Could Mouth Bacteria be a Cause of Colorectal Cancer

The U.S. Centers for Disease Control and Prevention shows that of all the cancers affecting both men and women, colorectal cancer is the second leading cause of cancer-related deaths in the United States and the third most common cancer in men and women.

In fact, according to the American Cancer Society, it's estimated that 142,820 people will be diagnosed this year alone with colon cancer and 50,830 will die from it in the United States.  

Many of the causes for this disease are unknown, but some believe certain environmental factors may play a part. However, recent studies suggest that gut microbes known as fusobacteria that can be found in the mouth are also prevalent in tissues of colorectal cancer patients and may play a part in the disease.

"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," senior study author Wendy Garrett, from the Harvard School of Public Health and the Dana-Farber Cancer Institute, via a press release.

Researchers found that fusobacteria can be particularly abundant in human adenomas, otherwise known as benign tumors that carry the possibility of becoming malignant over time.

Another study showed that the same bacteria relies heavily on a molecule commonly found on the surface of bacterial cells that attach and invade human colorectal cancer cells, called Fusobacteria adhesion A (FadA). These can trigger cancerous groups in genes and stimulate inflammatory cells. According to the study, these cells were seen and found at significantly higher levels in patients with adenomas and colorectal cancer compared to healthy individuals.

"We have proven there is an infectious component to colorectal cancer," said Prof Yiping Han who carried out the second study, via the BBC.  "We have shown that FadA is a marker that can be used for the early diagnosis of colorectal cancer and identified potential therapeutic targets to treat or prevent this common and debilitating disease."

More information regarding the study can be found in the journal Cell Host and Microbe.