Cox-2 expression on tissue microarray of breast cancer

Aim To measure cyclooxygenase-2 (Cox-2) expression in a series of breast cancers and evaluate its potential as a predictive marker for doxorubicin chemotherapy. Patients and methods Cox-2 expression was analyzed in 178 node-positive patients treated with doxorubicin-based adjuvant chemotherapy by immunohistochemistry on tissue microarray (TMA). Results Cox-2 was over-expressed in 70 out of the 178 invasive breast cancers. Cox-2 expression was significantly increased in undifferentiated tumors. There was no significant association between Cox-2 over-expression and tumor size, histologic grade, and estrogen receptor expression. Disease-free survival and overall survival of the patients having Cox-2 expressing tumor were significantly decreased when compared with the patients having Cox-2 negative tumor (p = 0.009 for DFS, p = 0.011 for OS). Conclusion Cox-2 expression may represent an aggressive phenotype of breast cancer which is resistant to doxorubicin.