Comparisons of EGFR mutation status in tumor tissues, pleural effusion cancer cells and cfDNA samples of patients with lung adenocarcinoma

Abstract

Objective To determine whether pleural effusion samples, including cell-free DNA (cfDNA) samples and pleural effusion cancer cells, could be an alternative of tumor tissue samples to test epidermal growth factor receptor (EGFR) gene mutation status. Methods A total of 46 patients with lung adenocarcinoma diagnosed in the Department of Respiratory and Critical Care Medicine, Xiangya Hospital from September 2013 to January 2015 were included in this study.The matched pleural effusion cfDNA samples, cancer cells, tumor tissues samples were collected from these patients.EGFR mutation status in different kinds of samples was determined by liquid-chip platform. Results EGFR mutation was identified in 20 out of 46 (43.5%) pleural effusion cfDNA samples, 13 out of 36 (36.1%) pleural effusion cancer cell samples, and 21 out of 46 (45.7%) matched tumor tissues.The overall concordance of the EGFR gene mutation detected in pleural effusion cfDNA samples and tumor tissue samples was 93.5% (43/46, κ=0.868). The overall concordance of the EGFR gene mutation detected in cancer cell samples and tumor tissue samples was 91.7% (33/36, κ=0.822). Conclusions Pleural effusion cfDNA samples and cancer cell samples have high concordance with matched tumor tissue samples, suggesting that pleural fluid is an alternative for detecting EGFR mutation when the biopsy of tumor tissue is infeasible. Key words: Lung adenocarcinoma; Receptor, epidermal growth factor; Tumor; Pleural effusion; Cell-free DNA; Cancer cells