ERCC1 expression by immunohistochemistry and EGFR mutations in resected non-small cell lung cancer

Abstract

7646 Background: To investigate whether excision repair cross-complementation group 1 (ERCC1) expression, as determined immunohistochemically, and mutations of epidermal growth factor receptor (EGFR) are related to the prognosis of curatively resected non-small cell lung cancer (NSCLC), and whether these two markers are related. Methods: One-hundred and thirty-three consecutive patients with NSCLC who did not receive adjuvant chemotherapy after curative surgery were included in this study. Representative areas from formalin-fixed paraffin-embedded tumor samples were chosen for tissue microarray analysis. Immunohistochemistry was performed for ERCC1 and the median semiquantitative H-score was used as a cut-off. EGFR mutations (exons 18, 19, and 21) were analyzed by the direct sequencing of tumor samples. Results: ERCC1 expression was evaluable in 130 patients and ERCC1 was found to be positive in 80 patients (61.5%). Moreover, ERCC1 was expressed more frequently in smokers and in squamous cell carcinomas. Patients with positive ERCC1 expression survived longer (median overall survival 2,742 days for ERCC1-positive vs. 1,423 days for ERCC1-negative, P=.0463). EGFR mutations were found in 27 patients (20.3%) but they were not found to affect overall survival. Interestingly, EGFR mutations were more frequent in ERCC1-negative tumors (12.5% in ERCC1-positive vs. 30% in ERCC1-negative tumors, P=0.014). Conclusions: ERCC1 expression was identified as a prognostic marker of longer survival in resected NSCLCs. In addition, EGFR mutations were more frequently found in ERCC1-negative tumors, but were not found to affect survival in our patient group. No significant financial relationships to disclose.