Oral health and disease are closely tied to changes in oral microbial status. The oral microbiome consists of over 700 species of bacteria that colonize the human mouth. Distinct oral microbial ecosystems have been characterized 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.
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. 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 Haemophilus 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. The findings were published in Cancer Medicine.
The authors acknowledged several limitations inherent to the case-control study design. Since saliva samples were collected at the time of diagnosis, it is difficult to show a causal relationship between microbial composition and pancreatic cancer risk. It is unknown if the differences in oral microbiota were present before the development of pancreatic cancer or post-onset of the disease. Additionally, the control group consisted of hospital- and clinic-based patients who did not have pancreatic cancer, but may have been referred for other underlying conditions that affected their microbial status.
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.
-article published in Medical News Bulletin
