PPARD and neoplasm: The first study to examine the potential role of PPARβ/δ in a colon cancer model suggested that PPARβ/δ was dispensable for colon carcinogenesis as no differences in tumor multiplicity or size was observed between control APCmin/+ mice and APCmin/+ mice crossed with a Pparb/d-null mouse line.49 However, only three double mutant mice on a mixed genetic background were examined in this study.