There are different communities of microbes, or microbiomes, in and on various parts of the human body like the skin, gut, and mouth. The microbes can have a significant influence on our health, and scientists are beginning to link specific types of microorganisms with certain health conditions. A new study has identified bacteria in the human oral microbiome that can affect head and neck squamous cell carcinoma (HNSCC) risk; some are associated with a 50 percent increased risk. The findings have been reported in JAMA Oncology.
Previous research has identified bacteria that can promote periodontal disease, which are gum infections that can seriously damage tissues around teeth and the jawbone. Scientists have also known that poor oral health, which can cause periodontal disease, can also increase the risk of HNSCC.
In this research, the investigators assessed the microbiomes of healthy human volunteers. They began with samples from 159,840 Americans, and the scientists followed health outcomes for about ten years. Then they focused on a set of 236 individuals who had been diagnosed with a form of HNSCC and 458 randomly selected individuals who did not have cancer.
After identifying the microbes in the oral microbiomes, and linking them with health outcomes of these people, the scientists determined that thirteen bacterial species can either increase or decrease HNSCC risk. These microbes affected the risk of HNSCC by 30 percent, and when considered in combination with five other microbial species that have been associated with oral cancer, the risk increase was 50 percent.
"Our findings offer new insight into the relationship between the oral microbiome and head and neck cancers. These bacteria may serve as biomarkers for experts to flag those at high risk," said lead study author Soyoung Kwak, PhD, a postdoctoral fellow in at NYU Grossman School of Medicine.
This study also considered fungal members of the oral microbiome that might influence HNSCC development. They did not find any fungi that affected HNSCC risk.
"Brushing your teeth and flossing may not only help prevent periodontal disease, but also may protect against head and neck cancer," said co-senior study author Richard Hayes, DDS, MPH, PhD, a professor at NYU Grossman School of Medicine and a member of its Perlmutter Cancer Center.
"Now that we have identified key bacteria that may contribute to this disease, we next plan to explore the mechanisms that allow them to do so and in what ways we can best intervene," added study co-senior author Jiyoung Ahn, PhD, a professor at NYU Grossman School of Medicine , among other appointments.
Ahn noted that while bacteria can increase the risk of HNSCC, these types of cancer are still generally uncommon.
Sources: NYU Langone Health, JAMA Oncology