Twenty-five years since landmark bowel cancer discovery

Professor Sir Walter Bodmer who helped locate the APC gene 25 years ago.

There’s a lot more to do before we can say we’ve beaten cancer, but every now and then, it’s good to sit back and reflect on how far we’ve already come.

Back in June, when the country was celebrating the Diamond Jubilee, we took time to think about how much cancer research has changed since the Queen came to the throne.

And this month, we’re proud to look back at one of our key achievements, which has played a big role in the lives of the one in twenty patients who’s bowel cancer is inherited.

It’s 25 years this month since we discovered the location in the DNA of our cells of a gene called APC. Thanks to this discovery, members of families in which many cases of bowel cancer occur – often at a young age – can now be offered genetic tests to look for inherited faults in this gene, and potentially life-saving screening if they carry them.

We now know that inherited faults in APC – which causes a disease called familial adenomatous polyposis (FAP) – account for about one in every hundred cases of bowel cancer.

When it’s working normally, the APC gene helps protect us from cancer by preventing cells from multiplying out of control.

But when it’s faulty, it greatly increases the risk of bowel cancer. And as well as its role in inherited disease, it’s also involved in non-inherited (or ‘sporadic’) bowel cancers. Overall, about eight out of ten cases of bowel cancer are fuelled by faults in the APC gene – making it a crucial part of the pathway that leads to bowel cancer.

And it was one of our former Chief Executive Officers, Professor Walter Bodmer, who made the breakthrough in 1987.  You can find out all about how Professor Bodmer tracked down the gene on this blog post.

Since Professor Bodmer’s discovery in the late 80s, death rates from bowel cancer in the UK have dropped by a third, thanks to improvements in prevention and screening, and better treatments.

But the story doesn’t stop there – and won’t stop until we beat the disease.

Ongoing story

Scientists have continued to study APC for the past two decades. They’re now getting a much clearer understanding of how APC works and what happens when it goes wrong.

Much of this groundbreaking work has been carried out by Cancer Research UK-funded scientists. For example, our scientists in Dundee discovered that APC helps bowel cells to know how to divide in an organised manner. And a team at the Cancer Research UK Beatson Research Institute in Glasgow discovered that blocking the activity of the APC gene in healthy bowel cancer stem cells causes tumours to grow.

Iron levels are the key

Earlier this month, there was yet more exciting news from our scientists in Glasgow. They found that levels of iron play a crucial role in controlling the development of bowel cancer in mice who carry a faulty APC gene. High levels of iron on their own do not cause bowel cancer, but they come into play if someone also has a faulty APC gene.

Although we’d known for a long time that people with a faulty APC gene have an increased risk of bowel cancer, it was not clear how this caused the disease. This latest research could help to answer that question. As study author Professor Owen Sampson says: “We’ve made a huge step in understanding how bowel cancer develops.”

Plans are afoot to investigate if treatments that cut the levels of iron in the bowel can help reduce the chances of bowel cancer developing in people who are at a greater risk of the disease.

Evolving science

In 25 years’ time, we’ll undoubtedly be looking back on this year’s breakthroughs and where they’ve taken us. For example, our landmark study that has completely reclassified breast cancer into ten new subtypes – and the in-depth research that has transformed the way we look at how cancers evolve.

How will we have built on these key discoveries? And how will things have changed for cancer patients as a result? As yet, we don’t have the answers, we’ll have to wait and see how the science unfolds. But it’s a tantalising prospect.

Josephine Querido, Science Information Manager

• Photo courtesy of WIMM, Oxford