University of Tsukuba researchers and colleagues found that tumor metastasis can be spurred by mutations in mitochondrial DNA that create reactive oxygen species (ROS).

Antioxidants helped prevent this metastasis in mice.

Two mutations caused the mitochondria to overproduce ROS, which are toxic, DNA-damaging molecules. Transplanting this DNA into non-metastasizing tumors made them more likely to metastasize, but transplanting it into ordinary cells did not cause them to make tumors, linking these mutations with metastasis only.

Mice that had been given metastatic cells under the skin developed almost no lung tumors when also given a drug to stop ROS.

Other researchers caution that clinical trials testing antioxidants to prevent cancer have yielded mixed results and that giving antioxidants to someone on chemotherapy could interfere with the treatment.