sensitivity to anticancer drugs. However, most of the genes (19/27; p < 0.05) were expressed in alveolar structures. Functional enrichment analysis showed that drug resistance is significantly associated with alveolar structures. Other structures demonstrated the similar number (10-13 out of 27) of expressed genes; however, the spectrum of resistance and sensitivity to different anticancer drugs varied., Conclusion: Different morphological structures of breast cancer show individual expression of drug resistance genes.

Inflammatory infiltration of tumor stroma is an integral reflection of reactions that develop in response to any damage to tumor cells including immune responses to antigens or necrosis caused by vascular disorders. In this review, we use the term "immune-inflammatory response" (IIR) that allows us to give an integral assessment of the cellular composition of the tumor microenvironment. Two main types of IIRs are discussed: type 1 and 2 T-helper reactions (Th1 and Th2), as well as their inducers: immunosuppressive responses and reactions mediated by Th22 and Th17 lymphocytes and capable of modifying the main types of IIRs. Cellular and molecular manifestations of each IIR type are analyzed and their general characteristics and roles in tissue regeneration and tumor growth are presented. Since inflammatory responses in a tumor can also be initiated by innate immunity mechanisms, special attention is given to inflammation based on them. We emphasize that processes accompanying tissue regeneration are prototypes of processes underlying cancer progression, and these processes have the same cellular and molecular substrates. We focus on evidence that tumor progression is mainly contributed by processes specific for the second phase of "wound healing" that are based on the Th2-type IIR. We emphasize that the effect of various types of immune and stroma cells on tumor progression is determined by the ability of the cells and their cytokines to promote or prevent the development of Th1- or Th2-type of IIR. Finally, we supposed that the nonspecific influence on the tumor caused by the cytokine context of the Th1- or Th2-type microenvironment should play a decisive role for suppression or stimulation of tumor growth and metastasis.

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.

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 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.

In order to understand invasive/adhesive and drug resistant properties of intratumor morphological heterogeneity of breast cancer, we compared the expression of genes responsible for the cell adhesion and for the drug resistance between distinct morphological structures of breast tumors. Tubular (hollow-like), alveolar (morula-like), trabecular, solid structures/patterns, and discrete (small) groups of tumor cells were isolated from invasive carcinoma of no special type (n=3) and invasive micropapillary carcinoma (n=1) of the breast using laser microdissection. The gene expression of cadherins, catenins, integrins, ABC transporters, GSTP1, and drug targets was analyzed using qRT-PCR. Expression of catenin genes was identified in almost all structures. In contrast, the expression of cadherin and integrin genes significantly varied depending on the morphological variant. Cadherin expression declined in the row: solid - alveolar and trabecular structures - discrete groups of tumor cells. Expression of integrins declined in the row: solid and alveolar - trabecular structures - discrete groups of tumor cells. For drug resistance genes, trabecular structures more often demonstrated activity of genes coding for ABC transporters compared to other morphological variants. These results indicate that intratumoral morphological heterogeneity in breast cancer correlates with expression profile of adhesion and drug resistance genes reflecting different patterns of invasive growth and responsiveness to chemotherapy.

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.

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.