PPARD and colonic neoplasm: In mouse models of colitis-associated colon cancer, PPARβ/δ increased IL-6 expression and phosphorylation of STAT3, promoting tumorigenesis, while the concomitant 15-lipoxygenase-1 in colon epithelial cells inhibited these effects by downregulating PPARβ/δ (Mao et al., 2015).