MMP13 and osteoarthritis: For example, Liu et al.5reported that Circ‐CER could be a therapeutic target for osteoarthritis (OA) via manipulating MMP13 expression through the Circ‐CER/miR‐136/MMP13 axis; latest research by Wen et al.6suggests that has_circ_0001200, has_circ_0001566, has_circ_0003972, and has_circ_0008360 might influence the onset and progression of rheumatoid arthritis (RA) and probably serve as predictive biomarkers for RA diagnosis.