A cellular stress protein (coded by the heme oxygenase-1 gene) that oxidizes heme to biliverdin, iron, and carbon monoxide in response to noxious stimuli, is significantly overexpressed in neurons and astrocytes of the AD hippocampus and cerebral cortex, which could produce iron in the AD brain (Schipper et al., 1995). This evidence concerns the gene HMOX1 and Alzheimer disease.