RB1 and Alzheimer disease: For instance: 1) our findings that cell-cycle-progression regulators, such as Cdk4, Cdk1, cyclin D, cyclin B, phospho-Rb, and E2F1, are upregulated in CP-AD compared with N are consistent with other studies that indicate that cell-cycle molecules are upregulated in AD neurons [34], [37], [40], [41], [46], [102]; 2) our finding that the cell-cycle inhibitor p27 is downregulated in CP-AD when compared with N, is corroborated by Ogawa et al. [39], who demonstrated a lower level of p27 expression in the nucleus of AD neurons.