APOE and Alzheimer disease: Each <i>APOE</i> ε4 allele roughly triples the relative risk for AD compared to that of the reference allele, <i>APOE</i> ε3.<h4>Methods</h4>We have employed hyperspectral fluorescence imaging with an amyloidspecific, conformation-sensing probe, p-FTAA, to elucidate protein aggregate structure and morphology in fresh frozen prefrontal cortex samples from human postmortem AD brain tissue samples from patients homozygous for either <i>APOE</i> ε3 or <i>APOE</i> ε4.<h4>Results</h4>As expected <i>APOE</i> ε4/ε4 tissues had significantly larger load of CAA than <i>APOE</i> ε3/ε3.