PPARG and lung cancer: However, PGI2 has been shown tosignal through activation of PPARs, with reports of both PPARγ [55]and PPARδ activation [56, 57].To define the downstream effector of PGI2 in thechemoprevention of lung cancer, studies were performed in which miceoverexpressing PGIS were crossed with mice deficient in IP (A. M. Meyer et al.,unpublished observations).