PTGS2 and cancer: Our gene expression microarray results strengthen the previously published data by which the anti-cancer effect of the selective COX2 inhibitors is mainly due to their anti-proliferative and pro-apoptotic properties (Guardavaccaro et al, 2000; Hung et al, 2000; Brown et al, 2001; Li et al, 2001; Zhang and DuBois, 2001; Nishikawa et al, 2004; Chen et al, 2009; Sooriakumaran et al, 2009; Zagani et al, 2009).