Since CA1 is one of the most affected regions in AD, mainly at early stages [37], we performed immunohistochemical staining and found a decrease of H3K27Ac-positive and FZD3-positive neuronal cells in the CA1 hippocampal area of AD mice compared with Wild Type, but could dramatically increase when administrated with metformin. The gene discussed is FZD3; the disease is Alzheimer disease.