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Historic tissue archive may hold clues to rising bowel cancer in young adults
Researchers are examining bowel cancer specimens preserved for nearly 100 years in an effort to uncover why rates among people under 50 have climbed sharply worldwide.
Global trend puzzles scientists
While most bowel cancer cases still occur in older adults, diagnoses among younger patients have surged in recent decades. In the UK, the disease has risen by 75% in those under 24 since the early 1990s, and by 51% in the 25-49 age group. The cause remains unknown.
Possible factors include obesity, ultra-processed foods, antibiotic use, changes in gut bacteria, air pollution, and microplastics. However, no single explanation has been confirmed.
Unique collection offers rare insight
St Mark's Hospital in London houses tens of thousands of archived bowel cancer samples, some dating back a century. These specimens, preserved in paraffin wax, are being analyzed using advanced molecular techniques at the Institute of Cancer Research (ICR).
Dr. Kevin Monahan, a gastroenterologist at St Mark's, called the collection a "unique resource" for identifying shifts in cancer causes over time. The samples include both tumor tissue and accompanying gut bacteria, allowing researchers to trace changes in disease patterns.
Searching for DNA signatures
Different cancer triggers leave distinct genetic "fingerprints" in tumor DNA. By comparing historical and contemporary samples, scientists hope to pinpoint which factors have become more prevalent in recent decades.
Professor Trevor Graham of the ICR suggested one leading theory: a specific strain of E. coli bacteria, now more common in young people's guts, may release toxins that damage bowel cells and trigger cancer. "If these so-called bad bugs are driving the increase, we should see their genetic signature become more frequent over time," he said.
A young patient's struggle
Holly, a 27-year-old actress, was diagnosed with advanced bowel cancer at 23 after her symptoms-bloating and weight loss-were initially dismissed as irritable bowel syndrome. She underwent aggressive chemotherapy, which she described as "affecting me in ways I never imagined."
Now cancer-free for over three years, Holly lives with a stoma and requires regular medical monitoring. While planning her wedding, she still grapples with the emotional toll. "It all feels really unfair," she said. "I think, oh why me?"
What's next
The analysis of the archived samples could take months, but researchers hope the findings will lead to better prevention strategies. "I think the answer might be in this room," Graham said, referring to the hospital's basement archive.
