Researchers in Montreal have reported new evidence supporting a strong causal association between human papillomavirus infection and tonsil-related oral cancers.
The study also found that human papillomavirus (HPV) 16 seropositivity contributes substantial independent risk prediction. “HPV 16 seropositivity may thus serve as a surrogate marker for the totality of HPV exposure that is relevant in oral carcinogenesis,” wrote Dr. Javier Pintos and his associates from the division of cancer epidemiology at McGill University.
Additionally, while some researchers have reported a positive correlation between markers of sexual activity and oral cancers, this study found no such association (Oral Oncol. 2008;44:242–50).
The investigation, as part of a multicenter study coordinated by the International Agency for Research on Cancer, followed a hospital-based case-control design.
A total of 72 patients with newly diagnosed squamous cell carcinoma of the mouth and 129 controls were recruited. Among patients, the most common cancer site was the tongue (21 patients), followed by the floor of the mouth (12) and palatine tonsil (12), “other” and “unspecified” parts of the mouth (18), the palate (4), the gums (2), the oropharynx (2), and the inner lip (1).
Patients ranged in age from 25 to 84 years, though most were between 55 and 74 years; men accounted for more than 70%.
HPV DNA was detected in 6 of 129 controls (5%) and 14 of 72 patients (19%). Most viral infections among patients harbored high-risk HPV types (13 of 14 samples), compared with 4 of the 6 HPV-positive controls, the investigators said, adding that HPV 16, which was not detected among controls, was found in 13 of the 14 positive samples from the oral cancer arm.
The association between HPV and cancers of the palatine tonsils and base of tongue seem to be genuine, because it is independent from the influence of smoking and alcohol.
The study was funded by the National Cancer Institute of Canada, and the authors said they had no conflicts of interest.
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