Abstract: Circular RNAs are a naturally occurring type of universal and diverse endogenous noncoding RNAs.They are usually stable, abundant, conserved RNA molecules and exhibit tissue specific expression. Functional circRNAs have been identified to act as microRNA sponges and RNA-binding protein sequestering agents as well as transcriptional regulators.There is a lot of evidence that circular RNA can participate in the transcription and translation of key genes and regulate the occurrence, progression and prognosis of tumors. The detection of specific circular RNAs in saliva, exosomes, and clinically standard blood samples will make them potential diagnostic or predictive biomarkers of tumors.

Key words: circRNAs, Gene regulation, Tumor, Targeted therapy