The Clinical Significance of the Estrogen Receptor beta Expression for Endocrine Therapy in Patients with ERalpha-negative and Progesterone Receptor-positive Breast Carcinoma / 한국유방암학회지

ABSTRACT

PURPOSE: Estrogen receptor (ER) is the key therapeutic target in breast cancer. ERbeta has recently been identified to be distinct from ERalpha. In contrast to ERalpha, the functions of ERbeta in breast cancer are still unclear. We sought to determine whether the expression of ERbeta can be used as a predictive marker for endocrine therapy for patients with ERalpha-negative breast cancer. METHODS: Formalin-fixed, paraffin-embedded tumor specimens from 52 patients with ER-/PR+ invasive breast cancer were immunostained for their ERbeta expression. These patients were treated with adjuvant tamoxifen. The results were correlated with various clinicopathological variables and the follow-up data. The expressions of p53 and HER-2/neu were also analyzed and correlated with the ERbeta status. RESULTS: An ERbeta expression was observed in 53.8% (28/52) of the breast cancer samples. There was no correlation between the ERbeta expression and the other clinicopathologic factors (age, tumor size, histologic type, nodal status, histological grade, stage, therapeutic modality, progesterone receptor (PR) expression, p53 expression and HER-2/neu expression). Recurrence was present in 7.7% (2/26) of the patients whose tumors had an ERbeta expression, as compared to the presence of recurrence in 36.4% (8/22) of the patients whose tumors had no ERbeta expression (p<0.05). The patients with ERbeta negative-tumors revealed lower disease free survival rate than those with ERbeta positive-tumors (p<0.05). Of the 52 patients, 10 (19.2%) were p53 positive, and 11 (21.2%) were HER-2/neu positive. No significant correlations were observed between ERbeta and p53 or HER-2/neu. CONCLUSION: These results suggest that ERbeta might be a predictive marker of a response to endocrine therapy in patients with ER-/PR+ invasive breast cancer, although this needs to be confirmed by additional studies.