Clinical Significance of Cyclooxygenase-2 Expression in Colorectal Adenoma and Carcinoma

ABSTRACT

PURPOSE: Interest is mounting in developing prevention strategies for patients at high risk of developing colorectal cancer. Recent epidemiological investigations indicate an inverse relationship between the intake of NSAIDs and colorectal cancer risk. Cyclooxygenase (COX) enzyme may be involved in the initiation and/or the promotion of carcinogenesis. A major action of NSAIDs is the inhibition of COX. We have studied the clinical significance of COX-2 expression in colorectal adenoma and carcinoma. METHODS: We studied 19 patients with colorectal adenomas (15 males and 4 females ages 30~73 years) and 20 patients with colorectal carcinoma (12 males and 8 females ages 35~80 years). COX-2 status were determined by immunohistochemical methods using the mouse monocolnal antibody for COX-2 (Transduction Lab, USA) on paraffin sections. RESULTS: Immunoreactive COX-2 were expressed in 9 patients (47%) of colorectal adenoma and 9 patients (45%) of colorectal carcinoma. 57% of villous adenoma and 42% of tubular adenoma were positive for COX-2 in colorectal adenoma (p=0.650). COX-2 were expressed in 12.5% of stage B and 73% of stage C of colorectal cancer (p=0.006). COX-2 expression did not relate with the size of adenoma and carcinoma. CONCLUSIONS: The data suggest that COX-2 may be more expressed in villous adenoma and advanced carcinoma. Therefore, enhanced expression of COX-2 may play a role in the carcinogenesis of colorectal cancer.