p16 status of oropharyngeal and oral cavity squamous cell carcinomas: A single institution experience

Introduction/Objective. New World Health Organization Classification of Head and Neck Tumors from 2017 has introduced significant changes, mainly considering tumors in the oropharyngeal region. New entities of HPV-positive and -negative squamous cell carcinomas have been acknowledged, not only based on the presence of an active viral infection and different tumor markers expression, but also because of their different histopathology, staging assessment, and prognosis. A retrospective study has been conducted, in order to determine p16 positivity in squamous cell carcinomas in oropharynx and in the oral cavity, and to see whether they differ in sex and age distribution. Methods. The presence of viral infection was verified based on p16 immunochemistry staining, p16 being the surrogate marker for HPV infection. A total of 177 cases of squamous cell carcinomas in the oropharynx and the oral cavity, found in the archives of the Histopathology Laboratory of the Clinic for Otorhinolaryngology and Maxillofacial Surgery, Clinical Centre of Serbia, have been revised. Results. Out of 177 cases, 50 (28.2%) were p16-positive. Compared with carcinomas in the oral cavity, p16 carcinomas were significantly more common in the oropharynx (34.3% in the oropharynx, compared to 10.3% in the oral cavity). Carcinomas in both regions were mostly associated with male sex (88.1% of all cases were in males), but p16 positivity was more common in females (11 out of 21 cases, 52.4%). The most common location of p16-positive carcinomas were palatine tonsils (41.03% of tonsillar carcinomas were p16-positive). Conclusion. P16-positive squamous cell carcinomas were the most numerous in the oropharynx, i.e. palatine tonsils, and were more common in females.