The damage was rare in the past and becomes increasingly common as we move towards the present day.
Colorectal cancer diagnoses in people under 55 have nearly doubled in the last decade, with younger patients developing more aggressive tumors. St. Mark's Hospital's 70-year collection of preserved tumor samples will be genome-sequenced to identify disease signatures and track changes over time.
- Colorectal cancer diagnoses in people under 55 have nearly doubled in the last decade
- St. Mark's Hospital has preserved tumor samples in paraffin wax since the 1950s
- Colibactin, a toxin produced by certain E. coli strains, is a leading suspect in the disease's rise
- Colorectal cancer is now the third-most common cancer in the United States
UK researchers analyzing tumor samples stored since the 1950s hope to identify why colorectal cancer rates are surging in young adults, with bacterial toxins emerging as a leading suspect.
Buried in the basement of a London hospital sits a collection of tumor samples that may finally answer one of modern medicine's most troubling questions: why are young people getting colorectal cancer at unprecedented rates?
Colorectal cancer has long been a disease of aging. But over the past decade, something has shifted. Cases in adults under 55 have nearly doubled. These younger patients are not simply developing the same disease their grandparents did—they're getting sicker, faster. Their tumors are more aggressive. They're diagnosed later, when the cancer has already spread. Colorectal cancer now ranks as the third-most common cancer in the United States, and the surge in young people has left researchers scrambling to understand what changed.
The answer may lie in tissue preserved in paraffin wax since the 1950s. St. Mark's National Bowel Hospital in the United Kingdom has maintained a tumor archive spanning more than seven decades. Researchers at the Institute of Cancer Research plan to extract DNA from these historical samples and compare them with tumors from patients today, using genome sequencing to map how the disease has evolved. Different causes of cancer leave different fingerprints in a cell's genetic code. By tracking these signatures across time, scientists hope to identify what is driving the current epidemic.
One leading theory has emerged from recent research: a bacterial toxin called colibactin, produced by certain strains of E. coli that colonize the colon and rectum. If this bacterium is responsible for the rise, the genetic evidence should show up clearly in modern tumors but rarely in samples from decades past. "If these so-called bad bugs are causing the increase, we should see the signature of these bad bugs," said Trevor Graham, a professor at the Institute of Cancer Research, speaking to the BBC. "The damage was rare in the past and becomes increasingly common as we move towards the present day."
Other suspects remain under investigation. Childhood infections, dietary shifts, and rising obesity rates have all been implicated in studies. But the tumor archive offers something those epidemiological surveys cannot: direct biological evidence, preserved in time, waiting to be read.
If the analysis succeeds and researchers pinpoint a cause, the implications could be transformative. A confirmed culprit would open pathways to prevention strategies tailored to young adults and to new treatments designed to target the specific mechanism driving their disease. For now, that remains a conditional hope.
In the meantime, doctors are urging vigilance. Persistent changes in bowel habits—diarrhea, constipation, or shifts in stool consistency—warrant a conversation with a physician. Rectal bleeding and unexplained weight loss are red flags. So is pain, cramping, or bloating that lingers without obvious cause. "If something feels off, trust your gut—literally—and talk to your doctor," said Dr. Cedrek McFadden, a colorectal surgeon and medical adviser to the Colorectal Cancer Alliance. The message is simple but urgent: in a disease where early detection saves lives, waiting to see if symptoms resolve on their own is a risk young people can no longer afford to take.
Citações Notáveis
If these so-called bad bugs are causing the increase, we should see the signature of these bad bugs. The damage was rare in the past and becomes increasingly common as we move towards the present day.— Trevor Graham, professor at the Institute of Cancer Research
If something feels off, trust your gut—literally—and talk to your doctor.— Dr. Cedrek McFadden, colorectal surgeon and medical adviser to the Colorectal Cancer Alliance
A Conversa do Hearth Outra perspectiva sobre a história
Why does it matter that these samples are from the 1950s specifically? Why not just study tumors from five years ago?
Because you need a baseline. If colibactin or some other factor is driving the rise, you need to see what the disease looked like before that factor became common. The 1950s samples are your control group—your proof that something genuinely changed.
But couldn't the samples have degraded over seventy years? How reliable is DNA extracted from tissue that old?
That's a real concern, but paraffin wax is actually a good preservative. The bigger risk is contamination or incomplete preservation in some samples. That's why they're sending them to a specialized institute with genome sequencing tools—they can work around degradation and extract what's usable.
Let's say they find colibactin signatures in modern tumors but not old ones. What happens next?
You've got your smoking gun. Then you move to prevention—maybe probiotics that suppress those E. coli strains, or dietary changes that make the colon less hospitable to them. You might develop screening protocols for people at risk. You're no longer guessing.
Why are young people getting hit harder than older people if this is a bacterial issue that's been around for decades?
That's the puzzle. Maybe the strains have evolved. Maybe our microbiomes have changed due to antibiotics, processed food, or something else. Or maybe older people were exposed to the same bacteria but their immune systems handled it differently. The samples might show that too.
What should someone actually do if they're worried?
Don't ignore your body. A change in your bowel habits that lasts more than a few weeks is worth mentioning to a doctor. Bleeding, weight loss you can't explain, persistent cramping—those are not things to wait out. Early detection is the difference between a treatable disease and a serious one.