The Study on Gene Amplification of EGFR in Bronchioloalveolar Carcinoma and Conventional Adenocarcinoma of the Lung

Abstract

Background and objective Patients with adenocarcinoma of the lung have disproportionately response to the epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI). The aim of this study is to analyze the difference of EGFR gene amplification in bronchioloalveolar carcinoma (BAC), adenocarcinma mixed subtype and conventional adenocarcinoma of the lung and provide some information to clinical therapies. Methods Lung cancer cases were collected and reviewed from the archives of the Department of Pathology, Chinese PLA General Hospital during the time period from 2004 to 2006. The definite diagnosis of BAC based on 2004 WHO classification of lung tumors was made by two pathologists. Fluorescence in situ hybridization (FISH) was performed to detect EGFR gene amplification in pure BAC, adenocarcinma mixed subtype and conventional adenocarcinoma. Results Conventional adenocarcinoma had higher EGFR amplification compared with pure BAC and adenocarcinma mixed subtype (χ2=11.632, P<0.05). EGFR gene amplification was found in 45.45% of conventional adenocarcinoma, 14.81% in pure BACs, and 22.58% in adenocarcinma mixed subtype. EGFR gene amplification was observed as scattered signals in most cases. Conclusion EGFR gene amplification was seen more frequently in the invasive components than in BAC. EGFR gene amplification might be associated with the development of adenocarcinoma of the lung.

Keywords

• Bronchioloalveolar carcinoma
• Adenocarcinoma
• EGFR
• FISH technic
• Tissue microarray