The discovery of a class of long noncoding RNAs (lncRNAs), including lncRNAs of the small nucleolar RNA (snoRNA) host gene family, SNHG, has led to growing interest in the study of both snoRNAs themselves and the genes encoding them. Currently, of the 232 known snoRNA genes, only 32 have been confirmed to have lncRNAs. At the same time, a positive correlation has been shown between the expression of lncRNAs and snoRNAs encoded by a common host gene of the SNHG family. Thus, lncRNA of the SNHG1 gene correlates with snoRNAs SNORD22 and SNORD25-31, and lncRNA of the SNHG16 gene, with snoRNAs SNORD1A, SNORD1B, and SNORD1C. There is evidence that SNHG lncRNAs can participate in oncogenesis both through regulatory functions inherent to lncRNAs and by influencing ribosome biogenesis. At the same time, information has accumulated on the "extraribosomal" functions of snoRNAs. In addition to a brief excursion into the biological functions of snoRNAs and SNHG lncRNAs, we present a comprehensive review of data on the role of these two types of noncoding RNAs in the pathogenesis of ovarian cancer, the most insidious cancer of the female reproductive system. The influence of these regulatory RNAs on the main processes of ovarian oncogenesis, such as apoptosis, epithelial-mesenchymal transition, cell cycle control, and DNA methylation mechanisms in this type of cancer is considered. The prospects for clinical application of regulatory RNAs due to their influence on the level of drug resistance are also discussed.

The main functional parts of the glymphatic system are perivascular spaces and surrounding astrocytes. Cerebrospinal fluid enters the brain parenchyma from subarachnoid cisterns through perivascular Virchow-Robin spaces and passes into the interstitium through aquaporin channels in astrocytes. Then, cerebrospinal fluid removes metabolic products and mixes with interstitial fluid. Outflow of cerebrospinal fluid with metabolic products from the brain parenchyma occurs in three ways. The first route is periarterial through intermuscular spaces in the middle layer of cerebral arteries. The second route is perivenous. The third route is lymphatic through meningeal or sinus-associated lymphatic vessels. They provide drainage of macromolecules and immunocompetent cells from the brain to the cervical lymph nodes. Gliomas are accompanied by inhibition of normal cerebrospinal fluid outflow pathways, mainly due to additional intracranial tissue, and compensatory cerebrospinal fluid outflow along the spinal cord. Reduced cerebrospinal fluid release with impaired outflow contribute to accumulation of toxic metabolic products, proinflammatory cytokines and chemokines. Transport of antigens to lymph nodes is inhibited that disrupts antitumor immunity. Impaired cerebrospinal fluid circulation also reduces the effectiveness of intracranial drug delivery. One of the mechanisms of pathogenesis of glioma metastasis is based on migration of tumor cells along classical and meningeal lymphatic pathways. Damage to the latter contributes to metastasis.

The majority of meningiomas - benign tumors with an extremely low metastasis tendency. Only singular observations of extracranial metastasis of WHO Grade I benign meningiomas are described in the literature. Despite the intensive study of meningiomas' molecular biology, there are currently no reliable markers indicating the possibility of their metastasis.

Surgery of meningiomas of the craniocervical region is one of the most difficult parts of neurosurgery due to the closeness of the brainstem, caudal group of the cranial nerves (CNs) and vertebral artery. According to the literature, suffering of the caudal group of CNs is between 20 and 55% according to different authors. In their dysfunction, the recovery of CNs is long-term and requires joint efforts by both the medical team and the patient and his family.

Malignant transformation of fibrous dysplasia in McCune-Albright syndrome is observed in less than 1% of cases, thus osteosarcoma is developing more frequently. According to the search in the PubMed database over the last 5 years, 13 publications were found, but none of them described cerebral cranium damage.

 Analysis and assessment of the role of convolutional neural networks in the cytological diagnosis of the thyroid pathology, exploring their potential for increasing the accuracy and automation of diagnostic processes.

Breast cancer (BC) is a multifactorial disease that is characterized by various genetic and epigenetic changes that occur due to the effect of various factors including that of environmental etiological agents. The obtained scientific data speak volumes for epigenetic dysregulation in BC pathogenesis. Out of all epigenetic markers, various microRNA regulating a wide spectrum of biological processes in a cell could be viewed as one of the predictors of potential risk. Understanding the functional role of these molecules will provide valuable information about the complex molecular mechanisms underlying the appearance and development of BC. This review summarizes currently existing publicly available data on aberrant expression of miR-125b, miR-181a, and miR-16 in case of various cancer localizations; analyzes their role in BC pathogenesis; presents an annotation of the target-genes; and evaluates the repression potential of microRNA and their diagnostic significance in case of BC. An analysis of changes in miRNA expression during radiation exposure was conducted. Interest in examining specific miRNAs is due to the results of long-term monitoring of the health of people living in radioactively contaminated areas of the Southern Urals, as well as data on the expression profiles of miR-125b, miR-181a, and miR-16 over the long term in exposed people.

Breast cancer (BC) with triple-negative molecular profile is characterized by special and rather serious problems in terms of clinical management of patients compared to other types. On the one hand this is due to the fact that tumors with such a status often do not respond to routine targeted therapy and only a minimal number of drugs are currently available for their treatment. On the other hand, cases of triple-negative BC (TNBC) are often diagnosed against the background of an extensive metastatic process, in which confirmation of the metastases histogenesis to breast tissue is a difficult task due to the low sensitivity of such carcinomas to specific organ markers. It is known that about 40-50% of all TNBC cases are characterized by the achievement of complete pathomorphological regression of the primary tumor as a result of neoadjuvant chemotherapy courses, which determines a favorable prognosis of the disease. In other cases (also up to 50%), TNBC do not respond to chemotherapy and exhibit persistent drug resistance, such tumors are more aggressive, have the highest relapse rate and a high risk of metastasis. For this group of patients, the issue of finding predictive markers and new therapeutic methods remains unresolved. The presented literature review reflects the data of the analysis of publicly available results of scientific studies devoted to potentially promising molecular markers, including IDO1, DCLK1 and FOXC1, their significance in BC, including TNBC is described. Based on the analysis of literary data, it can be argued that IDO1, DCLK1 and FOXC1 are promising objects for further research in the context of TNBC. Each marker has unique characteristics that make them important both for disease prognosis and for the development of new therapeutic approaches.

Solitary fibrous tumor is a rare mesenchymal neoplasm, the most common localization of which is the pleural cavity, but the tumor can also affect other organs. This neoplasm with localisation in the kidney was first described only in 1996. Solitary fibrous tumor accounts for 0.2% of all kidney neoplasms and is an exceptional phenomenon. Currently, there is no generally accepted theory explaining the etiology and pathogenesis, probably, its development is a multifactorial process including a combination of genetic, epigenetic and external factors. Despite the lack of unambiguous opinion on the nature of the neoplasm, the spectrum of molecular abnormalities in this tumor has been sufficiently studied. The literature presents a limited number of publications devoted to this pathology, in this regard it should be noted that in routine practice, the morphological picture may not always be so unambiguous and require the pathologist to conduct differential diagnostics with a fairly wide range of tumors. Given the rarity of this disease, we would like to share a description of our own clinical observation demonstrating the possible difficulties of morphology diagnostics.

Solitary fibrous tumor (SFT) is a rare mesenchymal tumor. SFT was first described by Klemperer and Rabin in 1931. They described a fibrous tumor of the pleura. Currently, isolated cases of SFT of the gallbladder and common bile duct have been described in the world. SFT is characterized by nuclear expression of STAT6 and the formation of chimeric genes NAB2-STAT6. A case report of a rare SFT of the common bile duct in a 66-year-old patient is presented. The description contains data from radiation and ultrasound diagnostic methods, macro- and microscopic characteristics of the tumor and immunohistochemical characteristics.

The article presents a literature review and a clinical case of an adenomatoid odontogenic tumor in a 3-year-old child. After the surgical treatment, an morphological and immunohistochemical (with antibodies to Ki-67, CK7, CK 14 and CK 18) studies of the remote material were performed. The histological features of the neoplasm are shown, and its origin from the odontogenic epithelium is substantiated.

The probability of meningiomas metastasizing is 0.18%, and the causes are unclear. The most common localizations of extracranial metastases are lung (37.2%), bones (16.5%) and liver (9.2%). There are no effective treatment algorithms for metastatic meningiomas. Treatment tactics consists of symptomatic surgery and radiotherapy.

Sellar tumors are predominantly benign neoplasms accounting for approximately 14-18% of all brain tumors. For many decades, there have been a few clinical cases confirming possible simultaneous coexistence of two nosological groups in one area. We present 2 rare cases of sellar collision tumors (a 61-year-old male with pituitary adenoma and craniopharyngioma; a 68-year-old female with pituitary adenoma and meningioma of tubercle), clinical features, anamnesis, preoperative neuroimaging, intraoperative picture and postoperative outcomes. Combination of pituitary adenoma and craniopharyngioma/ meningioma as a type of collision tumors requires caution at all stages of treatment due to impossible preoperative analysis of tumor density and, accordingly, correct choice of surgical access. Transsphenoidal endoscopic access reduces mortality rate according to literature data. Preoperative MR elastometry needs to be studied in depth including patients with sellar collision tumors.

Combination of different intracranial tumors is an infrequent phenomenon. Combination of pituitary adenomas with craniopharyngiomas is extremely rare.

Primary hyperparathyroidism (PHPT) is a common endocrine disorder characterized by autonomous secretion of parathyroid hormone by altered parathyroid glands. In most cases PHPT is a sporadic disease, 5-10% of observations are genetically determined syndromal and non-syndromal forms. Studies of families with hereditary forms of PHPT have led to the discovery of key oncosuppressor genes and proto-oncogenes whose somatic mutations underlie the development of many sporadic parathyroid tumors. Another interest in the pathogenesis of primary hyperparathyroidism is studying mechanisms of epigenetic regulation in tumor tissue. In the first part of this review, we will discuss the classification, morphology, and etiology of PHPT. In the second part, we will present a summary of the most important studies using genetic analysis, classified according to the method used.

Transurethral resection of the bladder tumor (TURBT) is not only the main method for staging of bladder cancer, but also the standard of surgical treatment for patients with non-muscle-invasive tumosr. Previously, the generally accepted technique for performing TURBT was electroresection using loop, but the active introduction of laser technologies has made the resection of the entire tumor in a single block (en bloc) widely available. According to some authors, en bloc resection of the bladder tumor allows to overcome some limitations of standard TURBT, including insufficient quality of the specimen containing the muscle layer and implantation of floating tumor cells in the bladder. However, the en bloc resection also has limitations. When using the en bloc resection for tumors larger than 3 cm, successful evacuation of the entire lesion becomes unlikely, therefore, it is usually recommended to use it for smaller tumors. Publications devoted to the successful en bloc resection for large bladder tumors are included in the literature review. According to most authors, all the advantages of en bloc resection are preserved regardless of the tumor size, such as potentially better local control, lower recurrence rates outside the resection area, and higher quality of specimens for pathological study. A significant limitation of the technique is the inability to evacuate the tumor through the endoscope channel, which requires additional interventions (morcellation, dissection, ablation) or equipment (endoscopic baskets, forceps, etc.). Taking into account the conclusions of the Delphi consensus held in 2020, tumor size should not limit the use of the en bloc resection of the bladder tumor in the routine practice. However, an effective method for evacuating large bladder tumors that suits all specialists has not yet been proposed.

Progression of metastatic prostate cancer after castration resistance is one of the main challenges in prostate cancer therapy. 177Lu-PSMA-617 has been recently investigated in castration resistant metastatic prostate cancer.

Transrectal prostate biopsy remains the standard method for prostate cancer diagnosis, but it is associated with a high risk of infectious complications. In recent years, fosfomycin has been increasingly used as an alternative for antibiotic prophylaxis due to the increasing resistance of pathogens to fluoroquinolones, its good safety profile and ease of use. Results of several studies dedicated to the efficiency of fosfomycin are highlighted in this review. Fosfomycin demonstrates significant advantages as a drug for the prevention of infectious and inflammatory complications in patients after prostate biopsy, especially in case of increasing resistance to fluoroquinolones. Its efficacy, safety and ease of use make it an attractive choice and a reliable alternative in the context of increasing antibiotic resistance. Combination regimens with fluoroquinolones may be preferable for high-risk group.

Inverted papilloma (SIP) is a relatively rare benign epithelial tumor of the nasal cavity which characterized by an aggressive course with local destruction of surrounding structures, a tendency to recurrence and associated with malignancy. Etiology remains little understood. SIPs is most commonly associated with human papillomavirus (HPV) and mutations in the epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGF) genes, which are upregulated in recurrent SIPs.These factors are responsible for theinverted papilloma transformation into squamous cell carcinoma (SCC). Prognosis of sinonasal SCC is poor, in most cases likely owing to its advanced stage at presentation. Treatment includes complete SIP removal by endoscopic approach with histological examination. Follow-up of these patients is critical to diagnosing relapse, which can be either early or late. It is important to diagnose recurrence to enable early treatment, especially in case of associated carcinoma or malignancy. In case of SCC, additional radiotherapy and/or neoadjuvant chemotherapy is needed, because it shows promising results in improving outcomes. In this article, we present a clinical case of managing a patient with malignancy of inverted papilloma, which led to extensive destruction.

Gastric cancer remains the fifth most common malignant neoplasm in the world and ranks fifth among the causes associated with cancer. The TNM system remains the gold standard for predictive stratification of patients with gastric cancer, but the search for new sensitive, specific and reproducible biomarkers to develop a personalized approach to the management of patients with gastric cancer does not lose its relevance. The phenomenon of tumor budding is a well-established independent prognostic factor in colorectal cancer. In 2017, the first guideline on the method of calculating tumor budding for colorectal cancer was published. Despite the promising potential of using tumor budding in gastric cancer this parameter is still not evaluated in everyday practice. This lection provides data on various methods of counting tumor budding in gastric carcinomas, describes the molecular mechanisms of interaction between tumor cells and the immune microenvironment, and summarizes the available data on the relationship of clinical and morphological characteristics of gastric cancer with the degree of tumor budding. The relationship between the degree of tumor budding and the prognostic characteristics of gastric cancer and the prospects for its use is also described.