This bacterial subtype was found in 50% of colon cancers

In the new study, researchers examined colorectal tumors from more than 200 patients and Fusobacterium nucleatum.

“This bacteria is considered to be a normal part of the mouth.” microbiome” said the study authors. Susan Bulman, Ph.D., assistant professor at Fred Hutchinson Cancer Center in Seattle. But “we don't usually see that in the lower part of the intestine.”

of microbiome A collection of bacteria, viruses, and other microorganisms that live in and on our bodies and contribute to health and disease.

Ten years ago, Fusobacterium nucleatum attracted attention when scientists discovered it linked Have colorectal cancer.

When colon cancer develops, Fusobacterium nucleatum It dominates the microbiome within a given patient's tumor, Bulman told Healthline. That's what she and her colleagues found in their research.

About half of the tissue samples they examined had higher abundances of this particular subtype of bacteria compared to healthy tissue.

This subtype was also detected more frequently in stool samples from some colorectal cancer patients compared to stool samples from healthy people.

One goal of the new research was to understand what types of viruses are present. Fusobacterium A relationship with colorectal cancer has been pointed out.

“Are there any particular high-risk groups?” Fusobacterium Does it actually reach the colorectal tumor and cause cancer progression? ” Bulman asked.

This finding confirms that it is primarily a specific subtype of this bacterium that travels from the mouth to colorectal tumors.

Additionally, researchers found that the following main groups exist: Fusobacterium nucleatum There is no single subspecies involved in colorectal cancer, but actually two distinct subtypes known as “clades.”

Both clades colonize the mouth, but only one of the Crucian carp C2 was detected in significantly higher abundance in colorectal tumors, appearing in approximately 50% of tissue samples.

“[Fna C2] is a high-risk subtype that actually reaches the lower gastrointestinal tract and promotes tumor growth,” Bulman said.

This subtype was also found in about 30% of stool samples from colorectal cancer patients and about 5% of stool samples from healthy people.

Mr. Weinberg stated the following facts: Crucian carp C2 was not detected in tissue or stool samples from all colorectal cancer patients, suggesting that this bacterium may not be involved in cancer progression.

However, this does not mean that other bacteria are not involved.

Weinberg's research focuses on the microbiome within colorectal tumors, with an interest in understanding why colorectal tumors develop. rise over the past few decades Colorectal cancer in people under 50 years of age.

In a study published last year in a magazine, Journal of Clinical OncologyHe and his colleagues identified differences in the types of bacteria found in the tumors of people diagnosed with colorectal cancer before age 45 and those diagnosed after age 65.

So, yeah Crucian carp Does C2 lead to the development of colorectal cancer, or does it just invade the tumor once it starts growing?

The authors of the new study sought to answer this question using experiments conducted on mice.

However, this result is[reveal] Limited chance, if any, of promoting cancer Fusobacterium “susceptible mouse model species,'' the authors of a companion paper wrote. Editor in Naturehowever, they suggest that this may be due to the limitations of this type of experiment.

Overall, “it's hard to say how much.” [Fna C2] It is itself involved in the carcinogenic process,” Weinberg said.

he suggests that Crucian carp C2 may act as “more of a companion, helping tumors develop and the bacteria help them grow and spread.”

A 2017 study confirms this. science Bulman and her colleagues discovered that Fusobacterium nucleatum It was present in a colorectal tumor that had spread to other parts of the body.

“clearly, [this bacterium] At least we're getting there,” Weinberg said.

A while ago the study suggested Fusobacterium nucleatum It enters the bloodstream when people brush their teeth or undergo dental treatment, and can then reach colorectal tumors.

It is thought that other bacteria can also travel to other tissues in the body by this route and cause a variety of health conditions, including: hebert disease.

However, Bulman and her colleagues found evidence that: Crucian carp Because C2 can travel through the intestines, it must survive the highly acidic environment of the stomach.

Genetic analysis reveals 195 genetic differences between the two Fusobacterium nucleatum clade. This analysis also revealed: Crucian carp C2 had unique genetic traits that allowed it to withstand stomach acid and grow in the lower intestinal tract.

“[The authors] show it Crucian carp “C2 has several characteristics that may allow it to survive in more acidic environments,” Weinberg said. [other subtype] Maybe not. “

Further research is required to fully understand the role of this subtype. Fusobacterium nucleatum In colorectal cancer.

“Our analysis shows that: [Fna C2] It goes into the mouth of a supposedly healthy person,” Bulman said. “However, we do not yet have information about whether these people are at increased risk for colorectal cancer.”

Larger, longer-term studies will be needed to determine this. This could include analyzing the presence of people's oral microbiomes. Crucian carp Create C2 and then follow it for over 10 years to see how many people develop colorectal cancer.

Bulman said the development of colorectal cancer is likely not solely due to the presence of this bacterial subtype.

Therefore, other factors should also be considered in longitudinal studies. factor Diet, tobacco, and alcohol use are known to increase the risk of colorectal cancer.

More immediately, look for the presence of Crucian carp C2 in stool samples may provide a non-invasive screening method for colorectal cancer.

“This particular subtype was elevated in the stool of patients with colorectal cancer compared to patients without colorectal cancer,” Bulman said. “So from a review standpoint, it might be worth it.”

Further research will be needed to show whether Crucian carp C2 is also present in stool samples from people with early stages of colorectal cancer, such as precancerous lesions or adenomas.

Another screening option is to use a blood test to look for: Crucian carp C2 or other bacteria associated with colorectal cancer.

“[My colleagues and I] There are several studies trying to look at the circulating microbiome,” Weinberg said. “Basically, can we detect bacterial DNA in the bloodstream?”

If a blood test shows that a particular person has a microbiome that puts them at higher risk of developing colorectal cancer, people in that group can be tested earlier. colonoscopyHe said.

Which specific subtype to know Fusobacterium nucleatum Its involvement in colorectal cancer may also allow scientists to develop new treatments.

In a previous study published in 2017, science, Bulman et al. transplanted colon tumors taken from human patients into mice.Mice treated with targeted antibiotics Fusobacterium nucleatum showed a reduction in tumor growth.

“Therefore, there is evidence that targeting this microorganism can inhibit tumor growth,” Bulman said. “It was just antibiotics.”

However, the goal is to remove only this specific subtype.

“We don't want to eliminate everything. Fusobacterium nucleatum Unless they're actively contributing to the disease,” Bulman said. “The key here is to maintain a somewhat normal structure of the microbiome.”

This could be done using targeted inhibitors that could be combined with standard chemotherapy or immunotherapy to see if they could increase the effectiveness of routine therapeutic approaches. ” Bulman said.

Another possible therapeutic approach is to take advantage of the bacteria's own abilities.

“because [this subtype] “Once we get to the tumor, we're thinking about how we can manipulate it to deliver a drug that kills the tumor,” Bulman said.

This 'bug-as-medicine' approach, so-called 'bug-as-medicine', uses attenuated versions of bacteria that cannot cause disease but can invade colorectal tumors.

Researchers have identified specific subtypes of bacteria Fusobacterium nucleatum It is associated with colorectal cancer. This subtype was found in 50% of tumor samples and 30% of stool samples taken from colorectal cancer patients.

Genetic analysis showed that this subtype has specific traits that allow it to reach the lower intestine from the mouth and multiply there. This includes tolerating the acidic environment of the stomach.

These findings could lead to new ways to screen for colorectal cancer early and treatments for this cancer, the second leading cause of cancer death among adults in the United States.