Why cancer survivors have a lower risk of Alzheimer disease

Tying up two recent lines of experimental evidence may help explain this vital issue. On the one hand, data indicate that cancerous transformations of cells include changes in expression level and/or the functionality of multidrug resistance modulators which then disturb chemotherapy. On the other hand, studies have shown that some of the ABC transporters - at the blood-brain barrier - work as effective efflux pumps for amyloid A beta peptides. Amyloid V peptides, cut from the amyloid precursor protein of neurons can be assumed to induce brain wide neuronal apoptosis via opening plasma lemma-standing type-1 VDAC/porin channels as shown by in vitro experiments using established neuronal cell lines. However, extrusion of apoptosis inductive A beta by increased ABC transporter activity at the blood-brain barrier from the brain of cancer survivors might abolish this effect. The hypothesis presented can be read as a clue on what in recent literature is referred to as the inverse association of cancer and Alzheimer disease. (C) 2012 Elsevier Inc. All rights reserved.