PTGS2 and cancer: It is suggested that increased serum PTGS2 levels lead to upregulation of the prostaglandin EP1 receptor, which in turn decreases PTGS2 levels through certain pathways.12 The levels significantly increase in cancerous tissues and this increase may constitute a mechanism that facilitates carcinogenesis.13 In addition, cyclooxygenase inhibitors could downregulate serum concentrations of potent angiogenic factors, thus suppressing angiogenesis and precluding tumor growth.14 Therefore, the PTGS2 gene may contribute to the progression of human cancer.