The role of cyclooxygenase enzyme 2 (COX-2), successional prostaglandin E2 (PGE2) and its receptors have been investigated in many different tumor entities, such as colon cancer, prostate and lung cancers, as well as in breast cancer and gynecological tumors such as ovarian, cervical and endometrial cancers [10,11,12,13]. The gene discussed is PTGS2; the disease is endometrial cancer.