Oral bacteria linked to decreased risk for head and neck cancer

Greater oral abundance of Corynebacterium and Kingella decreased risk for head and neck squamous cell cancer, according to published findings.

However, overall microbiome composition did not appear associated with risk for HNSCC, the research showed.

“The study provides the first comprehensive evidence that the oral microbiome may be associated with subsequent risk [for] HNSCC with the strongest links for larynx cancer and those with a history of tobacco use,” Richard B. Hayes, DDS, PhD, MPH, professor in the departments of population health and environmental science at NYU Langone Health, and colleagues wrote. “Maintenance of a healthy oral microbiome is essential to oral health; our findings may have implications for HNSCC prevention in conjunction with other control measures.”

Interest in the role bacteria may play in the etiology and predisposition of cancer is growing; however, investigations have been limited to specific oral cancers, small cohorts of patients and a small number of bacterial species for evaluation.

The researchers collected mouthwash samples and used bacterial 16S rRNA gene sequencing to compare oral microbiome composition and specific bacterial taxa abundances from 129 patients with HNSCC, including 58 patients from the American Cancer Society Cancer Prevention Study Nutrition Cohort (CPS-II; mean age, 71 years; 27.5% women) and 71 from the Prostate, Lung, Colorectal and Ovarian Cancer Screen Trial (PLCO; mean age, 62.7 years; 18.3% women). Researchers also collected samples from 254 controls (114 from CPS-II; 140 from PLCO) matched two per patient based on age, sex, race and ethnicity, and time since mouthwash collection.

Significant taxa included those with a two-sided false discovery rate-adjusted P value — or q value — of less than .1.

Analysis of oral microbiome taxa showed an association between greater abundance of phylum Actinobacteria and increased risk for HNSCC (fold change [FC] = 1.21; P = .01; q = .05), although researchers noted this statistical analysis may be limited.

Further analysis of lower-level taxa in phylum Actinobacteria showed a greater abundance of order Corynebacteriales, family Corynebacteriaceae and genus Corynebacterium appeared associated with reduced risk for HNSCC (FC = 0.58; 95% CI, 0.41-0.8; q = .06).

Class Betaproteobacteria, order Neisseriales, family Neisseriaceae and genus Kingella in phylum Proteobacteria also appeared associated with decreased risk for HNSCC (FC = 0.63; 95% CI, 0.46-0.86; q = .08).

Both Corynebacterium and Kingella remained significant after adjustments in multivariable models, suggesting each were independently associated with HNSCC, the researchers noted.

Researchers observed an inverse relation to HNSCC among Prevotella nanceiensis, Capnocytophaga leadbetteri and Selenomonas sputigena species (P < .05; q < .1).

After adjustments for tobacco and alcohol use, associations observed for all cases and controls appeared more prominent among current and former smokers than individuals who never smoked, including for Neisseriales and Kingella species. Although, the tests for interaction did not demonstrate significant differences by smoking status.

Researchers also observed an association between reduced risk for larynx cancer and a greater abundance of genera Corynebacterium, Kingella, Neisseria, Abiotrophia, Capnocytophaga and species Kingella dentificans and Streptococcus sanguinis (P < .01 for all; q < .1)

No bacterial genera appeared associated with oral cavity or pharynx cancer.

“These results are consistent with a role of the healthy oral microbiome in HNSCC prevention,” the researchers wrote. – by Melinda Stevens

Disclosure: The authors report no relevant financial disclosures.