Analysis of patient data and quantitative estimation of Cdh23 in human tissues (normal and tumor) also indicated that Cdh23 is down‐regulated via promoter methylation in lung adenocarcinoma (AD) and esophageal squamous cell carcinoma (SCC) cells; we also observed a clear inverse correlation between Cdh23 expression and cancer metastasis. This evidence concerns the gene CDH23 and Alzheimer disease.