EGFR gene copy number, ERCC1 and BRCA1 protein expression and their relationship in non-small cell lung cancer

Abstract

To evaluate the expression of epidermal growth factor receptor (EGFR) gene copy number and the expression of ERCC1 and BRCA1 proteins in patients with non-small-cell lung cancer (NSCLC) and the correlation between them. The status of EGFR gene copy number was determined by in situ hybridization (FISH), and the expression of ERCC1 and BRCC1 proteins was examined by immunohistochemistry (IHC). The relationship of EGFR gene copy number with the expression of ERCC1 and BRCA1 and the clinical pathologic features were analyzed. FISH-positive EGFR expression was identified in 40 of 166 samples (24.1%). More FISH-positive EGFR in the female than male patients (31.9% vs. 18.6%, P = 0.048), and non-smoker than smoker (32.8% vs. 16.7%, P = 0.045). FISH-positive EGFR was not associated with age, pathological type, clinical stage and metestasis status (P > 0.05). The expression of ERCC1 protein was identified in 60 of 132 samples (45.5%). The expression of ERCC1 protein varied significantly in tumors of different pathological types (P = 0.046), but not associated with age, gender, clinical stage, metestatic status and smoking status (P > 0.05). The expression of BRCA1 protein was identified in 46 of 131 samples (35.1%). The expression of BRCA1 was not associated with age gender, pathological type, clinical stage, metestatic ststus and smoking status (P > 0.05). There was a moderate correlation between the expressions of ERCC1 and BRCA1 (r = 0.449, P < 0.001), but EGFR gene copy number was not correlated with the expression of ERCC1 or BRCA1 protein. FISH-positive EGFR expression is associated with gender and smoking status, but not correlated with the expression of ERCC1 and BRCA1 proteins. There is a moderate correlation between the expressions of ERCC1 and BRCA1.