MicroRNAs (miRNAs) are a class of small non-coding RNA molecules of approximately 22 nucleotides that regulate gene expression at the post-transcriptional level. Alterations in miRNA expression patterns correlate with a wide spectrum of pathological conditions, including cancer. miRNA profiling was mostly performed, in solid tissues, obtained by invasive diagnostic procedures. However, miRNAs in biofluids, such as serum and plasma, show high stability resulting from the formation of complexes with specific protein or incorporation within circulating exosomes or other microvesicles. Circulating miRNAs could be reliable biomarkers for early-stage cancer diagnosis, prognosis and response to therapy. In this chapter, we analyze the major pre-analytical and analytical challenges in experimental design for circulating miRNA detection, focusing on exosome fraction and microarray-based approach.
Part of the book: Biomarker