The results of systemic review showed that the levels of platelet immunoglobulin, APP-N, BACE (36 kDa/BACE 57 kDa), matrix metalloproteinases-9 (MMP-9), MMP-2, platelet membrane fatty acids, phospholipase C (PLC), phenolsulphotransferase (PST), plasma-derived growth factor (PDGF), C-type lectin-like receptor 2(CLEC2), extracellular vesicles (EVs), glycogen synthase kinase 3-beta (GSK3β) ratios were significantly different between AD patients and controls (Fig. 3), but further studies were needed to verify the alterations of these markers in AD patients. Here, MMP9 is linked to Alzheimer disease.