MicroRNAs (miRNAs) are small (approximately 22 nt) noncoding RNAs that play an important role in the regulation of various biological processes through their interaction with cellular messenger RNAs. They are frequently dysregulated in cancer and have shown promise as tissue-based markers for cancer classification and prognostication. Extracellular miRNAs in serum, plasma, saliva, urine and other body fluids have recently been shown to be associated with various pathological conditions including cancer.

miRNAs circulate in the bloodstream in a highly stable, extracellular form, thus they may be used as blood-based biomarkers for cancer and other diseases. Circulating miRNAs are protected by encapsulation in membrane-bound vesicles such as exosomes, but the majority of circulating miRNAs in human plasma and serum cofractionate with Argonaute2 (Ago2) protein, rather than with vesicles.

In the present work, we performed a comprehensive classification of different extracellular circulating miRNA types. A direct link to the knowledge base miRò together with the inclusion of datamining facilities allow users to infer possible biological functions of the circulating miRNAs and their connection with the phenotype. To our knowledge miRandola is the first database that provides information about all kind of extracellular miRNAs and we believe that it will constitute a very important resource for researchers.

AVAILABILITY

miRandola is available online at: http://atlas.dmi.unict.it/mirandola/index.html