PTGS2 and neoplasm: Colon cancer is the most studied type of cancer and one of the proposed mechanisms of regulation is throughout the up-regulation of the adenomatous polyposis coli (APC)/β-CATENIN/transcription factor 4 (TCF4), pathway in which PPARβ/δ is activated by COX2-derived ligands (such as prostacyclins), leading to the expression of target genes that increase cell proliferation and promote tumor growth.