Human papillomavirus in laryngeal papillomas and in adjacent normal epithelium

Eleven adults with laryngeal papillomas were studied for the presence of human papillomavirus (HPV) DNA by in situ hybridization. As well as from the papillomas, three additional biopsies were taken from the normal-appearing mucosa as follows: the involved vocal cord, the opposite vocal cord (when the papilloma was unilateral), and from the ventricular fold on the side of the lesion. These normal tissues were analysed by polymerase chain reaction (PCR) to detect HPV DNA. All except one of the 11 papillomas contained HPV DNA; nine were HPV 6/11 DNA positive and one positive for HPV 16 DNA. The normal-appearing laryngeal mucosa harboured HPV DNA in eight out of 11 patients. The present results strongly support the concept that the adult-type laryngeal papilloma is an HPV-induced lesion, mostly due to HPV types 6 and 11. The persistence of HPV DNA in the adjacent normal epithelium is consistent with the frequent recurrence of these lesions.