Breast cancer is the most acute worldwide healthcare problem. Its incidence is rising. Development of this malignant tumor is associated with many risk factor, however primary cause of the disease stays usually obscure. Researches into breast cancer association with oncogenic papillomaviruses have been conducted for three decades, yet there is no definite conclusion on the problem. Actuality of the issue of breast cancer association with these viruses increases many times with the development of prophylactic vaccines against cervical cancer: in case such association does occur realistic perspective appears to prevent this extremely widespread cancer as well.

Exosomes are natural nanovesicles with a diameter of 40–100 nm, which are actively involved in the transfer of biologically active substances and participate in intercellular communication. The natural origin of exosomes determines its biological compatibility with cell cultures and makes them promising delivery vehicles for anticancer drugs. Methods of the artificial production of exosomes are not available, and exosome preparations obtained from tumor cells are not suitable for therapy. Milk is a biological fluid that is commercially available and may be a universal source of exosomes for treatment. Target delivery of anticancer drugs using milk exosomes can reduce the toxic effect of cytostatic agents during chemotherapy. This review discusses methods for isolating exosomes from milk, their additional purification, and analysis of their biologically significant components – proteins and nucleic acids, and prospects for using milk exosomes to treat cancer.

Introduction. Studies on non-metastatic colorectal cancer have demonstrated the prognostic role of circulating tumor (ctDNA) after surgery, and the ability to identify patients with the greatest risk of progression. This makes it possible in the future to personalize neoadjuvant and adjuvant treatment.

The study objective – to evaluate the correlation of the ctDNA status before and after surgery with a clinical outcome in patients with stage I–III colorectal cancer.

Materials and methods. The study included data from patients with morphologically verified colorectal cancer with stage I–III who were treated at the N. N. Blokhin National Oncology Research Center in the period from 2016 to 2021. Blood samples were collected before and after surgical treatment (on the 7–10^th day after surgery). The minimum permissible concentration at which ctDNA in a plasma sample was considered positive was 0.4 copies of mutant DNA in 1 mcL of plasma. The main criterion of effectiveness was disease-free survival (DFS). The presence of cDNA before and after surgery was a negative prognostic factor for progression in stage I–III of CRC. Patients with positive cDNA after surgery had worse DFS results despite adjuvant chemotherapy. Patients with stage II CRC with negative ctDNA, regardless of adjuvant CT after surgery, did not have disease progression in 100 % of cases.

Results. The study included 146 patients with stage I–III colorectal cancer. Progression was detected in 34 patients. The median follow-up time was 22 months (0–66 months). Data on progression were known in 119 patients. Positive cDNA data were detected before surgery in 55 of 120 patients (45 %), after surgery in 46 of 119 (38.6 %). In the group with positive cDNA before surgery, the median DFS was 35 months (95 % confidence interval (CI) 24,0–45.9), in the group with negative cDNA before surgery, the median DFS was not achieved (hazard ratio (HR) 4.6; 95 % CI 2.0–10.4), 1‑year DFS in the cDNA positive group was 62 % versus 100 % in the cDNA negative group (p <0.001). In the group with positive cDNA after surgery, the median DFS was 20 months (95 % CI 8,1–31,9), in the group with negative cDNA was not achieved (HR 27,7; 95 % CI 6,6–116,6; p <0,001). Patients with positive cDNA after surgery had worse DFS scores despite adjuvant chemotherapy. Patients with stage II CRC without ctDNA after surgery in 100 % did not have disease progression regardless of adjuvant CT.

Conclusion. The presence of cDNA before and after surgery was a negative prognostic factor of progression after surgical treatment at stage I–III. The high negative prognostic value of cDNA makes it possible to select patients with stage II who do not need adjuvant chemotherapy.

Introduction. Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract the character diagnostic feature of which is CD117 (KIT) expression. GISTs are clinically diverse and have different genetic alterations that may have predictive and prognostic significance.

Aim – the study of clinical, morphological and genetic features of GISTs to assess the overall survival (OS) of patients with various profiles of genetic disorders for elucidation the factors contributing to prognosis.

Materials and methods. A total 244 GIST patients who received combined treatment were enrolled in the study and their clinical characteristics and mutational status of KIT, PDGFRA, BRAF were analyzed. SDH-deficient GISTs were detected using IHC-analysis of SDHB expression.

Results. Stromal tumors developed in stomach (50 %), small intestine (37.7 %), colon or rectum (8.6 %), esophagus (0.4 %) and extraorganically (EGIST, 5.7 %). Overall survival correlated with gastric site (p = 0.005), tumor size <10 cm (p = 0,0001) and mitotic count HPF< 10 / 50 (p = 0.007). KIT mutations were found in 168 (68.9 %) and PDGFRA – in 31 (12.1 %) of GISTs, 14 novel mutations were detected. Mutations in KIT exon 11 were found in 140 (57.4 %) tumors, 10-year OS, 51 %, median 124 months. Patients with deletions had lower OS than patients with substitutions or duplications in KIT exon 11 (p = 0,023). The lowest OS was in patients with primary mutations in KIT exons 13 or 17 (median 28 months) and duplications in KIT exon 9 (median 71 months). There was a low OS of young patients with homozygous KIT mutations, mutations that begin in intron and two simultaneous KIT mutations. GISTs with PDGFRA mutations were located in stomach and had no metastases, 10-year OS, 63 %, median 175 months. KIT / PDGFRA mutations were not observed in 45 (18.4 %) patients (wild-type GIST), 10-year OS, 59 %, median 250 months. Wild-type GISTs with BRAF, NF1 mutations and SDH deficiency were detected. The better OS was demonstrated by patients with BRAFV600E (10-year ОS, 84 %, median 97 months) and SDH deficiency (10-year and 15-year OS, 82 %).

Conclusion. Genetic analysis is necessary to clarify GIST prognosis and predict the effectiveness of targeted therapy. The clinical, morphological and genetic diversity of GISTs was confirmed. Wild-type GISTs with BRAF mutations and SDHdeficiency were identified in the Russian population for the first time. The long-term 10- и 15-year OS of GIST patients were evaluated.

Introduction. The identification of predictive factors is a cornerstone task of modern oncology. The development of new targeted drugs determines the need for prediction of chemosensitivity of each patient to the prescribed therapy, in this regard, the search for biomarkers of predictive response to therapy is actively conducted.

The study objective to investigate the relationship between tumor cell resistance and the expression levels of CA IX (carbonic anhydrase IX) and VEGF A (vascular endothelial growth factor А) in patient-derived cultures of soft tissue sarcomas.

Materials and methods: ex vivo soft tissue sarcoma cell culture, resazurin test, immunoblotting.

Results. We obtained 46 ex vivo samples of soft tissue sarcoma cultures for which chemosensitivity to doxorubicin, ifosfamide, docetaxel, gemcitabine, and their combinations was assessed by the resazurin cytotoxicity test. We analyzed the relationship between the expression of hypoxic proteins VEGF A and CA IX and the resistance to drugs. A correlation between the CA IX expression in hypoxia and cell resistance to ifosfamide and its combination with doxorubicin was found. Soft tissue sarcomas with high VEGF A index were resistant to doxorubicin, docetaxel, and its combination with gemcitabine (p <0.05).

Conclusion. The data obtained on patient-derived cultures indicate the relationship between hypoxic signaling and resistance of soft tissue sarcomas to chemotherapeutics.

Introduction. Retinoic acid (RA) is a key regulator of cell differentiation and a critical player in such systemic processes in the body as embryonic development, immune system cell maturation and functioning, tissue remodeling and several others. This compound displays an antitumor activity due to its ability to stimulate differentiation, induce apoptosis  and inhibit proliferation of malignant cells. The rapid acquisition of resistance to RA and its analogues by solid tumor cells is one of the main problems limiting the widespread use of retinoids in the therapy of malignant neoplasms. The mechanisms of RA-resistance are still poorly understood.

The study objective – assessment of the relationship between the basal expression level of the nuclear RARα receptor and the RA-induced expression of the cytochromes CYP26A1and CYP26B1 with the resistance of breast cancer cells to the action of all-trans-retinoic acid.

Materials and methods. Cell lines were cultured, the sensitivity of breast cancer cells to the action of fully trans-retinoic acid, RNA isolation, reverse transcription reaction and real-time polymerase chain reaction were analyzed).

Results. In present study, using an experimental model represented by 9 breast cancer cell lines with different level of sensitivity to RA, we showed that the expression of the RA nuclear receptor RARα, as well as the level of mRNA induction of CYP26A1 and CYP26B1 cytochromes in response to RA treatment correlate with RA-sensitivity.

Conclusion. Thus, a decrease of RARα expression as well as the reduced ability to catabolize RA are factors associated with RA-resistance of breast cancer cells.

Itroduction. Immune checkpoint inhibitors have become the standard of care for patients with advanced non-small cell lung cancer. However, despite the determination of programmed death-ligand 1 expression in clinical practice, which determines the effectiveness of therapy, up to 80 % of patients with non-small cell lung cancer do not respond to treatment.

The study objective – investigation of the prognostic role of clinical and immunological markers during immune checkpoint inhibitor monotherapy in ≥2 lines in patients with advanced non-small cell lung cancer.

Materials and methods. The study included 45 patients with advanced non-small cell lung cancer receiving programmed cell death 1 / programmed death-ligand 1 inhibitors in monotherapy in 2 and subsequent lines (Group 1), as well as 30 patients with advanced non-small cell lung cancer receiving first-line chemotherapy (Group 2). All patients from 2 groups did not have autoimmune diseases before starting treatment. The determination of autoantibodies, β-2-microglobulin, neopterin, interleukin 6, interleukin 18 and the allelic variant of HLA-DRB1 in patients in the Group 1 was carried out 2 months after the start of therapy, and in the Group 2 – before the start of the next chemotherapy cycle.

Results. In Group 1, the presence of EGFR / ALK mutations is an independent predictor of shorter progression-free survival (p = 0.018). Also, in the univariate analysis, neutrophil-lymphocyte ratio <5 before immune checkpoint inhibitors (p = 0.009) and the appearance of immune-related adverse events (p = 0.038) are associated with long-term progressionfree survival. In Group 1, β-2-microglobulin was lower in patients with a response duration of ≥6 months than with a progression <6 months: 1.7 mg / L and 2.9 mg / L, respectively (p <0.0001). Patients receiving immune checkpoint inhibitors with a β-2-microglobulin level ≥2.5 mg / L have a shorter progression-free survival than patients with a marker value <2.5 mg / L: 168 days and the value is not reached, respectively (p = 0.017). In response duration ≥6 months neopterin value was lower than in disease progression: 8.6 nmol / l and 13.4 nmol / L, respectively (p <0,0001). Progression-free survival was lower in patients with neopterin ≥12 nmol / L than patients with neopterin <12 nmol / L: median was 164 days and the value was not reached, respectively (p = 0.0007). Based on the results of multivariate analysis, β-2-microglobulin ≥2.5 mg / L (p = 0.006) and neopterin ≥12 nmol / L (p = 0.027) were independent predictors of shorter progression-free survival. Low levels of interleukin 6 and interleukin 18, as well as antibodies to thyroperoxidase, are associated with a response of ≥6 months. HLA-DRB1*03 was associated with a duration of response of ≥6 months, as well as a longer progression-free survival compared with other allelic variants. The levels of β-2-microglobulin, neopterin, interleukin 6, interleukin 18 were higher in patients in Group 1 than in patients in Group 2 (p <0.0001).

Conclusion. Immunological markers can serve as promising prognosis markers in patients with advanced non-small cell lung cancer during immunotherapy.

Introduction. In the structure of cancer incidence, lung cancer ranks first among men. In order to study the molecular mechanisms of the initiation and progression of lung cancer, it is necessary to study not only the tumor cells themselves, but also the features of the systemic tryptophan metabolism. Tryptophan catabolites, being to a large extent product of the metabolic activity of the intestinal microbiota, can affect the effectiveness of immunotherapy with checkpoint inhibitors. The kynurenine pathway of tryptophan metabolism is intensified in the body of cancer patients; its products have a pro-oncogenic and immunosuppressive effect, which may hinder the effectiveness of immunotherapy.

Objective – to study the dynamics of changes in various metabolites of tryptophan metabolism in the blood serum and feces of patients with non-small cell lung cancer with various effects of immunotherapy with inhibitors of PD-1 (programmed cell death receptor 1) / PD-L1 (programmed cell death receptor 1 ligand).

Materials and methods. The study included blood serum and stool samples obtained from 20 patients with non-small cell lung cancer treated with PD-1 / PD-L1 inhibitors. Using high-performance liquid chromatography with mass spectrometric analysis, the levels of 13 tryptophan metabolites were assessed in patients with various effects of immunotherapy. The significance of differences between the samples was assessed using a nonparametric method according to the Mann – Whitney test. They were considered statistically significant at p <0.05.

Results. In fecal analyzes of patients in whom a positive effect of immunotherapy was observed, baseline levels of 5-hydroxyindole acetate and quinolinic acid were lower than in patients with tumor progression. Positive clinical dynamics was accompanied by a decrease in the content of indole-3-lactate, kynurenine and indole-3-carboxaldehyde in the feces of patients. In the serum of patients with a positive response, the initial content of 5-hydroxyindole acetate, indole-3-acetate, indole-3-butyrate and quinoline acid was lower than in patients with progression of non-small cell lung cancer. A positive response to immunotherapy was characterized by an increase in the levels of indole-3-butyrate and indole-3-propionate, and a negative response was not accompanied by statistically significant changes in the studied tryptophan metabolites.

Conclusion. Profiling tryptophan metabolites in feces and serum of patients with non-small cell lung cancer can be used to predict the effectiveness of immunotherapy with PD-1 / PD-L1 inhibitors.

Introduction. Uveal melanoma pathogenesis is determined by a number of factors, including the tumor molecular genetics, the organism’s immune response, and other ones. One of the approaches to studying the peculiarities of pathogenesis of this cancer is to determine the local subpopulations of lymphocytes and macrophages in combination with the study of the proliferative activity of tumor cells.

Objective – to study the immunohistochemical features of uveal melanoma and its cellular microenvironment.

Materials and methods. 24 enucleated eyes with uveal melanoma (144 histological and 216 immunohistochemicalpreparations) without previous treatment were analyzed. Cells of the immune microenvironment were analyzed: lymphocyte subpopulations and CD 68+ and CD 163+ antigens expressed by macrophages in the melanoma stroma and 2–3 mm from it. The tumor cell proliferation index Ki-67 was diagnosed.

Results. All tissue samples of uveal melanoma revealed the presence of lymphocytes in the microenvironment of tumor cells. A large proportion of the studied subpopulations of lymphocytes were T-cytotoxic CD28+ lymphocytes (absolute content: 607.3 ± 431.2, relative: 18.84 % ± 12.12 %) (p = 0.018). A smaller proportion, but in equal proportions, were  T-helpers CD4+, T-cytotoxic CD8+ and CD25+ lymphocytes (p = 0.6). The absolute number of natural killer cells subpopulation CD16+ was lower compared to CD56+ (p = 0.05). However, an almost equal relative content of the studied subpopulations was noted (p = 0.9). Histological examination revealed the presence of uveal melanoma macrophages in the microenvironment of the tissue. The immunohistochemical study of CD68+ and CD163+ antigens expressed by anti-inflammatory and pro-tumor macrophages showed that their absolute and relative content in the uveal melanoma tissue is almost the same with a slight predominance of CD163+ (p = 0.7). Immunohistochemical analysis showed that the nuclei of melanoma cells contain, on average, 575.2 ± 388.5 significant cells of the Ki-67 proliferation protein. This protein was found in 16.69 ± 10.88 % of tumor cells.

Conclusion. Immunohistochemical study allows to identify subpopulations of lymphocytes infiltrating the tumor, to determine the subtypes of macrophages and to estimate the Ki-67 index of tumor cell proliferation. The data obtained will make it possible to further evaluate the significance of individual immune cells (in particular, T-cytotoxic CD28+ lymphocytes) in the pathogenesis of uveal melanoma in order to develop targeted effects, substantiate new immunotherapeutic approaches to the treatment of primary tumors and reprogramming altered immune cells.

Introduction. Primary mediastinal large B-cell lymphoma is an aggressive variant of lymphoma characterized by genetic heterogeneity. First-time therapy for primary mediastinal large B-cell lymphoma usually includes immunochemotherapy. However, a substantial proportion of patients do not respond to this therapy.

Objective – to analyze clinical characteristics of primary refractory primary mediastinal large B-cell lymphoma taking into account the results of targeted next-generation sequencing (NGS).

Materials and methods. A 22‑year-old patient with primary mediastinal large B-cell lymphoma who had not responded to immunochemotherapy was tested using targeted NGS for 77 genes.

Results. We identified 2 rare mutations in the ALK gene with an unclear clinical value. According to the literature, these mutations are primarily found in solid tumors.

Conclusion. Missense mutations identified in the ALK gene are presumably associated with the course of primary mediastinal large B-cell lymphoma, in particular, with primary refractory disease.

Introduction. Immunotherapy, which is part of the complex and combined cancer therapy, is one of the priority areas in the treatment of cancer patients. However, the effectiveness of the use of immunotherapeutic drugs of the latest generation is not so high, and in some patients the effect of therapy was short-lived. Factors that prevent the full realization of the antitumor effect of cytostatics and immunopreparations may be the features of the antigenic composition of the tumor, as well as its cellular and stromal microenvironment. These facts contributed to the development of a new strategy, designated as immunoredaction of cancer by exposure to various biologically active agents that can change the body – tumor ratio in favor of the patient and make the tumor available for the implementation of antitumor effects of the host immune system.

The study objective – experimental substantiation of the development of new immunotherapeutic approaches in the treatment of aggressive forms of cancer.

Materials and methods. An experimental study of the effect of human recombinant interferon-gamma (IFNγ) on the growth of Ehrlich’s carcinoma during subcutaneous bilateral transplantation of tumor cells to animals was carried out. Transplantation of Ehrlich’s carcinoma to male F1 hybrids (SWAhC57Bl6) was performed by subcutaneous injection of 2.0 × 106 tumor cells (7‑day culture) in 0.1 ml of suspension into the lateral surface of the right and left femur with imitation of multicentric growth.

Results. A day after the course of drug administration (day 6 of tumor node growth), the effect of suppressing tumor growth in relation to growth in the control group was noted. The maximum inhibition effect of 19.8 % (p <0.05) of tumor growth was obtained 5 days after the course of the drug (10 days of tumor growth, right node) and 18.5 % (p <0.001) 9 days after administration (14 days of tumor growth, left node).

Conclusion. Thus, a distinct, statistically significant antitumor effect of IFNγ was established in relation to a tumor with a multicentric growth pattern.