A new ligand for the peroxisome proliferator-activated receptor-gamma (PPAR-gamma), GW7845, inhibits rat mammary carcinogenesis

We have tested a new ligand for peroxisome proliferator-activated receptor- gamma, GW7845, as an inhibitor of experimental mammary carcinogenesis, usin g the classic rat model with nitrosomethylurea as carcinogen. Rats were fir st 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, t umor number, and tumor weight at both doses. This is the first report of th e use of a ligand for peroxisome proliferator-activated receptor-gamma to p revent experimental breast cancer.