Despite the fact that IL-6 and TNFα are well recognized as the key cytokines in RA pathogenesis the precise mechanism of how IL-6 and TNFα interaction inhibits bone formation is still not fully understood and a proper understanding of such molecular mechanism(s) for functional contribution of IL-6 and TNFα interaction into inhibition of bone formation is critically important. The gene discussed is TNF; the disease is rheumatoid arthritis.