PTGS2 and neoplasm: We provided comprehensive evidences that (1) ANXA1 is differentially expressed in healthy human tissues; (2) ANXA1 expression is tumor type-specific: downregulation in squamous cell carcinoma, upregulation in pancreatic carcinoma, but controversial in other gastrointestinal tumors; (3) enforced expression of ANXA1 reduced cell viability by inhibiting the production of COX-2, while COX-2 overexpression could abolish this effect induced by ANXA1.