Clinicopathologic Analysis of Epidermal Growth Factor Receptor Status in Non-small Cell Lung Cancer: Protein Expression, Gene Amplification and Survival Analysis

ABSTRACT

BACKGROUND: Abnormal over-expression or gene amplification of epidermal growth factor receptor (EGFR) is important in the prognosis of non-small cell lung cancer (NSCLC). We investigated the frequency of EGFR protein expression and gene amplification, and the correlation between EGFR status and survival in NSCLC. METHODS: We examined 360 cases of microarrayed NSCLC tissues for the EGFR protein expression and EGFR gene amplification using immunohistochemistry and fluorescent in situ hybridization. RESULTS: EGFR protein expression and EGFR gene amplification occurred in 110 cases (30.6%) and 24 cases (6.7%), respectively. EGFR protein expression and gene amplification were more frequent in squamous cell carcinoma than in adenocarcinoma. Differences in EGFR protein expression did not dramatically affect survival curves (p=0.740), but differences in gene amplification did (p<0.05) EGFR gene amplification was associated with a lower 5-year survival rate. CONCLUSION: EGFR protein expression and gene amplification showed moderate correlation with each other. EGFR gene amplification predicted a poor prognosis, whereas EGFR protein expression did not.