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Is That How it Works?


Doctors have known since 2005 that the diabetes drug metformin could help lower a patient's risk for developing cancer, says the DNAIndia blog, but the mechanisms underlying the association have been unclear. In a new study published in Cancer Prevention Research, a team from McGill University and the University of Montreal say they may know why metformin has such an effect. "They learned that exposure to metformin reduces the cellular mutation rate and the accumulation of DNA damage," the blog says. "It is well known that such mutations are directly involved in carcinogenesis, but lowering cancer risk by inhibiting the mutation rate has never been shown to be feasible." Metformin seems to reduce a person's levels of reactive oxygen species, which are known to damage DNA. The drug didn't act as a classic antioxidant, says the University of Montreal's Gerardo Ferbeyre, but instead seemed to selectively prevent altered mitochondria — like those present in cells with oncogenic mutations — from producing reactive oxygen species.