Certain changes in a person's mouth microbiome has been linked to an increased risk of developing pancreatic cancer, a new study in New York revealed.
Two specific types of bacteria with impossibly tongue-twisting names – Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis – have long been tied to diseases such as periodontitis, or the inflammation of gums.
Now, scientists from New York University's Langone Medical Center found an association between the two bacteria and the risk for pancreatic cancer.
Specifically, researchers discovered that carrying both bacteria was tied to 50 percent higher chances of contracting the illness, said report lead author Jiyoung Ahn.
Methodology
The research team performed a nested case-control study based on samples and data from two different cohorts where healthy people were enrolled and tracked over a long period for different outcomes such as cancer development.
Researchers examined oral wash samples collected from 361 people who developed pancreatic cancer later in life, as well as from 371 corresponding controls. They used genomic tools to create bacterial species profile within each sample.
Afterwards, they conducted logistic regression analysis to investigate the association between individual bacteria species and pancreatic cancer risk, controlling for factors including smoking status, age, and body mass index (BMI).
The presence of P. gingivalis in collected oral wash samples was linked to a 59 percent higher risk for pancreatic cancer, while the presence of A. actinomycetemcomitans was tied to a 119 percent higher risk.
One limitation is that the participants included in the studies were not very diverse as it was predominantly non-Hispanic white, so the findings could not be applicable to the whole population.
What's The Next Step?
Dr. Andrew Coveler of Seattle said this small-scale study warrants further investigation.
"It remains unclear if the bacteria are the cause or a symptom or if it is really related at all," said Coveler, adding that if the bacteria is the cause, it is unknown if it is possible to change the bacteria at this time.
While it is true that the findings do not indicate a clear cause-and-effect relationship between the two factors, Ahn believes it is a strong first step in understanding a possible new risk factor for the disease.
About 1.5 percent of Americans will be detected with pancreatic cancer, and only 5 percent will survive for five years or more. Ahn said if experts could find out the role of mouth bacteria, there could be new ways to screen for and potentially prevent the illness.
Ahn admitted that scientists have yet to figure out the answer for this question: if the two bacteria are responsible for the increased likelihood of pancreatic cancer, how do they do it? She said they do not know yet how mouth bacteria affect a person's pancreas.
Geneticist Chris Mason of Weill Cornell Medicine, who was not involved in Ahn's study, agreed that the next move is to determine the mechanism for how mouth bacteria could damage the pancreas.
Mason believes the finding has vital implications for comprehending the genesis of cancer, as well as the interaction between human cells and other organisms in or around us.
Ahn and her colleagues' findings were featured on April 20 at the annual meeting of the American Association for Cancer Research.
The study, which was funded by the National Cancer Institute, is generally viewed as preliminary until it is published in a peer-reviewed journal.
Photo : Maria Morri | Flickr
