Experts have long noted that poor oral health increases vulnerability to pancreatic cancer, but the underlying reasons remained uncertain. Recent research suggests that bacteria from swallowed saliva can reach the pancreas, influencing disease risk. To pinpoint which species may be involved, scientists analyzed the genetic makeup of microbes from the saliva of 122,000 healthy individuals. Published in JAMA Oncology on September 18, the study highlights a clearer link between the oral microbiome and pancreatic cancer, offering new insights according to lead author Yixuan Meng, PhD, of NYU Grossman School of Medicine.

The oral microbiome a complex community of bacteria and fungi in the mouth is increasingly recognized for its impact on human health. Building on earlier findings that linked oral microbes to head and neck cancers and, in a smaller 2016 study, to pancreatic cancer, researchers have now conducted the largest and most detailed analysis to date. Led by Dr. Meng, the study is the first to implicate oral fungi, particularly Candida species, in pancreatic cancer, with these microbes even detected within patients’ pancreatic tumors.

In the study, researchers drew on data from two major U.S. investigations the American Cancer Society Cancer Prevention Study II and the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial designed to explore how lifestyle, diet, and medical history influence cancer risk. Participants provided saliva samples at enrollment, allowing microbial DNA to be preserved for analysis, and were then tracked for an average of nine years to monitor tumor development. The team compared bacterial and fungal DNA from 445 individuals who developed pancreatic cancer with that of 445 cancer-free participants, carefully adjusting for factors such as age, race, and smoking habits.

The study identified 24 bacterial and fungal species that either increased or reduced pancreatic cancer risk, including three bacteria already linked to periodontal disease, a severe gum infection. Collectively, these microbes were associated with a more than threefold rise in cancer risk. For the first time, researchers also developed a tool to estimate pancreatic cancer risk based on an individual’s oral microbiome profile, a finding that co-senior author Dr. Jiyoung Ahn of NYU Grossman School of Medicine says could help oncologists identify those most in need of early screening.

Dr. Jiyoung Ahn, associate director for population sciences at Perlmutter Cancer Center, highlighted the urgent need for better screening methods for pancreatic cancer, one of the deadliest malignancies. Co-senior author Dr. Richard Hayes emphasized that good oral hygiene, such as brushing and flossing, may not only prevent periodontal disease but also lower cancer risk. While the study establishes correlations between oral microbes and pancreatic cancer, it does not prove causation something future research must address. The team now plans to investigate the role of oral viruses and examine how the oral microbiome might influence patient survival.

Source: https://nyulangone.org/news/oral-microbes-linked-increased-risk-pancreatic-cancer