Importance of the immune system in head and neck cancer

Head and neck squamous cell carcinoma (HNSCC) are a heterogeneous group of tumors, mainly caused by exposure to cigarette smoke and/or alcohol. In recent years, a virally driven subset of cancers driven by human papillomavirus subtype 16 [HPV-16]) has emerged. Our own data and data from other groups have demonstrated the favorable clinical outcome of HPV-driven oropharyngeal tumors and in both HPV+ and HPV- cancers the importance of a high density of tumor-associated lymphocytes for survival. These data underpin manipulation and activation of the patients' immune system by treatment, and as a result immunotherapy is rapidly taking its place in the management of HNSCC. Here we review the role the immune system in relation to HNSCC and consider the implications these have for HNSCC immunotherapy. Studies to quantify survival benefits and treatment-associated toxicities are ongoing.