Expression of cyclooxygenase-2 (COX-2), receptors for estrogen (ER), and progesterone (PR), p53, ki67, and neu protein in endometrial cancer

Abstract

Objective: We aimed at investigating by immunohistochemistry the relationship between cyclooxygenase-2 (COX-2) and estrogen (ER), and progesterone (PR) receptors in a single institution series of 90 primary untreated endometrial cancer patients. The simultaneous assessment of p53 protein, ki67, and neu protein has been carried out.

Methods: Immunohistochemistry was performed on paraffin-embedded sections by using rabbit polyclonal antiserum against human COX-2, anti-ER (clone 1D5), and anti-PR (clone 1A6) monoclonal antibodies, anti ki67 (clone MIB-1) and p53 (clone DO-7), and polyclonal antibody anti human c-erbB2/neu.

Results: There was no difference in the distribution of COX-2, p53, and neu positive cases according to ER or PR positivity, while the percentage of ki67 positive endometrial tumors was significantly higher in ER negative versus ER positive tumors (54.5% versus 31.6%, P value = 0.044). ER and PR positive tumors showed a statistically significant association with clinicopathological parameters of better clinical outcome. There was no clear association between COX-2 positivity and any of the clinicopathological features. The percentage of ki67, p53, and neu positive tumors was found to be strictly related to more aggressive features. Only advanced stage of disease was found to be a predictor of poor prognosis (P value = 0.034). None of the biological parameters examined was shown to be associated with patient outcome.

Conclusions: We showed that COX-2 expression is not correlated with ER, PR, p53, and neu, thus suggesting that COX-2-mediated activities may follow independent pathways. Our findings provide the rationale to design trials based on the combination of antihormones with inhibitors of COX-2 and neu in recurrent/metastatic endometrial cancer.