Gastric cancer is one of the most common malignancies worldwide. Approximately 10 % of patients with gastric cancer are characterized by accumulation of gastric cancer cases in their family. The hereditary forms of gastric cancer account for 1–3 % of all gastric cancer cases. Hereditary diffuse GC syndrome is caused by germline mutations in CDH1 gene and determines a high risk of developing diffuse GC and lobular breast cancer. In this article, we present a clinical case of a 41-year-old patient with diffuse gastric cancer, who was found to be a carrier of novel germline mutation in the CDH1 gene. Next-generation sequencing (NGS) has facilitated an identification of CDH1 c.1596G>A genetic variant, thus enabling an accurate clinical diagnosis hereditary diffuse gastric cancer.

Background: germline mutations in the BRCA1 and BRCA2 genes are associated with a high risk of developing cancer of various localizations. Currently, the determination of BRCA status in such patients is important for choosing surgical tactics and determining indications for the administration of multiple chemotherapy drugs. Aim: to evaluate the results of mass genetic screening for mutations in the BRCA1 and BRCA2 genes in patients with various types of malignant neoplasms (MN). Patients and Methods: the results of genetic screening of 5043 patients who are reviewed in the study. The patients had the following diagnoses: breast cancer (BC, n=4216), ovarian cancer (OC, n=481), multiple primary malignant neoplasms (n=174), pancreatic cancer (n=96) and prostate cancer (n=75). Real-time PCR-based genetic testing for eight recurrent BRCA1/2 gene mutations specific for the Russian population was performed for all patients. The study of the entire coding sequence of the BRCA1/2 genes was carried out in 655 patients with negative screening results for mutations using high-resolution melting curve analysis, Sanger sequencing, and massively parallel sequencing. Results and Discussion: among 5043 cancer patients, the total frequency of BRCA mutations was 8%. In patients with BC the recurrent variants accounted for 6.7%, bilateral BC — 13.5%, OC — 17%, multiple primary malignant neoplasms (MPMN) — 13.1%, pancreatic cancer — 3.1%, while in patients with prostate cancer no mutations were found. The frequency of the c.5266dup mutation in the BRCA1 gene was 5.63%. Forty nine patients (0.97%) were carriers of another mutation — p.C61G, which is specific for the Slavic populations. Other variants were found much less frequently (0.1–0.38%). Thus, screening for common mutations helped to determine the prevalence of each of the variants and proved a high frequency of c.5266dup and p.C61G mutations. The analysis of the coding sequence of the BRCA1/2 genes in 655 patients revealed pathogenic mutations (class 5) in 13% of cases. The prevalence of rare variants in patients with BC was 11.1%, bilateral BC — 26.5%, OC — 14.9%, МPМN — 31%, pancreatic cancer — 2.3%, and prostate cancer — 2.5%. In the BRCA1 gene, 41 unique clinically significant mutations were found, and four of them were repeated in unrelated patients. In the BRCA2 gene, 29 unique clinically significant mutations were found, five of which were repeated. Moreover, 19 missense mutations were detected which, according to the databases, were categorized as variants with unknown clinical significance (class 3). They were analyzed using seven pathogenicity prediction algorithms. As a result, five mutations were interpreted by the most algorithms as likely pathogenic or pathogenic (class 4/5), five mutations were re-assessed as variants with unknown significance, and nine variants were identified as clinically insignificant. Conclusion: thus, the Russian population is characterized by the presence of multiple recurrent mutations, while in patients with different cancer types the prevalence of c.5266dup and p.C61G is significantly higher than the prevalence of other variants. Analysis of recurrent variants in the BRCA1/2 genes enables identification of approx. 80% of carriers of the pathogenic mutations. The use of the panel kit which includes such variants is considered as an inexpensive and sensitive algorithm for the first-step screening of the BRCA1/2 genes. A follow-on investigation of all coding gene regions (sequencing) is feasible for the studied patient groups and can significantly increase the detectability of pathogenic mutations in the BRCA1/2 genes. KEYWORDS: BRCA1 mutations, BRCA2 mutations, breast cancer, ovarian cancer, malignant neoplasms. FOR CITATION: Stroganova A.M., Pospekhova N.I., Golovina D.A. et al. Review of the results of mass screening for the BRCA1/2 gene mutations in patients with different types of malignant neoplasms. Russian Medical Inquiry. 2022;6(6):297–308 (in Russ.). DOI: 10.32364/2587-6821- 2022-6-6-297-308.

Colorectal cancer (CRC) is one of the leading causes of death from cancer in many countries of the world, both in men and women, and these rates are on the rise. The probability of suffering from CRC is about 4–5 % and the risk for developing CRC is associated with personal features or habits such as age, chronic disease history and lifestyle, but in most cases colorectal cancer develops as a result of the degeneration of adenomatous formations or along the jagged path. Immune dysregulation, dysbiosis, and epithelial destruction contribute to colorectal cancer carcinogenesis. The gut microbiota has a relevant role, and dysbiosis situations can induce colonic carcinogenesis through a chronic inflammation mechanism. Some of the bacteria responsible for this multiphase process include Fusobacterium spp., Bacteroides fragilis and enteropathogenic Escherichia coli. moreover, CRC is caused by mutations that target oncogenes, tumour suppressor genes and genes related to DNA repair mechanisms.Considering that the average time for the development of adenocarcinoma from precancer takes about 10 years, changes in the microbiota can be a prospective marker for screening precancerous conditions of the colon, as well as the detection of changes in DNA.The work will discuss the relationship between changes in the microbial composition of the colon with the genetic mutations identified by molecular genetic sequencing.

Background. According to the literature, BRCA1-associated breast cancer (BC) most often belongs to the triple negative (TNBC) molecular subtype. The data on the contribution of other molecular subtypes to this group of patients differ among different studies.The study objective is to evaluate the frequency of different tumor molecular subtypes in BC patients with BRCA1 gene mutation treated in N. N. Blokhin National Medical Research Center of Oncology in the period from 2017 to 2020.Materials and methods. The study included BC patients with a mutation in the BRCA1 gene (n = 209) identified as a result BRCA1 mutation screening of patients with BC. DNA diagnostics was carried out on blood samples of patients using the real-time polymerase chain reaction method. After analyzing the patients primary documentation clinical and morphological data were taken into account: the age of diagnosis, the stage of the disease, the results of immunohistochemical studies (estrogen receptor status, progesterone receptor status, HER2 expression, Ki-67 proliferation index). The assignment to the particular molecular tumour subtypes was performed according to estrogen receptor status, progesterone receptor status, HER2 status and Ki67 value.Results. Clinical and pathomorphological data of 209 patients with BRCA1-associated BC were analyzed. The age at diagnosis ranged from 23 to 72 years, the median age was 40 years, the mean age was 41.46 ± 9.82 years. BC associated with BRCA1 was found to be TNBC in 71.3 % and luminal B, HER2 negative (LumB–) in 19.1 % of the cases. Other tumour subtypes were much less common: luminal B, HER2 positive (LumB+) in 7.2 %, luminal A (LumA) in 1 % and HER2-positive (HER2+) in 1.4 % of the cases. The frequency of subtypes was estimated in different age groups (1st – patients 23–34 (n = 53), 2nd – 35–49 (n = 111), and 3rd – 50–72 (n = 45) years old). TNBC frequency was 81.1 % in the 1st group, 73.9 % in the 2nd and 53.4 % in the 3rd group; LumB– frequency was 15.1, 15.3 and 33.3 % respectively. Using the Fisher test it was shown that the differences in frequencies were statistically significant between groups 1st and 3 rd, as well as between groups 2 nd and 3 rd (p <0.05).Conclusion. TNBC was the main molecular subtype in all age groups of BC patients with BRCA1 germinal mutation, TNBC frequency was lower in the older age group. LumB– subtype was also common in BRCA1-associated tumors especially in older women.

Background. According to the literature, BRCA1-associated breast cancer (BC) most often belongs to the triple negative (TNBC) molecular subtype. The data on the contribution of other molecular subtypes to this group of patients differ among different studies. The study objective is to evaluate the frequency of different tumor molecular subtypes in BC patients with BRCA1 gene mutation treated in N. N. Blokhin National Medical Research Center of Oncology in the period from 2017 to 2020. Materials and methods. The study included BC patients with a mutation in the BRCA1 gene (n = 209) identified as a result BRCA1 mutation screening of patients with BC. DNA diagnostics was carried out on blood samples of patients using the real-time polymerase chain reaction method. After analyzing the patients primary documentation clinical and morphological data were taken into account: the age of diagnosis, the stage of the disease, the results of immunohistochemical studies (estrogen receptor status, progesterone receptor status, HER2 expression, Ki-67 proliferation index). The assignment to the particular molecular tumour subtypes was performed according to estrogen receptor status, progesterone receptor status, HER2 status and Ki67 value. Results. Clinical and pathomorphological data of 209 patients with BRCA1-associated BC were analyzed. The age at diagnosis ranged from 23 to 72 years, the median age was 40 years, the mean age was 41.46 ± 9.82 years. BC associated with BRCA1 was found to be TNBC in 71.3 % and luminal B, HER2 negative (LumB–) in 19.1 % of the cases. Other tumour subtypes were much less common: luminal B, HER2 positive (LumB+) in 7.2 %, luminal A (LumA) in 1 % and HER2-positive (HER2+) in 1.4 % of the cases. The frequency of subtypes was estimated in different age groups (1st – patients 23–34 (n = 53), 2nd – 35–49 (n = 111), and 3rd – 50–72 (n = 45) years old). TNBC frequency was 81.1 % in the 1st group, 73.9 % in the 2nd and 53.4 % in the 3rd group; LumB– frequency was 15.1, 15.3 and 33.3 % respectively. Using the Fisher test it was shown that the differences in frequencies were statistically significant between groups 1st and 3 rd, as well as between groups 2 nd and 3 rd (p <0.05). Conclusion. TNBC was the main molecular subtype in all age groups of BC patients with BRCA1 germinal mutation, TNBC frequency was lower in the older age group. LumB– subtype was also common in BRCA1-associated tumors especially in older women.

The most serious complication of breast cancer (BC), which affects life expectancy, is metastasis of the tumor. Metastasis is the cause of more than 80% of all breast cancer deaths. After surgical treatment and the use of adjuvant therapy, metastases occur in 8% 15% of cases. This indicates the need to develop markers for the prognosis of metastasis and clarify its mechanisms for the creation of anti-metastatic therapeutic agents. In this paper, we studied the association of LOX and uPAR gene expression with breast cancer metastasis in the lymph nodes. Gene expression was measured using real-time PCR in 40 paired samples (tumor-normal tissues). As a result of processing the measurements, the values of gene expression levels in the tumor tissue relative to normal were obtained. It is shown that the LOX gene is expressed in the tumor both lower and higher relative to the norm, and uPAR is expressed in most cases higher. In metastatic tumors, the frequency of expression increases above the norm for both LOX and uPAR genes. The association of expression of these genes with lymphatic metastasis was found: p = 0.01 and p = 0.02, for the LOX and uPAR genes, respectively. The relative risk (RR) was for the LOX gene RR = 1.9, 95% CI 1.2 3, p = 0.005, for uPAR RR = 3.6, 95% CI 1.2 10.9, p = 0.03. Thus, the data obtained contribute to understanding the mechanisms of metastasis and provide the basis for the development of new biomarkers. The LOX and uPAR genes may be candidates for predictive markers of breast cancer metastasis risk.

The most serious complication of breast cancer (BC) is metastasis, which causes more than 80% of all deaths from BC. The process of lymph nodes metastasis is not well understood. 47 paired frozen breast tissue samples were collected. All patients have no radiation therapy and chemotherapy. We studied the expression of two genes - FN1 and PDGFRβ - for the investigation of their relationship to lymph nodes metastasis. Expression of the FN1 and PDGFRβ genes showed an association with the risk of early metastasis (p = 0.012 and 0.03, correspondently). The relative risk (RR) for FN1 was RR = 1.5, 95% CI 1,1-1,9, and for PDGFRβ RR = 2.4, 95% CI 1,1-5,2.

Наиболее серьёзным осложнением рака молочной железы (РМЖ) является метастазирование опухоли, что является причиной более 80% всех случаев смерти от РМЖ. Процесс раннего метастазирования в лимфатические узлы изучен недостаточно. Нами были изучены 47 парных образцов ткани молочной железы. Все больные не подвергались воздействию лучевой терапии и химиотерапии. Найдена ассоциация экспрессии генов FN1 и PDGFRβ с риском раннего метастазирования (р = 0,012 и 0,03, соответственно). Относительный риск (ОР) составил для FN1 ОР = 1,5, 95% ДИ 1,1-1,9, для PDGFRβ ОР = 2,4, 95% ДИ 1,1-5,2. The most serious complication of breast cancer (BC) is metastasis, which causes more than 80% of all deaths from BC. The process of lymph nodes metastasis is not well understood. 47 paired frozen breast tissue samples were collected. All patients have no radiation therapy and chemotherapy. We studied the expression of two genes - FN1 and PDGFRβ - for the investigation of their relationship to lymph nodes metastasis. Expression of the FN1 and PDGFRβ genes showed an association with the risk of early metastasis (p = 0.012 and 0.03, correspondently). The relative risk (RR) for FN1 was RR = 1.5, 95% CI 1,1-1,9, and for PDGFRβ RR = 2.4, 95% CI 1,1-5,2.

Lynch syndrome is the most common cancer-prone syndrome associated with a high risk of colorectal cancer (CRC), neoplasms of the upper gastrointestinal system, the urinary tract, the female reproductive system, brain tumours and others. The only known form of hereditary endometrial cancer is also diagnosed as part of Lynch syndrome. One or more pathogenic germline mutations in one of the mismatch repair (MMR) genes are the cause of Lynch syndrome. Mapping of MMR genes and the discovery of microsatellite instability (MSI) have given rise to the possibility of using these clue characteristics of the pathogenic process for the elaboration of a screening test for Lynch syndrome. Being highly accurate and superior to all previously developed clinical criteria and guidelines, MSI-testing along with the assessment of the expression patterns of MMR proteins by immunohistochemistry has taken the leading role in the early diagnosis of Lynch syndrome. This article focuses on a brief review about the main evolutionary stages of clinical, anamnestic, molecular and genetic criteria for Lynch syndrome together with the results of our own research on the accuracy of the Amsterdam criteria, the Bethesda guidelines and MSI-diagnostics in the determination of the indications for MMR-genotyping in colorectal cancer patients suspected for Lynch syndrome.

Background. Leiomyosarcoma is one of the most common types of soft tissue sarcomas. Radical surgical resection with subsequent adjuvant chemotherapy remain the most effective treatment approach. Immunotherapy based on inhibition of PD-L1 (programmed death ligand 1) or its receptor PD1 (programmed death 1) is considered a promising treatment option. Level of PD-L1 expression in tumor cells and presence of microsatellite instability (МSI) could be considered prognostic and predictive markers of disease progression and effectiveness of immunotherapy.The study objective is to determine PD-L1 expression level and МSI status in patients with retroperitoneal leiomyosarcomas and evaluate their effect on overall and recurrence-free survival.Materials and methods. The study included 57 patients with retroperitoneal leiomyosarcomas who underwent surgical or combination treatment. Analysis of clinical and morphological characteristics was performed; results of surgical treatment were researched. Evaluation of PD-L1 expression and MSI status was performed using immunohistochemical and molecular genetic analysis.Results. PD-L1 expression and MSI status were evaluated in 41 patients of 57. In 10 (24 %) of 41 cases, positive PD-L1 expression was observed (expression level 3–50 %). In 1 (2.4 %) patient, the primary tumor and metastatic lesion had low MSI level (MSI-low, MSI-L). Median follow-up was 31 months. In patients with positive PD-L1 expression, higher Ki-67 proliferative index was observed compared to patients with PD-L1 negative tumors (58.8 and 47.8 % respectively; р = 0.02), as well as significantly lower median overall survival for grade II tumors (30 and 105 months; p = 0.043). In grade III leiomyosarcomas, a trend towards lower median overall survival in patients with PD-L1‑negative tumors (31.0 months) compared to patients with PD-L1 expression (61.2 months) (р = 0.11) was observed.Conclusion. Among patients with retroperitoneal leiomyosarcomas, positive expression of PD-L1 was observed in 24 % (10 / 41) of cases and MSI-low status was found in 2.4 % (1 / 41) of cases. In patients with grade 2 tumors, positive PD-L1 expression is associated with significantly lower overall survival. PD-L1 expression in patients with retroperitoneal leiomyosarcomas could be considered a prognostic marker and a potential therapeutic target.

Lynch syndrome is the most common cancer-prone syndrome associated with a high risk of colorectal cancer (CRC), neoplasms of the upper gastrointestinal system, the urinary tract, the female reproductive system, brain tumours and others. The only known form of hereditary endometrial cancer is also diagnosed as part of Lynch syndrome. One or more pathogenic germline mutations in one of the mismatch repair (MMR) genes are the cause of Lynch syndrome. Mapping of MMR genes and the discovery of microsatellite instability (MSI) have given rise to the possibility of using these clue characteristics of the pathogenic process for the elaboration of a screening test for Lynch syndrome. Being highly accurate and superior to all previously developed clinical criteria and guidelines, MSI-testing along with the assessment of the expression patterns of MMR proteins by immunohistochemistry has taken the leading role in the early diagnosis of Lynch syndrome. This article focuses on a brief review about the main evolutionary stages of clinical, anamnestic, molecular and genetic criteria for Lynch syndrome together with the results of our own research on the accuracy of the Amsterdam criteria, the Bethesda guidelines and MSI-diagnostics in the determination of the indications for MMR-genotyping in colorectal cancer patients suspected for Lynch syndrome.

1ФГБУ «Национальный медицинский исследовательский центр онкологии им. Н.Н. Блохина» Минздрава России, Москва, e-mail: alexandra_silina@mail.ru В последние годы отмечается неуклонный рост заболеваемости злокачественными новообразованиями среди пациентов молодого возраста. Снижение возраста постановки диагноза наблюдается и в группе больных раком толстой кишки, занимающим одно из лидирующих мест в структуре онкологической заболеваемости и смертности как в мире, так и в России. Наряду с наследственными факторами, обусловливающими высокий риск опухолей толстой кишки у пациентов – носителей герминальных мутаций в генах, ответственных за развитие синдромальной патологии (такой как синдром Линча, семейный аденоматозный полипоз, синдром Пейтца–Йегерса и др.), молекулярно-генетические изменения в клетках толстокишечного эпителия определяют отличительные клинико-морфологические черты, прогноз и ответ на специфическое лечение у больных колоректальным раком в молодом возрасте. На сегодняшний день выделены основные патогенетические пути, задействованные в реализации онкологического процесса в толстой кишке: хромосомная нестабильность, микросателлитная нестабильность, эпигенетические нарушения, заключающиеся в гиперили гипометилировании опухолевого генома. Несмотря на хорошо изученный молекулярный канцерогенез колоректального рака, остается много «пробелов» в понимании природы злокачественной патологии у пациентов с диагностированием заболевания в раннем возрасте. В настоящей статье представлено современное состояние изучения данной проблемы. Ключевые слова: рак толстой кишки, пациенты молодого возраста, хромосомная нестабильность, микросателлитная нестабильность, аномальное метилирование, мутации

The literature review represents the current state of research on molecular and genetic features of colorectal cancer in young patients. A steady increase in the incidence of colorectal cancer among young patients has been noted over recent years. Along with hereditary factors determining a high risk of colon tumours in patients who are carriers of germinal mutations in the genes responsible for the development of syndrome pathology (such as Lynch syndrome, familial adenomatous polyposis, Peutz-Jeghers syndrome, etc.), molecular and genetic changes in the cells of the colonic epithelium define the distinctive clinical and morphological features, prognosis, and response to specific therapy in young patients with colorectal cancer. To date, the main pathogenetic pathways involved in the promotion of carcinogenesis in the gut epithelium tissue have been identified: chromosomal instability, microsatellite instability, epigenetic abnormalities includinghyper- or hypomethylation of the tumour genome. Despite the well-studied molecular carcinogenesis of colorectal cancer, there are still many gaps in theunderstanding of the nature of such malignant neoplasms in patients with the disease diagnosed at an early age.

A serious complication of breast cancer is metastasis of tumor cells. The initiation of this process takes place in the nearby lymphatic vessels. To date, the molecular mechanisms of metastasis are not well understood and further research is required. In this regard, the level of miRNA expression can provide information both on the mechanisms of metastasis development and also be a source of markers for the prognosis of metastatic breast cancer. In the present work, according to the literature, we selected four microRNAs (miR-34a, miR-145, miR-125b and miR-222), potentially capable of being associated with metastasis, to study their association with metastasis to lymph nodes at an early stage. The measurement of the expression of four selected miRNAs on 40 paired samples (tumor-norm) was performed using real-time PCR. Frequencies of miR-34a, miR-145, miR-125b, and miR-222 relative to normal tissue were determined for reduced or increased miR-mRNA expression. For a more detailed study of the association of miRNA expression with lymph node metastasis, miR-125b and miR-222 were selected. An association of expression of these two miRNAs was found with the onset of metastasis to the lymph nodes: with the same level of confidence, differences (p = 0.01). Both miRNAs (miR-125b and miR-222) are involved in the metastasis of breast cancer, apparently by influencing the epithelial-mesenchymal transition. They can potentially act as prognostic biomarkers to assess the likelihood of early lymph node metastases in breast cancer.

УДК 616-006.6 МОЛЕКУЛЯРНО-ГЕНЕТИЧЕСКИЕ ОСОБЕННОСТИ РАКА ТОЛСТОЙ КИШКИ У БОЛЬНЫХ МОЛОДОГО ВОЗРАСТА Семьянихина А.В. 1 , Поспехова Н

The frequency and spectrum of mutations in RAS/BRAF genes were studied in rectal adenomas, carcinomas in situ, and adenocarcinomas. It is shown that the frequency of KRAS mutations decreases from adenoma to adenocarcinoma; most adenomas and carcinomas in situ are heterogeneous and consist of several subclones. Possible models of colorectal cancer pathogenesis are discussed.

The primary structure of the APC gene DNA was examined in 108 patients younger than 45 years old diagnosed with “familial adenomatous polyposis, classic form” using PCR, conformation-sensitive electrophoresis, and Sanger sequencing. Mutations in the APC gene were observed in 78 patients; de novo mutations were observed in 17 cases. In the majority of cases (n = 45), patients exhibited frameshift mutations, 28 patients had nonsense mutations, and other 5 patients showed splicing mutations. We also revealed recurring variants: p.Arg232X (2 cases), p.Asp849GlufsX11 (2), p.Ser1068GlyfsX57 (2), p.Arg216X (3), p.Gln1062X (5), p.Arg213X (5), and p.Glu1309AspfsX4 (16). It was shown that, compared with other pathogenic variants in the APC gene in Russian patients, mutation p.Glu1309AspfsX4 does not result in earlier development of colorectal cancer and polyps. Nineteen mutations were described for the first time. The identified mutations were located between codons 142 and 1492 of the APC gene. This indicates the importance of investigation of all the gene coding exons. Pathogenic variants were observed in 16 of 35 studied relatives of the mutation carriers. All 16 relatives were included in the “risk group” for lifelong clinical monitoring.