Correlation between COX-2 expression and hormone receptors in invasive ductal breast cancer

COX-2 is known to be elevated in breast cancer, but the clinical relevance is still a matter of debate. The purpose of this study was to determine the prognostic significance and relationship of COX-2 to hormone receptors. Between January 2005 and February 2007, 80 specimens from breast cancer patients at Korea University Anam Hospital were reviewed by one pathologist. COX-2 was analyzed as overexpressed if <10% of the cells were stained. Clinical characteristics, hormone receptor status, and other prognostic factors were investigated to determine their association with COX-2 expression. Results: COX-2 was overexpressed in 12 patients (15%). Two patients had locoregional recurrence, eight patients had systemic metastasis, and one patient died. There was no statistically significant correlation between COX-2 expression and age, size, nodal status, histological grade, hormone receptor status, and HER-2/neu positivity. Among tumors that had a positive expression of ER and PR, COX-2 expression was related to larger size (P-value 0.001 and 0.009, respectively) and nodal status (P-value 0.048 and 0.009, respectively). However, there was no statistically significant correlation with tumors that had negative ER or PR expression. This study suggests that in breast cancer, COX-2 expression has no relationship with clinicopathologic factors; however, a correlation was noted in size and nodal status for ER- and PR-positive tumors. Further prospective study with larger population to clarify the relationship between COX-2 expression and hormone receptor status is necessary.