New type of stem cell found in prostate

In collaboration with the Press Association

US scientists have discovered a new type of stem cell in the prostate tissue of adult mice. The stem cells could be a source of prostate cancer, although more research needs to be done to be sure.

Evidence is building for the role of rogue stem cells in many types of cancer. Previous research has suggested that they are involved in the development of bowel and skin cancers and leukaemia.

The latest research - which will be published in a forthcoming issue of the journal Nature and is now available online - led to the discovery of a rare type of stem cell called 'castration-resistant Nkx3.1-expressing cells' (CARNs).

These cells are involved in the regeneration of prostate tissue, but were also found to give rise to prostate cancer in mice if a tumour suppressor gene called PTEN was switched off within the cells.

Researchers at the Herbert Irving Comprehensive Cancer Centre at Columbia University Medical Centre and New York-Presbyterian Hospital identified the stem cells while carrying out studies on prostate tissue from mice.

The stem cells were located in the epithelial cells lining the inner cavity of the prostate gland.

They are capable of forming copies of themselves, and also of generating different, more mature cell types.

However, it is not yet known whether CARNs can produce cancer stem cells - rogue stem cells that are able to regenerate cancer from a single cell.

Lead researcher Dr Michael Shen, professor of medicine, genetics and development at Columbia University Medical Centre, noted: "The relationship between the normal prostate stem cells and potential cancer stem cells is not known yet.

"And even the existence of cancer stem cells in prostate tumours is not established."

Dr Owen Sansom, a stem cell researcher from Cancer Research UK's Beatson Institute for Cancer Research, commented: "These scientists have shown that a completely new type of stem cell exists in the prostate. These cells re-grow after injury and are resistant to hormone blocking treatments.

"This is particularly interesting as one of the main treatments for prostate cancer involves using drugs to block the hormones that feed the cancer. Cancers arising from these particular stem cells might be naturally resistant to therapy, which raises the possibility of the development of new prostate cancer treatments targeted against them."

The team hopes that by understanding which cells give rise to prostate cancer, they will ultimately be able to develop better treatments for the disease.

However, they do not yet know whether CARNs are present in human prostate tissue. The scientists are now carrying out studies to find out whether they do exist in the healthy human prostate and, if so, whether they are capable of giving rise to prostate cancer.