The association of antioxidants with the COX-2/Nrf2/ARE pathway, the antioxidant effects of polyphenols on P53/Gadd45/MDM2 gene expression and its association with DNA repair, as well as the role of hypoxia-inducible factor (HIF)-1 and S100A4 genes in the migration and invasion of cancer cells are also discussed. Here, PTGS2 is linked to cancer.