APP and Alzheimer disease: According to the hypothesis, the processing of APP could have two pathways, either cleavage within AβP by the secretase that can generate peptide products that do not precipitate to form amyloid, or cleavage in the endosomal-lysosomal compartment, which can result in an intact AβP and that can precipitate to form amyloid, and can turn into NFTs and cell death, the hallmarks of AD (Hardy and Higgins, 1992).