Scientists have found that individuals with specific bacteria and fungi in their mouths may face a dramatically higher risk of pancreatic cancer — more than three times greater — according to new research from NYU Langone Health and the Perlmutter Cancer Center. The study, published in JAMA Oncology, identified 27 types of bacterial and fungal species in the mouth’s microbiome that may contribute to the disease.
Pancreatic cancer is one of the deadliest cancers — in 2025, an estimated 67,440 Americans will be diagnosed and about 51,980 people will die from it, according to the American Cancer Society. The researchers analyzed saliva collected from 122,000 healthy adults who participated in two larger cancer studies and followed them for approximately nine years.
The investigators compared the oral microbiota found in 445 patients who developed pancreatic cancer with that of 445 randomly selected cancer-free participants. Factors such as medical history, smoking habits, race, and age were taken into account. The study authors also identified 24 species of bacteria and fungi that were associated with an increased or lowered risk of the disease, as well as three more bacteria known to be linked to both gum disease and pancreatic cancer.
Collectively, the microbes were associated with more than a threefold increased risk for developing this type of cancer. The co-senior study author, Jiyoung Ahn, Ph.D., emphasized the importance of finding new modifiable risk factors for preventing this disease due to the lack of effective early detection methods. She suggested that oral microbiome profiling could serve as a non-invasive biomarker to identify individuals at elevated risk who might benefit from enhanced surveillance.
The connection between poor oral health and pancreatic cancer has been observed in previous studies, but little was known about which species of bacteria are potential culprits. Ahn noted that maintaining good oral hygiene through regular brushing, flossing, and dental care is crucial for cancer prevention. Dr. Purnima Kumar, chair of the department of periodontics and oral medicine at the University of Michigan School of Dentistry, confirmed the link between oral health and systemic diseases, stating that the oral cavity cannot be separated from other diseases in the body.
While the study highlights the potential role of oral microbiota in cancer development, it also acknowledges limitations, such as the correlation rather than causation established. Further research is needed to determine whether microbes play a role in cancer development or if other factors like genetics or immunosuppression are at play. Moving forward, the research team plans to investigate whether viruses in the mouth contribute to cancer and if the microbiome plays a role in survival outcomes.
Experts suggest that promoting a healthy oral microbiome involves regular brushing and flossing, consistent dental exams, and mindful dietary choices and lifestyle habits such as reducing alcohol use and avoiding smoking and vaping. These findings align with broader public health messages emphasizing the importance of oral health in overall systemic well-being.