IGFBP3 and Alzheimer disease: Fifteen TP53 pathway genes showed elevated promoter methylation in AD samples including CDKN2A, IGFBP3 and TP73, while hypomethylation was detected in the promoter regions of 10 genes such as GTSE1, damage specific DNA binding protein 2 (DDB2) and cyclin dependent kinase 1 (CDK1).