Research for a Better Test for Prostate Cancer

The hunt for a better test

Research into prostate cancer is focused on finding a test to sort aggressive tumours, known as tigers, from the harmless ones, the pussycats.

Health experts agree that the current examination, the PSA (prostate-specific antigen) test, has major limitations in assessing prostate cancers. In particular it cannot determine whether a prostate cancer is slow- or fast-growing.

This means that many thousands of men are being given invasive treatment that they don’t require, says Professor Colin Cooper of the Institute of Cancer Research (ICR).

“This is because we’ve been unable to distinguish them from the men who urgently need life-saving treatment,” he says.

Cooper’s team at the ICR has been focusing its efforts into finding a test that can accurately determine the tigers.

Research has focused on identifying markers that can be used to distinguish harmless from aggressive prostate cancers. Markers are substances found in the body when someone has cancer. They are used to help diagnose the disease and determine optimal treatment.

“Such markers can be used to identify aggressive cancers early so that they may be treated and to minimise treatment for dormant tumours,” says Cooper.

He believes that new tests using markers to distinguish the tigers from the pussycats could be in use in clinics within "the next couple of years".

E2F3 gene

The team’s first breakthrough came in 2004 when they discovered that high levels of the E2F3 gene were present in aggressive prostate cancer cells. The protein produced by the E2F3 gene is known to have a crucial role in all human cells by controlling the production of cells.

Cooper believes that high levels of the E2F3 protein lead to excessive cell reproduction and the development of a tumour. Tests showed that prostate cancer patients with high levels of the E2F3 protein had more aggressive tumours.

“Research is now under way to translate this finding into a test in the hope that we can identify patients who have aggressive early cancers,” says Cooper.

Tissue microarrays

Continuing their research into identifying prostate cancer markers, the team developed the Checkboard Tissue Microarray Method. Many tissue samples, often from different people, are collected together and analysed.

It's a semi-automated process, which means it could be used in the future as a way of screening large numbers of samples for the signs of early prostate cancer.

The technique opened up the possibility for identifying many more markers from tissue samples obtained from a prostate biopsy than was previously possible. “Now we can look at hundreds of markers,” says Cooper.

“It will enable us to identify new markers to help us diagnose more accurately patients with aggressive tumours.”

2+Edel gene

One of the more significant markers discovered using this technique is the 2+Edel gene, which is present in the more aggressive forms of prostate cancer. This gene highlights cancers that are going to be fatal.

Markers like 2+Edel will help to identify those patients who require immediate treatment and those who require a 'watch and wait' approach.

Research into identifying markers is pivotal in developing a test for prostate cancer aggressiveness that is far more accurate than the PSA test.

“Prostate cancer markers could save thousands of men undergoing unnecessary surgery and living with debilitating side effects,” says Cooper.

Family genes

Research has also looked at how our genetic make-up might determine our risk of developing prostate cancer.

A study led by Dr Ros Eeles of the ICR found seven genetic faults that were present in more than half of all prostate cancer cases. They each increase a person’s risk of the disease by up to 60%, according to scientists at the ICR and the University of Cambridge.

It’s the first time that the link between family history and prostate cancer has been proven scientifically.

There are many different factors that influence the development of prostate cancer, but particular combinations of genes are thought to play a major part.

Eeles said, “These exciting results will help us to more accurately calculate the risk of developing prostate cancer.”

Last reviewed: 30/07/2008

Next review due: 30/07/2010