Survival effects of cyclooxygenase-2 and 12-lipooxygenase in Egyptian women with operable breast cancer

Background: Breast cancer (BC) is the commonest among women in Egypt as well as in many other countries. Cyclo-oxygenase-2 (COX-2) and 12-lipo-oxygenase (12-LOX) are over-expressed in 30-40% of patients and carry a poor prognosis. The objectives of this study were to correlate COX-2 and 12-LOX expression with various clinico-pathologic patients′ characteristics and their impact on overall survival (OS) and disease free survival (DFS) in Egyptian women with operable BC.
Materials and Methods: This prospective study included 57 consecutive BC cases presenting to the Egyptian National Cancer Institute. Sections from BC and nearby normal tissues were examined for expression of COX-2 and 12-LOX using reverse transcriptase polymerase chain reaction.
Results: The patients′ median age was 45 years. Fifty-three percent were premenopausal. Stage II and III disease represented 25 and 75% respectively. Adjuvant chemotherapy, radiotherapy and tamoxifen were used in 90, 75 and 60% respectively. Sixty percent had hormone-receptor positive tumors and 28% over-expressed HER2/neu. Forty-nine and sixty-five percent showed over-expression of COX-2 and 12-LOX respectively. Patients with higher TNM stage or who developed visceral metastases had significantly higher COX-2 expression. For the whole group of patients, the median DFS was 37 months, while the median OS was not reached. OS or DFS did not differ significantly between patients with normal and over-expression of COX-2. DFS but not OS was significantly higher in 12-LOX over-expression compared to normal expression.
Conclusion: COX-2 over-expression was associated with poor prognostic criteria in BC, but did not affect DFS or OS. 12-LOX over-expression was associated with better DFS, but not OS.