Taken together, these results indicated that ApoE4 and Aβ42 could induce cPLA2 activation in neurons and astrocytes, suggesting that greater cPLA2 activitation in the human cortex of AD APOE3/APOE4 compared to AD APOE3/APOE3 might arise from the combined effects of ApoE4 and greater Aβ42 accumulation. This evidence concerns the gene APOE and Alzheimer disease.