A variety of immune cells such as T cells, mononuclear phagocytes and mastocytes, and several cytokines such as tumor necrosis factor α (TNF-a), interleukin (IL)-1, IL-6, IL-8, transforming growth factor β (TGF-β), and fibroblast growth factor (FGF) participate in the pathogenesis of RA [6,7]. The gene discussed is TNF; the disease is rheumatoid arthritis.