Inherited genes linked to testicular cancer genes found

The first inherited risk factors in testicular cancer have been identified, researchers say.

Genetic variants on chromosomes 5, 6 and 12 were linked to an increased risk of the disease, according to studies in this week's online issue of the journal Nature Genetics.

In the first study, researchers compared the profile of 730 testicular cancer patients with 1,435 healthy controls. Inheriting all three genetic variants was associated with a fourfold higher risk of testicular germ cell tumours, but only a small proportion of men carrying the variants will actually develop 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 investigators, Dr. Elizabeth Rapley of the Institute of Cancer Research in Surrey, England, said in a release.

"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."

All three genetic variants were found near genes involved in nurturing testicular cells that go on to form sperm.

The variants are the first in the context of testicular cancer that show clear evidence of being inherited, and findings on two of them were confirmed in a U.S. study appearing in the same issue of  the journal.

"While more than 95 per cent of testicular cancer patients are successfully treated, finding genes that increase the risk of this cancer is important," Ed Yong of Cancer Research UK said in a statement.

"It tells us more about its basic biology and presents new opportunities to prevent, diagnose and treat the disease in those men most at risk — men aged under 50."

Testicular germ cell tumours are the most common malignancy in men between the ages of 15 and 45, the researchers said. 

The incidence of testicular cancer in Canada rose at a statistically significant rate of 1.8 per cent per year between 1995 and 2004, according to the Canadian Cancer Society's 2008 report on cancer statistics. The society estimates that 900 men will be diagnosed with new cases of testicular cancer in 2009.