Circulating status of microRNAs 660-5p and 210-3p in breast cancer patients.

Background: MicroRNAs (miRs), which are stable in the blood, comprise small non-coding RNAs that regulate gene expression. They have important roles in almost all biological pathways, especially in cancer-relevant processes, and have an abnormal expression in breast cancer. In recent studies, the aberrant expression level of various microRNAs has been demonstrated in human cancer.