Immunohistochemical Expression of Estrogen Receptor-α and Progesterone Receptor in Patients with Papillary Thyroid Cancer

Abstract

BACKGROUND Papillary thyroid cancer (PTC) prevalence is nearly 3 times higher in females than in males. This gender difference suggests that growth and progression of PTC might be influenced by female sex hormones. OBJECTIVES To analyze the expression of both estrogen receptor (ER)-α and progesterone receptor (PR) by immunohistochemistry in 203 PTC patients. METHODS ER-α and PR expression was evaluated in paraffin-embedded tumor tissue samples of 45 males and 158 females followed up for 7.2 ± 3.7 years. RESULTS ER-α was expressed in 52 (25.6%) patients (41 females and 11 males) and PR in 94 (46.3%) patients (75 females and 19 males). ER-α and PR were coexpressed in 31 (15.3%) patients (27 females and 4 males). ER-α expression correlated significantly with tumor size in the whole sample (ER-α positive 22.8 ± 11.8 mm vs. ER-α negative 15.1 ± 12.4 mm;p= 0.02) and in the subgroup of women (ER-α positive 18.8 ± 12.8 mm vs. ER-α negative 14.9 ± 12.3 mm;p= 0.048). In addition, ER-α expression significantly correlated with remission of the disease. In fact, of the 192 patients followed up, 50/153 (32.7%) disease-free patients were ER-α positive, in contrast to only 3/39 (7.7%) with evidence of disease persistence/recurrence (χ2= 8.5,p= 0.0036). PR expression was not associated with any of the parameters analyzed. CONCLUSIONS The present study confirmed recent data indicating that ER-α and PR expression is a common finding in thyroid tumor tissue. However, in contrast to previous reports, we observed an association between ER-α expression and a more favorable outcome in PTC patients.