Healthcare professionals have been uncertain as to why colon cancer cases have doubled in people under 55 within the past two decades. Now, a new study is giving some answers, and the answer has to do with damage caused by gut bacteria.
Colon cancer cases have doubled in people under 55 within the past two decades. Doctors and healthcare workers have been concerned and perplexed by this rise in these rates among younger people, and now, a new study may be revealing why this particular increase is occurring.
In a new study published in Nature this week from the University of California, San Diego, researchers have identified a strong link between colibactin, a toxin made by certain strains of E. Coli, and colon cancer, especially among younger patients.
The team of researchers involved analyzed tissue samples from about 1,000 colorectal cancer patients throughout four continents, according to reports from NPR. They found that a majority of the cancers studied had mutations that showed a past encounter with colibactin.
“You can think of it as the weapon system of a bacteria to fight other bacteria and to defend themselves,” said Ludmil Alexandrov, lead author of the study.
More specifically, individuals under the age of 40 with early-onset colon cancer were three to five times more likely to have the mutations than people in their 70s or older. The researchers believe that this “bacterial weaponry” referred to as “genotoxin” can become directed to patients’ gut cells and start mutating which puts one at a higher risk of developing colorectal cancer.
Alexandrov explained that the exposure to this isn’t ongoing when the cancer is officially diagnosed, but actually occurs during childhood.
“Our estimate is that it happens within the first 10 years of life, so if you get that mutation at age 5, that puts you 20 to 30 years ahead of schedule for getting colorectal cancer.”
The study emphasized that this is a strong connection, but the current data doesn’t prove that colibactin is the direct cause of patients developing cancer at a younger age, nor do the researchers expect any singular microbe to be the main factor of this rise in colorectal cancer. However, it is a clarifying step to better understand this phenomenon.
Christian Jobin, a microbiome researcher at the University of Florida told NPR “that would be too simple,” referring to colibactin being the main reason for the spike in colorectal cancer.
He said it’s more likely that colibactin is just “one hit” among many others within our microbiome that contribute to a more rapid development of the cancer.
Scientists believe that there are also environmental and lifestyle factors that contribute as well, such as diet, lack of exercise, medication, and more. “It’s been really perplexing. “The microbes that may contribute to cancer risk are tricky to understand,” said Dr. Neelendu Dey, a gastroenterologist.
The family of microbes which E. coli is a part of is the most prevalent kind of bacteria in your gut when you’re in the earlier stages of life. 20% to 30% of people have strains of E. coli that can synthesize the toxin, “but that doesn’t mean it’s necessarily having deleterious effects,” Jobin said.
He explained that something is provoking the bacteria to behave the way it does and give it the advantage to grow in more abundance.
“What triggers this weapon or the deployment? We don’t know but we have to consider the environment.”
“We know that some of these E. coli that produce colibactin are influenced by diet, inflammation, and medication.”
Jobin hailed the new research because it not only provides a bit of clarity, but opens the door for even more questioning to lead to something potentially concrete. It also connects to earlier preclinical research in animals.
Studies conducted on animals show colibactin exposure can increase cancer development. Deleting the genetic region responsible for producing the toxin in E. coli can incapacitate the bacteria from promoting cancer in animals, NPR reports.
Alexandrov said that the research and evidence combined with early childhood exposure now gives scientists more hypotheses about what could be causing this increase in colorectal cases in young people.
As of right now, he stated that their top suspects are the mode of birth, breastfeeding, the use of antibiotics, and nutrition as well.
“All of these factors are known to substantially affect the microbiome and there is some evidence they may impact this [colibactin producing] bacteria, but we really need to investigate each one carefully.”
Dey stated that all of these possibilities are plausible and should be further looked into. He stated that he’s hoping researchers can find microbes that will serve as “biomarkers” for identifying individuals at risk of developing pre-cancers. Even further, ideally in the future drugs can be developed that will directly target toxins to counter their effects.
“Of course, it sounds simple, but we have to acknowledge the ecological lessons learned in other contexts,” he says.
“When you try to take out, or introduce a species, it can have effects that you didn’t anticipate, so this all needs to be done very thoughtfully.”
Eric Mastrota is a Contributing Editor at The National Digest based in New York. A graduate of SUNY New Paltz, he reports on world news, culture, and lifestyle. You can reach him at eric.mastrota@thenationaldigest.com.
