Cyclooxygenase (COX-2) is an inducible
enzyme involved in production of prostaglandins in inflammatory processes.
It is involved in the response of cells to growth factors, tumor promoters, and
cytokines that induce its expression. Given its role in synthesizing
prostaglandins, COX-2 is therefore of interest in studying immune response
regulation. COX-2 is induced by a wide variety of stimuli and was initially
identified as immediate-early growth response gene. There is now increasing
evidence that a constitutive expression of COX-2 plays a role in
development and progression of malignant epithelial tumors. In studies, COX-2
positivity retained independent roles in predicting a poor chance of response to
treatment. COX-2 positive patients had a shorter overall survival rate than
COX-2 negative patients.