We’re all aware of how certain bacteria increase our risk of cancer. For instance, studies have shown that people infected with Helicobacter pylori (H. pylori) are up to eight times more likely to get a certain kind of stomach cancer.
A new study published in the journal Nature suggests that a specific type of bacteria, called Fusobacterium nucleatum, commonly found in the mouth, might be involved in colorectal cancer. As per the researchers, this bacteria is found more often in tumours and seems to be linked to worse outcomes for patients.
The researchers at the Fred Hutchinson Cancer Center in Seattle started out to unravel how certain oral bacteria travel down to the lower gastrointestinal tract, holding out against the stomach acids and growing inside the colorectal tumours.
They looked at colorectal cancer tumours from 200 patients, half of whom had elevated levels of a Fusobacterium nucleatum subtype, called Fna C2, in their tumour tissue. The bacterium was also found in 30% of stool samples collected from people with colorectal cancer.
This suggests that Fna C2 may be especially good at colonising the gut and contributing to colorectal cancer development.
In a press release, Susan Bullman, PhD, a cancer microbiome researcher at the Fred Hutchinson Cancer Center and co-corresponding study author, said, "We’ve consistently seen that patients with colorectal tumours containing Fusobacterium nucleatum have poor survival and a poorer prognosis compared with patients without the microbe," adding, "Now, we’re finding that a specific subtype of this microbe is responsible for tumour growth. 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."
What Is Colorectal Cancer?
Colorectal cancer is cancer that starts in the colon or the rectum. According to the American Cancer Society (ACS), most colorectal cancers start as a growth, also known as polyps, on the inner lining of the colon or rectum. While most polyps are benign (non-cancerous), some types can change into cancer over time if left unchecked.
The World Health Organization (WHO) reports that colon cancer is the second-leading cause of cancer deaths worldwide.
In 2020, more than 10.9 lakh new cases of colorectal cancer and more than 9.3 lakh deaths due to colorectal cancer were estimated to have occurred worldwide, says the global health body, adding that the prevalence is likely to increase to 30.2 lakh new cases and 10.6 lakh deaths per year by 2040.
The Risk Of Oral Bacteria
Fusobacterium nucleatum has been increasingly linked to a surprising number of oral issues, ranging from gum disease and bad breath to even cancer, according to a study published in Frontiers in Cellular and Infection Microbiology.
However, it has been found that F. nucleatum isn't confined to the mouth and can contribute to problems in other parts of the body too.
Similar to the latest study, past research has also linked Fusobacterium nucleatum to cancers like colon cancer, suggesting that these bacteria can move from the mouth to the gut and contribute to tumour growth.
Taking Care Of Oral Health
.jpg)
Since gum disease is linked to these bad mouth bacteria, good oral hygiene might be an important part of cancer prevention. Here are a few habits that can help you maintain your oral health:
- Brush your teeth twice a day with a fluoride toothpaste.
- Clean between teeth regularly.
- Visit the dentist for routine check-ups and cleanings.
- Avoid smoking, as it increases your chance of gum disease.
- Limit alcohol intake.
- Eat a well-balanced diet.
- Limit sweets and sugary drinks, such as soda.
Conclusion
Colorectal cancer is one of the leading causes of cancer-related death worldwide. Several factors, including old age, a history of inflammatory bowel disease, such as Crohn’s disease or ulcerative colitis, a personal or family history of colorectal cancer or colorectal polyps, and unhealthy lifestyle habits, such as a lack of regular physical activity, a low-fibre and high-fat diet, tobacco use, and alcohol consumption, can all contribute to a person's risk of colorectal cancer.
Research also links a certain strain of bacteria (Fusobacterium nucleatum) in the mouth with colorectal cancer, suggesting that the microbe could withstand stomach acids, travel down to the lower gut, and form inside colorectal tumours. As per experts, these findings could help discover new screening methods or effective treatments for colorectal cancer.