CCND1 and early-onset autosomal dominant Alzheimer disease: Additionally, 9 hub genes (HSP90AA, ACTB, MAPK1, GSK3B, CCNE2, CDK6, AKT1, IGF1R, CCND1) were revealed as the genes considerably related to Alzheimer’s disease by a protein–protein interaction network using the cytohubba in Cytoscape software.