Objective: to evaluate the effectiveness of a convolutional neural network model for automated cytologic diagnosis of papillary thyroid cancer and benign thyroid nodules.

Material and Methods. The convolutional neural network was developed in the Python programming language using the TensorFlow 2.15.0 open source library. For the study, a dataset that included two categories of pathologies was generated: 1597 microphotographs of papillary carcinoma and 767 microphotographs of benign nodules (colloid goiter and adenomatous nodules). To form a training sample and evaluate the model’s performance metrics on the test sample, the dataset was divided in a ratio of 80/20.

Results. In classifying papillary carcinoma, the model achieved precision of 89.3 %, recall of 92.4 %, specifcity of 77.4 % and F1 score of 91.4 %. When identifying benign nodules, the presicion, recall, specifcity and F1 score were 83.3 %, 77.4 %, 92.4 %, and 80.3 %, respectively, indicating a higher rate of false-positive and false-negative predictions. The AUC was 0.91 at the individual microphotograph level and 0.94 at the serial microphotograph level from one patient, indicating the high ability of the trained model to differentiate between malignant and benign thyroid lesions based on microphotographs of fne-needle aspiration biopsy specimens.

Conclusion. Further improvement of the neural network model by training on larger and more diverse datasets of microphotographs of cytological specimens of the thyroid gland will help improve its diagnostic range and performance. The developed model can be used to develop software for identifying thyroid pathologies.

Aim: to determine the effectiveness of primary treatment of patients with ovarian cancer of stages IA–IIA.

Material and Methods. The study included 336 (100 %) patients with histologically confrmed ovarian cancer of stages IA–IIA, who were treated at the Primorsky Regional Oncology Center from 2004 to 2021. The overall survival (s) and progression-free survival (PFS) were analyzed depending on clinical and morphological factors: histological type of cancer, BRCA1/2 mutation, profle of the clinic where surgical treatment was performed, surgical staging and chemotherapy option. The examination for a mutation in the BRCA1/2 gene was performed by a new generation sequencing method. The data were statistically processed using the IBM SPSS Statistics 26 program.

Results. The average age of patients with stage IA–IIA ovarian cancer was 52.12 ± 12.13 years. Statistically signifcantly higher survival rates were in patients with histological tumor type low-grade serous carcinoma compared with high-grade serous carcinoma (S: p=0.010 and IBP: p=0.020), with surgical treatment in specialized hospitals compared with patients operated in gynecological hospitals (s: p=0.040 and IBP: p=0.020), during adequate surgical staging (OV: p=0.008 and IBP: p=0.010), during treatment with platinum and taxanes (OV: p=0.001 and IBP: p=0.001).

Conclusion. It was shown that about 30 % of patients with stage IA–IIA ovarian cancer in Primorsky Krai received primary surgical treatment in non-specialized hospitals, which increased the risk of progression and death by 1.7 times. A low percentage of adequate surgical staging was noted (12.5 %). Adjuvant chemotherapy with platinum and non-oxane agents worsened the prognosis of the disease. Patients with low-grade serous carcinoma had a more favorable prognosis (by 60 %). There was no statistically signifcant effect of the presence of a mutation in the BRCA1/2 genes on survival rates.

The purpose of the study was to evaluate the effectiveness of treatment of patients with recurrent nasal cavity and paranasal sinus cancer using photodynamic diagnosis (PDD) and photodynamic therapy (FDT).

Material and Methods. The study included 40 patients with locally advanced nasal cavity and paranasal sinus cancer, who were admitted to the clinics of the Cancer Research Institute of Tomsk National Research Medical Center with disease progression or recurrence. All patients were divided into the study group (n=20) and the control group (n=20). Patients in both groups received chemotherapy combined with radiotherapy, chemotherapy combined with surgery or a combination of chemotherapy, radiotherapy and surgery. Treatment of patients included intraoperative assessment of resection margin using a laser electron spectral analyzer LESA-01 BIOSPEC. The bed of the removed tumor was examined to detect residual tumor tissues. Photodynamic therapy of the bed of the removed tumor was then performed using Photoditazine at a dose of 1 mg/kg body weight. Radiotherapy at a dose of 300–350 J per feld was given using a Latus–T apparatus, the feld diameter ranged from 1 to 2 cm. The power density varied from 0.4 W/cm2 to 0.5 W/cm².

Results. Nonparametric tests revealed a statistically signifcant difference in disease-free survival: 3.10, p=0.001 by Gehan-Wilcoxon test and 3.03, p=0,002 by Log-Rank test. When assessing overall survival, there were 10 (50.0 %) completed cases in the control group, 4 (20.0 %) in the study group, and 10 (50.0 %) and 16 (80.0 %) censored cases, respectively. Gehan-Wilcoxon test – -2.02 p=0.04. Log-Rank test –2.10 p=0.04. The results of the study showed that according to any of the criteria, there were statistically signifcant differences in survival between the control and study groups.

Conclusion. Inclusion of intraoperative PDD and PDT in the treatment algorithm for nasal cavity and paranasal sinus recurrent carcinomas signifcantly increases the disease-free and overall survival of patients.

Hereditary breast cancer (HBC) is a heterogeneous disease caused by mutations in genes characterized by ethnic specifcity. The clinical heterogeneity of this disease signifcantly complicates its diagnosis. The use of high-throughput sequencing is one of the approaches that allow the search for genes and their variants associated with the development of HBC. The purpose of the study was to search for new genes associated with HBC in the understudied ethnic groups of Siberia by using whole exome sequencing (WES).

Material and Methods. WES was performed on a cohort of 16 probands with BC (Tuvan, Yakut, Altai ethnos). The study material was genomic DNA isolated from peripheral blood leukocytes. Libraries were prepared using a BGI Optimal DNA Library Prep kit. An Agilent SureSelect Human All Exon V6 kit was used for hybridization. High-throughput sequencing was performed on a DNA nanoball sequencing platform (DNBSeq-G400).

Results. In the overall group of patients with signs of HBC, pathogenic variants were detected in 12.5 % of cases (2/16). For the frst time, BRCA1 (rs80357635) pathogenic variant was identified in a young patient with metachronous BC (Yakut ethnic group). A pathogenic variant of the ATM gene (rs780619951 NM_000051:exon16:c.C2413T:p.R805X) was identified in a young patient with BC (Tuvinian ethnic group). A pathogenic variant of the TDP2 c.G4T:p.E2X, rs770844602 gene (DNA repair gene) was identified for the frst time in a Tuvan BC patient (metachronous) with a family history, but its contribution to HBC remains to be proven. The TDG gene variant (rs764159587 NM_001363612:exon7:c.536dupA:p.E179fs) found in the Tuvan ethnic group and affecting splicing (SpliceAI: 0.580) requires special attention.

Conclusion. This report is the frst to describe the germinal variant in the BRCA1 (rs80357635) gene in the Yakut ethnic group. Further studies are required to confrm pathogenicity of germinal variants in non-well studied genes TDP2, TDG in ethnic BC patients.

Assessment of tumor infltrating lymphocytes (TiLs) has been recognized as an additional tool for predicting survival in triple negative (TN) and HER2/neu positive (HER2+) subtypes of breast cancer (BC). Recently, BC, including the above-mentioned subtypes and characterized by low/undefined expression of HER2/neu, has been isolated into a separate group, designated HER2-low BC. The relationship between clinical and morphological parameters of HER2-low breast cancer and infiltration by immunocompetent cells, including tumor associated macrophages (TAM), has not been studied to date. The purpose of the study was to identify significant relationships between the level of subpopulations of immunocompetent cells (Tils + TAM) and the clinical and morphological parameters of HER2-low BC.

Material and Methods. The study examined the surgical specimens of 33 patients with HER2-low BC. Visual counting of TILs and assessment (IHC) of the level of T-helpers, T-killers, M1 and M2 macrophages were carried out in intratumor sites and the invasive edge of the primary tumor.

Results. The study of mastectomy specimens showed that infiltration of Tils (Me=5 [5; 10] %) was observed in all 33 patients. The level of M2 of macrophages was found to be the highest both in the invasive margin and in the intratumor sites (CD163inv: Me=20 [10; 40] %; CD163c: Me=15 [7; 30] %, respectively). In patients with high (≥20 %) levels of M2 macrophages in the invasive margin, there was also a high level of other immunocompetent cells, and perineural invasion was detected significantly more often (р=0.019).

Conclusion. A high level of infiltration by M2 macrophages of the invasive margin is combined with the detection of perineural invasion in primary HER2-low breast cancer, which is one of the predictors of a high risk of progression. In combination with other clinical and morphological parameters, the level of M2 macrophages in HER2-low breast cancer may become another factor in predicting disease prognosis.

One of the predictors of adverse prognosis in breast cancer is the overexpression of the EpCAM protein. However, a signifcant part of tumor cells have low or no EpCAM expression. The molecular features and the ability to grow in 2D and 3D cultures, indirectly refecting metastatic potential of tumor cells without EpCAM expression, have not been sufficiently studied.

The aim of the study was to compare phenotypic variants of stem cells and EMT depending on the EpCAM expression in the primary tumor of breast cancer and 2D and 3D cultures.

Material and Methods. The study included 7 patients with invasive breast carcinoma of no special type. Luminal A subtype was found in 2/7 patients (29 %), and luminal B HER2-negative molecular subtype was found in 5/7 patients (71 %). The patients didn’t have neoadjuvant chemotherapy. Cells from the primary tumor were cultured in 2D and 3D. The primary tumor cells, 2D and 3D cultures were phenotyped using fow cytometry with antibodies targeting: CD45, EpCAM (CD326), CD44, CD24, N-cadherin (CD325), and CD133, CK7/8, EpCAM (CD326).

Results. No significant differences were found in the frequency of detection and the number of cells exhibiting stem cell features among EpCAM- and EpCAM+ tumor cells, 2D and 3D cultures. All phenotypic variants of co-expression of stemness markers CD44, CD24, CD133, and ALDH were present both in the primary tumor and 2D/3D cultures. Stem cells in mammospheres had features of both epithelial and hybrid EMT phenotypes. In primary tumors and 2D/3D cultures, the smallest proportion consisted of stem cells with the CD44+CD24- phenotype and cells co-expressing CD44+CD24- with other stemness markers, while the largest proportion comprised stem cells with ALDH+ and ALDH+CD133+ phenotypes. Marked intra- and inter-tumor heterogeneity in the phenotypic composition of primary tumors, 2D, and 3D cultures was noted.

Conclusion. The results indicate that EpCAM-negative and EpCAM-positive tumor cells of luminal molecular subtype of breast cancer are capable of exhibiting various phenotypic variants of stemness and EMT in the primary tumor and 2D and 3D cultures. In most cases, individual tumor cells show co-expression of several stemness markers. The phenotypic composition of primary tumors, 2D and 3D cultures is characterized by pronounced intra- and inter-tumor heterogeneity.

The aim of study is to conduct in vivo biological testing of titanium nickelide samples modifed with Ag/Pt or AuAg/Pt flm heterostructures in comparison with the bare carrier.

Material and Methods. Titanium nickelide plates modifed with flm heterostructures made of noble metals and the laboratory mini-pigs used for in vivo tests were the objects of the study. To form flm structures on titanium nickelide samples, the physical gasphase deposition methods: ion plasma deposition (IPD) and thermal (PVD) sputtering were used. The Ag/ Pt or AuAg/Pt heterostructures were characterized by X-ray diffraction and scanning microscopy methods.

Results. The biocompatibility of implants before (TiNi, control) and after (Ag/Pt/TiNi and AuAg/Pt/TiNi) modifcation with flm heterostructures was tested in in-vivo experiments on a laboratory animal (mini-pig). General toxic reactions of the body to the injected samples were absent. A comparative macroscopic and histological analysis of the condition of peri-implant tissues after 39 days of implantation was performed. The connective tissue capsule around the TiNi sample revealed the presence of a certain number of lymphocytes, eosinophils and macrophages, but these indicators decrease in the order of TiNi > AuAg/Pt/TiNi > Ag/Pt/TiNi.

Conclusion. The positive effect of modifying the titanium nickelide surfaces with noble metal heterostructures on the biocompatibility of metal implants was demonstrated in an in vivo experiment.

Background. Compliance with principles of surgical oncology is necessary to choose effective treatment options for locally advanced rectal cancer (LARC).

Objective: to show the basic surgical principles for LARC using a new option of complex therapy.

Material and Methods. The basic surgical principles for LARC using a new option of complex therapy with polyradiomodifcation (local microwave hyperthermia + intrarectal administration of a polymer composition with Metronidazole) in combination with polychemotherapy (oral administration of Capecitabine + intravenous administration of Oxaliplatin) with concurrent prolonged hypofractionated radiation therapy were presented.

Results. The treatment outcomes of the new option of complex neoadjuvant therapy with the compliance of surgical oncology principles were studied in 46 patients with LARC (T3cd-T4a N1c-2ab M0, CRM+, EMVI+). An analysis of the immediate outcomes showed that postoperative complications were diagnosed in only 4 (8.7 %) of 46 patients and no deaths were recorded. The local control was achieved: cancer recurrence was diagnosed in only 1 (2.2 %) and distant metastases in 4 (8.7 %) of patients. The 5-year recurrence-free survival rate in these patients was signifcantly higher than that observed in patients who received conventionally fractionated radiotherapy in combination with Capecitabine (81.0 vs 56.8 %, p=0.02). The improvement of results was achieved both by adhering to the principles of surgical oncology and increasing the radiosensitivity of the tumor: pathologic complete response was achieved in 35 (76.1 %) patients. This made it possible to perform sphincter-preserving surgeries in 71.7 % (33 out of 46) patients and in 66.7 % (18 out of 27) with lower-ampullary cancer.

Conclusion. The use of a new method of complex therapy for LARC and compliance with the basic principles of surgical oncology allowed the improvement of long-term treatment outcomes by achieving local control of the tumor, contributing to the expansion of indications for performing sphincter-preservingsurgeries.

The purpose of the study was to analyze surgical treatment outcomes for renal cell carcinoma (RCC) with inferior vena cava tumor thrombosis (IVC-TT) on the basis of one cancer center.

Material and Methods. A retrospective analysis of treatment outcomes of 25 patients with locally advanced and metastatic RCC with IVC-TT, who underwent surgery from 01.2021 to 12.2022, was carried out. The median follow-up was 21 months (95 % CI 14.3–33 months). The patients were divided into groups according to the Mayo IVC-TT classifcation: Type I: 8 patients, type II: 8 patients, and type III: 9 patients.

Results. Tangential IVC resection was done in 20 (80 %) cases, circular-in 3 (12 %) cases, and IVC extirpation was done in 2 (8 %) cases. The median intraoperative blood loss was 600 ml (from 250 to 1700 ml). The incidence of postoperative complications was 28 %, distribution by Clavien–Dindo classes was: III – 4, IV – 2, V – 1, an increase in the incidence of complications of class III–IV was revealed in patients with Mayo type III, however, no statistically signifcant differences were found (p=0.153). The most common complication was acute kidney injury. Two (8 %) patients required repeated surgical intervention. One patient died due to sepsis. Statistically signifcant differences were obtained in blood loss (p=0.003), the number of erythrocyte suspension blood transfusions (p=0.006), and the time of surgery (p=0.014) and prevailed in the group with the Mayo III level. However, the median length of hospital stay did not differ in the subgroups (p=0.978) and amounted to 6 bed days in the range from 4 to 20 days in the general group. The 30-day postoperative mortality rate was 4 %.

Conclusion. Our experience has shown that surgical treatment of RCC with IVC-TT is feasible and provides acceptable surgical and oncological outcomes. However, the complication rate and postoperative mortality are higher in patients with Mayo III thrombus levels, requiring careful patient selection.

Laryngeal and laryngopharyngeal cancer is the most common malignancy within the head and neck. Although there are many treatments for laryngeal and laryngopharyngeal cancer, the treatment still faces great challenging.

The aim of the study was to evaluate the effectiveness of personalized treatment and one-year recurrence-free survival in patients with stage III–IV laryngeal and laryngopharyngeal, including postoperative complications (VTE, bleeding) within a year.

Material and Methods. From July 2022 to October 2023, 100 patients with stage III–IV laryngeal and laryngopharyngeal cancer were treated in the Department of Head and Neck Tumors at the Altai Regional Oncology Center (AROC), Barnaul. There were 95 men (95 %) and 5 women (5 %). Patients were divided into two groups. Group I patients (n=50) with locally advanced laryngeal cancer underwent laryngectomy followed by radiation therapy with a total dose of 54 Gy delivered to the bed of the removed tumor and lymph node drainage region. Group II patients (n=50) received 3 courses of chemotherapy followed by radiation therapy at a dose of 70–74 Gy.

Results. In group I patients, clinically insignifcant bleeding from the upper third of the trachea (in the area of contact with the tracheostomy tube) was observed in 3 patients (6.0 %) 3–4 days after surgery. No VTE during hospital stay and within 6–12 months after completion of treatment was observed. The 1-year cumulative survival rate in this group of patients was 90.0 %. In group II patients receiving chemotherapy, bleeding from a pharyngeal tumor was detected in 4 (8.0 %) patients. There were no signs of VTEO in this group. The 1-year cumulative survival rate of these patients was 70 %.

Conclusion. Patients with laryngeal/laryngopharyngeal cancer require an individual approach not only in determining therapeutic strategies, but also in the prevention of VTE and hemorrhagic complications.

The aim of this study was to conduct a systematic review and meta-analysis of the literature to evaluate the impact of different antibiotic prophylaxis (АР) strategies on the incidence of infectious complications within 30 days after radical cystectomy (RC).

Material and Methods. The meta-analysis protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO): ID-CRD42023480525. A systematic search for studies published in the last 10 years (November 2013 – November 2023) was conducted in the PubMed and Cochrane Library databases by two independent researchers. A total of 7 full-text articles were included in the final statistical analysis (data from 90,935 patients). The analysis focused on three aspects: comparison of the effectiveness of different durations of antibiotic prophylaxis (24 hours or more), the impact of the type of antibacterial agent used, and the application of Enhanced Recovery after Surgery (ERAS) protocols on the overall incidence of infectious complications, the development of soft tissue infections, and upper urinary tract infections (UTIs). Meta-analysis was performed using R 4.3.2 (R Foundation for Statistical Computing, Vienna, Austria) and the metafor 4.2-0 package.

Results. The median overall incidence of infectious complications was 31.78 % (23.8–58.8 %), surgical site infections – 16.46 % (6.25–35.41 %), and UTIs – 25.11 % (3.86–35.7 %), including cases leading to urosepsis. The meta-analysis did not reveal a statistically signifшcant effect of the duration of AP (24 hours or more) on the risk of infectious complications: for overall infectious complications, the risk was OR 1.11 (95 % CI 0.92–1.33; p=0.27), for surgical site infection OR 1.00 (95 % CI 0.87–1.15; p=0.97), and for UTIs OR 0.96 (95 % CI 0.84–1.10; p=0.59). However, the overall incidence of infectious complications was significantly higher in the standard perioperative management group, without ERAS protocols (OR=3.02 [95 % CI 2.07; 4.39], p<0.001, I 2 =93.1 %). Conclusion. The results of this study indicate that existing AP strategies may be ineffective in reducing postoperative infectious complications in patients undergoing cystectomy with urinary diversion. Extending AP beyond 24 hours, as well as the standard regimen, did not demonstrate a reduction in infection risk, highlighting the need for a revision of clinical guidelines in this area. The principles of the ERAS program may play a crucial role in reducing infectious complications, showing promising results and requiring further research and implementation in clinical practice. Key words: radical cystectomy, antibiotic prophylaxis, complications, surgical site infection, upper urinary tract infections, ERAS> ˂ 0.001, I² =93.1 %).

Conclusion. The results of this study indicate that existing AP strategies may be ineffective in reducing postoperative infectious complications in patients undergoing cystectomy with urinary diversion. Extending AP beyond 24 hours, as well as the standard regimen, did not demonstrate a reduction in infection risk, highlighting the need for a revision of clinical guidelines in this area. The principles of the ERAS program may play a crucial role in reducing infectious complications, showing promising results and requiring further research and implementation in clinical practice.

Pancreatic ductal cancer is one of the most aggressive malignancy with a high incidence of advanced stages at the time of diagnosis and unsatisfactory long-term treatment results. It is believed that pancreatic ductal cancer in the presence of distant metastases identified at the stage of intraoperative revision or before surgery is a contraindication to surgical treatment. There is currently renewed interest in surgical treatment of patients with oligometastatic pancreatic cancer.

Material and Methods. The search for sources was carried out in the PubMed and Elibrary systems from January 1995 to January 2024. Of the 1321 sources found, 37 were used to write the review. Data from both retrospective and prospective clinical studies that focused on the results of combined modality treatment of pancreatic cancer with isolated liver metastases were included.

Results. To date, a standard treatment strategy for patients with oligometastatic pancreatic cancer has not yet been established; there are no definitive criteria for selecting patients who may benefit from surgical treatment. The current selection criteria for surgery for metastatic pancreatic cancer are far from ideal, extremely heterogeneous and, as a rule, are based only on certain clinical and instrumental data. The starting point for developing selection criteria for surgical treatment of patients with metastatic pancreatic cancer is a common understanding of what “oligometastatic pancreatic cancer” is.

Purpose of the study: to summarize the available data on the structure and function of EpCAM and its domains, their roles in promoting proliferation and epithelial-mesenchymal transition (EMT), contributing to cell stemness, and facilitating interactions with cell adhesion and invasion molecules.

Material and Methods. A comprehensive search was conducted for articles in Russian and English within the scientifc databases PubMed, Scopus, Web of Science, and E-library. A total of seventy-nine articles ranging from 1996 to 2024 were utilized to compile this review.

Results. This review summarized the pathogenetic and clinical signifcance of various EpCAM expression variants: EpCAM^high, EpCAM^low, and EpCAM^loss. It described the causes and mechanisms behind the loss of membrane EpCAM expression, each holding distinct biological and clinical implications. Features of EpCAM expression in normal epithelial tissues, during regeneration, and in dysplasia/ neoplasia as well as carcinomas were carefully outlined. The clinical implications of EpCAM expression remain a subject of debate; overexpression of EpCAM has been linked to both unfavorable and favorable prognoses. Special emphasis was placed on the expression variants of EpCAM in circulating tumor cells, disseminated cells, and carcinoma metastases.

Conclusion. The pathogenetic and clinical signifcance of EpCAM expression in various nosological forms of carcinoma is complex and multifaceted. Weak expression or absence of EpCAM acts as independent factors infuencing the unique progression patterns of these diseases. Achieving a deeper understanding of the role of EpCAM in disease progression necessitates the simultaneous examination of both its extracellular and intracellular domains.

Purpose of the study: to determine the role of retroelements in chromoanagenesis mechanisms in cancer etiopathogenesis.

Material and Methods. The search for relevant sources was carried out in the Scopus, Web of Science, PubMed, Elibrary systems, including publications from February 2002 to December 2023. Of the 864 scientifc articles found, 60 were used to write a systematic review.

Results. According to original works and meta-analyses results, the cause of complex chromosomal rearrangements during cancer development may be retroelement pathological activation. Chromoanagenesis involves LINE1, SVA, Alu, HERV, which cause double-stranded DNA breaks, insertions in tumor suppressor genes region, the formation of chimeric oncogenes due to retroelement use as new promoters, and function as molecular “band-aids” in non-homologous end junctions and form bridges of distal DNA fragments. Global structural rearrangements of chromosomes observed during chromoanagenesis may be consequences of retroelements activation, which participate in non-allelic homologous recombination and in microhomology-mediated joining of ends characteristic. Certain types of neoplasms, such as colon cancer, are characterized by both high levels of chromothripsis and retroelement activity. In head and neck squamous cell carcinoma, chromoplexy is specifc, the sources of sequences at the breakpoints of which are retroelements. During chromoanagenesis, activation of proto-oncogenes and inactivation of tumor suppressor genes are observed, which is also a consequence of retroelement activation. This is due to the presence of retroelement sequences in proto-oncogenes promoter regions and introns (which become the basis for chimeric oncogene formation) and hot spots of insertional mutagenesis in tumor suppressor genes (transpositions into these regions inactivate these genes).

Conclusion. The results obtained on the driver effect of retroelements in chromothripsis, chromoplexy and chromoanasynthesis mechanisms, which are the basis for the formation of clonal evolution of tumors, indicate promise of targeted therapy aimed at silencing the activity of retroelements in cancer patients treatment. For this purpose, it is possible to use microRNAs complementary to retroelements, which are also involved in tumor development, as tools.

The purpose of the study was to carry out a systematic analysis of the data available in the modern literature on the essentiality of selenium in biological systems and the importance of selenoproteins in oncogenesis.

Material and Methods. The publications were analyzed using Scopus (415), PubMed (521), Web of Science (139), eLibrary.ru (240) databases. To obtain full-text documents, the electronic resources PubMed Central (PMC), Science Direct, Research Gate, eLibrary.ru were used.

Results. The need to use selenium compounds for the prevention and treatment of malignant neoplasms is controversial, and some selenoproteins have demonstrated a permissive role in oncogenesis, thus requiring further in-depth study in neoplasms of various histogenesis.

Conclusion. It is necessary to continue comprehensive molecular studies of bioorganic selenium compounds at the morphological, ultrastructural and biochemical levels in tumors of various localizations, depending on the genetic characteristics of the studied population and the geochemical characteristics of the region.

Background. Epithelioid hemangioendothelioma (EHE) is a malignant vascular tumor of mesenchymal origin. In the mediastinum, EHE originates from the large venous vessels of the superior vena cava.

The purpose of the study was to describe a rare clinical case of EHE of the unpaired vein and analyze literature data to improve diagnosis and treatment of this disease.

Case presentation. We present a rare case of EHE of the unpaired vein in a 23-year-old male patient who admitted to the Herzen Moscow Oncology Research Institute with a posterior mediastinal tumor detected in August 2022. It was known from the medical history that the patient had undergone diagnostic right-sided thoracotomy and tumor biopsy at the place of residence. Morphologically, the tumor was an epithelioid hemangioendothelioma. The histological re-assessment of biopsy specimens at the Herzen Moscow Oncology Research Institute confrmed the diagnosis of EHE. Computed tomography of the chest organs revealed a mass in the posterior mediastinum (in the projection of the lumen of the unpaired vein), measuring 16×14×41 mm, with relatively clear even contours, close to the posterior wall of the trachea at the bifurcation level, the posterior wall of the right main bronchus, the left semicircle of the esophagus (without signs of invasion). Based on the data on the presence of a vascular tumor in the posterior mediastinum on the right, a multidisciplinary medical consilium recommended surgical treatment: right thoracotomy, removal of a posterior mediastinal tumor with resection of the azygos vein, marginal resection of the superior vena cava, and thrombectomy from its lumen. The duration of surgery was 180 minutes, blood loss was 200 ml. Morphological examination confrmed EHE of the unpaired vein. No complications were observed in the postoperative period. The patient was discharged from the hospital on the 8th day after surgery in a satisfactory condition.

Conclusion. EHE of the unpaired vein is an extremely rare vascular tumor. The clinical feature of EHE of the unpaired vein is the absence of any pathognomonic signs, which complicates differential diagnosis of mediastinal tumors. Surgery is currently the optimal treatment approach.

Background. Yolk sac tumors (YST) are classified as rare malignant germ cell tumors of the ovaries, most commonly found in young patients interested in preserving fertility. YST is characterized by large size, predominantly unilateral involvement, and increased production of alpha-fetoprotein, which can be used as an important diagnostic criterion for this condition. Among all germ cell tumors, YST has the least favorable prognosis. The primary goals of YST treatment are not only to improve prognosis and quality of life but also to enable the patient to fulfill her reproductive plans in the future.

Description of the clinical case. We present a clinical case of an aggressive course of yolk sac tumor in the ovary of a 15-year-old girl, requiring multiple surgeries, repeated courses of high-dose drug therapy, and bone marrow transplantation.

Conclusion. This is a rare case of YST with successful preservation of reproductive function due to modern medical technologies despite aggressive treatment.

Purpose: to describe rare cases of orbital metastases from breast cancer.

Material and Methods. Three cases of Luminal A(1) and B(2) breast cancer with orbital metastases were identified and studied during the period from 01.01.2018 to 01.05.2024. Metastasis to the orbit was detected 5, 2 and 1.5 years after radical mastectomy for breast cancer. Patients received chemotherapy and radiation therapy.

Results. Cases of orbital metastasis originating from breast cancer were found to have a low frequency, but may be associated with a long period between cancer diagnosis and initiation of treatment. Early detection of breast cancer and its active treatment with chemotherapy and radiation therapy are important factors in preventing orbital metastasis.

Conclusion. A routine follow-up surveillance after radical treatment of breast cancer is important because there is an increase risk of developing orbital metastasis. Comprehensive strategies for treating breast cancer metastases can provide long-term disease control.