MicroRNAs: Are they indicators for prediction of response to radiotherapy in breast cancer?

Radiotherapy is one of the most important methods for the treatment of breast cancer. There is great interest in identifying factors that help to predict patient response to radiotherapy. MicroRNAs (miRNAs) are a class of small RNA molecules that regulate gene expression at the post-transcriptional level and play a key role in cellular responses to ionising radiation. Several regulatory proteins participate in breast tumour cell radiosensitivity and there are crosstalks between miRNAs and these proteins at multiple levels. By analysing the relationships between miRNAs and these proteins, we concluded that radioresistant and radiosensitive breast cancer patients might have different patterns of some specific miRNAs. MiRNAs are present in body fluids in a remarkably stable form and can easily be detected and quantified by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). It seems that profiling circulating miRNAs have the potential to be used for the prediction of radiotherapy outcome in breast cancer.