The changing face of head and neck cancer in the 21st century: the impact of HPV on the epidemiology and pathology of oral cancer.

The longstanding notion that head and neck squamous cell carcinoma (HNSCC) is a uniform disease process is changing. Divergence in epidemiologic trends among HNSCCs arising in different anatomic subsites has introduced a view that HNSCC is a heterogeneous group. Analysis of molecular genetic changes discloses not just individual tumor differences, but also consistent large-scale differences that permit the recognition of important tumor subtypes. One recently recognized subtype is the human papillomavirus (HPV)-positive oropharyngeal carcinoma. HPV-positive oropharyngeal cancer now dominates the head and neck oncology landscape, and its escalating incidence is impacting on diagnostic, preventive and therapeutic practices.