PTGFRN and Alzheimer disease: A proteomics analysis on EV separated from CSF samples of AD patients, MCI patients and corresponding controls identified the heat shock 70 kDa protein 1A (HSPA1A), puromycin-sensitive aminopeptidase (NPEPPS) and prostaglandin F2 receptor negative regulator (PTGFRN) as differentially expressed proteins, whereby HSPA1A and NPEPPS are significantly increased in AD patients versus MCI patients and PTGFRN is significantly increased in AD patients versus controls [128].