Emerging roles of non‑coding RNAs in the response of rectal cancer to radiotherapy (Review).

Radiotherapy (RT) followed by radical surgery is an effective standard treatment strategy for various types of cancer, including rectal cancer. The response to RT varies among patients, and the radiosensitivity of cancer cells determines the clinical outcome of patients. However, the application of RT to patients with radioresistant tumors may result in radiation‑induced toxicity without clinical benefits. Currently, there are no effective methods to predict the response to RT. The limitations of the methods currently used to evaluate tumor radiosensitivity, which are mainly based on clinical and radiological features, are low sensitivity and specificity. Non‑coding RNAs (ncRNAs) have emerged as a class of biomarkers for predicting radiosensitivity. In particular, the expression pattern of ncRNAs can predict the response to RT in patients with rectal cancer. Thus, ncRNAs may be used as potential biomarkers and therapeutic targets to improve the diagnosis and treatment outcome of patients with rectal cancer. In the present review, the current knowledge on the limitations of RT for rectal cancer and the association between ncRNA expression and sensitivity of rectal cancer to RT are presented. Additionally, the potential of ncRNAs as predictive biomarkers and therapeutic targets to mitigate resistance of rectal cancer to RT is discussed.