Cancer Research UK scientists have discovered that gut stem cells replace each other in a 'one in, one out' system, which is completely different to previously accepted theories. The research is published online in Science1.

Before now, scientists thought that stem cells in the gut replace each other according to a predetermined system where the fate of the daughter cell is already decided. There was a hierarchy where only a handful of stem cells are able to produce the many different types of stem cells in the gut. These stem cells go on to make the cells responsible for absorption and for other essential functions of the gut.

But this research shows that instead there is one overall stem cell population with no hierarchy. Instead, stem cells replace their neighbours as they are lost. This means that each stem cell has an equal chance of producing other stem cells and ultimately all types of cells in the gut.

The gut wall is continually dividing, regrowing and regenerating and is able to achieve this because it is supported by a group of stem cells - stem cells produce a range of different cells.

These findings demonstrate the gut wall's flexibility so that any stem cell can be deployed to make any type of stem cell, reacting quickly to lost stem cells and changes in the environment.

Dr Doug Winton , lead researcher at Cancer Research UK's Cambridge Research Institute, said: "We've shown for the first time how the population of stem cells is maintained in the gut and essentially it is a random process with no predetermined fate for the stem cells. This research is a great example of collaborative research - we've brought together biologists and physicists to answer questions about how stem cells divide - and it's through these type of collaborations we hope to answer more questions about stem cells and their links to cancer."

In the gut healthy stem cells normally multiply to maintain the lining of the gut, but when these stem cells develop faults they become cancer stem cells and divide out of control causing a tumour to form.

Dr Lesley Walker, director of cancer information at Cancer Research UK, said: "This basic biology research could one day lead to real benefits for patients. Cancer stem cells are more resistant to chemotherapy and radiotherapy than the cells that make up the bulk of a tumour, so understanding more about how they behave could lead to better treatments for bowel cancer."

Reference

1. Lopez-Garcia et al. Intestinal stem cell replacement follows a pattern of neutral drift (2010) Science

Source: Cancer Research UK