PTGS2 and rheumatoid arthritis: The transcription factor NF-κB, the major controller of both inflammatory responses and the immune system, is activated in the synovium of patients with RA and regulates genes that contribute to inflammation, including TNF-α, IL-6, interleukin- 8 (IL-8), inducible nitric oxide synthase (iNOS), lipoxygenase-5 (LOX-5) and COX-2.