Thus, in this study, we utilize a large number of human iPSC lines from healthy subjects and AD patients carrying APOE ε3/ε3 or ε4/ε4 genotype, and investigate AD-related phenotypes using the iPSC-derived three-dimensional (3-D) cerebral organoid model system, which is highly reminiscent of human brain structure with diverse cell types20–22. This evidence concerns the gene APOE and Alzheimer disease.