MODERN CONCEPTS ON THE ROLE OF HYPOXIA IN THE DEVELOPMENT OF TUMOR RADIORESISTANCE

The purpose of the study was to systematize and summarize modern ideas about the role of hypoxia in the development of tumor radioresistance.Material and Methods. PubMed, eLibrary and Springer databases were used to identify reviews published from 1953 to 2020, of which 57 were selected to write our review.Results. Radiation therapy is one of the most important components in cancer treatment. The major drawback of radiation therapy is the development radiation resistance in cancerous cells and secondary malignancies. The mechanisms of cancer radioresistance are very complicated and affected by many factors, of which hypoxia is the most important. Hypoxia is able to activate the mechanisms of angiogenesis, epithelial-mesenchymal transformation and contribute to the formation of the pool of cancer stem cell, which are characterized by chemo- and radioresistance. In turn, the severity of hypoxia largely dependent on tumor blood flow. Moreover, not only the quantitative but also the qualitative characteristics of blood vessels can affect the development of tissue hypoxia in the tumor.Conclusion. A comprehensive assessment of the severity of hypoxia, as well as characteristics of angiogenesis and EMT can contribute to a better understanding of the mechanisms of development of cancer radioresistance.