Prognostic Value of Elevated Cyclooxygenase-2 Expression in Breast Cancer

ABSTRACT

PURPOSE: Cyclooxygenase-2 (Cox-2) is the rate-limiting enzyme in the conversion of arachidonic acid to prostaglandins and can be induced by various agents such as growth factors and tumor promoters. Cox-2 contributes to carcinogenesis and tumor growth. This study was performed to demonstrate the correlation between elevated expression of Cox-2 and pathologic factors in breast cancer. METHODS: Cox-2 expression was analyzed immunohistochemically in paraffin-embedded tumor samples from 40 patients with breast cancer. Cox-2 expression was defined as negative or positive. The correlation between Cox-2 expression and pathologic factors (tumor size, axillary lymph node metastasis, TNM stage and histologic grade) was analyzed. RESULTS: Cox-2 was highly expressed in proportion to tumor size, but the difference was not significant (P>0.05). High Cox-2 expression was observed in the presence of axillary lymph node metastasis and TNM stage III, but was not significant (P>0.05). The Cox-2 expression rate was significantly associated with high histologic grade (I 42.9%, II 50.0%, III 80.0%) (P=0.046). CONCLUSION: Elevated levels of Cox-2 expression were associated with large tumor size, presence of axillary lymph node metastasis, high TNM stage and high histologic grade, and can therefore be a possible marker for poor prognosis. Due to the small number of cases, we couldn't confirm the statistical significance except in terms of histologic grade. Further prospective studies with a large number of cases are required.