Epidermal growth factor receptor mutations in cells from non-small cell lung cancer malignant pleural effusions

Background: The prevalence of epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancer (NSCLC) patients is about 40-50% in Taiwan, and there are significant correlations between EGFR mutations and clinical responses after gefitinib treatment. For most patients with advanced disease, surgical intervention for tissue sampling is not feasible. We therefore conducted this study to survey EGFR mutations in cells from NSCLC malignant pleural effusions and to evaluate the clinical significance. Methods: In the present study, malignant pleural effusion cells from 29 NSCLC patients were studied for EGFR mutations. Exons 18,19,20, 21 of the EGFR gene were analyzed by polymerase chain reaction (PCR) and automated sequencing. For 11 patients who had received gefitinib therapy, correlations between gefitinib effect and EGFR mutations were also evaluated. Results: EGFR mutations were detected in 12 of 29 specimens (41%). In-frame deletion mutations in exon 19 (8 of 12 specimens, 67%) and missense mutations in exon 21 (3 of 12 specimens, 25%) were the most frequent mutations detected. The frequency of EGFR mutations was significantly higher in gefitinib responders (4/4) than non-responders (1/7) (p = 0.015). Conclusion: Our results suggest that detecting EGFR mutations in cells from malignant pleural effusions is a feasible adjunct method to finding the subgroup with favorable response to gefitinib therapy among patients with advanced NSCLC.