Accordingly, the level of many enzymes responsible for AA metabolism (e.g. cPLA2, sPLA2, iPLA2, COX-1, COX-2, mPGES-1, 12-LOX, 15-LOX, cPGES-1, p450 epoxygenase) is changed in postmortem AD brain samples [136]. This evidence concerns the gene PTGS1 and Alzheimer disease.