Treatment with γ-tocotrienol (2 μM), the PPARγ agonist, rosiglitazone (3.2 μM), and the PPARγ antagonist, GW9662 (3.2 μM), alone had no significant effect on PGD2 synthesis in PPARγ siRNA transfected MCF-7 and MDA-MB-231 breast cancer cells compared to vehicle-treated or scrambled RNA transfected cells. This evidence concerns the gene PPARG and breast carcinoma.