PTGS2 and Alzheimer disease: Several biomarkers significantly associated with APOEɛ4 ‘risk’ and ɛ2 ‘protective’ genotypes (versus neutral ɛ3/ɛ3) for AD [214] are likely to be associated with the activities of PLA2s, COX-2, and LOX enzymes and the formation of various pro- and anti-inflammatory bioactive lipids.