Oral Bacteria’s Link to Colon Cancer
Two independent studies from Harvard School of Medicine and Case Western Reserve University, published in the August 2013 journal Cell Host & Microbe, have found links between bacteria called Fusobacterium nucleatum and colorectal cancers. According to the Colon Cancer Alliance, "Colon cancer is the third most commonly diagnosed cancer and the second leading cause of cancer death in men and women combined in the US. The American Cancer Society estimates that 142,820 people will be diagnosed in 2013 and that 50,830 will die from colon cancer in the United States."
Fusobacterium nucleatum is an anaerobic Gram negative bacterium found in dental plaque that plays a role in periodontal disease. Bacteria within the mouth can migrate throughout the body to trigger other medical conditions. While Fusobacteria have previously been linked to preterm births, there is now evidence that the same bacteria may trigger colorectal cancer by influencing an immune response and switching on cancer genes.
Researchers from Harvard found Fusobacterium imbedded within benign colon tumors that can potentially turn malignant, suggesting that they may contribute to the early stages of tumor formation. "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," said senior study author Dr. Wendy Garrett of the Harvard School of Public Health and the Dana-Farber Cancer Institute.
The second study, led by Dr. Yiping Han, a professor of periodontics at Case Western, found Fusobacteria produce an adhesion molecule called "FadA" that allows the microbe to attach to blood vessels. FadA levels were found to be between 10 and 100 times higher in patients with colorectal adenomas and adenocarcinomas. A synthetic peptide was developed that could block FadA and prevent Fusobacteria from invading cells growing in a Petri dish. The team is filing for a patent and believes this work will lead to possible treatments for colon cancer as well as oral disease. According to Han, "FadA can be used as a diagnostic marker for early detection of colon cancer. It can also be used to determine if treatment works effectively at reducing Fn load in the colon and the mouth."