Altered expression of estrogen receptor β2 is associated with different biological markers and clinicopathological factors in papillary thyroid cancer.

Estrogen and estrogen receptor (ER)-α and -β play a role in the development and progression of thyroid cancer. ERβ2 is one major splicing variant of ERβ. In this study, we investigated the clinical significance of ERβ2 protein expression in the papillary thyroid carcinoma (PTC) lesion. ERβ2 expression was immunohisto-chemically examined in formalin-fixed, paraffin-embedded thyroid tissues from 106 patients with PTC by Elivision™ plus two-step system as previously described. The relationships between ERβ2 expression and clinicopathological/biological factors were then analyzed. ERβ2 protein was expressed in all the PTC patients studied. It was positively associated with Ki-67 expression in female PTC patients with advanced reproductive age (>45 years, in low-estrogen status) and with VEGF expression in male PTC patients with reproductive age (18~45 years, in low-estrogen status) (P=0.005 and P=0.044, respectively). There was no association between ERβ2 expression and tumor size, extrathyroidal extension and tumor-node-metastasis stage in PTC patients. In addition, ERβ2 expression was lower in female patients of reproductive age (18~45 years, in relatively high-estrogen status) with lymph node metastasis than that in those patients without lymph node metastasis (P=0.035). The present results suggest that the expression of ERβ2 in PTC is associated with the progression of the disease. Its potential effect may vary with different estrogen status. Further study will assess the underlying molecular mechanisms of ERβ2 in PTC.