Quantitative analysis of the expression of TGF-alpha and EGFR in papillary thyroid carcinoma: clinicopathological relevance

Aims: There are no quantitative data on the mRNA expression of epidermal growth factor receptor (EGFR) and transformation growth factor alpha (TGF-alpha) in thyroid carcinoma. The aims of this study were to detect, quantify and analyse the clinicopathological correlations of the expression of these genes in a large cohort of patients with thyroid carcinoma. Methods: EGFR and TGF-alpha expression were investigated using real time quantitative polymerase chain reaction and immunohistochemistry on 71 papillary thyroid carcinomas (PTCs), 68 paired non-cancer thyroid tissues adjacent to the PTC and 20 benign thyroid lesions. Results: TGF-alpha and EGFR mRNA increased in PTC when compared with benign thyroid lesions. In many PTCs with high level of expression of TGF-alpha and EGFR mRNA, the morphological non-cancer tissue adjacent to the cancer also showed high levels of expression of these mRNAs. The levels of expression of mRNA of TGF-alpha and EGFR correlated with each other and with the level of protein expression. The level of expression of TGF-alpha mRNA was significantly related to lymphovascular permeation while the expression of EGFR mRNA was related to the pathological subtype of PTC and cancer recurrence. Conclusions: TGF-alpha and EGFR were overexpressed, correlated with each other and associated with the pathological parameters in papillary thyroid carcinoma. The results provide information for management of thyroid cancer in the era of gene targeting therapy.