Biomarker for Pancreatic Cancer

In the future, when the dentist says, “open wide,” he or she may be looking for more than just cavities or evidence of flossing. As it turns out, the bacteria in your mouth might be a biomarker for pancreatic cancer.

People with pancreatic cancer have higher levels of two specific types of bacteria, leptotrichia and campylobacter, in their mouths than people who are disease-free, report researchers from San Diego State University (SDSU). That difference in the oral microbiome may eventually lead to an early detection test for pancreatic cancer. A team from SDSU presented their findings this weekend at the annual meeting of the American Society for Microbiology in Boston. 

“[There] are differences in proportions of leptotrichia and campylobacter… that are significantly increased in people with pancreatic cancer when we compared it to other people that are healthy, people that have other sorts of cancers and diseases, and even people with pancreatic diseases,” said study co-author Pedro Torres, a microbiology graduate research student at SDSU, at a discussion of the findings.

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By looking at the genes of oral bacteria in simple saliva samples, researchers found a slight difference between study participants who had pancreatic cancer and those who did not.

Eventually, researchers foresee a simple detection test administered at the dentist's office that compares ratios of specific bacterial biomarkers for pancreatic cancer—leptotrichia and campylobacter—to the overall oral microbiome. A high ratio of the pancreatic cancer biomarkers could indicate that the patient needs to see a doctor for more screening tests.

“The mouth, looking at all the things like diabetes, obesity, and cancers and chemotherapy… the mouth is almost a signal of greater health in the body,” said study co-author Scott Kelley, Ph.D., a professor of biology at SDSU, at the meeting this weekend.

“We think that other issues can be reflected in the chemistry and the microbiology in the mouth,” he added.

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Kelley, Torres, and their team compared the bacteria in saliva samples from 131 patients with an average age of nearly 63. Of those, 14 had been diagnosed with pancreatic cancer and 10 were disease-free. 

After analyzing the bacterial microbes, results showed that participants with pancreatic cancer had higher levels of leptotrichia and campylobacter,and lower levels of streptococcus, treponema,and veillonella.

The exact reason for the correlation between the ratio of oral microbes and pancreatic cancer is unknown. There may, however, be a connection between amylase production in the pancreas and bacteria in the mouth. Amylase is an enzyme that helps the body convert starches into sugars.

“One of the things the pancreas does is [produce] amylase. It’s serum amylase… if you did have… a deregulation of amylase in the mouth it would change the carbohydrates and sugar in the mouth, and that certainly would have a big impact on the microbiome,” Kelley said.

While this research is in its very early stages and there are still many details to nail down, scientists hope they’ll someday be able to catch pancreatic cancer early. Currently, only 23 percent of pancreatic cancer patients live for one year after diagnosis. Symptoms often don’t appear until the cancer is at an advanced stage, so an early detection test could make all the difference.

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