Researchers at Queen's University have identified a possible cause for the loss of a tumour suppressor gene (known as PTEN) that can lead to the development of more aggressive forms of prostate cancer.

"This discovery gives us a greater understanding of how aggressive prostate cancer develops because we now have some insight into the mechanism by which the PTEN gene is destroyed," says Jeremy Squire, a professor in the Department of Pathology and Molecular Medicine.

PTEN is one of a small class of tumor suppressor genes that closely regulates the growth of cells. When PTEN is altered or deleted in prostate cells, they lose the ability to make a protein that controls normal growth. Cells can then grow uncontrolled and can develop into a prostate cancer.

Dr. Squire, with his postdoctoral fellow Maisa Yoshimoto, examined cancerous tissue samples and determined that the loss of the PTEN gene occurred close to a large, unstable segment of DNA. Their discovery suggests that proximity of PTEN to this region makes cancer-suppressing genes more prone to being deleted or inactivated.

Researchers discovered the gene using a novel gene-detection technology developed by Dr. Squire and his laboratory. They identified and analyzed with unprecedented accuracy the loss of critical tumour genes using a highly sensitive fluorescent labelling system. The technology significantly improves on current methods for identifying PTEN loss and has the potential to lead to better treatment of prostate cancer patients.