Table 1.

Progress in the role of circRNA in IBD and its associated CRC

circRNA	Regulation trend in IBD or CRC	Mechanism and Function	Clinical significance	Reference
circ_103516	Upregulated in IBD	Dysregulation of circRNA_103516 may participate in the molecular mechanism of IBD through hsa-miR-19b-1-5p sponging, which shows a positive correlation with disease activity and inflammatory cytokines such as TNF-α and IFN-γ.	A novel biomarker of IBD diagnosis.	[77]
circ_0007919	Downregulated in UC	Enhances the expression levels of EPC1 and VIPR1 by sponging let-7a and miR-138; related to clinical characteristics and epithelial integrity.	Potential diagnostic and therapeutic implications.	[73]
circ_004662	Upregulated in IBD	Correlated with mammalian target of rapamycin (mTOR) pathway which involved in the inflammation and activation of intestinal T cells.	Preferable diagnostic biomarker of CD and novel candidate for differentiating CD from UC.	[74]
CDKN2B-AS1	Downregulated in IBD	Exhibites inhibitory effects in colonic epithelial cell proliferation by interacting with claudin-2 that can decrease barrier function.	A novel lncRNA affecting UC biology.	[80]
circ_102610	Upregulated in CD	Promote the proliferation and EMT of intestinal epithelial cells via sponging of miR-130a-3p, trigger intestinal fibrosis accompanying CD.	Serve as a potential target for CD therapy and novel drug research.	[82]
circPACRGL	Upregulated in CRC	Enhances the proliferation, migration and invasion of CRC cells, as well as the differentiation of N1 and N2 granulocytosis through miR-142-3p/miR-506-3p-TGF-β1 axis.	Promoting role in the course of CRC.	[83]
circ_0000069	Upregulated in CRC	Promote the expression of cancer cells and improve the survival rate, apoptosis rate and invasiveness of CAC cells.	Potential diagnostic markers.	[86-88]
circ_0020397
circ_001569
circ_0004585	Upregulated in CRC	Positively correlated with tumor size.	Potential diagnostic marker.	[89]
circ_0001178	Upregulated in CRC	Not available.	Used as potential biomarkers for liver metastasis of CRC.	[90]
circ_0000826
circDDX17	Downregulated in CRC	Potentially binds to miR-21-5p, and participates in the KEGG pathways of CRC.	Tumor suppressor and a therapeutic target for CRC.	[75]
circ_103809	Downregulated in CRC	Related to the metastasis, differentiation, and perineural infiltration of CRC.	Potential diagnostic and prognostic marker.	[91]
circ_104700
circBANP	Upregulated in CRC	Knockdown of circBANP with siRNA significantly attenuate the proliferation of CRC cells.	Serve as a prognostic and therapeutic marker.	[93]
CCDC66	Upregulated in CRC	Controls cell proliferation, migration and anchorage-independent growth.	Negatively correlated with poor prognosis.	[85]
circ_102958	Upregulated in CRC	Promote the proliferation, migration and invasion of CRC cells through circRNA_102958/miR-585/CDC25B axis.	Potential prognostic marker.	[94]