A New Ligand for the Peroxisome Proliferator-Activated Receptor-g (PPAR-g), GW7845, Inhibits Rat Mammary Carcinogenesis

We have tested a new ligand for peroxisome proliferator-activated receptor-g, GW7845, as an inhibitor of experimental mammary carcinogenesis, using the classic rat model with nitrosomethylurea as carcinogen. Rats were first treated with a single dose of nitrosomethylurea (50 mg/kg body weight, i.p.). Starting 1 week later, they were fed GW7845, at either 60 or 30 mg/kg of diet, for 2 months. This agent significantly reduced tumor incidence, tumor number, and tumor weight at both doses. This is the first report of the use of a ligand for peroxisome proliferator-activated receptor-g to prevent experimental breast cancer.