Scientists have shown that in HeLa and N2a cells, after beta-cleavage of amyloid precursor protein (APP) in early endosomes, a minute fraction of Aβ peptides can be secreted from the cells in association with exosomes; not only that but also exosomal proteins have also been found to accumulate in the plaques of AD patients’ brains (Rajendran et al., 2006). This evidence concerns the gene APP and Alzheimer disease.