Genes which increase testicular cancer risk

Gene variations associated with testicular cancer have been identified in two different studies published in Nature Genetics. The study may be a step towards a screening programme for relatives of men who have had testicular cancer.

Although testicular cancer is the most common cancer in younger men, deaths from it remain rare — these findings should make them rarer still.

Testicular cancer is five times more common in men of European ancestry than in those of African ancestry. One of the risk-associated genes the researchers found - KITLG — is also associated with differences in skin and hair colour and may be part of the explanation for this big difference.

The British study from the at the Institute of Cancer Research 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.

Two, three or four times the risk

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 doubles or even triples a man's risk, while inheriting all of them quadruples the risk.

One of the lead scientists, Dr Elizabeth Rapley from the ICR, says: '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.

'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 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.