Epidermal growth factor receptor gene and protein abnormalities in non-small cell lung cancer

Abstract

Objective To evaluate the presents of molecular predictors of epidermal growth factor receptor (EGFR) inhibitors, including EGFR protein over-expression, EGFR gene high copy number and gene mutations in non-small-cell lung cancer (NSCLC) samples from Chinese patients. Methods 226 surgically resected NSCLC samples were constructed into tissue micro-array, and investigated for EGFR gene copy number by fluorescence in situ hybridization (FISH) with commercial probe from Vysis and protein over-expression by immunohistochemistry. 94 adenocarcinoma samples were tested for EGFR gene mutations by PER sequencing. Statistical analysis was performed testing association of these abnormalities with clinical parameters and with each other. Results EGFR protein over-expression was found in 55.3% of the NSCLC samples, and was closely associated with squamous carcinoma (P=0.001 ). 42.0% of the samples had gene high copy number, which showed no statistical association with clinical parameters. 42.6% adenocarcinoma samples carried EGFR gene mutation. Among these EGFR abnormalities, only EGFR protein over-expression and gene high copy number was significantly associated (P=0.005). Conclusion Two of the molecular predictors of EGFR inhibitor, EGFR protein over-expression and gene high copy number were found in NSCLC samples from Chinese patients at similar frequency with those from Caucasian patients. EGFR gene mutation is the only predictors identified so far occnrred more often in Chinese patients who benefits more from EGFR inhibitors. Key words: Receptor,epidermal growth factor; Carcinoma,non-small-cell lung; Gene duplication; Gene converion