PTGS2 and selenium deficiency: Selenium deficiency may cause a reduced GPx activity that indirectly regulates the expression of COX and LOX via the Mitogen-activated protein kinase (MAPK) pathway and Cyclooxygenases-2 (COX-2), by controlling the Nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-κB), the “central mediator of immune and inflammatory responses”.