Fux R et al. (2005) Cyclooxygenase-2 expression in human colorectal cancer is unrelated to overall patient survival. Clin Cancer Res 11: 4754–4760

The cyclo-oxygenase-2 (COX2) pathway is thought to play an important role in colorectal cancer development. COX2 expression is elevated in cancers and adenomas compared with normal bowel tissue, and experimental evidence suggests that inhibition of COX2 (through the use of agents such as nonsteroidal anti-inflammatory drugs) suppresses development of adenoma and colorectal cancer. The results of previous small studies examining the impact of COX2 expression on survival of colorectal cancer have been difficult to interpret. This large single-center retrospective study aimed to clarify that relationship.

COX2 expression was analyzed by immunostaining of colorectal cancer specimens from 747 individuals treated in the years 1987–1997, and survival was ascertained by review of patient records. Multivariate analysis showed that only node status and metastasis were significantly related to survival and that COX2 expression on its own did not influence either overall or disease-free survival. Results were similar after the exclusion of patients with either stage IV disease or rectal cancer.

This study suggests that COX2 expression does not play a role in colorectal cancer survival. The authors propose that pathways other than those involving COX2, such as the peroxisome proliferative activated receptor pathway, might be influenced by the use of nonsteroidal anti-inflammatory drugs. These other pathways, rather than COX2, might mediate the chemopreventive action of these agents and merit further investigation.