MicroRNAs: Promising biomarkers for diagnosis and therapeutic targets in human colorectal cancer metastasis

Colorectal cancer (CRC) is the third most common cancer and the fourth most common cause of cancer-related death worldwide. Distant metastasis is a major cause of mortality in CRC. MicroRNAs (miRNAs) are small non-coding RNA molecules involved in the post-transcriptional and translational regulation of gene expression. Many miRNAs are aberrantly expressed in cancer and influence tumor progression. Accumulating studies suggest that multiple miRNAs are actively involved in the CRC metastasis process. Thus, we aim to introduce the role of mi- RNAs in multi-steps of CRC metastasis, including cancer cell invasion, intravasation, circulation, extravasation, colonization, angiogenesis, and epithelial-mesenchymal transition (EMT). Moreover, we suggest the potential application of miRNAs as biomarkers for CRC patients with metastasis.