CCH is considered to be the preclinical stage of mild cognitive impairment (Du et al., 2017); and it has already been proved to participate in the β-amyloid deposition, tau phosphorylation, neuronal death, impairment of hippocampal pre-synaptic plasticity, and theta oscillation in rats (Ai et al., 2013; Sun et al., 2015; Liu et al., 2016; Chen et al., 2017; Li et al., 2019; Yan et al., 2020). The gene discussed is MAPT; the disease is columnar cell hyperplasia of the breast.