TABLE 2.

Comparison of features and role in tumor of miRNA, lncRNA and circRNA.

	Features	Role in tumor	Refs
miRNA	a. NcRNAs of approximately 22 nt in length	a. Translation inhibition	Krol et al. (2010); Ryan et al. (2010); Pallante et al. (2014); Slack and Chinnaiyan (2019)
	b. Not easy to degrade, with high stability	b. Degradation of mRNA	—
	c. Highly conservative	c. Transcriptional regulation	—
	d. Timing expression specificity	—	—
	e. Tissue expression specificity	—	—
	f. The regulation is not very strong	—	—
lncRNA	a. NcRNAs greater than 200 nt in length	a. Regulation of transcription levels	Hart and Goff (2016); Slack and Chinnaiyan (2019); Alessio et al. (2020)
	b. No or weak protein coding ability	b. Regulation of the level of epigenetic modification	—
	c. Low conservatism	c. Regulation of post-transcriptional levels	—
	d. Timing expression specificity	—	—
	e. Tissue expression specificity	—	—
circRNA	a. High stability	a. Regulation of transcription, splicing, and chromatin interactions	Li et al. (2015); Qu et al. (2015); Slack and Chinnaiyan (2019)
	b. Highly conservative	b. A miRNA sponge	—
	c. Timing expression specificity	c. Acting as a protein scaffold	—
	d. Tissue expression specificity	d. Competitive binding proteins	—