Prostate cancer risk factors identified in African Americans

Researchers at the Harvard Medical School in the USA say they have identified a DNA segment that is a major risk factor for prostate cancer in African American men. The discovery of the significant 3.8megabase region, which is located on human chromosome number eight, is discussed in the August 21 electronic edition of the Proceedings of the National Academy of Sciences.

The research team, under the leadership of David Reichs, an assistant professor of genetics at the HMS, used the newly-established "admixture mapping" technique to search the genomes of 1,597 African American males with prostate cancer for individuals with a higher than average proportion of African ancestry (between 78% and 85%). The rationale behind this approach was the fact that prostate cancer occurs approximately 1.6 times more often in this group than in other populations.

The group identified a region, referred to as 8q24, linked with a substantially increased risk of the disease in those that inherited it. Additionally, the results corroborate the discovery in May of this year of a genetic variant in this region that was associated with increased prostate cancer risk. The HMS team added that the earlier identified risk factor did not explain the proportional increase in cancer susceptibility, concluding therefore that other, as yet uncharacterized, major genetic variants must play a role.