Background: Ovarian cancer is one of the most aggressive gynecological malignancies with a high mortality rate related to delayed diagnosis and high rates of resistance to conventional therapies. Results of clinical trials indicate that soluble galectin-3 could be considered as a potentially significant biomarker for malignant neoplasms of various locations. Its increased serum levels are frequently associated with aggressive tumors, risk of metastasis, resistance to therapy, and poor prognosis. However, data on its role and diagnostic value in ovarian cancer remains limited and contradictory. Aim: To analyze the diagnostic and prognostic value of the soluble galectin-3 in patients with various ovarian neoplasms. Methods: This retrospective study included 176 patients with ovarian tumors and 20 healthy donors who were examined and treated from January 2017 to December 2024 at the N. N. Blokhin National Medical Research Center of Oncology and Khabarovsk Territory Regional Clinical Center of Oncology. In all patients, the diagnosis was confirmed by morphological examination of the tumor according to the 2020 World Health Organization (WHO) Classification of Female Genital Tumors. Serum levels of soluble galectin-3 were measured in samples obtained before the initiation of specific treatment with the Human Galectin-3 Quantikine ELISA enzyme immunoassay kit (RD Systems, USA) in accordance with the manufacturer's instructions. Measurements were performed on a BEP 2000 Advance automated enzyme immunoassay analyzer (Siemens Healthcare Diagnostics, Germany) according to the manufacturer’s specifications. Results: One hundred and sixteen patients (116/176) had epithelial ovarian cancer (EOC), 6/176 had non-epithelial ovarian cancer (NEOC), 32/176 were diagnosed with benign ovarian tumors (BOT), and 22/176 with borderline ovarian tumors (BLOT). In the healthy controls, the median galectin-3 level was 8.02 ng/mL being significantly lower than that in the patients with EOC (10.35 ng/mL) (p = 0.0219). In the BOT group, the median galectin-3 level was 7.43 ng/mL, in the BLOT group 7.22 ng/mL, and in the NEOC group 5.49 ng/mL (p 0,999 for all comparisons to the control group). The ROC analysis demonstrated a moderate diagnostic significance of galectin-3 for EOC, with the area under the curve (AUC) of 0.702 and 95% confidence interval (CI) of 0.585 to 0.818 (p = 0.004). With a threshold value of galectin-3 concentration of 8.84 ng/mL, the test sensitivity was 62.93% and specificity 65%. If the median value were used as a cutoff, the sensitivity decreased to 50%, while the specificity increased to 75%. In the EOC group the galectin-3 levels were significantly associated with the patients age, in those above 57 of age its median value was 11.69 ng/mL, being significantly higher compared to the patients ≤ 57 years of age (9.03 ng/mL, p = 0.009). No associations were found between galectin-3 levels and other clinical and morphological characteristics, such as tumor size, disease stage, cancer spreading / metastasis). Depending on the histological type of epithelial tumors, median galectin-3 levels ranged from 9.64 ng/mL (serous type) to 13.18 ng/ml (clear cell type), but the differences were not significant (p = 0.358). In the univariate and multivariate analysis, elevated galectin-3 levels were significant predictors of unfavorable outcome (hazard ratio [HR]: 2.246, p = 0.046 and HR: 1.137, p = 0.017, respectively). Conclusion: Elevated soluble galectin-3 levels is a predictor of unfavorable prognosis in EOC. High serum concentration of this protein may be a promising additional diagnostic marker for EOC.

Background: Cadherins are calcium-dependent transmembrane glycoproteins whose extracellular domains mediate homophilic intercellular interactions. Their soluble forms (s-cadherins), generated through proteolytic cleavage of transmembrane proteins or alternative mRNA splicing, are not anchored in the cell membrane and circulate in the extracellular space or peripheral blood. In the context of carcinogenesis, the role of P-cadherin remains a matter of debate: some studies associate P-cadherin with tumor growth suppression, while others indicate its tumor-promoting properties. Publications on the significance of the soluble P-cadherin in various disorders are scarce. Aim: To perform a comparative analysis of serum sP-cadherin levels in healthy women and in patients with malignant and benign ovarian tumors to assess the clinical significance of the marker. Methods: The retrospective study included 56 patients with epithelial malignant ovarian tumors (median age 57 years), 10 patients with benign ovarian tumors (median age 55 years), and 11 healthy women (median age 56 years) who underwent examination and treatment from 2023 to 2024 in three oncology clinics. Serum levels of sP-cadherin before the initiation of specific treatment were determined with the Human P-Cadherin ELISA Kit (RayBiotech, USA). Results: In the ovarian cancer group, the majority of the patients had the serous type of the tumor (n = 46, 82%), stage III to IV of the disease (n = 45, 80%), T3 and T4 tumors (n = 42, 75%), mostly without regional (N0: n = 41, 73%) and distant metastases (M0: n = 43, 77%). The results of the ROC analysis showed that serum levels of the soluble P-cadherin could not be used as a reliable diagnostic criterion for ovarian malignancies: the area under the curve (AUC) was 0.793 (confidence interval 0.671 to 0.915; p = 0.002). At the optimal cut-off value of 3.01 ng/mL, the test’s sensitivity and specificity were 77% and 73%, respectively. The serum sP-cadherin levels did not show a significant correlation with the key clinical and morphological characteristics of ovarian cancer. Conclusion: Patients with ovarian cancer have an increased serum sP-cadherin level. Further research on this glycoprotein to assess its role in disease outcomes and chemotherapy efficacy is expedient.

Background: Renal cell carcinoma (RCC) is a highly immunogenic neoplasm and a promising target for the development of new approaches to immunotherapy. Galectins can modulate immune response, actively participating in inflammation, and help the tumor cells to escape host immune reaction. Some members of the galectin family could further become promising diagnostic or prognostic markers of various malignancies. However the data obtained are not unambiguous, and in some observations are extremely contradictory. We have demonstrated previously a significant increase of soluble galectins-1, -3 and -9 levels in serum of RCC patients before the initiation of anti-tumor therapy. Aim: To analyze an association between serum galectins-1, -3, -4, -7, -9 levels and overall survival of RCC patients with various stages of the tumor process. Methods: We retrospectively analyzed the impact of baseline soluble galectins-1, -3, -4, -7, -9 levels on overall survival of 129 patients with primary RCC who had undergone examination and treatment at the N. N. Blokhin National Medical Research Center of Oncology from 2019 to 2023. Surgery had been performed in all patients, and 10 of them had systemic target treatment or immunotherapy after surgery. Serum galectins concentrations were measured before the start of specific treatment with standard enzyme immunoassay kits. Results: The patients (n = 129) were followed up for 0.3 to 64.6 months (median, 39.3 months) after surgery. During this follow-up 32 (24.8%) patients died. They survived from 0,3 to 50.8 months (median, 20.2 months) after the initiation treatment. The patient groups selected depending on the corresponding marker levels (above or below the median) were not different in their clinical and pathologic characteristics and the treatment performed. Only pre-treatment serum galectin-3 and galectin-9 levels were associated with overall survival rates. Serum concentrations of galectin-3 and galectin-9 above the median level (10.1 ng/mL and 9.2 ng/mL) significantly decreased the 5-years overall survival of RCC patients by 21.1% and 17.6% respectively. Conclusion: Measurement of serum galectin-3 and galectin-9 concentrations can be used as supplementary criteria for the assessment of overall survival prognosis in patients with RCC.

Aim. To conduct a comparative assessment of the content of kisspeptin (KISS1) metastasis suppressor in the blood serum of apparently healthy individuals and patients with lung cancer (LC) and to analyze the associations between the KISS1 level and clinical and pathological characteristics of the disease.Materials and methods. The study included 74 LC patients and 46 apparently healthy individuals. Stage I LC was diagnosed in 8 patients, stage II LC – in 7 patients, stage III LC – in 28 patients, and stage IV LC – in 31 patients. According to the histologic pattern, 32 tumors were characterized as adenocarcinoma, 29 – as squamous-cell carcinoma, 11 – as small-cell LC (SCLC), and 2 – as large-cell lung carcinoma. The pre-treatment KISS1 level in the blood serum was determined using the enzyme-linked immunosorbent assay kit (KISS1, CloudClone Corp., USA).Results. The median serum KISS1 level in LC patients was 213 (range 7.8–716) pg / ml and was significantly higher than in the control group – 83.4 (0–180) pg / ml (p < 0.0001). The ROC analysis of the diagnostic value of serum KISS1 level demonstrated that the sensitivity of the test in relation to the healthy controls was 70% at a cutoff value of 152 pg / ml, and the specificity was 85% (AUC – 0.817; р < 0.0001). In stage I–II LC, the sensitivity did not exceed 50%. The level of KISS1 in the blood serum did not depend on the histologic type of the tumor. No significant differences in the serum KISS1 levels were observed both between non-small cell lung cancer (NSCLC) on the whole and neuroendocrine SCLC and between the main histologic types of NSCLC. The level of KISS1 increased with the disease stage (p < 0.05). However, none of the TNM staging system indices significantly influenced the level of the marker. No differences were found between serum KISS1 levels in patients with central or peripheral localization of the tumor.Conclusion. The KISS1 level was elevated in LC patients compared to healthy controls and was a stage-dependent marker. It has high diagnostic specificity but insufficient sensitivity, especially at early stages of the disease. Based on the results of this study and literature data on the role of KISS1in NSCLC, we conclude that clinical implications of KISS1 in this disease require further research.

Introduction. Despite advances in the diagnosis and drug therapy of some cancers over the past decade, solid tumors, particularly gastric cancer, still have a poor prognosis and remain a leading cause of death worldwide. Therefore, the development of methods for timely diagnosis, identification of new targets for therapy and biochemical prognosis factors is an urgent problem in clinical oncology. In recent years, the focus of clinical attention has been on immune checkpoint receptors and ligands that can identify patients for immunotherapy. The clinical and prognostic significance of the levels of soluble forms of the programmed cell death receptor PD-1 and its ligand PD-L1 in the blood of patients with gastric cancer is currently not fully determined.Aim. Comparative study of the levels of sPD-1 and sPD-L1 in the blood plasma of healthy donors and patients with gastric cancer, taking into account the prevalence of the tumor process and the prognosis of overall survival.Materials and methods. The study included 100 patients with stomach cancer aged from 25 to 81 years (57 men, 43 women), who underwent examination and treatment at the N. N. Blokhin National Medical Research Center for Oncology. The concentration of sPD-L1 and sPD-1 was determined in blood plasma obtained according to standard methods before the start of specific treatment, using reagent kits for enzyme-linked immunosorbent assay “Human PD-L1 Platinum ELISA” and “Human PD-1 ELISA kit” (Affimetrix, eBioscience, USA) in accordance with the manufacturer’s instructions. The content of markers was expressed in picograms (pg) per 1 ml of blood plasma. To compare indicators and analyze their relationships, the nonparametric Mann–Whitney test was used. Overall survival analysis was performed using the Kaplan–Meier method. For all statistical tests, p values <0.05 were considered statistically significant.Results. The analysis did not reveal a connection at a threshold level of sPD-1 of 8.0 pg / ml in the blood plasma of patients with gastric cancer with overall survival rates (p = 0.59). However, an additional analysis conducted in a group of patients with gastric cancer with stages I–II demonstrated that a marker level ≥8.0 pg / ml is a favorable prognostic factor (p = 0.0039), while in advanced stages III–IV the disease it has no prognostic significance. There was no significant correlation between sPD-L1 concentrations in the blood plasma of patients with gastric cancer and overall survival rates (p = 0.35), however, the best long-term results were found at a threshold level of marker concentrations in blood plasma <35 pg / ml.Conclusion. An sPD-1 level ≥8.0 pg / ml can serve as a favorable prognostic factor in stages I–II of gastric cancer, while in advanced stages III–IV of the disease it has no prognostic significance. The prognostic role of sPD-L1 in patients with gastric cancer has not been identified. The study needs to be continued in combination with additional predictive biomarkers for gastric cancer.

The cells of the multicellular organism interact with each other through the system of cell contacts. In particular, epithelial cells are characterized by the formation of dense intercellular contacts that allow effectively carry out intercellular transport. A large number of proteins take part in the formation of tight contact, in particular the proteins of the claudin family and zonulin. In the process of malignant transformation, there is a loss of intercellular interactions and a change in the expression of proteins responsible for their formation by acquiring the mesenchymal phenotype by neoplastic cells. Objective A comparative analysis of the content of zonulin and claudin-5 in blood serum patients with ovarian cancer and healthy women, their connection with the main clinical and morphological characteristics of the tumor and the prognosis. Mediana and the quartiles of zonulin in the blood serum of patients with ovarian cancer were 57.4; 40.1–72.4 ng/ml, which is significant than in the control group: 11.4; 8.3–16.0 ng/ml, p <0.0001, while there were no such differences for claudin-5. Analysis of the Association of Zonulin and Claudin-5 in the blood serum of patients with ovarian cancer with clinical and morphological characteristics of the disease showed that an increase in the content of zonulin in blood serum is associated with a more common stage of the disease, a large tumor size and the presence of regional metastases, while for claudin-5 no significant associations were observed. The analysis did not reveal the prognostic role of the proteins studied in patients with ovarian cancer in blood serum. However, they have changes in the content of soluble forms of zonulin and claudin-5 in blood serum, which with further examination can help improve the monitoring systems of the clinical course of this disease.

Background. Due to diversity of cancer, the functional role of galectin-3 is rather controversial; however, for many types of neoplasms, the marker acts as a tumor growth promoter.Aim. To perform a comparative analysis of galectin-3 levels in the blood serum of healthy individuals and patients with benign, borderline, and malignant bone tumors divided into two age groups (under and over 18 years of age) based on the main clinical and morphological characteristics of the disease and prognosis.Materials and methods. The study included 201 patients with benign, borderline (giant cell tumors, locally aggressive tumors), and malignant bone tumors and 31 healthy donors. The galectin-3 level was determined in the blood serum before treatment with Human Galectin-3 ELISA kit (R&D, USA).Results. The level of galectin-3 in the blood serum of patients with benign and malignant bone tumors was statistically significantly higher than that in the control group of patients both under and over 18 years. In patients with borderline bone tumors, a trend toward an increase in the galectin-3 concentration compared with the controls was revealed. The ROC analysis for galectin-3 in patients with bone sarcomas showed that the area under the curve (AUC) comprised 0.795 (р < 0.0001) in the group of patients over 18 years and 0.868 (р = 0.0008) in the individuals under 18 years. For malignant bone tumors in patients over 18 years, the sensitivity of this method was 71.3%, and specificity was 71.43% (optimal cut-off level was 8.09 ng / ml; р < 0.0001), while in patients under 18 years, the sensitivity of the method was 80%, and specificity was 90% (optimal cut-off level was 5.49 ng / ml; р < 0.001). No significant associations between the serum galectin-3 level and the clinical and morphological characteristics of bone neoplasms were found both in patients under and over 18 years of age. However, it could be noted that the highest concentration of the marker was found in chordomas and at earlier stages of the disease. In patients over 18 years with chondrosarcoma and osteosarcoma, no correlation between the marker and the disease prognosis was found.Conclusion. An increase in the galectin-3 level in the blood serum was observed in all age groups of patients with both benign and malignant bone tumors. However, the sensitivity and specificity of the method assessed by the ROC analysis do not allow to apply this marker for the diagnosis of bone tumors.

Background: High incidence of gastric cancer (GC), its aggressive clinical course, rapid tumor dissemination, low sensitivity to chemotherapy and lack of reliable laboratory diagnostic criteria urgently require a search for the most informative markers associated with key biologic properties of the tumors. Aim: Comparative analysis of galectin-3, matrix metalloproteinase (MMP)-2, and MMP-9 levels in peripheral blood of GC patients and healthy donors, assessment of association of these markers with clinical morphological characteristics of the disease, and prognosis of overall and relapse-free survival. Materials and methods: Sixty (60) primary treatment-nave GC patients (38 men, 22 women) aged 29 to 81 years and 90 healthy donors compatible with their age and sex were included into the study. Galectin-3 was measured in EDTA plasma, MMP-2 and MMP-9 in serum with standard direct enzyme immunoassay kits "Human MMP-2 (total)", "Human MMP-9 (total)", "Human Galectin-3" (RD Systems, USA). Results: Plasma galectin-3 concentration in the GC patients was significantly higher than in the healthy controls (median 12.9 and 10.6 ng/ml, respectively; p 0.0001). No difference in serum MMP-9 levels between GC patients and control subjects were found, while MMP-2 level in the control group was significantly higher, than in the GC patients (p = 0.039). No association between galectin-3, MMP-2, and MMP-9 blood levels in the GC patients could be identified. In contrast to GC patients, there was a positive correlation of plasma galectin-3 with age in the control group (rs = 0.51, p 0.005). No associations between the biomarkers levels in blood and clinical and morphological characteristics of GC were established, except MMP-9 being higher at Т4а invasion depth as compared to the earlier Т2 level. Marked differences in the overall survival depending on plasma galectin-3 levels were found, with the cut-off level of 12.9 ng/ml: the 5-year overall survival in the patients with low galectin-3 was better, than in those with its higher level (50 and 43%, respectively; however, the difference was non-significant, р 0.1). Both overall and relapse-free survival of the GC patients was higher in those with low ( 212 ng/ml) serum MMP-2: the 5-year overall survival in this group comprised 60% versus 23% in the patients with higher MMP-2 (p = 0.018). The difference in relapse-free survival was non-significant. Serum MMP-9 levels had no significant impact on the survival of GC patients. Conclusion: The ambiguous data on the clinical role of galectin-3, MMP-2, MMP-9 in GC obtained in this study indicate the necessity of further investigation of their possible utility for the diagnostics and prognosis of treatment results.

Introduction . Enzyme-linked immunosorbent assay of biochemical markers is one of the most important methods for diagnosing tumors. One of these markers is an inducer of expression of matrix metalloproteases EMMPRIN/CD147. Changes in its expression are associated with the progression of some tumors. This study is the first work devoted to the study of the content of the soluble form of the transmembrane glycoprotein EMMPRIN (sEMMPRIN) in the blood serum of patients with various bone tumors. Aim . To study the content of sEMMPRIN in the blood serum of patients with malignant bone tumors, its relationship with the clinical and morphological characteristics of neoplasms and prognosis. Materials and methods . The study included 88 patients with malignant tumors (osteosarcoma – 37 cases, chondrosarcoma – 39, chordoma – 5, Ewing’s sarcoma – 7) and borderline (11 cases) bone neoplasms, of which 14 patients were under the age of 18 years. The control group consisted of 29 healthy donors, 8 of which were under the age of 18 years. The concentration of EMMPRIN was determined in the serum of patients and donors with reagents for direct enzyme immunoassay “Human EMMPRIN” (R&D, USA) in accordance with the manufacturer’s instructions and expressed in nanograms (ng) per 1 ml of blood serum. The obtained data were processed using the GraphPad Prizm 9.4 program. When comparing indicators and analyzing their relationships, we used the nonparametric Mann–Whitney and Kruskal–Wallis tests. Overall survival was analyzed using the Kaplan–Meier method. Results . Our analysis of the sEMMPRIN content in the blood serum of patients with bone tumors did not reveal statistically significant differences between the control group and patients with borderline and malignant tumors, both in adults and in children. At the same time, a trend towards a decrease in the level of sEMMPRIN in the blood serum was noted in the presence of a malignant neoplasm of the bone compared with the corresponding control group. Additionally, we found that the content of sEMMPRIN is associated with age and higher in the group of patients under 18 years of age, both among healthy donors and oncological patients. An analysis of the association of sEMMPRIN content with clinical and morphological characteristics did not reveal statistically significant patterns, however, a trend towards an increase in the level of the marker with disease progression in both studied age groups was observed, which is consistent with other studies conducted on other solid tumors. Conclusion . ELISA revealed the marker sEMMPRIN in the blood serum of all examined children and adults with borderline malignant bone tumors and healthy donors. At the same time, the levels of sEMMPRIN did not differ between the above groups, however, there was a tendency for a decrease in the concentration of the marker in patients with bone sarcomas compared with the control group, regardless of age.

The content of the soluble forms of immune checkpoint components sPD-1, sPD-L1 in blood serum, and sB7-H3, sCD314, sULBP1, sHLA-G in blood plasma of 30 melanoma patients receiving immunotherapy with anti-PD-1 antibodies (nivolumab, pembrolisumab) was measured before and in 4 and 8 weeks after the start of immunotherapy. The control group comprised 70 practically healthy donors. Standard immunoassay kits were used. In melanoma patients, the levels of sPD-L1 and sB7-H3 were significantly higher than in the control group ( p <0001), sPD-1 level did not differ from the control, while sCD314 and sHLA-G levels were insignificantly decreased. During therapy, opposite changes in the levels of markers in individual patients were observed, and frequently after the initial increase (or decrease) after the first 4 weeks normalization did occur in the further 4 weeks. No statistically significant associations between the initial levels of markers and direction of their changes during treatment were found, but some trends indicating to the potential benefits from assessment of soluble forms of immune checkpoint proteins for evaluation and monitoring of the efficiency of the therapy with immune checkpoint blockers were revealed: significant decrease of sB7-H3 and sPD-1 levels in the course of treatment, higher initial sPD-1 level in patients with future progression than in those with stabilization or partial effect, and lower progression frequency in patients with increasing sPD-1 and sPD-L1 levels than in those with decreasing markers levels.

We present the results of comparative ELISA of the concentration of soluble form of immunity checkpoint B7-H3 (sB7-H3) in the serum of patients with colorectal cancer (CRC) at different stages before treatment and healthy control donors. The analysis revealed a statistically significant difference between the median levels of sB7-H3 in the blood serum of CRC patients (19.66 ng/ml) and healthy donors (16.76 ng/ml) ( p =0.0025). ROC analysis showed 62.9% sensitivity and 56.7% specificity for CRC patients (cut-off 17.62 ng/ml; p =0.0028). An association of sB7-H3 levels with tumor progression was revealed. We demonstrated that sB7-H3 levels were significantly lower in patients with regional metastases than in patients without metastases ( p =0.039) and that sB7-H3 concentration tends to decrease at the late stages of the disease. Thus, high serum level of sB7-H3 in CRC patients can be a favorable prognostic factor in future.

Background. The PD-1/PD-L1 pathway plays an important role in tumor evasion from immunological surveillance. In addition to the membrane forms of PD-1 and PD-L1, there are soluble variants: sPD-1 and sPD-L1. Both membrane and soluble forms have immunoregulatory properties and can affect the function and number of different immune cell populations. Aim. To study the relationship between the initial level of CD8⁺PD-1⁺ and CD4+PD-1⁺ lymphocytes and soluble forms of sPD-1 and sPD-L1 with the percentage of the main effector and regulatory populations of peripheral blood (PB) lymphocytes and tumor-infiltrating lymphocytes. Materials and methods. The study included melanoma, breast cancer and the oral mucosa cancer patients. The percentage of cell populations of PB lymphocytes and tumor-infiltrating lymphocytes was determined by flow cytometry before treatment. The concentrations of sPD-1 and sPD-L1 proteins were studied in blood serum using enzyme immunoassay. Results. The relationship of the level of CD8⁺PD-1⁺ cells with certain populations of CD8-lymphocytes in PB and tumor tissue was found. In the PB of melanoma patients with CD8⁺CD11b⁺CD28⁺ and CD8⁺CD11b⁻CD28⁻ T cells, in breast cancer patients with a population of CD8⁺CD11b⁺CD28⁺ lymphocytes. In the tumor tissue of all patients there was a positive correlation with a population of regulatory CD8⁺CD11b⁻CD28⁻ T cells. The immunoregulatory properties of sPD-1 and sPD-L1 were confirmed. Both sPD-1 and sPD-L1 levels were positively correlated with the number of suppressor CD8⁺CD11b⁻CD28⁻ T cells and negatively with the level of CD8 lymphocytes, CD8⁺CD11b⁺CD28⁺ cytotoxic/memory T cells, B cells and activated CD25 lymphocytes. Conclusion. The results of the study can make a certain contribution to the study of the prognostic significance of membrane and soluble forms of PD-1 and PD-L1, taking into account the peculiarities of their relationship with suppressor and effector populations of lymphocytes of systemic and local immunity.

Background. The most important problems in improvement of treatment outcomes in patients with renal cell carcinoma (RCC) are search and validation of molecular markers for its early diagnosis and prognosis. Genes suppressing distant metastasizing but not affecting the primary tumor are called metastasis suppressors. Study of these genes and their products not only improves understanding of the mechanisms of tumor progression, but has practical value for diagnosis, prognosis, and establishment of new molecular targets for antitumor therapy. One of such genes is KISS1 with its product kisspeptin (KISS1) protein.Aim: comparative evaluation of KISS1 concentration in blood serum of practically healthy persons and patients with renal cancer; analysis of correlations between the marker’s level and clinical and morphological characteristics of the disease.Materials and methods. 140 patients with RCC (88 men, 52 women) aged between 29 and 82 years were included in the study. Among them, clear cell RCC was diagnosed in 84 patients, papillary in 38, chromophobe in 18. The control group was comprised of 40 healthy persons of matched age and sex. Pre-treatment KISS1 concentration in blood serum was measured using a direct enzyme immunoassay kit (Kisspeptin 1 – KISS1, Cloud-Clone Corp., USA).Results. Median serum KISS1 concentration in the control group was 51.7 pg/mL which was significantly lower than in the total RCC patient group – 243.6 pg/mL (p <0.0001). ROC analysis of diagnostic value of serum KISS1 level was performed both for the total RCC group and for each of its three histological types. In the total group the sensitivity of the test was 75 %, specificity – 80 % (AUC 0.877; 95 % confidence interval (CI) 0.827–0.927; optimal cut-off level 130.8 pg/mL; р <0.0001). For clear cell RCC, both sensitivity and specificity were 85 % (AUC 0.941; 95 % CI 0.902– 0.979; cut-off 141.8 pg/mL; p <0.0001). In non-clear cell RCC types, sensitivity of this marker was only 58 % while the specificity remained 80 % (for papillary RCC AUC 0.787; 95 % CI 0.684–0.889; cut-off level 135.5 pg/mL; p <0.0001, and for chromophobe RCC AUC 0.774; 95 % CI 0.617–0.929; cut-off level 132.1 pg/mL; p <0.001). KISS1 level increased with disease progression: it is significantly higher at more advanced stages above stage I, and in patients with distant metastases compared to those without metastases. Higher serum KISS1 level is also observed in patients with poorly differentiated high-grade (per Furhman) clear cell RCC and papillary RCC (G3–G4) than in those with well differentiated low-grade (G1–G2) tumors.Conclusion. KISS1 level is significantly increased in patients with RCC compared to healthy controls and is a stagedependent marker of this disease. It has relatively high diagnostic sensitivity and specificity (both 85 %) for the most frequent histological type of RCC – clear cell RCC. Thus, clinical significance of kisspeptin in RCC requires further investigation.

ЦЕЛЬ ОБЗОРА Проанализировать и обобщить данные литературы за 20-летний период и дольше для оценки важности определения зонулина в качестве биомаркера при неинфекционных соматических заболеваниях, в том числе аутоиммунных, метаболических и онкологических. ОСНОВНЫЕ ПОЛОЖЕНИЯ В обзоре представлены данные о структуре и функции межклеточных плотных контактов, участвующих в регуляции проницаемости кишечного барьера, нарушение которой рассматривается как один из важных патогенетических механизмов развития многих неинфекционных соматических заболеваний. Зонулин относится к числу ключевых эндогенных регуляторов межклеточной проницаемости, в связи с чем большое количество работ посвящено изучению зонулина и белков его семейства как маркеров проницаемости слизистой оболочки кишечника в первую очередь при заболеваниях желудочно-кишечного тракта. В то же время повышенный уровень сывороточного зонулина выявлен при аутоиммунных заболеваниях и ожирении, что затрудняет адекватную интерпретацию полученных данных. Интерес онкологов к белкам системы зонулина обусловлен тем, что дисрегуляция сигнального пути зонулина может вносить вклад в патогенез различных заболеваний, связанных с нарушением межклеточных коммуникаций, в том числе злокачественной трансформации и метастазирования. Возможность влияния на уровень зонулина с помощью специфического ингибитора или приема пробиотиков с выраженным клиническим эффектом показана в ряде публикаций последних лет. Важным аспектом в изучении зонулина остается методика его определения, которую, по данным ряда авторов, необходимо совершенствовать. ЗАКЛЮЧЕНИЕ Определение уровня зонулина в сыворотке крови и других биологических средах является полезным инструментом для диагностики, мониторинга, а возможно, и коррекции патологических процессов, связанных с нарушениями кишечной проницаемости, что должно быть изучено в дальнейшем.

Zonulin content in blood serum of patients with colorectal cancer (CRC; n =152; 30-84 years) and patients with large bowel adenomas ( n =32; 39-82 years) was measured by standardized kit IDK Zonulin ELISA (Immundiagnostik AG). The healthy control group ( n =50) comprised volunteers (27 women, 23 men; 25-68 years); pathological control group ( n =84) — patients (55 women, 29 men;18-84 years) with irritable bowel syndrome ( n =29), Crohn’s disease ( n =5), and ulcero-necrotic colitis ( n =50). In comparison to healthy control group, the level of zonulin was significantly increased in CRC patients ( p <0.0000001) and in patients with benign large bowel tumors ( p <0.004), as well as in patients with inflammatory intestine diseases and with irritable bowel syndrome ( p <0.0002). Zonulin level in blood serum of CRC patients was slightly, but significantly higher ( p <0.05) than in the group of pathological control. ROC curve construction revealed that at optimal zonulin cut-off level (52.2 ng/ml), the diagnostic sensitivity of CRC detection was 66.7% and specificity relative to healthy control was 81.8%. The specificity relative to the combined control group (healthy control+non-tumor bowel diseases) was only 68.9%. Thus, no acceptable cut-off levels for differentiation between malignant and benign tumors, as well as between tumor and non-tumor large bowel pathologies were found. Analysis of the associations between serum zonulin level and the main clinical and pathological characteristics of CRC demonstrated that the level of this marker increased with disease progression ( p <0.01; Kruskal—Wallis test), but was not associated with individual criteria of the TNM system, tumor localization, histological structure, and malignancy grade.

Results of enzyme-linked immunosorbent assay of the soluble forms of PD-1/PD-L immune checkpoint receptor and ligand (sPD-1 and sPD-L1) in pretreatment blood serum of 88 breast cancer patients at various disease stages aged 30-83 years are presented. The control group included 55 practically healthy women aged 19-82 years. Serum sPD-1 and sPD-L1 levels in breast cancer patients highly significantly (p<0.0001) differ from control and these changes are opposite: soluble receptor level is more than 6-fold decreased, while soluble ligand concentration - 5.5 fold increased. Both markers separately, as well as their ratio demonstrate very high sensitivity (94-100%) and specificity (95-100%) in relation to healthy control. No statistically significant associations of sPD-1 and sPD-L1 levels with clinical stage, individual TNM system criteria, tumor histological structure, grade, receptor status, and molecular type were established. In particular, no significant peculiarities of the markers’ levels in triple negative breast cancer successfully treated with anti-PD-1/PD-L1 preparations were revealed. Long-term follow-up and dynamic studies of sPD-1 and sPD-L1serum levels in the course of treatment are required for evaluation of their independent from clinical and morphological factors prognostic significance and the possibility of application as low invasive tests for prediction and monitoring of corresponding targeted therapy efficiency.

Ovarian cancer (OC) is mostly detected at late stages weighed down with metastasis, and the five-year survival rate of patients is only 30%, which dictates the necessity to develop gentler and more selectively targeted drugs that current chemotherapeutic agents. The search for factors that can influence on the activity of the PD-1/PD-L1 immune checkpoint signaling pathway in tumors is relevant, and micro RNAs (miRNAs) play an important role in it. Over the past 5 years, only a few miRNAs (miR-34a, miR-145, and miR-424), which have a regulatory effect on the PD-1/PD-L1 system in OC patients, have been discovered. In present work, the methylation levels of 13 miRNA genes in 26 primary tumors and 19 peritoneal metastases of OC patients were determined and compared with the level of the soluble form of PD-L1 (sPD-L1) in the blood plasma of the same patients. It was shown that the methylation levels of five miRNA genes (MIR124-2, MIR34B/C, MIR9-1, MIR9-3, and MIR339) in tumors are in direct correlation with the sPD-L1 level in the blood plasma. In addition, when analyzing these five genes, a significant association of the methylation level of the MIR9-1 gene with a decrease in the three-year relapse-free survival, and a trend for decrease in the three-year survival rate with the methylation level of the MIR124-2 gene of OC patients were determined. Thus, the first data suggesting the role of inhibitors of the sPD-L1 immune checkpoint for five miRNAs (miR-124, miR-34b, miR-34c, miR-9, miR-339) and the possibility of using hypermethylated MIR9-1 and, presumably, MIR124-2 genes as independent prognostic markers of poor disease-free survival in OC patients were obtained.

Due to the low efficiency of immunotherapy for colorectal cancer (CRC), it is extremely promising and relevant to study the mechanisms of immunosuppression. In this work, a comprehensive study of the expression of soluble and tissue forms of PD-1 and PD-L1 in blood serum and tumors of patients with CRC, as well as IDO1 in tumors was performed for the first time. The diagnostic and prognostic significance of the studied parameters was determined. A statistically significant decrease in the number of soluble forms of PD-1 and PD-L1 in the blood serum and the association of the number of PD-L1+ cells in the stroma of tumors with the CRC stage were established. The absence of correlations between soluble and tissue forms of the studied proteins was shown, indicating the presence of independent mechanisms of immunosuppression in CRC, which may explain the ineffectiveness of immunotherapy for this type of tumor.

Analysis of long-term treatment results of 101 primary gastric cancer patients at various stages of the tumor process followed during 1 - 41 months (median - 6,4 months) from the onset of specific treatment are presented depending on the levels of soluble forms (s) of PD-1 receptor and its ligand PD-L1 in blood plasma. Overall survival assessed by Kaplan-Meyer analysis and with the help of Cox multiparametric regression model was applied as the criterion of prognostic value. It was found that at high (≥ 35 pg/ml) sPD-L1 levels in blood plasma, the overall survival of patients with gastric cancer was statistically significantly lower than at the marker's levels below 35 pg / ml (p <0.045): 1-year survival comprised 78 and 96%, 2-year - 52 and 78%; 3-year - 40 and 61% at high and low sPD-L1 respectively. Median survival of patients with high plasma sPD-L1 comprised 29 months, of those with low sPD-L1 was not achieved during the whole follow-up period. This trend was observed not only in the total group of stage I-IV gastric cancer patients, but also in patients at the early stages of the disease, though sPD-L1 did not show an independent prognostic value in multiparametric model. At the same time, the overall survival of patients with gastric cancer did not depend on the baseline levels sPD-1 in blood plasma. Thus, soluble ligand sPD-L1 can be considered as a potentially valuable factor for prognosis of gastric cancer patients' survival, and, probably, of anti-PD-1/PD-L1 treatment efficiency, but further studies and patients' monitoring are required to prove this statement.

The analysis of long-term results of treatment of 88 primary patients with colon adenocarcinoma at various stages of tumor process is presented, taking into account the TNM system criteria, and serum IGF-1, IGF-2, IGFBP-1, IGFBP-2, IGFBP-3, VEGF, and MMP-7 levels. The overall survival rate assessed by Kaplan-Meier method and Cox multivariate regression model was used as the criterion of prognosis. It was established that IGF-1, IGFBP-2 and VEGF serum levels along with the stage of colorectal cancer might be considered as statistically significant independent predictors of overall survival in patients.