Droplet digital PCR improved the EGFR mutation diagnosis with pleural fluid samples in non-small-cell lung cancer patients

Droplet digital polymerase chain reaction (ddPCR) is a promising method for analyzing minor amounts of nucleic acid. However, its application has not been reported in pleural fluid, which is an ideal sample source for epidermal growth factor receptor (EGFR) mutation analysis in non-small-cell lung cancer (NSCLC) patients. The extracted DNA from supernatants of pleural fluid was selected from our sample bank and re-analyzed by our previously established ddPCR assay. The results were compared with the former outcomes detected by direct sequencing or the amplification-refractory mutation system (ARMS). A total of 95 samples were selected, and 64 and 31 of them had been performed with direct sequencing and ARMS tests, respectively. The EGFR mutation detection rate of ddPCR was significantly elevated, compared with both direct sequencing (75.4% vs. 43.8%, P