The problem of finding more precise stratification criteria for identifying the cohort of patients who would obtain the maximum benefit from immunotherapy is acute in modern times. In our study were enrolled 18 triple-negative breast cancer patients. The Ventana SP142 test was used for PD-L1 detection. Spatial transcriptomic analysis by 10x Genomics was used to compare PD-L1-positive and PD-L1-negative tumors. The seven-color multiplex immunofluorescence (by Akoya) was used for the detection of the type of cells that carried the PD1 receptor and the PD-L1 ligand. Using pathway analysis, we showed that PD-L1-positive tumors demonstrate signatures of a cell response to cytokines, among others, and PD-L1-negative tumors demonstrate signatures of antigen presentation. PD-L1-positive and PD-L1-negative tumors have different tumor microenvironment (TME) compositions according to CIBERSORT analysis. Multiplex immunohistochemistry (IHC) confirmed the prevalence of PD1-negative M2 macrophages and PD1-negative T lymphocytes in PD-L1-positive tumors. PD-L1-positive tumors are not characterized by direct contact between cells carrying the PD1 receptor and the PD-L1 ligand. So, the absence of specific immune reactions against the tumor, predominance of pro-tumor microenvironment, and rare contact between PDL1 and PD1-positive cells may be the potential reasons for the lack of an immune checkpoint inhibitor (ICI) effect in triple-negative breast cancer patients.

Most studies on CTCs have focused on isolating cells that express EpCAM. In this study, we emphasize the presence of EpCAM-negative and EpCAM^low CTCs, in addition to EpCAM^high CTCs, in early BC. We evaluated stem cell markers (CD44/CD24 and CD133) and EMT markers (N-cadherin) in each subpopulation. Our findings indicate that all stemness variants were present in both EpCAM^high and EpCAM-negative CTCs, whereas only one variant of stemness (nonCD44+CD24−/CD133+) was observed among EpCAM^low CTCs. Nearly all EpCAM^high CTCs were represented by CD133+ stem cells. Notably, the hybrid EMT phenotype was more prevalent among EpCAM-negative CTCs. scRNA-seq of isolated CTCs and primary tumor partially confirmed this pattern. Therefore, further investigation is imperative to elucidate the prognostic significance of EpCAM-negative and EpCAM^low CTCs.

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.

Only one-third of patients with advanced MSS/pMMR endometrial cancer exhibit a lasting response to the combination treatment of Pembrolizumab and Lenvatinib. The combined administration of these two drugs is based on Lenvatinib’s ability to modulate the tumor microenvironment, enabling Pembrolizumab to exert its effect. These findings underscore the importance of exploring tumor microenvironment parameters to identify markers that can accurately select candidates for this type of therapy. An open non-randomized observational association study was conducted at six clinical centers, involving a total of 28 patients with advanced MSS/pMMR endometrial cancer who received Pembrolizumab and Lenvatinib therapy. Using TSA-associated multiplex immunofluorescence, we analyzed the proportion of CD8+ T lymphocytes, CD20+ B lymphocytes, FoxP3+ T regulatory lymphocytes, and CD163+ macrophages in tumor samples prior to immunotargeted therapy. The percentage of CD20+ B lymphocytes and the CD8-to-CD20 lymphocytes ratio was significantly higher in patients who responded to treatment compared to non-responders (responders vs. non-responders: 0.24 (0.1–1.24)% vs. 0.08 (0.00–0.15)%, p = 0.0114; 1.44 (0.58–2.70) arb. unit vs. 19.00 (3.80–34.78) arb. unit, p = 0.0031). The sensitivity and specificity of these biomarkers were 85.71% and 70.59%, and 85.71% and 85.71%, respectively. The proportion of CD20+ B lymphocytes and the CD8-to-CD20 lymphocytes ratio in the stroma of endometrial cancer serves as both a prognostic marker of response to immunotargeted therapy and a prognostic factor for progression-free survival in patients.

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.

Aim. To study the association between the functional potency and degree of maturity of B lymphocytes and PD-L1 expression in breast cancer patients.Materials and methods. The study included 37 patients with the morphologically verified diagnosis of invasive breast cancer of no special type (IBC NST). The PD-L1 status was determined immunohistochemically using the Ventana SP142 assay (Roche, USA). Using the multiplex flow cytometry-based assay and high-throughput sequencing of the tumor microenvironment, subpopulations of B lymphocytes and their CD27 and PD1 expression profiles were determined, taking into account the PD-L1 status.Results. In the tumor microenvironment, regardless of the PD-L1 status, expression signatures of five lymphocyte subpopulations were determined. However, in PD-L1-positive patients, the levels of B lymphocytes and immunoglobulin class-switched B lymphocytes were higher compared with PD-L1-negative patients. Evaluation of the number of different B lymphocyte subpopulations by flow cytometry showed that PD-1-positive B lymphocytes predominated in the tumor microenvironment in PD-L1-positive patients, regardless of the degree of lymphocyte maturity.Conclusion. The results of the study showed predominance of mature committed B lymphocytes and memory B lymphocytes capable of synthesizing immunoglobulins of different classes and Th2 cytokines involved in type 2 immune response in PD-L-positive tumor microenvironment. It suggests that immunotherapy with PD-L1 inhibitors is highly likely to activate cells with protumor potential and can ultimately contribute to breast cancer progression.