Zerkowski MP et al. (2007) Quantitative analysis of breast cancer tissue microarrays shows high cox-2 expression is associated with poor outcome. Cancer Invest 25: 19–26

There is evidence to indicate that cyclo-oxygenase 2 (COX2) might promote tumor growth and spread by stimulating angiogenesis and inhibiting apoptosis; however studies examining the association between COX2 expression and prognosis have produced conflicting results. A study by Zerkowski and colleagues has now demonstrated a relationship between high COX2 expression and poor outcome in breast cancer.

The study included 669 stage I–III primary breast cancer specimens analyzed by automated, quantitative analysis (AQUA) of immunostains on tissue microarrays. Low ER levels, large tumor size, positive nodal status and high nuclear grade were significantly associated with poor prognosis in this cohort. COX2 expression was higher in malignant than in benign tissue, and the protein was mainly expressed in the membrane and cytoplasm, with very low nuclear expression. High non-nuclear expression of COX2 was also significantly related to poor disease-specific and overall survival (P = 0.0189 and P = 0.0055, respectively). In addition, chi square analysis showed that positive COX2 expression was associated with low ER and PR expression, and with high nuclear grade. In multivariate analysis, high COX2 expression had independent prognostic significance (relative risk [RR] 1.66, 95% CI 1.12–2.16), as did both tumor size and nodal status (RR 1.68, 95% CI 1.20–2.33 and RR 2.39, 95% CI 1.67–3.45, respectively).

The authors conclude that high COX2 expression is an independent prognostic marker for poor survival in primary breast cancer.