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

ERα, ERβ, PR, ERα36, 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 ERα and PR were gradually increased and those of ERβ 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 ERα36, 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 ERα, ERβ and PR, and between ERα36, EGFR and HER2 protein expression in PTCs. As for ERα, ERβ and PR, there was a significant positive correlation between ERα and PR, and a significant negative correlation between ERα and ERβ and between PR and ERβ protein expression. As for ERα36, EGFR and HER2, there was a significant positive correlation between ERα36, EGFR and HER2 protein expression in PTCs. Concomitant high expression of ERα36, 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).