Chronic Gum Disease Linked to HPV-related Head and Neck Cancers

Chronic periodontitis, or inflammation of the gums, is associated with a great risk of squamous cell carcinomas of the mouth and throat that contain human papillomavirus (HPV), according to a study published in the June 18, 2012, advance online edition of Archives of Otolaryngology - Head and Neck Surgery.

High-risk HPV, especially types 16 and 18, can cause abnormal cell growth leading to various malignancies, including cervical cancer, anal cancer, and so-called "head and neck cancers," which in the case of HPV generally refers to cancers of the oral cavity and throat. HIV positive people are more likely to be infected with multiple HOV types, less likely to spontaneously clear the virus, and more likely to develop precancerous cervical and anal lesions. Mouth and throat cancers have not been as extensively studied in this population.

Mine Tezal from University at Buffalo and colleagues retrospectively looked at tissue samples and dental records from 124 people with primary squamous cell carcinoma of the oral cavity, oropharynx, or larynx diagnosed between 1999 and 2007. They found that patients with periodontitis were more likely to have HPV-positive tumors, and each millimeter of bone loss due to periodontal disease increased the odds of HPV-positive cancer by more than 2-fold.

Below is an edited excerpt from a University at Buffalo press release describing the study and its findings in more detail.

Study Links Gum Disease and HPV-status of Head and Neck Cancer

Buffalo, N.Y. -- June 20, 2012 -- Human Papilloma Virus (HPV), once almost exclusively associated with cancer of the cervix, is now linked to head and neck cancer. According to a new University at Buffalo study just published in the Archives of Otolaryngology - Head & Neck Surgery, a JAMA publication, gum disease is associated with increased odds of tumors being HPV-positive.

Mine Tezal, DDS, PhD, assistant professor of oral biology in the UB School of Dental Medicine who is the primary investigator on the study, and a team of scientists from UB evaluated data from 124 patients diagnosed with primary head and neck squamous cell carcinoma (HNSCC) between 1999 and 2007.

"The aim of the study was to test the presence of periodontitis, a persistent inflammatory process and HPV-status of HNSCC," she said.

Of the 124 tumor samples Tezal and her team studied, 50 were positive for HPV-16 DNA and that subjects with HPV-positive tumors had a significantly higher severity of periodontitis when compared to subjects with HPV-negative tumors.

According to the National Cancer Institute, there has been a steady increase in the prevalence of oropharyngeal cancers in the U.S. since 1973 despite the significant decline in tobacco use since 1965.

Tezal notes that this increase has mainly been attributed to oral HPV infection.

Understanding the natural history of the oral HPV infection and targeting factors associated not only with its acquisition but also with its persistence, says Tezal, will lead to more effective strategies, not only for prevention, but also for treatment.

"While there is an effective vaccine for cervical HPV infection if given prior to the exposure of the virus (females 9-26; males 9-21), oral HPV infection can be transmitted at or any time after birth, and the target population for a vaccine to prevent oral HPV infection has not yet been defined," said Tezal.

Tezal pointed out that though many previous studies combined periodontitis and dental decay as indicators of poor oral health, dental decay was not significantly linked to tumor-HPV status in the present study.

"The fact that only periodontitis was associated with tumor HPV status points to the potential association of inflammation with tumor HPV status," she says.

When Tezal and colleagues started their research about eight years ago they were looking at the potential association between chronic inflammation and head and neck cancers because the importance of the local oral environment for malignant tumor growth was widely accepted. However there wasn’t research evaluating the role of local oral factors in the natural history of HNSCC, Tezal said.

"The next step in this research will be intervention studies to test whether treating the sources of inflammation, like gum disease, can reduce the acquisition and/or persistence of oral HPV infection and improve the prognosis of HPV-related diseases," she said.

6/26/12

Reference

M Tezal, FA Scannapieco, J Wactawski-Wende, et al. Local Inflammation and Human Papillomavirus Status of Head and Neck Cancers. Archives of Otolaryngology - Head and Neck Surgery. June 18, 2012 (Epub ahead of print).

Other Source

University at Buffalo. Study Links Gum Disease and HPV-status of Head and Neck Cancer. Press release. June 20, 2012.