Mechanisms, roles and potential in taking into account the bystander effect in radiobiology and medicine

Smirnova Maria V.

The review deals with the phenomenon which is displayed on the non-radiated cells experiencing indirect radioactive forcing at the expense of signals and factors developed by the cells exposed to radiation, and which is referred to as the radiation-induced bystander effect. The paper presents the recent developments in understanding the mechanisms of the bystander effect origination and running, with the emphasis being put on the recent assumptions on the communicative role of biogenic photon radiation. This phenomenon exerts both positive and negative effect, with the negative effect dominating. To smooth out carcinogenesis under the radiation-induced bystander effect, a great number of studies are carried out at present into different medicines, hormones and antioxidants, as well as into stem cells as inductors in affected tissues recovery. In spite of the fact that the bystander effect is not taken into account in the radiation risks assessment, it is shown to play a significant role in the onset of second primary cancers after radiotherapy. This phenomenon is intensively studied for the last thirty years, but no clear understanding has been achieved by the present of all the mechanisms of the phenomenon and of the predictability of its consequences.

Keywords:radiation effects, bystander effect, second primary cancer, radiotherapy, radiation oncology, risk assessment.