Pancreatic cancer is not the most common of cancers, but it is one of the most deadly. The American Cancer Society found that just 8 percent of people diagnosed with the cancer will live more than five years. This is the lowest five-year survival rate of the more than 20 different common cancers surveyed. A fascinating new study inspired by traditional Chinese medicine could offer a promising way to detect the disease early, increasing the chances of survival.

The reason pancreatic cancer is so deadly is that it often progresses to an advanced stage of growth without presenting any obvious symptoms, so by the time someone is diagnosed it is too late to effectively treat. Finding a way to cheaply, and easily, detect the disease at its earliest stages has been a focus of great study. While some researchers have been looking for pancreatic cancer biomarkers in conventionally analyzed body fluids, such as urine or blood, a study from a group of Chinese scientists is suggesting bacteria on the tongue could serve as an indicator of the disease.

While the gut microbiome has been receiving a lot of attention from researchers in recent years, it certainly isn't the only part of the human body that harbors large populations of bacteria. The oral microbiome is slowly revealing itself to be just as intriguing, with studies suggesting bacteria in our mouth could play a role in everything from cancer to Alzheimer's disease.

The newly published study investigates the possible link between bacteria on the tongue and pancreatic cancer. The research was inspired by tongue inspection, one of the principle diagnostic methods used in traditional Chinese medicine, whose practitioners believe that by inspecting the tongue closely one can gain insights into the status of several organ functions.

The scientists decided to put this traditional technique to the test and, using modern DNA sequencing technology, try to find out if there was any significant difference in tongue microbiome composition between healthy subjects and those with early-stage pancreatic cancer.

The research studied the tongue microbiomes of 55 subjects, 30 with early-stage pancreatic head carcinoma, and 25 healthy controls. None of the subjects had taken any antibiotics or other drugs for three-months leading up to the study. The results were compelling, with the pancreatic cancer patients exhibiting notably different tongue microbiomes compared to the healthy subjects.

Four types of bacteria prominently appeared to be markedly different in pancreatic cancer patients. Levels of Leptotrichia, Fusobacterium, Haemophilus and Porphyromonas were all significant bacterial biomarkers distinguishing pancreatic cancer patients from healthy subjects.

It is unclear at this point what kind of causal relationship could be connecting these tongue bacterial levels and pancreatic cancer, or whether these microbiome alterations could be associated with other cancers. The researchers hypothesize that the body's inflammatory response, associated with the development of cancer, could be simultaneously causing this bacterial alteration to the tongue microbiome.

Lanjuan Li, lead author on the new study, readily admits that further work needs to be done to verify the results in larger cohorts of patients but the initial study is undoubtedly promising.

"Although further confirmatory studies are needed, our results add to the growing evidence of an association between disruptions to the microbiome and pancreatic cancer," says Li. "If an association between the discriminatory bacteria and pancreatic cancer is confirmed in larger studies, this could potentially lead to the development of new microbiome-based early diagnostic or preventive tools for the disease."

The new research was published in the Journal of Oral Microbiology.