Concomitant high expression of ERα36, EGFR and HER2 is associated with aggressive behaviors of papillary thyroid carcinomas

ER alpha, ER beta, PR, ER alpha 36, EGFR and HER2 mRNA and protein expression in papillary thyroid carcinoma (PTC) were examined by real time RT-PCR and immunohistochemical staining. The mRNA and protein expression of ER alpha and PR were gradually increased and those of ER beta were gradually decreased from normal thyroid tissues to nodular hyperplasias (P < 0.05) and to PTCs (P < 0.05). However, the mRNA and protein expression of ER alpha 36, EGFR and HER2 were only significantly increased in PTCs when compared with those in normal thyroid tissues (P < 0.001) and nodular hyperplasias (P < 0.001). There was some correlation between ER alpha, ER beta and PR, and between ER alpha 36, EGFR and HER2 protein expression in PTCs. As for ER alpha, ER beta and PR, there was a significant positive correlation between ER alpha and PR, and a significant negative correlation between ER alpha and ER beta and between PR and ER beta protein expression. As for ER alpha 36, EGFR and HER2, there was a significant positive correlation between ER alpha 36, EGFR and HER2 protein expression in PTCs. Concomitant high expression of ER alpha 36, EGFR and HER2 was strongly associated with aggressive behaviors including extrathyroidal extension (ETE), lymph node metastasis (LNM) and high TNM stage in PTCs (P < 0.001).