PTGS2 and Parkinson disease: The presence of activated microglia expressing the inflammatory cytokines interleukin- (IL-) 6 and tumor necrosis factor- (TNF-) α, as well as enzymes associated with inflammation, such as inducible isoform of nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) was also evidenced by immunohistochemistry assays in post-mortem brain tissue from PD patients [13, 16, 20].