A new type of non-coding RNA: circular RNA

Circular RNA (circRNA) is a new type of non-coding RNA. It is mainly composed of exons, and prevalent and stable presence among living organisms. Research has revealed that circRNA has many functions such as microRNA (miRNA) sponges, and regulation of alternative splicing and gene expression. Recent evidence suggests that circRNA plays an important role in many diseases. This review summarizes our current understanding of theclassifications, characteristics, functions, and the relationships of circRNA with diseases, in order to aid diagnosis, treatment, and prevention of clinical related diseases. Key words: Circular RNA; Non-coding RNA; MicroRNA sponges