Research progress of circular RNA in digestive tract tumors: a narrative review

Circular RNA (circRNA) is a newly discovered non-coding RNA with a closed loop structure. The 3' end and the 5' end of circRNA are covalently bonded and not easily degraded by nucleases. Besides, circRNA can exist in eukaryotes widely and conservatively, and it is stably expressed in human liver, brain, lung and other organs. CircRNA can also regulate gene expression by acting on miRNA just like "miRNA sponge". With the deepening of research, growing literature has evidence shows that circRNA is related to tumors closely. For tumors, a large part of malignant ones are gastrointestinal tumors (GIST). In recent years, there are some researches which show that circRNA plays an important role in the occurrence and development, detection and treatment, and prognostic evaluation of malignant tumors of the digestive system. This article summarizes the literature reports on circRNA and GIST since March 2019. From 326 records screened, 79 full text articles were assessed for eligibility and 29 studies met the inclusion criteria. We reviewed the relationship between circRNA and GIST, and its role in the development of tumors. These studies show that in the future, circRNA has the potential to be used as a molecular marker for the detection and treatment of GIST.