The allelic loss, mutation and methylation of CSMD1 have been detected in breast cancer, head and neck cancer, oral squamous cell carcinoma, prostate cancer, rectum, liver, lung and skin cancer and many other malignant tumors such as breast cancer, head and neck cancer, oral squamous cell carcinoma, prostate, colorectal cancer, liver cancer, lung cancer and skin cancer, etc 5,6,8-16. This evidence concerns the gene CSMD1 and oral cavity squamous cell carcinoma.