Selenium-Protein Deficiency Raises Cancer Risk

Helping to find a way out of
cancer disease: transgenic mice

Selenium, an essential dietary mineral that can act as an antioxidant when incorporated into proteins, has been shown in many studies to reduce the incidence of cancers - notably lung, colorectal and prostate. "The problem is, nobody seems to know how the mechanism works, and that's not trivial," said Alan Diamond, professor of human nutrition at the University of Illinois at Chicago and principal investigator. "Knowing how it works allows you to maximise-out its benefits," he said.

Diamond and colleagues report findings using specially bred transgenic mice that suggest it is the level of these selenium-containing proteins in the body that is decisive in preventing cancer. Two genetically manipulated mice were mated. One was prone to developing prostate cancer. The other had lower levels of selenoproteins. Approximately 50 offspring that carried both traits were studied to see if the reduced levels of selenoproteins accelerated cancer development.

As the researchers suspected, it did: "It's a hardcore link in an animal model system of selenium-containing proteins to prostate cancer and, by extrapolation, the mechanism by which selenium prevents cancer," said Diamond.

Further research is underway to corroborate the stimulating effect of dietary selenium in enhancing levels of protective selenoproteins. Diamond added that much work remains to be done to discover exactly how selenoproteins play their protective role, and in whom.

The effectiveness of selenium may be due to its effects on a single selenoprotein, or combinations of several members of this class. One selenoprotein in particular, glutathione peroxidase, is of special interest to Diamond and his associates. "If reductions result in accelerated prostate cancer, then we have our player," he said with regard to further studies.; Source: University of Illinois at Chicago