APP and Alzheimer disease: Otherwise, it is a normal physiological process shared by healthy individuals and (future) AD patients; if the stage two of AD, i.e., the self-perpetuating AβPP-independent iAβ generation pathway, is “cancelled”, as depicted in the panel E of Figure 2 above, and only the AβPP proteolytic pathway remains operational, there could be no AD because AβPP-derived iAβ would not reach AD neurodegeneration-causing levels within the lifespan of an individual.