Human Papillomavirus (HPV) Testing of Head and Neck Cancers

Abstract

Human papillomavirus (HPV) has been found in approximately 25% of head and neck cancers and in 70% of oropharyngeal squamous cell carcinomas. HPV-associated oropharyngeal squamous cell carcinomas have been found to have a distinctly better prognosis and outcome as compared to conventional squamous cell carcinomas of the head and neck, making the detection of HPV in these tumors integral to patient management. The most common HPV type found in HPV-positive oropharyngeal squamous cell carcinomas is HPV 16. Several different testing modalities have been validated for HPV testing on surgical pathology specimens, including p16 immunohistochemistry, HPV PCR, and in situ hybridization of HPV DNA or RNA. Current guidelines recommend HPV testing in all cases of oropharyngeal squamous cell carcinoma diagnosed on cytology when the HPV status is unknown and in squamous cell carcinomas of unknown primary site. Fine-needle aspiration (FNA) biopsies are increasingly used for diagnosis of oropharyngeal squamous cell carcinoma, which frequently present with a low tumor (T) but high nodal (N) stage, with involved cervical lymph nodes often being amenable to FNA biopsy. There is no specific recommendation for which testing modality to use on cytologic material; therefore, familiarity with these various testing options and their advantages and limitations is essential for the practicing cytopathologist.