CSMD1 has been proven to be a tumor suppressor gene in multiple tumors and has copy number variations, somatic mutations, deletions, aberrant splicing, and chromosome aberrations in leukemia, primary lung cancer, head and neck squamous cell carcinoma, breast cancer, liver cancer, and other cancers [18,19,20,21]. This evidence concerns the gene CSMD1 and head and neck squamous cell carcinoma.