A large case-controlled study in Iran has shown the association between human oral microbiota and pancreatic cancer risk.
Pancreatic cancer is the 12th most commonly occurring cancer worldwide and the 7th leading cause of cancer-related death. Prevention strategies for pancreatic cancer are imperative, however, the etiology of this disease is poorly understood.
Of interest, recent research has associated periodontal (gum) disease with increased pancreatic cancer risk.
Oral health and disease are closely tied to changes in oral microbial status. The oral microbiome consists of over 700 species of bacteria that colonise the human mouth. Distinct oral microbial ecosystems have been characterised for conditions like gingivitis and dental caries. Specific microbes, including Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, have been implicated in periodontal disease etiology.
This evidence suggests that changes in oral microbiota may mediate the relationship between periodontal disease and pancreatic cancer risk. To date though, few robust epidemiological studies have been conducted examining the relationship between oral microbes and pancreatic cancer.
Researchers from the National Cancer Institute and Tehran University of Medical Sciences compared the oral microbiota of patients with pancreatic cancer (cases) to non-cancerous controls, and published their findings in Cancer Medicine.
Briefly, 273 cases and 285 clinic-based controls were enrolled from hospitals and clinics in Tehran, Iran from 2011 to 2015. DNA was extracted from patient saliva samples to determine the individual’s oral microbial profile.
The researchers found that the overall oral microbial communities in pancreatic cancer cases were significantly different from that of controls.
Moreover, specific microbial taxa were associated with the presence of pancreatic cancer. Increased levels of Haemophiluswas was associated with reduced odds of pancreatic cancer, while the presence of Enterobacteriaceae, Lachnospiraceae, Bacteroidaceae, and Staphylococcaceae was associated with greater odds of pancreatic cancer.
In this study, the periodontal pathogen, P gingivalis was not associated with increased risk of pancreatic cancer, while the presence of A. actinomycetemcomitans did confer additional risk.
Large, prospective cohort studies are required to further validate these findings. Ultimately, the identification of oral microbiota related to cancer development may provide predictive biomarkers for the early detection of pancreatic cancer.