The Clinical Significance of the Estrogen Receptor β Expression for Endocrine Therapy in Patients with ERα-negative and Progesterone Receptor-positive Breast Carcinoma

摘要

Purpose Estrogen receptor (ER) is the key therapeutic target in breast cancer. ERβ has recently been identified to be distinct from ERα. In contrast to ERα, the functions of ERβ in breast cancer are still unclear. We sought to determine whether the expression of ERβ can be used as a predictive marker for endocrine therapy for patients with ERα-negative breast cancer. Methods Formalin-fixed, paraffin-embedded tumor specimens from 52 patients with ER-/PR+ invasive breast cancer were immunostained for their ERβ 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-2eu were also analyzed and correlated with the ERβ status. Results An ERβ expression was observed in 53.8% (28/52) of the breast cancer samples. There was no correlation between the ERβ 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-2eu expression). Recurrence was present in 7.7% (2/26) of the patients whose tumors had an ERβ expression, as compared to the presence of recurrence in 36.4% (8/22) of the patients whose tumors had no ERβ expression ( p Conclusion These results suggest that ERβ 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.