UK (Parliament Politics Magazine) – A study finds E. coli’s colibactin toxin may raise bowel cancer cases in 25‑49-year-olds, highlighting a potential early-life trigger for the disease.
As reported by The Independent, researchers suggest a possible link between an E. coli toxin and increasing bowel cancer in young people.
Colibactin link to early-onset bowel cancer
A toxin called colibactin, from a type of E. coli, can change DNA and may raise bowel cancer risk in young people. Scientists call this finding a help in understanding and fighting bowel cancer in younger adults.
UK scientists, with support from Cancer Research UK, found that early exposure to colibactin leaves a genetic imprint in bowel cells, which may raise cancer risk before 50.
A December study warned that bowel cancer is rising sharply among young people in England, compared to other countries. From 2007 to 2017, bowel cancer in 25-49-year-olds in England grew by 3.6% each year.
Cancer Research UK reports a 52% rise in bowel cancer for adults aged 25-49 since the early 1990s.
Experts said rising bowel cancer in young people is linked to poor diet, processed foods, obesity, and inactivity.
New study about colibactin and young-onset bowel cancer
A recent study led by the University of California San Diego, points to another potential factor in bowel cancer. Researchers examined 981 bowel cancer genomes from 11 countries, covering both early- and late-onset cases.
The study found colibactin-related DNA mutations are 3.3 times more frequent in early-onset bowel cancer than in cases diagnosed after 70. Researchers revealed these mutation patterns to be most common in countries with rising early-onset bowel cancer rates.
The research found that around 15% of APC driver mutations in bowel cancer are linked to colibactin, key early changes driving tumor development.
What did UCSD’s research authors say about colibactin’s role in early-onset cancer?
Ludmil Alexandrov, an author of the study and a professor at UCSD, stated,
“These mutation patterns are a kind of historical record in the genome, and they point to early-life exposure to colibactin as a driving force behind early-onset disease.”
He added,
“If someone acquires one of these driver mutations by the time they’re 10 years old, they could be decades ahead of schedule for developing colorectal cancer, getting it at age 40 instead of 60.”
Marcos Diaz-Gay, the first author and a former postdoctoral researcher, said,
“When we started this project, we weren’t planning to focus on early-onset colorectal cancer.”
He said,
“Our original goal was to examine global patterns of colorectal cancer to understand why some countries have much higher rates than others.”
Mr Diaz-Gay added,
“But as we dug into the data, one of the most interesting and striking findings was how frequently colibactin-related mutations appeared in the early-onset cases.”
What did Dr David Scott reveal about colibactin and early-onset cancer risks?
The director of Cancer Grand Challenges, Dr David Scott, stated,
“Globally and in the UK, we’re witnessing an alarming increase in some types of cancer in people under the age of 50.”
He said,
“It is unlikely that there will be one clear driver but Cancer Grand Challenges scientists are racing to solve this puzzle, and our Mutographs team has uncovered a surprising clue.”
Mr Scott stated,
“Many early-onset colorectal cancer patients appear to have been exposed to a toxin, called colibactin, produced by some strains of the bacteria E. coli in early life. It’s unclear how the exposure originates, but we suspect that a combination of factors – including diet – may intersect during a crucial phase in the development of the gut microbiome.”
He said,
“This study adds an important piece to the puzzle of early-onset cancers, but it isn’t conclusive, and more research will be needed to establish a definitive link between colibactin and an increased risk of early-onset colorectal cancer,”
adding,
“Other Cancer Grand Challenges teams, like Optimisticc and Prospect, are looking deeper into the microbiome and other environmental factors to uncover what’s behind the global rise.”
Symptoms of bowel cancer
According to the NHS, symptoms of bowel cancer include:
- Softer stools, diarrhea, or constipation
- More or less frequent toilet visits
- Blood in stool, red or black
- Rectal bleeding
- Constant urge to go
- Stomach pain
- Lumps in the tummy
- Bloating
- Unexplained weight loss
- Ongoing tiredness
Key details about bowel cancer patients in the UK
Britain has about 44,100 new bowel cancer cases every year. Around 390,000 people were living with bowel cancer in 2025. This shows that cancer cases are increasing over time
Cancer Research UK projects 609,000 new cases in England by 2040, posing a major healthcare challenge.