Gum Disease Could Be Linked to Colorectal Cancer

Scientists have identified a specific gum disease-related bacteria in the mouth that may boost colorectal cancer tumor growth.

With rates of colorectal cancer increasing, especially among young people, the need to understand risk factors for the disease and identify new and effective prevention and treatment strategies is critical.

While commonly known risk factors for colon cancer include obesity, type 2 diabetes, an unhealthy diet, and smoking, a recent NIH-funded study may have found an unlikely risk factor for the disease that originates in the mouth's microbiome.

The study, published in Nature, revealed that a specific type of bacteria found in people with gum disease is also found in certain colorectal cancer tumors. The bacteria Fusobacterium nucleatum (F. nucleatum) is rarely seen in people with healthy gastrointestinal tracts.

However, it's unclear how this particular periodontal disease-related bacteria could impact the development of colon cancer.

To investigate further, the researchers analyzed the genes of 80 F. nucleatum strains from the mouths of cancer-free individuals and 55 strains from tumors of people with colorectal cancer.

They discovered that a specific strain of F. nucleatum, called Fna, was found more often in colorectal cancer tumors. After looking more closely, the scientists identified two types of Fna. However, only one type, Fna C2, was linked to colon cancer.

In further experiments on mice, the team found that infecting the rodents with Fna C2 caused them to develop more cancer tumors. In addition, a microbiome analysis of cancer tissue from 116 individuals with colorectal cancer showed higher numbers of Fna C2.

Moreover, Fna C2 could survive longer in highly acidic conditions that mimic the gut environment. The scientists say this could explain how Fna C2 makes its way from the mouth to the colon unscathed.

Though more research is needed, the study's authors suggest that the findings could lead to treatments targeting this gum disease-related bacteria or the development of screening tests that identify if a person harbors Fna C2.