AM251, which expresses molecular similarities with cyclo-oxygenase-2 (COX-2) inhibitor celecoxib, demonstrated a synergistic interaction with 5-fluorouracil (5-FU) increasing their anti-cancer activity when administered in appropriate ratios as demonstrated by a combination index of 0.52 (Fogli et al. 2006). Here, PTGS2 is linked to cancer.