2021 Vol. 12, No. 12
Circular RNA (circRNA) is a novel class of single-stranded RNAs with a closed loop structure. Their expression is dynamically regulated and shows spatiotemporal patterns among cell types, tissues and developmental stages. CircRNAs have important biological functions in many physiological processes, and their aberrant expression is implicated in many human diseases. In this cover paper, the authors focus on the translational potential of using human blood circRNAs as liquid biopsy biomarkers for human diseases and highlight their abundant expression, essential biological functions and significant correlations to human diseases in various components of peripheral blood, including whole blood, blood cells and extracellular vesicles. In addition, they also summarize the current knowledge of blood circRNA biomarkers for disease diagnosis or prognosis.