PPARG and neoplasm: When MK866 was combined with ciglitazone andthe RXR agonist, 13-cis-retinoic acid, there was a superadditive growthinhibitory effect compared to each drug alone [54].These results suggest that the induction of PPARγ and RXRα by MK866 sensitizes tumor cells to apoptosisby PPARγ ligands or retinoids.