Glioma cell cultures are used in basic researches of tumor processes, personalized medicine for selecting treatment regimens depending on individual characteristics of patients and pharmacology for assessing the effectiveness of chemotherapy. Suppression of glioma culture growth without reduction of malignancy grade is common. Drug cancellation may be followed by substitution of precursor cells by more malignant clones. Therefore, analysis of culture cell malignancy grade is important. In the future, intraoperative analysis of glioma cell malignancy grade can be used to select individual therapy.

The review summarizes data on the features of antigen presentation in tumor cells. The molecular mechanisms of the antitumor immune response are considered with an emphasis on the ability of tumor cells to avoid the action of immune surveillance. The features of expression of MHC molecules depending on treatment regimens are provided. Ways to improve existing and create new treatment regimens aimed at elimination of tumor cells because of antitumor immune response are discussed.

Describe the structure of pathogenic germline variants and clinical and anatomical features in colorectal cancer patients in Moscow.

Timely referral of patients for genetic testing to rule out MEN1-associated primary PHPT is important factor in determining treatment strategy and prognosis. In the context of the limited availability of genetic testing, the search for clinical markers indicative of MEN1 gene mutations remains an extremely relevant task.

The exploration of molecular genetic mechanisms that underlie carcinogenesis, hereditary factors of various oncological diseases, including basal cell carcinoma, the most common type of skin cancer is especially actual and significant for target strategies of public health. The diagnosis of basal cell carcinoma is based on complex clinical, radiologic and genetic examination data. The further research in the field of somatic or hereditary mutations in genes associated with basal cell carcinoma, including Patched 1 (PTCH1), Patched 2 (PTCH2), Smoothed (SMO) continue to be topical. The strategies of primary prevention of basal cell carcinoma, discussions of complex issues of decision-making concerning treatment at primary health care level, training courses and development of guidelines for general practitioners and interdisciplinary recommendations for effective early diagnosis and comprehensive care of basal cell carcinoma are to be suggested.

A hybrid tumor is not officially included in the latest International Histological Classification of Kidney Tumors (WHO, 2022), however, according to the literature, a number of researchers still consider a hybrid tumor as an independent nosological unit. In this regard, the development of morphological and molecular genetic criteria for a hybrid tumor, today, is the main task in the differential diagnosis of oncocytic renal tumors.

Schwannomatoses is a new classification unit for all the hereditary diseases caused by chromosome 22 damage followed by multiple benign neoplasms of the peripheral and central nervous system. Schwannomatosis occurs as a result of damage to different genes: NF2, SMARCB1, LZRT1, loss of heterozygosity of the long arm of chromosome 22. Nevertheless, clinical manifestations are similar. Molecular diagnostics not only confirms the diagnosis, but also predicts the course of disease. Thus, the most severe clinical manifestations are observed in patients with violation of semantic sequences and reading frame shift in exons 2-13 of the NF2 gene. A more favorable course with less number of tumors is observed in patients with somatic mosaicism. Stereotactic irradiation and surgery are the main treatment options for schwannomatosis. However, there is evidence of effective targeted therapy with bevacizumab (inhibitor of vascular endothelial growth factor). Bevacizumab is used in patients with bilateral vestibular schwannomas and high risk of hearing loss, as well as for intramedullary tumor growth control.

Atypical fibroxanthoma (AFX) is a rare skin tumor characterized by a combination of a «malignant» morphological features and non-aggressive clinical course. Diagnosing AFX is challenging due to histological «diversity» and heterogeneous immunophenotype. The presented review describes the history and evolution of AFX as a nosological form of cancer, its histogenetic origin, pathogenesis and biological potential. The clinical, morphological, immunohistochemical, molecular cytogenetic characteristics and histological subtypes of the tumor as well as differential diagnosis have been presented in detail.

The article reviews the changes in the structure of classification, diagnostic criteria for myeloid and histiocytic neoplasms in the 5th edition of the WHO Classification of Tumors of Hematopoietic and Lymphoid Tissues (2022). Information is presented regarding new nosological forms, renaming and abolition of some previously existing ones. The importance of molecular genetic studies in the isolation of myeloid and histiocytic neoplasms and the need to apply these studies in clinical practice are emphasized. Myeloid and histiocytic precancerous and proliferative processes, genetic tumor syndromes, introduced into the classification for the first time, are considered.

The group of undifferentiated round cell sarcomas, according to the World Health Organization Classification, in addition to Ewing's sarcoma (ES), includes round cell sarcoma with rearrangement of the EWSR1 gene with partners not from the ETS gene family, sarcoma with BCOR gene alterations, CIC -rearranged sarcoma. Despite the fact that all tumors have clear histological and immunological criteria, their diagnosis can be difficult, given the fact that there are overlapping variants of the morphological picture and immunophenotype both within the group and with other round cell tumors.

Study of PD-L1 expression in squamous and adenosquamous cell cervical cancer (CC) by immunohistochemical (IHC) method, assessment of the relationship between PD-L1 tumor status and its clinical and morphological characteristics, TILs, MSI/dMMR, and HPV tumor status.

Cancer-associated fibroblasts (CAFs) often form a major component of the tumor microenvironment (TMA), providing conditions for cancer cells to thrive. CAFs may contribute to tumor growth, invasion, metastasis, and resistance to therapy. However, clinical trials of treatment strategies targeting CAFs have largely failed. Moreover, there is evidence that CAFs are capable of inhibiting tumor development. The review considers the current data on the functional heterogeneity of CAFs and their bimodality in tumor development and progression. Understanding the tumor-promoting and tumor-inhibiting activities of CAFs can help to develop new diagnostic and therapeutic approaches.

Peutz-Jeghers Syndrome (Peutz-Jeghers Syndrome, PJS) refers to syndromes of hereditary tumor predisposition and is caused by pathological variants of the STK11 gene, leading to a defect in the synthesis of serine/threonine kinase 11 protein, which acts as a tumor suppressor.Clinical symptoms of the syndrome are combination of hamartomatous polyposis of the gastrointestinal tract and specific skin-mucosal hyperpigmentation. Also, this disease is characterized by a high risk of developing gastrointestinal and extra-intestinal tumors, including benign or malignant tumors of the reproductive system.One of the first signs of the disease in male patients may be prepubertal gynecomastia associated with large-cell calcifying Sertoli cells tumors expressing aromatase. In contrast to from pubertal gynecomastia, prepubertal is extremely rare, and it is often based on pathological causes. Early diagnosis of patients with pre-pubertal gynecomastia, including Peitz-Jaegers syndrome, defines the tactics of gynecomastia management and protocols for monitoring the development of other components of the disease in the future.This article describes two patients with pre-pubertal gynecomastia and Peitz-Jaegers syndrome with different molecular genetic defects: in one case associated with duplication of the STK11 gene site, in the other - with microdeletion of the short arm of chromosome 19 containing this gene.

Meningioma is the most common primary tumor of the central nervous system. Traditional classification is based on histological properties of tumors and distinguishes different grades of meningioma malignancy. However, knowledge about different molecular mechanisms of tumor provided new data on genetic features of meningiomas. The authors analyze current available data on the main driver mutations, new classifications based on molecular genetic characteristics and potential targets for therapy.

The article summarizes the literature data on the results of clinical, histological and molecular genetic studies of polymorphic adenocarcinoma. It is shown that the diagnosis of polymorphic adenocarcinoma presents difficulties due to the variety of morphological structure of its various components, which may correspond to the characteristics of other tumors of the salivary glands, such as pleomorphic adenoma and adenoid cystic carcinoma. Immunohistochemical markers characteristic of this pathology of the salivary glands are described. The article presents a rare clinical case of a male patient with polymorphic adenocarcinoma. Histological examination revealed perineural invasion and a characteristic immunohistochemical profile of tumor cells: low cell proliferative activity for the Ki-67 protein, a positive reaction to antigens: S100, SOX10, P63 and reverse transcriptase TERT. A study conducted by the FISH method revealed the amplification of the TERC gene, which indicates the malignant nature of this neoplasm. Conducting molecular genetic studies is of paramount importance for the diagnosis of polymorphic adenocarcinoma.

This review is dedicated to E-cadherin, a calcium-dependent cell-cell adhesion molecule with pivotal roles in epithelial cell behavior, tissue formation, and carcinogenesis. We summarize the structure of the E-cadherin, its role in the development of the body and in the carcinogenesis. The structure of the E-cadherin/β-catenin/αE-catenin complex and its relationship with the actin cytoskeleton are described in detail. The role of E-cadherin in the development of some infectious diseases, the function of E-cadherin as both a tumor suppressor and a promoter of tumor dissemination, its influence on signal transduction pathways in cells are highlighted. Particular attention is paid to the expression of E-cadherin in Helicobacter pylori infection and in tumor tissue in gastric cancer.

The article describes a rare case of small cell neuroendocrine carcinoma of the endometrium in a 67-year-old woman. According to the literature, only about 90 such observations have been described worldwide. Histological examination revealed three necessary features: the small-cell nature of the tumor, the presence of epithelial and neuroendocrine markers. An IHC study revealed a positive expression of Syn, Chrom A, CD56, CK AE1/AE3 markers; the proliferative activity index was 70%.

Neuroblastoma (NB) is a malignant neoplasm originating from the primary cells of the sympathetic nervous system. Patients with NB are risk-stratified using a number of features including age at diagnosis, disease stage, tumor histology and genetic profile (status of NMYC, ALK genes, regions 1p and 11q). The interpretation of the results of genetic studies can become a source of problems because neuroblastoma has a heterogeneous histological pattern. The article describes 2 cases with classical for NB chromosomal aberrations in the stromal component of the tumor.

In 2022, the 5th edition of the of the WHO Classification of Tumours of Endocrine Organs was published, which outlines the current understanding of adrenocortical cancer (ACC), resulting from interdisciplinary research over the past decade. This article highlights the new provisions of the WHO classification for the morphological diagnosis of ACC.

The paper discusses changes in the structure of the classification, criteria for the diagnosis of lymphoid neoplasms in the 5th edition of the WHO Classification of Tumors of Hematopoietic and Lymphoid Tissues (2022). Changes are presented regarding new nosological units, renaming and abolition of some previously existing ones. The importance of molecular genetic studies in the isolation of many lymphomas and the need to apply these studies in everyday clinical practice are emphasized. Lymphoid precancerous processes and lymphoid proliferations introduced into the Classification for the first time are considered.