It can be concluded that: 1) COX-2-derived PGs play a key role in the tumorogenesis; 2) The tumor-promoting effect of PGs may be attributed to their ability to stimulate the cell proliferation and migration, to inhibit the apoptosis and to increase angiogenesis and invasiveness; 3) in accordance to the proposed major role of COX-2 in cancerogenesis, selective COX-2 inhibitors have been shown in numerous studies to exhibit strong chemopreventive effect on the development of cancers. Here, PTGS2 is linked to cancer.