The Role of Repair Processes in the Formation of Radiosensitivity of Healthy and Tumour Cells in Humans

Abstract

Despite significant progress in the development and implementation of new radiotherapeutic techniques over the past decade and positive results of radiotherapy for cancer patients, overall and progression-free survival rates are still poor. The analysis of literature data and our own research in the field of clinical radiobiology and radiation oncology shows that cellular DNA repair systems increase the radioresistance of tumours and thus hinder the improvement of the effectiveness of patient therapy. The role of repair processes in shaping the radiosensitivity of tumours compared to healthy tissues is discussed in detail, and their differences are described. It is emphasized that the repair of irradiated DNA damage in tumour cells is more intensive than in healthy tissue cells due to increased expression of repair enzymes. Together with the instability of the tumour cell genome, this causes a large variation in their radiosensitivity and indicates the priority of research aimed at finding and developing radioprotectors to protect the genome of healthy cells from the environment of the irradiated tumour without affecting (reducing) its radiosensitivity. Such a way to optimize the results of therapeutic radiation will help minimize radiation complications that require additional therapy and worsen the quality of life of treated patients.