Biomarkers of radio-sensitivity and radio-resistance

One fundamental problem of most malignancies, including those of haematological origin, is the development of multiple mechanisms of resistance, which progressively reduce or suppress the therapeutic efficacy of conventional radio-chemotherapy. To be highly successful, a radio-therapeutic dose must be sufficient to destroy radio-resistant tumours without damaging the surrounding healthy tissue. However, many patients exhibit high radio-sensitivity and may develop radiation-induced early and late side effects. To avoid or limit radio-sensitization of normal tissues, current radiotherapy protocols limit the dose given, risking delivering an insufficient dose to a significant number of less sensitive patients. In this scenario, one of the main challenges of radiobiology is to predict a patient's tumour radio-resistance and normal tissue radio-sensitivity to tailor a personalized treatment to that individual. Up to date, none of the existing predictive assays has been proved so useful to translate into the clinical practice. Therefore, new promising approaches to identify new relevant predictive biomarkers are needed.
In this Research Topic, we will first explain the main characteristics and markers of tumour radio-resistance and normal tissue radio-sensitivity. Then, we will summarize and review the existing predictive assays. Finally, we will focus our attention on novel and promising approaches for identifying new relevant biomarkers able to predict radiotherapy outcomes. Of course, the presentation of ongoing original works is greatly encouraged.