Genetic link to prostate cancer

Scientists based in Iceland, the US and Sweden have discovered a common genetic variation linked to an increased risk of prostate cancer. The team, based at Icelandic firm deCODE genetics, have found that men who inherit the variant have a 60 per cent increased risk of developing the disease. The researchers say that their findings, published in the journal Nature Genetics, could account for around eight per cent of all prostate cancer cases in men of European ancestry, and up to 16 per cent of all cases among African Americans.

Prostate cancer is one of the most common cancers, and is second only to lung cancer in the number of deaths among men affected by the disease. It is more common in black American men than in those of European ancestry, for reasons previously unknown. In an effort to identify inherited factors that influence the risk of disease, the deCODE team looked at a common genetic variation located on chromosome 8, in a region of DNA often found to be disrupted in prostate tumours.

The scientists looked at DNA samples from 3430 prostate cancer patients and 2675 unaffected controls, living in Iceland, Sweden and the US. They found that about 19 per cent of men with European ancestry have at least one copy of the variant, but it is roughly twice as common in African Americans. This finding could help explain the higher incidence of prostate cancer in this group, say the scientists. 'This discovery is important from a medical standpoint because the only firmly established risk factors for the disease until now have been age, family history and ethnicity', said deCODE chief executive and senior author Kari Stefansson.

The finding may also help doctors decide how to treat men with prostate cancer, since the variant appears to be linked with the more life-threatening form of the disease. Most affected men develop the disease after the age of fifty and, while it can become aggressive in some, many never have symptoms and eventually die of other causes. A diagnostic test to help doctors identify patients at high risk of the aggressive form could help them make more informed treatment decisions, say the scientists. 'We plan to use this discovery as the basis for such a test', said Stefansson.