Epidermal growth factor receptor protein overexpression and gene amplification are associated with aggressive biological behaviors of esophageal squamous cell carcinoma

Abstract

Alterations of the epidermal growth factor receptor (EGFR), including overexpression or gene mutations, contribute to the malignant transformation of human epithelial cells. The aim of this study was to assess EGFR overexpression or gene amplification in esophageal squamous cell carcinoma (ESCC) tissue samples and investigate their correlations with biological behaviors. Tissue specimens from 56 patients with surgically resected ESCC were obtained for immunohistochemical analysis of EGFR expression and fluorescence <i>in situ</i> hybridization analysis of <i>EGFR</i> amplification. The data were statistically analyzed to determine the associations with patient clinicopathological and survival data. EGFR was overexpressed in 30 of the 56 (53.6%) ESCC samples and was associated with poor tumor differentiation (P=0.047). <i>EGFR</i> amplification was detected in 13 cases (23.2%) and was associated with advanced pathological stage (P=0.042) and tumor lymph node metastasis (P=0.002). The univariate analysis identified no association between EGFR overexpression and the overall survival (OS) of the patients. By contrast, <i>EGFR</i> amplification predicted ESCC prognosis (P=0.031), while the multivariate analysis revealed a marginal statistical significance for the association between <i>EGFR</i> amplification and OS (P=0.056). EGFR overexpression and increased <i>EGFR</i> copy number were common events in ESCC and contributed to malignant biological behaviors, including tumor dedifferentiation and lymph node metastasis. <i>EGFR</i> amplification may therefore be useful in predicting OS in patients with ESCC.