A total of 142 proteins were differentially abundant (PFDR<0.05) between MCI (due-to-AD) and asymptomatic AD, of which 61.97% (n=88 proteins) were decreased in individuals with MCI (due-to-AD), including key proteins such as ADAMTS8, DCC, and ADGRB2, while 38.03% (n=54 proteins) were increased, with notable examples including PEA15, YWHAE, YWHAG, FABP3, ENOPH1, and AChE (Fig. 3A). Here, DCC is linked to Alzheimer disease.