• Posted March 21, 2024

A Bacteria in the Mouth Might Speed Colon Cancers

A germ commonly found in the human mouth can travel to colon tumors and appears to speed their growth, new research shows.

The finding might lead to new insights into fighting colon cancer, which kills more than 52,000 Americans each year, according to the American Cancer Society.

Researchers at the Fred Hutchinson Cancer Center in Seattle looked at levels of a particular oral bacterium, Fusobacterium nucleatum, in colon tumor tissues taken from 200 colon cancer patients.

The microbe has several subtypes, but only one, dubbed Fna C2, appeared to be linked to tumor tumor and not healthy tissue, they reported March 20 in Nature. The Fna C2 subtype also appeared more often in stool samples collected from colon cancer patients compared to healthy folks. 

"We've consistently seen that patients with colorectal tumors containing Fusobacterium nucleatum have poor survival and poorer prognosis compared with patients without the microbe,"co-corresponding study author Susan Bullman said in a cancer center news release. 

"Now we're finding that a specific subtype of this microbe is responsible for tumor growth," added Bullman, who is a cancer microbiome researcher at the center. "It suggests therapeutics and screening that target this subgroup within the microbiota would help people who are at a higher risk for more aggressive colorectal cancer."

During their research, the researchers first discovered that F. nucleatum bacteria that colonize the mouth have distinct subtypes. But only the Fna C2 subtype has the ability to travel from the mouth to the stomach and then propagate in the lower gastrontestinal tract, including the colon. 

In the end, 50% of the colon tumors tested showed the presence of the Fna C2 subtype of F. nucleatum, the team said.

Microbe-based "cellular therapies" might be a new frontier in attacking colon cancers, according to Bullman's group. These treatments used tweaked forms of bacteria to deliver medicines directly to the tumor, they explained.

"We have pinpointed the exact bacterial lineage that is associated with colorectal cancer, and that knowledge is critical for developing effective preventive and treatment methods,"co-corresponding author Christopher Johnston said in the news release. He is a molecular microbiologist at Fred Hutch. 

More information

Find out more about colon cancer at the American Cancer Society.

SOURCE: Fred Hutchinson Cancer Center, news release, March 20, 2024