Expression of ER-α36, a Novel Variant of Estrogen Receptor in Endometrial Carcinoma and Its Clinical Significance

Objective: Estrogen receptor-alpha 36 (ER-alpha 36), a newly identified variant of ER-a, is predominantly membrane-based and mainly mediates nongenomic estrogen signaling. In this study, we investigated the expression of ER-alpha 36 in human endometrial carcinoma tissues to understand the relationship between its expression and clinicopathological characteristics. Methods: ER-alpha 36 expression was assessed by innmunostaining in 73 endometrial carcinomas, 20 normal endonnetrial tissues, and 9 with atypical endonnetrial hyperplasia. Correlations between ER-alpha 36 protein expression and clinicopathological characteristics were investigated. Results: The expression of ER-alpha 36 in endometrial carcinoma tissues was significantly lower than in normal endonnetrial tissues and atypical hyperplasia (p < 0.01). ER-alpha 36-negative tissues were significantly more likely than ER-alpha 36-positive tumors to have tumor involvement of the cervix (p < 0.05). The disease-free survival rate of patients with ER-alpha 36 expression was poorer than that of those who were negative for ER-alpha 36 expression (p < 0.01). There was no significant relationship between ER-alpha 36 expression and patient age, surgical staging, histological differentiation, myometrial invasion, lymph node metastasis, and pathological types (p > 0.05). Conclusions: ER-alpha 36 may be an important biomarker for diagnosis, prognostication, and treatment choice in endometrial carcinoma. copyright (c) 2012 S. Karger AG, Basel