PTGS2 and cancer: Cyclooxygenase (COX) exists in the form of two isozymes, COX-1 and COX-2, and is a key enzyme in the biosynthetic pathway of PGE2 and COX-2 facilitates the conversion of arachidonic acid into prostaglandin, which in turn upregulate the expression of PGE2, another mediator of inflammation, known to induce cancer by activating angiogenesis [12,13,14].