This document discusses the rising incidence of oropharyngeal cancer, which is increasingly associated with human papillomavirus (HPV) infection. HPV-positive oropharyngeal cancer has distinct clinical and biological features compared to HPV-negative cancer, including younger patient age, fewer risk factors, and better prognosis. Detection of HPV status is important for prognostication and potentially de-escalating treatment intensity for HPV-positive patients due to their improved survival. Immunohistochemistry for p16 is a practical and widely applicable method for determining HPV status in clinical specimens.