MDK and Alzheimer disease: Among 6963 proteins detected in both datasets, 190 DEPs were identified between AD and controls (FDR <0.05, |log2FC| >0.66 [2 SD], supplemental Table S4), of which 165 proteins were elevated in the AD cases, including Aβ, MAPT, APOE, SNPRP70, MDK, PTN, SMOC1, NTN1, and so on, and 25 proteins were decreased in the AD cases (Fig. 4B).