We investigated whether PPARγ activity was involved in COX-2 regulation in human ovarian carcinoma cells, and found that 15d-PGJ2, a PPARγ ligand, reduced COX-2 expression in a dose-related manner, suggesting that COX-2 expression was regulated through PPARγ activity in ovarian carcinoma cells. This evidence concerns the gene PPARG and ovarian carcinoma.