Circular RNA and exosomes in pancreatic cancer progression

Circular RNA (circRNA) is a type of noncoding RNA that forms a covalently closed continuous loop. CircRNAs were discovered in the 1980s but were thought to be an artifact of aberrant RNA splicing or specific to a few pathogens such as hepatitis delta virus (1). The development of next-generation sequencing and bioinformatics tools has led to the discovery of numerous endogenous circRNAs, the expression of which is considerably higher than previously thought.