Could the Oral Microbiome Play a Role in Head and Neck Cancer?

Researchers at the Head and Neck Cancer Research Program at Mount Sinai are trying to understand why people respond differently to human papillomavirus (HPV) infection. Known foremost as the cause of cervical cancer in women, more than 80 percent of sexually active individuals will be infected with HPV in their lifetime. Despite this high rate, not all patients develop a persistent infection that leads to cancer. Investigators within the Program say the answer may be in the oral microbiome.

Studies have found that the microbiome plays an important role in immune regulation and tumor development in both the oral cavity and other areas of the body. While certain microbes live in harmony with the body and are known to protect against carcinogens, other bacteria compromise the immune process and trigger inflammation. These microbiotas have been linked to numerous diseases, including laryngeal and gastrointestinal cancers.

“At the Head and Neck Cancer Research Program, we are trying to characterize the microbiome in cancer patients—including nonsmokers and nondrinkers—and identify ways to modify it to reduce the risk of cancer and its recurrence. This will help us answer patients’ frequent questions about why and how they developed this cancer,” says Eric Genden, MD, MHCA, FACS, the Isidore Friesner Professor and Chair of Otolaryngology-Head and Neck Surgery, Senior Associate Dean for Clinical Affairs, and Professor of Neurosurgery and Immunology at the Icahn School of Medicine at Mount Sinai.

Within the oral cavity, there are more than 700 known species of microbiota. Investigators at Mount Sinai have found differences in the microbiome of patients with HPV-associated throat cancers when compared with patients who had non-HPV-associated throat cancers. For example, individuals with persistent oral HPV infection were found to have elevated levels of salivary IgG and decreased levels of matrix metalloproteinase 8.

Advancements in gene sequencing and metagenomics have allowed researchers to identify unculturable microbes and study the relationship between the microbiome and various diseases. The goal is to identify specific species—as well as the genes expressed by those species—and generate effector proteins and metabolites that incite or protect against cancer types. The researchers will also collect samples from patients being treated for oral cavity squamous cell carcinoma to determine how the microbiome changes during treatment and whether specific microbiome signatures are associated with recurrence.

“We hypothesize that the oral microbiome modulates the development of carcinoma,” adds Dr. Genden. “Our hope is that this study will lay the foundation for future advancements in this rapidly advancing field.”