APP and Alzheimer disease: APP, the precursor of Aβ, which derives from sequential cleavage of APP by β-secretase (also known as BACE1) and γ-secretase (Cole and Vassar, 2007; De Strooper, 2007), has a central role in AD pathogenesis and might act as both an Aβ precursor and a cell surface receptor (Deyts et al., 2016).