Cyclooxygenase (COX), the key enzyme in the conversion of arachidonic acid to prostaglandins, exists in two isoforms namely COX-1, constitutively expressed in most tissues, and COX-2, which is inducible by growth factors, prostaglandins, and tumour promoters and associated with the inflammatory response (Williams and Dubois, 1996). The gene discussed is PTGS2; the disease is neoplasm.