TNF and rheumatoid arthritis: In this study we applied 5-Aza-2′-deoxycytidine (5-AzadC), which has a high potency to inhibit methylation and has been used to treat hematological malignancies [8], to RA-FLS and then examined its impact on the growth of RA-FLS and the expression of inflammatory cytokine tumor necrosis factor-α (TNF-α).