First testicular cancer risk genes found

Researchers have found the first inherited genetic risk factors for testicular cancer, according to research published online in Nature Genetics today.

A team led by scientists at The Institute of Cancer Research (ICR) compared the genes of 730 men who had developed testicular cancer with the genes of healthy men. They found many of the men who had suffered cancer shared common DNA variants on chromosomes 5, 6 and 12 that the healthy men did not have.

Their results mean that men who inherit any of these genetic variants are at a higher risk of developing the disease than those who do not. Inheriting the strongest of the three factors increases men's risk by two- to threefold, while inheriting all of them increases the risk by up to fourfold.

The publication of the research coincides with Everyman Male Cancer Awareness Month in June.

This study is an important step towards developing a targeted screening programme for relatives of men who have had testicular cancer.

'We have known for some time that men whose father, brothers or sons had testicular cancer are much more likely to get it themselves and we have been searching for this genetic link,' one of the lead scientists, Dr Elizabeth Rapley from the ICR, says.

'In this research, we have identified three genetic factors linked to an increased risk of testicular cancer. We believe there are more still to be found and we are working on identifying the rest.'

'The risk conferred by each gene differs, but in one case it is two-to threefold,' Professor Mike Stratton from the Wellcome Trust Sanger Institute and the ICR says.

'The risks also add together to some extent, so that men who inherit all the risk variants we found are four times more likely than the general population to develop testicular cancer. By combining these genetic risks with other known risk factors it may be possible in future to identify men who are at high risk of developing testicular cancer, particularly those who have a brother or father already affected by the disease. This may allow early detection or prevention.'

The study - funded by the Everyman Campaign, Cancer Research UK and the Wellcome Trust - has also given researchers a clue to the mechanism by which testicular cancer develops.

The three markers were all found near genes involved in the same biochemical pathway - one which is important in the survival and development of germ cells (cells that go on to form sperm). Disrupting this important pathway may be one mechanism by which cancer can grow.

'By understanding the biology of this disease we hope to improve treatment options,' Dr Rapley says.

The researchers are now looking for up to 3000 men who have had testicular cancer to participate in the study to identify more genetic risk factors. These new volunteers would provide a blood sample and fill in a questionnaire.

'We are hopeful we can find more risk factors but we do need more people affected by testicular cancer to help in this research,' Dr Rapley says.

'We are grateful to all those men who have participated in this study so far, and would like anybody who has suffered testicular cancer to contact us - even if they were treated 20 years ago. They could ultimately help us develop treatments and improve diagnostic techniques to improve the lives of sufferers in the future.'