Oropharyngeal cancer is a disease in which malignant cells form in the tissue of oropharynx. Oropharynx is a middle part of the throat which includes the base of the tongue, the tonsils, the soft palate, and the walls of the pharynx. Oropharyngeal cancers can be divided into two types, HPV-positive, which are related to human papillomavirus infection, and HPV-negative cancers, which are usually linked to alcohol or tobacco use.