High cyclooxygenase-2 expression is associated with advanced stages in colorectal cancer

Despite compelling evidence from the genetic background and clinical studies indicating that cyclooxygenase-2 (COX2) up-regulation is a key step in carcinogenesis of colorectal carcinoma (CRC), controversy regarding its role as a prognostic factor exists. However, all evidence indicates that increased COX2 activity promotes progression of CRC. This study, aimed to evaluate the expression of COX2 in CRC, and correlate it with different patient clinicopathological data, emphasizing on the role of COX2 as a prognostic factor for CRC.

In the present study, archival samples from 145 patients with stage I, II, III, or IV CRC treated during 1981-1990 at the Turku University Hospital (Finland) were used (as microarray blocks) to analyze COX2 expression by immunohistochemistry (IHC).

Higher levels of COX2 expression were associated with higher TNM class (p<0.06), and higher Dukes' stage (p<0.045). In contrast, there was no significant correlation with age, gender, tumor grade or lymph node status. However, univariate survival analysis of metastases showed borderline association with COX2 expression in that patients with metastases with COX2-positive tumors were alive for shorter periods of time compared with patients whose tumors had no COX2 expression (p<0.023, log-rank).

COX-2 expression has shown a significant correlation with tumor stage and hence is assumed to be a prognostic factor in our cohort of colorectal cancer patients.