Epidermal Growth Factor Receptor (EGFR) Gene Amplification in Non-Small Cell Lung Cancer: A Comparison of Fluorescence In Situ Hybridization and Chromogenic In Situ Hybridization Study
SB Yoo, HJ Lee, JH Chung, DH Chung, JW Seo. Seoul National University College of Medicine, Seoul, Republic of Korea; Seoul National University Bundang Hospital, Seongnam, Republic of Korea
Background: Fluorescence in situ hybridization (FISH) is the most representative and standardized test for assessing gene amplification. However, FISH requires a fluorescence microscope, interpretation of FISH slides is time-consuming and rapid fading of the fluorescent signal is problematic. Recently, of chromogenic in situ hybridization(CISH) has emerged as a potential alternative to FISH. The aim of this study was to test the reliability of CISH technique for the detection of epidermal growth factor receptor (EGFR) gene amplification in non-small cell lung carcinoma (NSCLC), to compare CISH results with FISH and to assess interobserver reproducibility among three pathologists.
Design: A total of 170 formalin fixed and paraffin embedded NSCLC tissue samples were retrieved from the surgical pathology archives at Seoul National University Bundang Hospital. FISH and CISH examinations were performed to test EGFR gene amplification status. FISH and CISH results were independently evaluated by the three pathologists.
Results: There was high concordance in the assessment of EGFR gene copy number between CISH and FISH tests and between observers (p<0.000). Also, there was substantial consistency between immunohistochemical results and CISH results, showing correlation of protein overexpression and gene amplification.
Conclusions: There was nearly perfect agreement between the CISH and corresponding FISH results, and interpretation of CISH results were highly reproducible among the pathologists. In conclusion, EGFR gene amplification status can be reliably assessed by CISH.
Tuesday, March 10, 2009 1:00 PM
Poster Session IV # 236, Tuesday Afternoon