Clinical relevance of circulating cell-free microRNAs in cancer

Alterations in microRNAs (miRNAs) are involved in the pathogenesis of various types of human cancers, and because of the stability of tumour-derived cell-free microRNAs, these show potential as novel biomarkersCell-free miRNAs can be detected not only in plasma and serum, but also in other body fluids, such as urine and saliva, and serve as a non-invasive diagnostic toolmiRNAs also have an important role in chemo-resistance of cancer cells, and could be useful predictors of therapeutic responseMethods of detection, such as microarray analysis and deep-sequencing, enable a comprehensive profiling of cell-free miRNAs (including various isoforms) from low amounts of RNA samples