Background/Objectives: In gastric cancer, only a subset of patients benefit clinically from neoadjuvant chemoimmunotherapy, underscoring the need for robust biomarkers that can predict treatment responses and guide personalized immunotherapy. This study aimed to characterize the immune microenvironment of gastric tumors and identify predictive markers associated with therapeutic efficacy. Methods: We prospectively enrolled 16 patients with histologically confirmed, PD-L1–positive (CPS ≥ 1) gastric adenocarcinoma (T_2–4N_0–1M₀). All patients received eight cycles of FLOT chemotherapy combined with pembrolizumab. Treatment response was assessed by Mandard tumor regression grading. Spatial transcriptomic profiling (10x Genomics Visium) and multiplex immunofluorescence were used to evaluate tumor-infiltrating immune cell subsets and PD-1 expression at baseline and after treatment. Results: Transcriptomic analysis differentiated the immune landscapes of responders from non-responders. Responders exhibited elevated expression of IL1B, CXCL5, HMGB1, and IFNGR2, indicative of an inflamed tumor microenvironment and type I/II interferon signaling. In contrast, non-responders demonstrated upregulation of immunosuppressive genes such as LGALS3, IDO1, and CD55, along with enrichment in oxidative phosphorylation and antigen presentation pathways. Multiplex immunofluorescence confirmed a higher density of FoxP3⁺ regulatory T cells in non-responders (median 5.36% vs. 2.41%; p = 0.0032). Notably, PD-1⁺ CD8⁺ T cell and PD-1⁺ FoxP3⁺ Treg frequencies were significantly elevated in non-responders, suggesting that PD-1 expression within cytotoxic and regulatory compartments may contribute to immune evasion. No substantial differences were observed in PD-L1 CPS or PD-1⁺ B cells and PD-1⁺ macrophages. Conclusions: Our findings identify PD-1⁺ CD8⁺ T cells and PD-1⁺ FoxP3⁺ Tregs as potential biomarkers of resistance to neoadjuvant chemoimmunotherapy in gastric cancer. Transcriptional programs centered on IL1B/CXCL5 and LGALS3/IDO1 define distinct immune phenotypes that may guide future combination strategies targeting both effector and suppressive arms of the tumor immune response.

Due to its small size and high affinity binding, the engineered scaffold protein ADAPT6 is a promising targeting probe for radionuclide imaging of human epidermal growth factor receptor type 2 (HER2). In a Phase I clinical trial, [^99mTc]Tc-ADAPT6 demonstrated safety, tolerability and capacity to visualize HER2 expression in primary breast cancer. In this study, we aimed to select the optimal parameters for distinguishing between breast cancers with high and low expression of HER2 using [^99mTc]Tc-ADAPT6 in a planned Phase II study. HER2 expression was evaluated in primary tumours and metastatic axillary lymph nodes (mALNs). SPECT/CT imaging of twenty treatment-naive breast cancer patients was performed 2 h after injection of [^99mTc]Tc-ADAPT6. The imaging data were compared with the data concerning HER2 expression obtained by immunohistochemical evaluation of samples obtained by core biopsy. Maximum Standard Uptake Values (SUV_max) afforded the best performance for both primary tumours and mALNs (areas under the receiver operating characteristic curve (ROC AUC) of 1.0 and 0.97, respectively). Lesion-to-spleen ratios provided somewhat lower performance. However, the ROC AUCs were still over 0.90 for both primary tumours and mALNs. Thus, lesion-to-spleen ratios should be further evaluated to find if these could be applied to imaging using stand-alone SPECT cameras that do not permit SUV calculations.

Introduction. Bone tumors are heterogeneous group of skeletal neoplasms characterized by frequent recurrences, aggressive clinical course and low survival rates. The development of new treatment methods continues to pose pressing challenges. Radical intraoperative thermal ablation (RIT) using high-temperature exposure is emerging as a new and promising strategy for organ-preserving treatment. This study focuses on the effect of thermal ablation (TA) on tumors.Objective of the Study to assess the impact of TA (using the RIT method) on the viability of tumor cells.Material and Methods. The study included 8 patients with bone tumors. Tumors underwent TA at a temperature of 60 °C for 30 minutes ex vivo. Apoptosis was studied in tumor tissue samples before and after TA. Apoptosis was assessed using two methods: flow cytometry and the TUNEL assay.Results. The TA procedure developed by our scientific group represents a promising organ-preserving approach for treating malignant bone tumors. A temperature regime of 60 °C for 30 minutes was effective in initiating tumor cells death. This was confirmed by two independent methods – flow cytometry and TUNEL assay – which demonstrated a significant increase in the number of apoptotic cells immediately following the procedure and a notable rise in the number of cells exhibiting signs of late apoptosis one hour post thermal ablation. Therefore, the collected data confirm a pronounced antitumor effect immediately after implementing RIT.Conclusion. The findings confirm that RIT is a viable organ-preserving method for treating bone tumors, meriting further investigation to expand its application in clinical practice.

The aim of the study: to examine the relationship between the morphological diversity of non-small cell lung cancer and the frequency of lymph node metastasis in groups of patients with different epithelial conditions in the bronchi adjacent to the tumor. Material and methods. Surgical specimens from 90 patients with non-small cell lung cancer, who were treated in the Thoracoabdominal Department Of The Research Institute Of Oncology Of The Tomsk National Research Medical Center in the period from 2009 to 2017 were studied. The histological type of cancer was determined according to the who classification (2020). Lepidic, acinar, papillary, micropapillary, solid and solitary tumor cells were isolated in the parenchymal component of adenocarcinoma. In the parenchymal component of squamous cell carcinoma, 5 types of structures were distinguished: with keratinization, consisting of atypical cells of the prickly type without keratinization, consisting of atypical cells of the basaloid type, built of atypical cells with pronounced polymorphism, single tumor cells. Results. In patients with isolated basal cell hyperplasia, acinar (37 %), papillary (29 %) and solid (27 %) patterns were found less frequently in cases with metastatic regional lymph nodes compared to those without metastatic lymph nodes (63 %; p=0.05; 71 %; p=0.05; 73 %; p=0.01, respectively). In patients with isolated basal cell hyperplasia of the bronchial epithelium, in cases with the presence of lymph node metastasis in the parenchymal component of squamous cell carcinoma, structures 1 (with keratinization) (17 %), 2 (spiky pattern) (33 %) and 4 (polymorphic pattern) (29 %) were less frequently detected compared to those without metastases in regional lymph nodes (83 %; p=0.01; 67 %; p=0.02 and 71 %; p=0.01, respectively). In patients with a combination of basal cell hyperplasia and squamous metaplasia, a spiny pattern (65 %), a basaloid pattern (100 %), a polymorphic pattern (82 %) and single tumor cells (89 %) were more frequently detected in cases with metastatic lymph nodes than in cases without metastatic lymph nodes (35 %; р=0.04; 0 %; р=0.01; 18 %; р=0.01; 11 %; р=0.01, respectively). Conclusion. The data obtained clarify the available information on the significance of the morphological heterogeneity of the tumor for predicting the course of adenocarcinoma and squamous cell carcinoma of the lung.

Understanding the molecular mechanisms of carcinogenesis, including disruptions in the homologous recombination system, is fundamental to understanding malignant transformation. Dysfunction of homologous recombination genes, such as BRCA1 and BRCA2, contributes to genomic instability and the development of more aggressive tumor clones. The use of chemical carcinogens enables the modeling of tumor formation and the monitoring of changes in molecular genetic parameters. This approach is important for understanding how tumor cells adapt to genotoxic stress and for advancing the development of personalized cancer therapies. The objective of this study was to evaluate the expression of key homologous recombination system genes in a model of chemically induced carcinogenesis in mice. Materials and Methods: Male outbred ICR (CD-1) laboratory mice (n = 40) were used to study chemically induced carcinogenesis. The animals were divided into four groups: two control groups and two experimental groups, which received 3-methylcholanthrene (MC) or trichloroacetic acid (TCA). Tumor cells were identified by histological analysis of autopsy material using light microscopy after standard hematoxylin and eosin staining. RNA and DNA were extracted from cell suspensions using the RNeasy Plus Mini Kit and QIAamp DNA Mini Kit (Qiagen, Hilden, Germany), respectively. The expression levels of homologous recombination genes were assessed by RT-PCR and microarray analysis. Digital PCR was performed to assess chromosomal aberrations in the Brca1 gene. Results: Tumor formations were identified in laboratory animals two months after 3-methylcholanthrene. Histological analysis revealed morphological changes in a pleomorphic cell tumor, forming diverse, multidirectional fascicular and swirling structures, as well as large solid foci composed of markedly polymorphic spindle-shaped and epithelioid cells. Analysis of copy number aberrations in the examined samples showed that the frequency of Brca1 deletions was 60%, while 40% of animals had normal gene copy number. To further characterize the molecular changes, we assessed gene expression levels through expression microarray analysis. A total of 14 genes were hypoexpressed in the tumor compared to the normal tissue, with p < 0.05. A high level of differential expression was characteristic for Rad50, Rad51, Brca1, Brca2, and Pold4. Two genes, Rad52 and Bard1, exhibited increased expression levels. It was shown that as the tumor mass increased, so did the frequency of homologous recombination genes with hypoexpression. Conclusions: Our findings confirm that MC and TCA influence tumor formation and reveal that suppression of homologous recombination genes may contribute to this process. In addition, it has been established that as tumors progress, the expression of DNA repair genes declines and aberrant gene states accumulate. These data emphasize the importance of studying the state of DNA repair genes for the development of more effective strategies for cancer diagnosis and therapy.

Solitary fibrous tumor is a rare mesenchymal neoplasm, the most common localization of which is the pleural cavity, but the tumor can also affect other organs. This neoplasm with localisation in the kidney was first described only in 1996. Solitary fibrous tumor accounts for 0.2% of all kidney neoplasms and is an exceptional phenomenon. Currently, there is no generally accepted theory explaining the etiology and pathogenesis, probably, its development is a multifactorial process including a combination of genetic, epigenetic and external factors. Despite the lack of unambiguous opinion on the nature of the neoplasm, the spectrum of molecular abnormalities in this tumor has been sufficiently studied. The literature presents a limited number of publications devoted to this pathology, in this regard it should be noted that in routine practice, the morphological picture may not always be so unambiguous and require the pathologist to conduct differential diagnostics with a fairly wide range of tumors. Given the rarity of this disease, we would like to share a description of our own clinical observation demonstrating the possible difficulties of morphology diagnostics.