CCND1 and rheumatoid arthritis: Circ_0000396 overexpression suppressed the proliferation and inflammatory response and triggered the apoptosis of RA synovial fibroblasts (RASFs), accompanied by decreases in PCNA, Cyclin D1, Cyclin E1, Bcl2, IL-1β and TNF-α protein expression and an increase in Bax protein expression.