APOE and Alzheimer disease: More recently, a link was established between the APOE genotype and LD accumulation within AD brain tissue; Oil-red O neutral lipid staining revealed an APOE genotype–nested expression pattern of lipid bodies within postmortem brain tissue, with APOE3/3 AD patients showing a significant induction in lipid bodies distributed within the brain parenchyma compared to age-matched control subjects, and APOE4/4 AD patients showing a statistically higher expression over the APOE3/3 subjects.