PTGS2 and cancer: Interactions between the cancer cell and the tumor microenvironment (TME) following COX-2 silencing became apparent in functional imaging assays that revealed a significant decrease of invasion into reconstituted extracellular matrix (ECM;  Stasinopoulos et al., 2007;  Shah et al., 2012), an altered interaction between endothelial cells and cancer cells following COX-2 silencing ( Stasinopoulos et al., 2008), and a significant alteration in glycolysis, pH, and choline metabolism ( Stasinopoulos et al., 2008;  Shah et al., 2012).