Lung cancer occupies a leading position in the structure of global cancer morbidity and mortality, due to the biological properties of the key pool of tumor cells — cancer stem cells (CSCs). The effects of SARS-CoV2 on tumor CSCs and its niche have not been studied. Objective. To study CSCs in lung adenocarcinomas after COVID19. Material and methods. Surgical material from lung adenocarcinoma from 12 patients who had a new coronavirus infection and from 12 patients who did not have COVID19 was examined. Analysis of clinical and anamnestic data, macroscopic and microscopic examination of tumor samples and adjacent intact tissue, immunohistochemical reactions using antibodies to virus proteins and CSC markers ALDH1, CD133 and CD34 were performed. Results. Adenocarcinoma samples from patients in the main group showed a significant increase in the number of cells expressing the CSCs markers ALDH1, CD133 and CD34 compared to adenocarcinoma samples from control group patients without SARS-CoV2 infection. We found an increase in the number of CSCs in patients with adenocarcinoma metastasis in lymph nodes in both the main and control groups. CSCs of lung adenocarcinomas from SARS-CoV2 survivors contain virus proteins Nucleocapside and Spike protein. Conclusions. We found an increase in the number of CSCs with expression of ALDH1, CD133 and CD34 in lung adenocarcinoma in patients with new coronavirus infection. Increased number of ALDH1+, CD133+ CD34+ CSCs in tumor tissue enhance the metastatic potential of lung adenocarcinoma. The Nucleocapsid and Spike proteins of SARS-CoV2 virus are detectable in lung tissue from patients with new coronavirus infection, both in adenocarcinoma cells, CSCs, and in type II pneumocytes, macrophages, and endothelial cells, suggesting prolonged persistence of the virus proteins and probably the virus.

Against the background of a steady increase in the number of oncological diseases, as well as the complexity of the primary morphological diagnosis of malignant neoplasms (MNT) and precancerous conditions, especially in the regions of the Russian Federation, in 2019, the creation of a number of Reference Centers (RCs) for immunohistochemical, pathomorphological, molecular genetic methods was initiated research within the framework of the federal project “Fight against oncological diseases”. In 2020, on the basis of the centralized pathoanatomical department of the Clinical Center of Sechenov University, the RC began its work. Aim. To analyze the work of the RC of Sechenov University and compare the results obtained with the tasks of the federal project.Materials and methods. The data of histological, immunohistochemical studies from the registers of receipt of biopsy (surgical) materials and the issuance of the results of intravital pathoanatomical studies (account forms 014-2 / y and 057-y / 04), as well as data from the Telemedicine system of remote consultations, were analyzed. Results. For 21 months of work, the RC consulted 1476 requests received from 70 constituent entities of the Russian Federation. More than 10 % of reference diagnoses were made in a remote format through the Telemedicine system of remote consultations at the federal and regional levels using digital pathology techniques.Conclusion. Despite the obvious need for the work of RCs, there are still a number of issues that have a signifcant impact on the quality of diagnostic processes: specialization of specifc RCs, expansion of the range of incoming clinical and morphological diagnoses. It also requires attention to regularly improve the skills of RC employees in Russian and international educational systems and to equip the RC, frst of all, with virtual resources. The experience of the RC has demonstrated the importance of a second medical expert opinion in the primary diagnosis and verifcation of the diagnosis of malignant neoplasms of various localizations for the regions of the Russian Federation, where the acute problem is the general shortage of general pathologists and expert doctors.

Extramammary Paget’s disease is a rare malignant tumor that frequently presents in areas rich in apocrine glands, most often affecting the skin of the perianal area: the labia minora, clitoris, scrotum, penis, skin of the lower abdomen, and inguinal folds. Tumors localized outside the perianal region are relatively rare. We present a clinical case of a 70-year-old patient with a tumor localized on the skin of the right axillary region, with clinical, histological, and immunohistochemical characteristics. The diagnosis of extramammary Paget’s disease with atypical localization is relatively difficult to reach in time, as tumors are often mistakenly considered as inflammatory skin lesions, and the appropriate treatment may therefore be delayed.

SARS-CoV-2 infection can lead to potentiation of oncological diseases, including due to virus interaction with cancer stem cells (CSC). The aim of this pap

Lung cancer occupies a leading position among malignant neoplasms throughout the world, and the issue of carcinogenesis of this disease today still remains relevant. This review examines in detail the issue of the participation of cancer stem cells in the development of lung cancer, the concept of the stem cell niche, and options for their detection using molecular and immunohistochemical studies. A separate section examines the impact of the new coronavirus infection COVID-19 on CSC and lung cancer carcinogenesis in general, as well as the successful results of the use of photodynamic therapy in the treatment of both diseases.