CDKN2A and head and neck neoplasm: The VIII edition of the TNM Staging System of Head and Neck Tumors deals separately with the staging of p16INK4a positive and p16INK4a negative oropharyngeal tumors in order to improve prognostic stratification, as different aspects of the disease, including category T and N, and the presence of extracapsular lymph node extension, have a different prognostic impact in the two groups [12].