Biomarker (A) and therapeutic (B) potential of circRNAs in stem cells. These circRNAs can be measured from different samples (e.g., blood and urine) and are potential biomarkers for the diagnosis and prognosis of diseases. RNAi and antisense oligonucleotide (ASO) agents can efficiently target circRNAs in the cytoplasm and nucleus, respectively, and circRNAs can be transferred by exosomes or nanoparticles. Abbreviations: RISC, RNA-induced silencing complex; RNase H, ribonuclease H; siRNA, small interfering RNA.