The application of COX-2 inhibitors in lung, colon, breast, and prostate cancers appears to reduce cancer risk.31 However, several points must be highlighted: certain types of cancers are resistant to COX-2 inhibitors, even the expression is controversial depending on the site and tumor type; both the suppression and activation of COX-2 are associated with tumorigenesis, among other issues. Here, PTGS2 is linked to cancer.