APOA1 and Alzheimer disease: A recent meta-analysis of proteomic candidate biomarkers for AD described six markers consistently replicated in at least three independent cohorts: alpha-2-macroglobulin (α2M)ps, pancreatic polypeptide (PP)ps, apolipoprotein A-1 (ApoA-1)ps, afaminp, insulin growth factor binding protein-2 (IGFBP-2)ps, and fibrinogen-γ-chainp [21].