Inactivation of many tumour suppressor gene products such as p53, p16INK4a, E-cadherin and PTEN[23-27] or activation of proto-oncogenes such as Cyclin D, EGFR and p63[28-30] have been found to be implicated in HNSCC occurrence. This evidence concerns the gene CDH1 and head and neck squamous cell carcinoma.