Comparison of EGFR Mutation Status in Malignant Pleural Effusion and Plasma from Lung Adenocarcinoma Patients

Abstract

Malignant pleural effusion (MPE) and blood samples can be used as practical sources for the detection of epidermal growth factor receptor (EGFR) mutations in advanced non-small cell lung cancer patients. We compared EGFR mutation status of cell blocks, cell-free fluid of MPE, and plasma from lung adenocarcinoma patients. We obtained paired samples of MPE and plasma from 14 pathologically-confirmed lung adenocarcinoma patients. EGFR mutation status was determined by peptide nucleic acid (PNA)-mediated real-time polymerase chain reaction (RT-PCR) clamping. EGFR mutations were detected in five (35.7%) cell blocks of MPE, which showed identical results as the corresponding cell-free fluid, whereas mutations were detected in the plasma of only two (40.0%) of the five patients. Of the seven patients treated with EGFR tyrosine kinase inhibitors (TKIs), EGFR mutations were detected in cell blocks, cell-free fluid of MPE, and plasma for only one of the four patients who responded to EGFR TKIs, while mutations were detected only in cell blocks of MPE and cell-free fluid of the three remaining patients. Our results suggest that it may be feasible to detect EGFR mutations in cell-free pleural fluid from lung adenocarcinoma patients by using highly sensitive methods, but that analysis of free plasma may lead to undetected mutations and misdiagnosis.