PECAM1 and Alzheimer disease: We immunostained and analyzed the brains of 27 individuals with known APOE genotypes (8 APOEε4/4 homozygous carriers with AD, 8 APOEε3/4 heterozygote carriers with AD, and 11 APOEε4 non-carriers (APOEε3/3) with AD (Supplementary Table 7) for FN1 and CD31 (endothelial cell marker), and COL6A2 and COL4 (a vascular basement membrane marker) (Fig. 5, Supplementary Dataset 1, Supplementary Dataset 2).