RB1 and rheumatoid arthritis: While overexpression of RB1 fails to fully abolish miR-199a-3p’s effect, probably due to the already high expression level of miR-199a-3p, these data strongly suggest that RB1 is a target of miR-199a-3p, and miR-199a-3p regulates proliferation and apoptosis of RA-FLS, at least partially, by directly targetting RB1.