Bacteria involved in periodontal disease are associated with increased risk of head and neck cancer

Experts have long observed that people with poor oral health are statistically more likely to develop HNSCC (a group that includes the most common cancers of the mouth and throat) than those with healthier mouths. I did. Small studies have linked some bacteria in these areas (oral microbiome) to cancer, but the exact types of bacteria most involved have remained unknown until now.

The new analysis, led by researchers at NYU Langone Health and its Perlmutter Cancer Center, examined the genetic makeup of oral microbes from healthy men and women. Of the hundreds of bacteria commonly found in the mouth, 13 have been shown to increase or decrease the risk of HNSCC. Overall, this group was associated with a 30% higher chance of developing cancer. When combined with five other species commonly found in periodontal disease, the overall risk increased by 50%.

“Our findings provide new insights into the relationship between the oral microbiome and head and neck cancer,” said study lead author Dr. Soyoung Kwak. “These bacteria could serve as biomarkers for experts to alert people at high risk,” added Kwak, a postdoctoral fellow in the Department of Population Health at New York University's Grossman School of Medicine.

Kwak said previous research had already found specific bacteria in tumor samples from people diagnosed with these cancers. Then, in a smaller evaluation in 2018, the current research team investigated how healthy participants' microbiome contributed to their risk of future HNSCC over time.

Their latest report will be published online on September 26 in the journal JAMA Oncologyis the largest and most detailed analysis of its kind to date, Kwak said. They were also among the first to investigate whether common fungi, organisms such as yeast and molds that make up the oral microbiome along with bacteria, may be involved in HNSCC. New experiments found no such role for fungal organisms.

The research team followed 159,840 Americans across the country in three ongoing studies to better understand how diet, lifestyle, medical history and many other factors contribute to cancer. analyzed data from the survey. Data were collected for the American Cancer Society's Cancer Prevention Study II. Screening tests for prostate, lung, colorectal, and ovarian cancer. and the Southern Community Cohort Study.

Immediately after enrollment, participants rinsed with mouthwash and provided a saliva sample that preserved the number and type of microorganisms for testing. The researchers then followed them for approximately 10 to 15 years and recorded the presence of tumors.

In the current study, the researchers analyzed bacterial and fungal DNA from saliva samples. They then identified 236 patients diagnosed with HNSCC and compared their oral microbial DNA to that of 458 randomly selected subjects without cancer. In their study, the researchers identified factors known to play a role, including age, race, and how often people smoke cigarettes or drink alcohol.

“Our results provide new reasons to maintain good oral hygiene habits,” said Richard Hayes, DDS, MPH, PhD, co-senior author of the study. “Brushing and flossing not only helps prevent periodontal disease, but it may also protect against head and neck cancer,” says Professor of Population Health at New York University's Grossman School of Medicine and member of the Perlmutter Cancer Center. added Hayes. .

The researchers said the study aimed to identify a correlation between cancer risk and specific bacteria in the mouth, not to establish a direct cause-and-effect relationship. he emphasized. That requires further research.

“Now that we have identified the key bacteria that may cause this disease, we will next investigate the mechanisms that enable them to do so and how we can most effectively intervene. '' said study co-author Dr. Jiyoung Ahn. Anne is a professor in the Department of Population Health Medicine at New York University Grossman School of Medicine and associate director for population research at Perlmutter Cancer Center.

Dr. Ahn cautions that while the additional risk from bacteria is concerning, overall cases of head and neck cancer remain fairly rare.

Funding for this research was provided by National Institutes of Health grants P20CA252728, R01CA159036, U01CA250186, and R01LM014085.