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Breast Cancer Health Center

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Genes Tied to Selenium's Cancer Benefits

Selenium Supplements May Reduce Breast Cancer Risk in Some

WebMD Health News

June 16, 2003 -- A person's genes may determine whether or not selenium supplements may reduce the risk of breast cancer.

New research suggests that people with a certain genetic variation may benefit more from taking the popular nutritional supplement to reduce their risk of breast cancer.

Selenium is a trace element found naturally in foods like nuts and liver. Researchers say that for more than 20 years animal studies have suggested that tiny amounts of selenium in the diet can reduce the risk of cancer in several organs, but much less is known about the anti-cancer benefits of selenium in humans.

"We believe there are certain proteins in mammalian cells that can mediate the protective effects, but proving this is difficult," says researcher Alan Diamond, professor and head of human nutrition at the University of Illinois at Chicago, in a news release.

Decoding DNA for Differences

In this study, published in the June 15 issue of Cancer Research, researchers looked at the role a particular protein that contains selenium plays in breast cancer.

"The way we studied this was to look at a certain selenium-containing gene that encodes for selenium-containing proteins, then examine their nucleotide -- or genetic code -- for differences," says Diamond.

"We looked to see if there were differences in the frequency of versions of these genes both in tumor cells and from DNA from people who didn't have cancer."

They compared the gene in 517 healthy, cancer-free people with that from 79 breast cancer tissue samples.

Researchers found that a certain version of the gene was associated with a higher breast cancer risk. That same gene was also less responsive to selenium stimulation.

Diamond says that means people with this genetic variation may benefit from selenium supplements but they require a higher dose to achieve selenium's protective effect against cancer.

Although it's too early to recommend selenium supplements to reduce breast cancer risk for the general population, Diamond says that someday genetic testing may allow doctors to prescribe selenium supplements accordingly to those who would benefit most.

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