PTGS2 and cancer: Moreover, TZD drugs elicit tumor-suppressive effects to induce apoptosis and inhibit cell proliferation in various cancer cells by regulating apoptosis-associated proteins, such as cyclooxygenase-2 (COX-2), B-cell lymphoma 2 (Bcl-2), epidermal growth factor receptor (EGFR) and Fas ligand (FasL) [18,19,20,21,22].