AP - Scientists have identified a common genetic marker that signals a 60 percent heightened risk of prostate cancer in men who carry it, and it may help explain why black men are unusually prone to the disease, a new study says.

The DNA variant may play a role in about 8 percent of prostate cancers in men of European extraction and 16 percent of the cancers in blacks, researchers said.

The study was published online Sunday by Nature Genetics and will appear in the journal's June issue. The work is reported by Kari Stefansson and colleagues at deCode genetics in Reykjavik, Iceland, and scientists elsewhere.

The variant is about twice as common in blacks as whites, so that may contribute to the higher incidence of prostate cancer in blacks, the researchers said.

Stefansson said in a statement that deCode plans to use the discovery to develop a genetic test that might help doctors decide how closely to follow men at high risk and how to treat prostate cancer cases. The study indicated the variant might be associated with more aggressive forms of the disease.

It's not clear whether the heightened risk comes from the variant itself or from another that lies nearby on chromosome 8.

In general, men run a 1-in-6 chance of developing prostate cancer at some point in their lives. The risk is greater for those who are older, black or have a brother or father who's had the disease. More than 230,000 new cases are expected this year in the United States, with about 27,000 deaths.

The researchers found that the DNA variant was more common in prostate cancer patients than in the general population, suggesting an association with the disease. They compared a total of 3,430 patients with more than 2,000 others, drawing on study populations in Iceland, Sweden, Illinois and Michigan.

Among whites, the variant appeared in about 19 percent of patients and 13 percent of the other participants. Among blacks, both numbers were about twice as high.