HPV infections and tonsillar carcinoma.

Since human papillomavirus (HPV) was first linked to laryngeal/oral carcinomas in 1983, several studies have confirmed its causal role in a subgroup of upper aerodigestive tract tumours. Of the non-genital cancers, tonsillar carcinomas (TCs) have the strongest association with HPV. By the end of 2002, 432 TCs had been analysed for HPV DNA. Overall detection rate was 51%, with HPV-16 being the most prevalent (84%). The original proposal that HPV-33 would be the most frequent HPV in TCs has not been confirmed, being present in only 4.6% of cases. HPV copy numbers are similar to those found in genital carcinomas (10-300 copies/cell), although HPV is mainly episomal in TC. The importance of this observation is unclear, although a role for subepithelial proliferative lymphatic tissue has been speculated. Patients with HPV-16 positive tumours have better overall and disease specific survival than HPV negative patients. They are also younger and the association with conventional risk factors-smoking and drinking-is less significant than in HPV negative patients. Thus, recent data suggest a distinct pattern for HPV-16 positive TCs.