Several early-stage AD-related markers were significantly upregulated in the hippocampus of the AD rats, such as APOE (apolipoprotein E; p = 0.028), EIF2AK2 (eukaryotic translation initiation factor 2 α kinase 2; p = 0.003) and B2M (β-2-microglobulin; p = 0.037), together with the finding of a trend toward the upregulation of the tau-phosphorylating enzyme GSK3β (glycogen synthase kinase 3 β; p = 0.052; Fig. 6C). Here, B2M is linked to Alzheimer disease.