Forced expression of PPARβ/δ in colonocytes by use of the villin promoter increased colon tumor multiplicity in two strains of the PPARβ/δ transgenic mice as compared with controls.70 Although these studies are of interest, it is important to note that transgenes are known to become incorporated into the genome in multiple sites and in tandem repeats and can disrupt genes near the site of integration. This evidence concerns the gene PPARD and colonic neoplasm.