PTGS2 and cancer: The anti-cancer effects of celecoxib are associated with the following: (i) the inhibition of the highly over-expressed tumor cyclooxygenase-2 (COX-2), which in turn has been related to the acquisition and maintenance of an invasive metastatic phenotype [14]; (ii) the activation of the intrinsic apoptosis pathway [15]; (iii) the inhibition of oxidative phosphorylation (OxPhos) [12,13]; and (iv) the blocking of cell migration and invasiveness [12].