Researchers have identified several novel oral bacterial species that appear to significantly elevate the risk of developing head and neck squamous cell carcinoma (HNSCC). In a prospective nested case-control study, 13 specific bacterial species were found to be differentially associated with HNSCC development. A 1-standard deviation increase in a microbial risk score, which was based on the abundance of 22 bacteria, was linked to a 50% increased risk of HNSCC (OR 1.50, 95% CI 1.21-1.85), according to Richard B. Hayes, DDS, PhD, from the NYU Grossman School of Medicine, and his colleagues.
The study, published in JAMA Oncology, highlights the potential for these bacteria to serve as biomarkers for identifying individuals at high risk of developing HNSCC, enabling more personalized cancer prevention strategies. “The identified bacteria and bacterial complexes hold promise as potential biomarkers for identifying high-risk individuals for personalized prevention of HNSCC,” the researchers wrote.
The study revealed that certain bacteria, such as Prevotella salivae, Streptococcus sanguinis, and Leptotrichia species oral taxon 212, were associated with a lower risk of HNSCC. Similarly, four species from the Proteobacteria family—Eikenella corrodens, Simonsiella muelleri, Rodentibacter pneumotropicus, and Pasteurella multocida—were linked to reduced risk. On the other hand, species such as Porphyromonas cangingivalis, Prevotella species HUN102, Lactobacillus paracollinoides, and Pyramidobacter piscolens were associated with an elevated risk of HNSCC.
These associations were consistent across multiple disease sites within the study, including the oral cavity, pharynx, and larynx. “Our results offer yet another reason to maintain good oral hygiene habits,” Dr. Hayes noted, adding that brushing and flossing may help reduce not only periodontal disease but also the risk of head and neck cancer.
The study also found a moderate association between the well-known periodontal pathogen “red” and “orange” bacterial complexes and HNSCC risk (OR 1.06 per 1 standard deviation increase, 95% CI 1.00-1.12). These complexes, which are already associated with periodontal disease, seem to play a role in the early stages of head and neck carcinogenesis. The study’s findings bolster the hypothesis that poor oral health, and specifically the presence of certain pathogenic bacteria, is causally linked to HNSCC development.
Oral samples were taken from participants in three epidemiological cohorts: the American Cancer Society Cancer Prevention Study II Nutrition Cohort, the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, and the Southern Community Cohort Study. During a mean follow-up period of 5.1 years, 236 participants developed HNSCC. The control group was matched by factors such as age, sex, race, and time since oral sample collection.
Among the participants who developed HNSCC, the average age was 60.9 years, and 24.6% were women. Unsurprisingly, those who developed cancer were more likely to be frequent tobacco and alcohol users and had a higher prevalence of oral human papillomavirus 16 (HPV-16).
The study’s researchers emphasized the value of analyzing the microbial profile as a community rather than focusing on individual bacteria. To this end, they developed a “microbial risk score” based on the relative abundance of bacterial species associated with HNSCC. This research was supported by the National Cancer Institute and the National Library of Medicine, with sequencing conducted at the NYU School of Medicine Genome Technology Center.
Dr. Hayes disclosed receiving grants from the NIH. No other conflicts of interest were reported.
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