PPY and Alzheimer disease: pancreatic polypeptide (PP) was an indirect indicator of the AD pathology, in which the plasma level was determined through Myriad RBM-Luminex xMAP-190 (Hu et al., 2012), Myriad RBM-Luminex xMAP-146 analytes (Nazeri et al., 2014), Myriad RBM-Luminex xMAP-151 analytes (Doecke et al., 2012), and Slow Off-rate Modified Aptamer (SOMAmer)–“SOMAscan”-1001 analyte (Sattlecker et al., 2014).