A history of periodontal disease and the presence of circulating antibodies to selected oral pathogens have been associated with increased risk of pancreatic cancer.
However, direct relationships of oral microbes with pancreatic cancer have not been evaluated in prospective studies.
Dr Xiaozhou Fan and colleagues examined the relationship of oral microbiota with subsequent risk of pancreatic cancer in a large nested case–control study.
|Porphyromonas gingivalis was associated with higher risk of pancreatic cancer|
The researchers selected 361 incident adenocarcinoma of pancreas, and 371 matched controls from 2 prospective cohort studies, the American Cancer Society Cancer Prevention Study II and the National Cancer Institute Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial.
From pre-diagnostic oral wash samples, we characterized the composition of the oral microbiota using bacterial 16S ribosomal RNA (16S rRNA) gene sequencing.
The team found that the associations between oral microbiota and risk of pancreatic cancer, controlling for the random effect of cohorts and other covariates, were examined using traditional and L1-penalised least absolute shrinkage and selection operator logistic regression.
Carriage of oral pathogens, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, were associated with higher risk of pancreatic cancer.
The researchers found that Phylum Fusobacteria and its genus Leptotrichia were associated with decreased pancreatic cancer risk.
Risks related to these phylotypes remained after exclusion of cases that developed within 2 years of sample collection, reducing the likelihood of reverse causation in this prospective study.
Dr Fan's team concluded, "This study provides supportive evidence that oral microbiota may play a role in the etiology of pancreatic cancer."