Mouth Bacteria May Trigger Certain Types of Cancer

Not one, but two recent studies suggest that a certain type of bacteria found in the mouth may trigger colorectal cancer, the second leading cause of death from cancer among Americans.

Both studies published last week suggest that if a certain type of gut bacteria is found in the mouth it can influence the immune response and switch on cancer genes and thus trigger colorectal cancer, more commonly known as colon cancer.  These studies were published in the August online issue of the Journal Cell, Host & Microbe.

The human body contains trillions of bacteria in its gut, bacteria that maintains our health by training the immune system and also by assisting in the digestion of food.  However, these bacteria can also trigger disease.

Researchers found that an imbalance between the “good” and the “bad” gut bacteria in our bodies can promote colon cancer.  They found that a genus of bacteria called Fusobacteria, a bacteria found in the mouth, is abundant in tissues from colorectal cancer patients. 

In the first study, Fusobacteria was found in benign tumors that can become cancerous over time.  Researcher believe this suggests that this bacteria can contribute to the early stages of tumor formation.

In the second study, researchers found that Fusobacteria use a molecule that lives on the surface of the bacterial cell to stick to and then invade human colorectal cancer cells.  This molecule – FadA – “switches on genes that trigger inflammation in human cancer cells, spur cancer growth, and spurs tumor formation.”

The study revealed that tissue from healthy individuals have much lower levels of FadA than that tissue from patients with benign or cancerous colorectal tumors. 

One may wonder how this research may help in the prevention of colorectal cancer?  Researchers believe these findings will lead to more timely and improved ways of diagnosing, preventing and treating colon cancer.

Wendy Garrett of the Harvard School of Public Health and a senior author of one study said, “Fusobacteria may provide not only a new way to group or describe colon cancers but also, more importantly, a new perspective on how to target pathways to halt tumor growth and spread.”