September 1, 2012
Genetic Link To Prostate Cancer Found In Europeans, African-Americans
redOrbit Staff & Wire Reports - Your Universe Online
African-American and European men have an increased risk of prostate cancer due to changes in one of their immune system genes, claims a new study published online in the journal Cancer Epidemiology, Biomarkers & Prevention.
Researchers from the University of Illinois at Chicago (UIC) College of Medicine, as well as colleagues from Northwestern University and Washington, D.C.'s Howard University Hospital, isolated changes in the IL-16 gene, an immune system protein, the school reported in an August 31 statement.
"Previously identified changes in the gene for IL-16“¦ were associated with prostate cancer in men of European descent. But the same changes in the gene's coded sequence -- called 'polymorphisms' -- did not confer the same risk in African Americans," the university said.
"Doubt was cast on IL-16's role in prostate cancer when researchers were unable to confirm that the IL-16 polymorphisms identified in whites were also important risk factors in African Americans," they added.
Using a new technique known as imputation, which the school describes as a form of statistical extrapolation, the research team was able to discover new patterns of association, which in turn showed them new locations within the gene where they could search for polymorphisms. With that knowledge, they were able to find changes in a different part of the IL-16 gene that were both linked to prostate cancer and unique to African-American males.
According to the UIC statement, polymorphisms occur as a result of DNA mutations and are prevalent in the ancestry of different populations. Lead researcher Rick Kittles, an associate professor of medicine in hematology/oncology at the university, explained that searching for polymorphisms associated with diseases like prostate cancer is more difficult in African-Americans than in Caucasians, as the former race is said to be far more genetically diverse than the latter.
Kittles said that the research "provides us with a new potential biomarker for prostate cancer," adding that it "confirms the importance of IL-16 in prostate cancer and leads us in a new direction. Very little research has been done on IL-16, so not much is known about it. We now need to explore the functional role of IL-16 to understand the role it is playing in prostate cancer."
The research was supported by grants from the US Department of Defense and the National Cancer Institute/National Institutes of Health.