APOE and Alzheimer disease: Moving forward, the following subjects warrant further investigation: the topographic distribution of Δtau314 proteins in various anatomical brain regions of individuals at different stages of AD, the relationships of Δtau314 proteins to AD risk factors (e.g., aging and Apolipoprotein E genotype), the detection and quantitative analysis of Δtau314 proteins in biological fluids (e.g., lumbar puncture CSF and blood), and the correlation between catalytically active Casp2 and Δtau314.