PPARG and cholangiocarcinoma: The PPARγ ligand, 15-deoxy-delta 12,14-PGJ2,induces apoptosis in cholangiocarcinoma cell lines although regulation ofapoptosis-related protein expression varies [4, 5], while artificial regulationof PPARγexpression in cholangiocarcinoma cell lines suggests that PPARγ may actually promote tumor cell growth viathe Smad pathway [6].