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29 Jun 2016

Bad breath may not only be unpleasant for those around you, it could be seriously bad for your health, according to research into the link between oral bacteria and pancreatic cancer.

While an association between poor oral hygiene and pancreatic cancer has been previously established, researchers at New York University have for the first time found that an imbalance of bacteria in the mouth precedes the development of the cancer, opening up potential methods for early detection and the tantalising possibility of a causal link.

The study, which involved sequencing DNA extracted from the saliva of 361 pancreatic cancer patients and 371 healthy participants, found that those with porphyromonas gingivalis in their mouth were at 59 per cent greater risk of developing pancreatic cancer than those who did not, while those with aggregatibacter actinomycetemcomitans were at 50 per cent greater risk (though the association was not considered to be as statistically strong).

Significantly, the increased risk remained the same even after excluding pancreatic cancer cases that occurred less than two years after the samples were taken. Lead researcher Jiyoung Ahn says this means it is unlikely that the imbalance in oral bacteria has occurred as a result of the pancreatic cancer, and instead predates it.

The discovery provides for several promising new avenues for investigation.

It raises the potential for developing a screening test for pancreatic cancer using the two oral bacteria as markers – an important advance for a disease that often goes undetected until it reaches an advanced stage, contributing to its high mortality rate.

Researchers are also intrigued by the possibility that the two bacteria may somehow cause the cancer to develop, though Ahn cautions that it is premature to reach such a conclusion.

Ahn says it is possible that the imbalance of the two bacteria in the mouth is the correlate of systemic inflammation or other processes occurring within the body.

“Inflammation is related to cancer,” she says. “The bacteria could be causing inflammation in the pancreas – that’s one theory. But maybe the bacteria in the mouth is just a marker for the susceptibility of the body to inflammation.”

Ahn and her colleagues are planning further research, including injecting the two bacteria into the pancreas of mice genetically engineered to be susceptible to pancreatic cancer to see what effect this might have, as well as examining possible links between viruses in the mouth and pancreatic cancer.

In the meantime, the scientist says, it is too soon to advise people that flossing and brushing their teeth will help stave off pancreatic cancer.

Adrian Rollins

Published: 29 Jun 2016