Steroid Receptor Expression in Thymomas and Thymic Carcinomas

BACKGROUND: Although protein expressions of glucocorticoid receptor (GR), estrogen receptors (ER alpha and ER beta), progesterone receptor A (PgR-A), and androgen receptor (AR) were shown to play roles in the growth and differentiation of normal thymus and thymic tumors, to the authors' knowledge their association with patient characteristics and prognosis has yet to be determined. METHODS: A series of 140 thymic epithelial tumors (57 type A + AB thymomas, 40 type B1 + B2 thymomas, 6 type B3 thymomas, and 37 thymic carcinomas) were examined for GR, ER alpha, ER beta, PgR-A, and AR expression using immunohistochemistry. In addition, the correlation between expression of these hormone receptors and clinicopathologic factors and overall survival (OS) was assessed. RESULTS: GR and ERb demonstrated a high rate of expression in thymomas and thymic carcinomas (82.9% and 76.4%, respectively), whereas rates of ERa, PgR-A, and AR expression were low (13.6%, 0.71%, and 23.6%, respectively). A significant correlation (P < .05) was found between ERa expression and tumor size and between ERb expression and tumor stage. Multivariate analyses revealed that histologic subtype (P = .0039), tumor stage (P = .0012), and GR expression (P = .0025) were significantly correlated with the 10-year OS rate. CONCLUSIONS: GR and ERb demonstrated high rates of expression in thymomas and thymic carcinomas. Furthermore, multivariate analysis revealed that GR expression was associated with better prognosis in patients with surgically resected thymomas and thymic carcinomas. Cancer 2011; 117: 4396-405. (C) 2011 American Cancer Society.