[MicroRNA in Body Fluids - Development of the Novel Plat Form for Cancer Therapeutics and Diagnosis].

MicroRNAs(miRNAs)are small non-coding RNAs that function in diverse biological processes and are approximately 20-22 nucleotide RNAs that regulate the expression of target genes, mainly at the post-transcriptional level. A number of studies report that miRNAs are involved in homeostatic maintenance such as cell cycle regulation, cell division and apoptosis, and that aberrant expression of miRNAs is often detected in various types of diseases, including cancer. In cancer biology, miRNAs play functional roles in tumor seeding, drug sensitivity, and metastasis. MiRNAs are also secreted through the small vesicles called exosomes, which are endosome-derived vesicles from various cell types including immune and tumor cells. In addition to cellular miRNAs, secreted miRNAs also play important roles in cancer development and metastasis. Therefore, secreted miRNAs in body fluids have been investigated as a promising biomarkers and therapeutic targets for the treatment of cancer patients. In this review, we introduce the current knowledge of miRNA functions in cancer development and discuss the clinical applications of se-miRNAs, eg, as diagnostic markers and therapeutic targets.