Expression of cyclooxygenase-2 and 12-lipoxygenase in human breast cancer and their relationship with HER-2/neu and hormonal receptors: impact on prognosis and therapy.

BACKGROUND A number of studies have shown over-expression of cox-2 in breast cancer. Also it has been recorded that human breast cancer expresses high level of cox-2 and 12-lipoxygenase which may be beneficial in future therapy plan for those patients. AIMS The present study aims to examine the level of transcripts of cox-2 and 12-lipoxygenase in Egyptian breast cancer patients and to compare between the expressions of both enzymes and TNM staging, hormone receptors status (including estrogen and progesterone) and HER2/neu expression. MATERIALS AND METHODS Total cellular RNA was extracted from 64 frozen tissue samples of breast carcinoma and their corresponding normal adjacent tissues. Cox-2 and 12-lipooxygenase expressions were detected using RT-PCR. Hormonal receptors as well as HER2/neu were detected immuno-histochemically for each patient. RESULTS About 47 and 62.5% of carcinoma samples showed over-expression of cox-2 and 12-lipooxygenase respectively as compared to their corresponding normal tissues. The results revealed that cox-2 significantly associated with TNM staging (P = 0.0047) and hormonal receptors status (P = 0.0201). The relationship between cox-2 and HER2/neu expression was close to a significant value (P = 0.0747). 12-lipooxygenase showed only significant association with TNM staging (P = 0.0076). Neither hormonal receptors nor HER2/neu showed significant association with this enzyme. CONCLUSION Elevated levels of cox-2 and 12-lipoxygenase expression were detected in human breast cancer. Also, the results revealed that cox-2 and 12-lipooxygenase mRNA expressions are associated with TNM staging in human breast cancer. Furthermore, there is an inverse association between cox-2 expression and hormonal receptor status. This observation may drive us to the possible role of those two enzymes in determining the plan of therapy of breast cancer patients.