APOE and Alzheimer disease: Several post-mortem brain studies reported elevated RNA expression of APOE in Alzheimer’s disease patients regardless of APOE genotype.11,42 In APOE ε3/ε3 human brain, APOE-mRNA levels were significantly increased in brains affected by Alzheimer’s disease compared with controls.11 Concordantly, we demonstrated that APOE had a strong negative correlation with brain glucose metabolism in an older population (Fig. 3).