Development of next generation sequencing technologies allows to identify a large number of genetic landscape types in various cancers including breast cancer. Frequent genetic abnormalities identified using whole genome sequencing are point mutations (missense, nonsense mutations), deletions, insertions, which usually lead to activation of protooncogenes and inactivation of tumor suppressor genes. Genome sequencing of malignant tumors allowed, on one hand, to identify driver mutations in carcinogenic genes in different organs, and on the other – to use mutated genes for targeted therapy. Study of biological functions of these genes from the point of view of their contribution to carcinogenesis allows to better understand its mechanism. In this review, signaling cascades of breast cancer with identified mutated genes – targets for therapy – are analyzed.

Vasculogenic mimicry is a unique process through which tumor cells imitate normal vascular endothelial cells to secure access to the blood flow. In this review, we consider molecular mechanisms underlying this phenomenon and its importance in the context of solid tumor development. We have analyzed survival strategies of tumor cells using vasculogenic mimicry and described potential therapeutic approaches aimed at tumor growth and metastasis suppression. Highlighting the methods of histological and molecular identification of vasculogenic mimicry promotes better understanding of this phenomenon and its early diagnosis. The review focuses on the necessity of further research in the area of vasculogenic mimicry to conceptualize mechanisms underlying carcinogenesis. We have analyzed 109 articles from the leading biomedical databases including SciVerse Scopus, PubMed, Web of Science and RSCI (Russian Science Citation Index) which allowed us to summarize current scientific data and identify the key trends in the area of molecular oncology.

The study of the role of the immune system in tumor progression has been ongoing for over a century, starting with Paul Ehrlich’s hypothesis on its role in limiting the development of oncological diseases. The development of cancer immunology has confirmed this concept and identified mechanisms of complex interactions between immune system cells and both foreign agents and transformed cells within the organism. Macrophages, natural killers, and T-lymphocytes play key roles in destroying tumor cells. Among them, special attention is given to tumor-associated macrophages. Tumor cells can modulate macrophage activity, transforming them into cells with immunosuppressive properties that promote angiogenesis and extracellular matrix remodeling. As a result, the largest population of tumor-associated macrophages consists of cells with an anti-inflammatory/pro-tumor phenotype (M2).
Macrophages with an anti-inflammatory phenotype (M1) are characterized by the production of pro-inflammatory cytokines, reactive oxygen species, and strong cytotoxic activity. They can directly or indirectly destroy tumor cells by involving other immune cells. Traditionally, the cytotoxic activity of macrophages is considered an important mechanism in limiting tumor growth, but in some cases, it is insufficient for effective tumor control. Recent data suggest that tumor cells can develop defense mechanisms against macrophage cytotoxicity and acquire the ability to overcome it. Moreover, tumor cells resulting from interaction with cytotoxic macrophages possess other properties that provide growth advantages.
This review is dedicated to describing a new pro-tumor function of M1 macrophages, traditionally considered anti-tumor.

Introduction. Currently in routine clinical practice, standard methods based on polymerase chain reaction (PCR) and immunohistochemical examination are used to determine microsatellite instability (MSI) and deficient mismatch repair system (dMMR). MSI identification using high-throughput sequencing (next generation sequencing, NGS) is of special interest because it allows to analyze a large number of microsatellites and simultaneously study alterations in therapeutically significant genes.
Aim. To validate of amplicon-based NGS panel for analysis of MSI and alterations in clinically significant genes in colorectal cancer.
Materials and methods. High-throughput sequencing for MSI analysis was performed on formalin-fixed paraffinembedded (FFPE) samples from patients with colorectal cancer of any stage using amplicon-based panel “Solo-test Driver” (Russia) which covers 38 genes and 39 short tandem repeats (mononucleotides). As a reference method, 5-loci (BAT25, BAT26, NR21, NR24 and NR27) PCR was used. In NGS, MSI was evaluated based on κmer distribution. Statistical analysis was performed using Cohen’s kappa (κ), Mann-Whitney u test, and Fisher’s exact test.
Results. An amplicon-based NGS panel for analysis of MSI in 39 loci and alterations in 39 genes was developed and validated on 160 archival FFPE samples of colorectal cancer. Per PCR, 42 (26.25 %) samples were MSI-positive, 118 (73.75 %) were MSI-negative. The results of PCR and NGS were concordant in 98.75 % (158/160) cases.
Conclusion. The κ coefficient was 0.97 which demonstrates high concordance of MSI analyses using PCR and the developed NGS-based assay system.

Introduction. Evaluation of when and how to include taxanes in preoperative chemotherapy is becoming more important in the era when molecular and genetic approaches allow to develop biologically targeted therapeutic medications and select patients who can benefit from certain cytotoxic agents.
Aim. To analyze the use of CNA genetic landscape (CNA – copy number aberration) luminal B HER2-negative (HER2 – human epidermal growth factor receptor type 2) breast cancer during taxane-containing neoadjuvant chemotherapy (NCT) for identification of the groups of potential CNA markers of objective response to treatment and CNA markers of prognosis of hematogenous metastases.
Materials and methods. The study included 28 patients with luminal B HER2-negative breast cancer T1–4N0–3M0 stage IIA–IIIB aged 24–67 years (mean age 44.6 ± 0.3 years). In neoadjuvant regimen, the patients received 4–8 courses of chemotherapy per the ACT, AT schemes and taxotere as monotherapy. As study samples, paired tumor biopsies taken prior to treatment under ultrasound control and operative material after neoadjuvant therapy were used. Micromatrix analysis was performed using high density DNA CytoScanTM HD Array (Affymetrix, uSA). The results were processed using Chromosome Analysis Suite 4.0 (Affymetrix, uSA) software. Statistical data processing was performed in Statistica 8.0 (StatSoft Inc., uSA) software.
Results. Objective response was observed in the absence of amplification in the 20q11.22 (р = 0.003) region and presence of amplifications in the 16p13.2 (р = 0.027) locus in the tumor prior to treatment. After NCT, hematogenous metastases developed in the tumor in the presence of a small number of amplifications in the 20q13.33 (р = 0.002) locus.
Conclusion. Potential predictive CNA markers of objective response to treatment and prognostic CNA markers of hematogenous metastases during administration of taxane-containing schemes of neoadjuvant chemotherapy were identified.

In recent years, treatment of tumors associated with the RAS oncogene has become an important problem. High level of mutations in this gene is characteristic of tumors of various locations which makes it an attractive target. Modern drugs selectively inhibiting mutant KRAS have significant benefits compared to traditional treatment methods but also have shortcomings including high rate of adverse events. Therefore, development of new drugs – Ras GTPase inhibitors – with better pharmacodynamics characteristics is an important task.
Aim. To study in vivo specific pharmacological activity of a new peptide inhibitor of Ras GTPase (Inh-Ras) in a xenograft model of human non-small cell lung cancer.
Statistically significant data on increased lifespan of mice who were administered Ras GTPase inhibitor compared to the control group were obtained: by 16 % for dose 5 mg/kg and by 36.3 % for dose 10 mg/kg. Additionally, dose-dependent slowing of tumor growth by 30.5 and 57.3 %, respectively, was observed. High specificity due to the mechanism of action of the peptide construct allows to anticipate minimization of side effects of the potential drug Inh-Ras.

Introduction. Claudin 5 is belongs to a family of transmembrane proteins mediating formation of tight junctions between cells, maintenance of cell polarity in epithelial and endothelial layers, regulation of cell membrane permeability, and control of signal transduction inside the cells. Results of a small number of studies show that vascular endothelial growth factor (VEGF) also affects formation of tight junctions, in particular through regulation of claudin 5 expression. In addition to their physiological functions, claudin 5 and VEGF play an important role in pathogenesis of various diseases including malignant neoplasms.
Aim. To study the levels of claudin 5 and VEGF in serum of patients with ovarian cancer and evaluate their clinical significance.
Materials and methods. In total, 123 patients with ovarian cancer (median age 54 years) and 32 control group healthy women (median age 54 years) were examined. Claudin 5 and VEGF levels in serum were measured prior to treatment using Human CLDN5 (Claudin 5) ELISA Kit (Elabscience, China) and Human VEGF Immunoassay (Quantikine®, R&D Systems, uSA) in accordance with the manufacturer’s instructions. Statistical analysis of the obtained data was performed using the GraphPad Prizm v. 10 software. The values were compared and their correlations quantified using nonparametric Mann–Whitney, Kruskal–Wallis tests and Spearman’s rank correlation coefficient. Overall survival was analyzed using the Kaplan–Meier method.
Results. Claudin 5 was found in serum of 97 % of patients with ovarian cancer and 94 % of the control group women. Median (1st quartile (Q1) – 3rd quartile (Q3)) level of claudin 5 in serum of healthy women was 0.77 (0.48–1.17) ng/mL, patients with ovarian cancer – 0.95 (0.43–1.77) mg/mL. ROC analysis of informational value of claudin 5 in ovarian cancer showed unsatisfactory diagnostic accuracy of the model (area under the ROC curve (AuC) 0.613 (95 % confidence interval (CI) 0.513–0.713); p = 0.049): for median threshold value of 0.95 ng/mL the assay had sensitivity of 50 % and specificity of 60 %. VEGF was found in all patients with ovarian cancer and healthy women; median (Q1–Q3) VEGF level in serum of healthy women was 45.6 (13.3–89.09) pg/mL and was statistically significantly lower than in patients with ovarian cancer: 274.7 ng/mL (199.0–472.5). ROC analysis for ovarian cancer showed good diagnostic accuracy of the model (AuC 0.942 (95 % CI 0.886–0.997); p <0.0001) which allows to use serum VEGF level as a diagnostic criterion. The best results for sensitivity and specificity (71 and 100 %, respectively) were obtained at VEGF threshold level of 226.2 pg/mL. Serum claudin 5 and VEGF levels are associated with ovarian cancer progression. However, claudin 5 and VEGF are not statistically significant prognostic markers for this disease.
Conclusion. Serum levels of VEGF and claudin 5 in patients with ovarian cancer are significantly higher than in control group women and positively correlate with each other. Additionally, VEGF has relatively good diagnostic characteristics compared to healthy women of the control group. VEGF and claudin 5 levels are associated with the presence of distant metastases which points at their potential role in tumor progression. However, at this research stage, these markers cannot be recommended as diagnostic or prognostic criteria in ovarian cancer and require further study.

Introduction. The development of malignant tumors of the uterine body is influenced by many factors, including disturbances in the mitochondrial genome. Abnormalities in the regulation of the mitochondrial genome lead to a decrease in oxidative phosphorylation, as well as inhibition of the mitochondrial apoptosis pathway. To develop effective minimally invasive methods for diagnosing endometrial adenocarcinoma and fibroids, screening of molecular markers in blood plasma is necessary. Such markers may be the gene copy number and the levels of microRNA transcripts. These indicators are sufficiently stable in the extracellular environments of the human body, including blood plasma.
Aim. Тo identify molecular minimally invasive differential markers for endometrial adenocarcinoma and fibroids.
Materials and methods. Laboratory studies of the gene copy number and the levels of microRNA transcripts were carried out using real-time polymerase chain reaction in the blood plasma of 26 patients with endometrial adenocarcinoma, 14 fibroids patients and 20 conditionally healthy women.
Results. Statistically significant differences (p <0.05) were found in the copy number of the HV2 and MT-ND1 genes, as well as in the levels of microRNA transcripts hsa-miR-122-5p and hsa-miR-7106-5p in patients with endometrial adenocarcinoma and fibroids, in patients with endometrial adenocarcinoma and conditionally healthy women. In the blood plasma of patients with endometrial adenocarcinoma, the copy number of HV2 and MT-ND6 was lower by 1.5 (p <0.005) and 1.4 (p <0.05) times, respectively, compared to the level in patients with fibroids, and 1.5 times lower than the level in conditionally healthy women. In the blood plasma of patients with endometrial adenocarcinoma, the levels of microRNA transcripts hsa-miR-122-5p (p <0.005) and hsa-miR-7106-5p (p <0.005) was lower by 8.9 and 3.9 times, respectively, relative to the levels in patients with fibroids. In the blood plasma of endometrial adenocarcinoma patients, the levels of hsa-miR-143-5p, hsa-miR-122-5p and hsa-miR-7106-5p microRNA transcripts was 2.1 (p <0.005), 10.8 (p <0.005) and 5.2 (p <0.005) times lower, respectively, than the levels in conditionally healthy women.
Conclusion. The obtained data on differential differences in the copy number of HV2, MT-ND1, the levels of hsa-miR-122-5p and hsa-miR-7106-5p microRNA transcripts in the blood plasma of patients with endometrial adenocarcinoma and myoma have significant potential for improving minimally invasive diagnostics of these diseases.

Introduction. Worldwide, cervical cancer is the 4th most common cancer in women, and morbidity continues to grow. Supposedly, development of human papilloma virus-associated cervical cancer depends on genetic and epigenetic factors, but molecular pathogenesis of this pathology has not yet been established. Recently obtained data show that germline substitutions not only increase the risk of cancer but also affect tumor progression and form the picture of somatic changes in this malignant neoplasm.
Aim. To investigate germline variants of the MTHFR, MET and CHEK2 genes and evaluate their significance in development of genetic predisposition towards cervical cancer.
Materials and methods. DNA of 108 women with cervical cancer was analyzed. The comparison group included 51 patients with human papilloma virus elimination and 333 relatively healthy women. In the patient cohort, an analysis was performed using next-generation sequencing (NGS) and a custom panel aimed at genes participating in tumor designed by us. Additionally, clinical significance of the identified substitutions was evaluated using literature data, databases and bioinformatics methods. Additional association studies were performed for с.677С>Т and с.1298A>C variants of the MTHFR gene, c.2962C>T variant of the MET gene, с.972G>C variant of the CHEK2 gene.
Results. It was observed that polymorphic variants с.972G>C and c.1312С>A of the CHEK2 gene have pathogenic potential. Among 11 substitutions in the MET gene identified during the study, variants c.2962C>T, c.2975C>T and c.3895G>C are liable to be pathogenic. Correlations between T locus allele c.2962C>T of the MET gene (p = 0.002; χ2 = 9.8) and C locus allele с.972G>C of the CHEK2 gene (p = 0.05; χ2 = 3.8) with the risk of cervical cancer development were found.
Conclusion. During the study, a group of germline substitutions in the MTHFR, MET and CHEK2 genes with unclear clinical significance was identified. It was shown that substitutions с.972G>C and c.1312С>A in the CHEK2 gene and c.2962C>T, c.2975C>T, c.3895G>C in the MET gene have pathogenic potential in the context of cervical cancer. Additionally, previously unknown associations between loci c.2962C>T of the MET gene and с.972G>C of the CHEK2 gene with this pathology were described.

Introduction. Lung cancer ranks second in incidence and first in mortality among other oncological pathologies. Despite significant success in the diagnosis and treatment of tumors, the five-year survival rate for lung cancer is only 19 % and has not improved significantly in recent decades, which is mainly associated with late detection of the disease. In addition, the development of metastases reduces the five-year survival rate to 6 %.
Aim. To analyze the plasma proteome of healthy volunteers and patients with lung adenocarcinoma (LAC), as one of the most common forms of lung cancer, to identify proteins that are potential biomarkers of LAC and of the presence of distant metastases.
Materials and methods. The study included 30 healthy donors and 30 patients with diagnosed LAC. using a combination of liquid chromatography and tandem mass spectrometry in combination with the method of multiple reactions monitoring, we analyzed the representation of a wide range of proteins in the blood plasma of the study participants. The data obtained were analyzed using modern methods of biological statistics, including machine learning algorithms.
Results. Based on the quantitative analysis of 118 proteins in blood plasma between the experimental groups, we proposed a panel of 12 significant proteins that are specific markers of LAC. Additionally, we identified three proteins that predict the presence of distant metastases among patients with LAC. Classifiers developed based on these protein panels make it possible to distinguish between patients with LAC and healthy controls, as well as to detect the presence of metastases among patients with LAC, with sensitivity and specificity of more than 90 %.
Conclusion. The data obtained can be used to develop new tests for LAC screening and predicting disease outcomes based on the blood plasma proteome. After additional validation and implementation into clinical practice, these tests can contribute to the early diagnosis of LAC and, as a result, increase patient survival.