Oral Pathogen Blocks Immune System from Attacking Colorectal Cancer

Researchers in Israel have uncovered a new role that periodontal pathogen Fusobacterium nucleatum plays in colorectal cancer, according to research published in the journal Immunity.

They found that F. nucleatum is able to protect colorectal cancer cells from being destroyed by the body’s immune response:

“Our results identify a bacterium-dependent, tumor-immune evasion mechanism in which tumors exploit the Fap2 protein of F. nucleatum to inhibit immune cell activity via TIGIT.”

Previous research has revealed that F. nucleatum plays a role in the development of colorectal cancer, a condition that kills approximately 50,000 people each year.

This is not the first time that an oral bacterium has been shown to disrupt immune function. Another common oral pathogen, P. gingivalis, is capable of disarming the immune system and even converting white blood cells from destroyers to carriers.

According to the study authors, this means that targeting F. nucleatum in tumors might be an effective treatment for colorectal cancer.

Advances in screening technology have improved survival rates for colorectal cancer drastically over the years, but nevertheless, it is estimated that this year, more than 130,000 individuals will be diagnosed with colon or rectal cancer in the United States alone.

If periodontal pathogens play a role in the development of cancerous cells and, as this most recent study suggests, the protection of these cells from the body’s immune system, it follows that oral management of F. nucleatum and its equally virulent counterparts might help reduce risk for colorectal cancer.

Source: Binding of the Fap2 protein of Fusobacterium nucleatum to human inhibitory receptor TIGIT protects tumors from immune cell attack.