PTGS2 and Alzheimer disease: Salivary samples exhibit unclear results with significant decrease in interleukin-1 (IL-1), interlukin-6 (IL-6), and tumor necrosis factor α (TNF-α) in AD patients and opposite results for cyclooxygenase-2 (COX-2), caspase-8, interleukin 1β (IL-1β), and metalloproteinase-9 (MMP-9) [195].