PURPOSE: Although protein expressions of glucocorticoid receptor (GR), estrogen receptors (ERα and ERβ), 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, their association with patient characteristics and prognosis is undetermined yet. The purpose of this study is to disclose the steroid receptors expression status in thymic tumors.
METHODS: We examined 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) for GR, ERα, ERβ, PgR-A, and AR expression using immunohistochemistry. In addition, the correlation of these hormone receptor expressions with clinicopathologic factors and overall survival (OS) was assessed.
RESULTS: GR and ERβ showed high rate of expression in thymomas and thymic carcinomas (82.9% and 76.4%, respectively), whereas ERα, PgR-A, and AR expression rates were low (13.6%, 0.71%, and 23.6%, respectively). A significant correlation (P < 0.05) was found between ERα expression and tumor size and between ERβ expression and tumor stage. Multivariate analyses revealed that histologic subtype (P = 0.0039), tumor stage (P = 0.0012), and GR expression (P = 0.0025) were significantly correlated with the 10-year OS rates.
CONCLUSIONS: GR and ERβ showed high rates of expression in thymomas and thymic carcinomas. Furthermore, multivariate analysis revealed that GR expression is associated with better prognosis in surgically resected thymomas and thymic carcinomas.
CLINICAL IMPLICATIONS: To our knowledge, this is a first report of GR expression status in more than 100 patients with thymic tumors.
DISCLOSURE: The following authors have nothing to disclose: Takahiro Mimae, Koji Tsuta, Morihito Okada, Hitoshi Tsuda
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