Biological Implications and Clinical Potential of Metastasis-Related miRNA in Colorectal Cancer

Colorectal cancer (CRC), ranking as the third commonest cancer, leads to extremely high rates of mortality. Metastasis is the major cause of poor outcome in CRC. When metastasis occurs, 5-year survival rates of patients decrease sharply, and strategies to enhance a patient's lifetime seem limited. MicroRNAs (miRNAs) are evolutionarily conserved small non-coding RNAs that are significantly involved in manipulation of CRC malignant phenotypes, including proliferation, invasion, and metastasis. To date, accumulating studies have revealed the mechanisms and functions of certain miRNAs in CRC metastasis. However, there is no systematic discussion about the biological implications and clinical potential (diagnostic role, prognostic role, and targeted therapy potential) of metastasis-related miRNAs in CRC. This review mainly summarizes the recent advances of miRNA-mediated metastasis in CRC. We also discuss the clinical values of metastasis-related miRNAs as potential biomarkers or therapeutic targets in CRC. Moreover, we envisage the future orientation and challenges in translating these findings into clinical applications.