Inhibition of each kinase pathways appropriately by STA-21, LY294002, and PD98059 attenuated IL-21-induced migration of RA-FLS and secretion of MMP-3 and MMP-9; however, inhibition of the STAT3 by AG490 had no influence on IL-21-induced RA-FLS migration. This evidence concerns the gene STAT3 and rheumatoid arthritis.