PTGFRN and Alzheimer disease: Data from the proteomic analysis of brain- and CSF-derived extracellular vesicles from AD patients show that heat shock protein 70 (HSP70), puromycin-sensitive aminopeptidase (NPEPPS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), transthyretin, cystatin C, and prostaglandin F2 receptor negative regulator (PTGFRN) can also be implicated in AD pathogenesis, since their expression varies during the pathogenic process [41].