PPARD and colonic neoplasm: Activation of PPAR-δ by the synthetic ligand GW501516 in colon cancer cell lines or primary mouse intestinal epithelial cells upregulated COX-2 expression and PGE2 production, subsequently increasing macrophage production of proinflammatory cytokines (e.g., CXCL1,CXCL2,CXCL4, and IL-1β) [75].