New gene test for prostate cancer at hand

Men with susceptibility for prostate cancer will soon be identifiable through a simple DNA test. So hope scientists at the Swedish medical university Karolinska Institutet, who have shown that men carrying a combination of known risk genes run a four to five times higher risk of developing prostate cancer.

At present, men with suspected prostate cancer are identified mainly using what are known as PSA tests. However, the test has a relatively low sensitivity and better methods are needed.

"In the near future, it will be possible to combine PSA tests with simple genetic tests," says Professor Henrik Grönberg at Karolinska Institutet. "This means that fewer men will have to undergo unnecessary biopsies and that more prostate cancer diagnoses can be made."

It has long been known that prostate cancer is partly caused by inherited factors, which makes some men more likely to develop the disease than others. Five relatively common gene variants that affect this risk have so far been identified. However, each of these variants affects the risk only marginally, and knowledge of them has been of no real benefit to individual patients.

Now, however, a research group at Karolinska Institutet and their American colleagues have analysed for the first time the cumulative effect of these gene variants. The results, which are published in the prestigious scientific periodical The New England Journal of Medicine, shows that men who carry four or more risk variants run a four to five times greater risk of developing prostate cancer. This risk is increased even more if they also had close relatives with the disease.

According to the researchers, this is the first time that anyone has been able to demonstrate how a combination of genes affect the risk of developing the disease. Scientists the world over are currently searching for gene combinations behind common diseases like cancer, diabetes and asthma.

"For the first time, this type of study has made it possible to develop a clinically viable gene test," says Professor Grönberg.

The study was based on genetic analyses of approximately 4,800 Swedish men, of whom 3,000 had prostate cancer and 1,800 had no prostate cancer diagnosis.
Publication:

S. Lilly Zheng, Jielin Sun, Fredrik Wiklund, Shelly Smith, Pär Stattin, Ge Li, Hans-Olov Adami, Fang-Chi Hsu, Yi Zhu, Katarina Bälter, A. Karim Kader, Aubrey R. Turner, Wennuan Liu, Eugene R.Bleecker, Deborah A. Meyers, David Duggan, John D. Carpten, Bao-Li Chang, William B. Isaacs, Jianfeng Xu, and Henrik Grönberg
Cumulative association of five genetic variants with prostate cancer

New England Journal of Medicine, online 16 januari 2008.