To date approximately 77 distinct human papillomavirus (HPV) genotypes have
been described and the genomic sequences of most of them have been fully
analyzed. About 30 additional partial sequences have been obtained from
putative novel HPV types, suggesting that the total number of existing HPV
genotypes is in excess of 100. HPV cause benign tumors in the respiratory
tract. Mounting evidence suggests that they also play a role in the
etiology of a subset of head and neck cancers. Carcinomas in patients with
a history of recurrent respiratory papillomatosis are caused clearly by
persistent HPV interacting with one or more carcinogenic agents.
Previous studies have suggested squamous neoplasia of the larynx and may
also be HPV related.