Bowel cancer link to stem cells

http://news.bbc.co.uk/2/hi/health/7788645.stm

Scientists may be narrowing down the hunt for the cells which are the source of bowel cancer.

When genetic damage was inflicted on stem cells from the intestines of mice, the result was a speedy transformation into fast-growing tumours.

UK and Dutch scientists believe that the discovery, reported in the journal Nature, could make it easier to target and prevent the disease.

Cancer Research UK said it was a "leap forward" in understanding bowel cancer.

Bowel Cancer is one of the most common cancers in the UK, and can be hard to treat because it is often diagnosed late.

Scientists want to know what event causes a normal, healthy bowel cell to turn cancerous and start to form tumours.

First of all, however, they have to identify which cells within the intestine are vulnerable to cancerous changes.

All cell types in the colon arise from stem cells - so-called "master cells" - which can form a variety of different tissue types.

When a stem cell divides in two, one half becomes another stem cell, while the other "daughter" cell has begun the transformation into the cell needed to form another tissue type.

A key question is whether cancer starts back at the stem cell change, or later on, in one of the cell types it produces.

The research by the Beatson Institute in Glasgow, Cardiff University, and the Hubrecht Institute in the Netherlands, isolated intestinal stem cells in mice, then "knocked out" a specific gene called APC from them.

The APC gene is described as a "tumour suppressor gene" and plays a role in regulating the way a cell divides.

'Seek and destroy'

Within days, the stem cell populations had started to form tumours. When the same technique was applied to non-stem cell "daughter" cells, far fewer tumours were formed.

This points the finger clearly at stem cells as a primary source of bowel cancer changes.

Professor Hans Clevers, from the Hubrecht Institute, said: "We are very excited by these findings but we need to establish whether the stem cells will behave the same way in human cancers as they do in mice."

Dr Owen Sansom, from the Beatson Institute, added: "We are now looking to understand how we can use these results to seek out and destroy stem cells that are lacking the APC gene."

Dr Lesley Walker, from Cancer Research UK, said: "As in most cancers, the cell that the cancer originates from has remained elusive in bowel cancer.

"So this work is a big leap forward in our understanding of the origins of the disease."