UK scientists analyze century-old samples to uncover why bowel cancer is rising among young people

By Aysu Bicer

LONDON (AA) - Scientists in the UK are analyzing bowel cancer samples stored for up to a century in an effort to understand the mysterious rise of the disease among young people, according to British media on Wednesday.

Although most bowel cancers are still diagnosed in older adults, cases in younger age groups have been increasing worldwide.

In the UK, bowel cancer rates among under-24s have risen by 75% since the early 1990s, while cases in people aged 25 to 49 have increased by 51% over the same period. The reasons for this trend remain unclear.

A unique archive held in the basement of St Mark’s The National Bowel Hospital in London may help provide answers.

The collection contains tens of thousands of bowel cancer samples from every patient treated at the hospital, preserved in paraffin wax along with accompanying gut bacteria.

The samples are now being examined using advanced molecular techniques at the Institute of Cancer Research (ICR), allowing scientists to study changes in cancer-causing mechanisms over time.

“Bowel cancer in people under the age of 50 is increasing worldwide, including in the UK, and it's becoming more and more of a problem,” Dr Kevin Monahan, consultant gastroenterologist at St Mark’s hospital, told BBC.

“We need to develop ways that we can prevent these cancers effectively,” he added.

Different causes of cancer leave distinct molecular signatures in DNA. By tracking how frequently these signatures appear across decades, researchers hope to identify what has changed for younger patients.

“Our leading idea is that there's a particular kind of E. coli that lives in the bowels of young people today that wasn't there in the past,” said Trevor Graham, a professor at the ICR.

The bacteria are thought to release toxins that damage DNA in bowel tissue, potentially triggering cancer.

Researchers will look for evidence that this type of DNA damage was rare in earlier samples and has become more common over time.

“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... we can also test other ideas too,” Graham said.