HPV infection in oral, pharyngeal and laryngeal papillomas

Background. HPV infections play a major role in the pathogenesis of squamous cell carcinomas of the head and neck. Regarding benign papillomas, the role of HPV is still uncertain. Materials and methods. To clarify this issue, 100 exophytic papillomas of the oral cavity, pharynx and larynx were subjected to histopathological and molecular pathological examination. Excision biopsies were taken from 62 male and 38 female patients with an age range of 18 to 87 years. Biopsies were tested for p16 expression by immunohistochemistry and analyzed for HPV subtypes 6/11 (low-risk), 16/18 and 31/33/53 (high-risk) by chromogenic in situ hybridization. Results. HPV infections were verified molecularly in 34% of biopsies; in all cases with the low-risk HPV subtypes 6/11. Only one case showed infection with both 6/11 and 31/33/53 subtypes, but not subtype 16/18; whereas expression of p16 was found in 67%. The rate of positive molecular verification of HPV infection (in situ hybridization) was highest in the laryngeal lesions with 61.1%, followed by the oral cavity with 52.9%, and lowest in pharyngeal lesions (21.5%). Recurrent papillomas were seen in 18 cases (18%), of which 14 were molecularly positive for HPV (in situ hybridization). A correlation between inflammatory infiltration and HPV infection could be verified in 82%. Conclusion. Our data demonstrate an important role of HPV infection for the development of benign papillomas of the head and neck region. Furthermore, there is a positive correlation between HPV infection and recurrent papillomas. Therefore, a molecular morphological HPV analysis of papillomas could provide important prognostic data.