A Combined test using both cell sediment and supernatant cell‐free DNA DNA in pleural effusion shows increased sensitivity in detecting activating EGFR EGFR EGFR mutation in lung cancer patients

摘要

Introduction The aim of this study was to examine whether a combined test using both cell sediment and supernatant cytology cell‐free DNA (ccf DNA ) is more useful in detecting EGFR mutation than using cell sediment DNA or supernatant ccf DNA alone in pleural effusion of lung cancer patients. Methods A total of 74 lung adenocarcinoma patients with paired samples between primary tumour and corresponding metastatic tumour with both cell sediment and supernatant ccf DNA of pleural effusion cytology were enrolled in this study. Cell sediment and supernatant ccf DNA were analysed separately for EGFR mutations by polymerase chain reaction. Results Out of 45 patients with mutant EGFR in primary tumours, EGFR mutations were detected in 23 cell sediments of corresponding metastases (sensitivity; 51.1%) and 20 supernatant ccf DNA corresponding metastases (sensitivity; 44.4%). By contrast, the combined test detected EGFR mutations in 27 corresponding metastases (sensitivity; 60.0%), and had a higher sensitivity than the cell sediment or the supernatant ccf DNA alone ( P ??.05). Out of 45 patients with mutant EGFR , 24, three and 18 were cytologically diagnosed as positive, atypical or negative, respectively. The detection rate in the combined test was highest (95.8%) in the positive group, and mutant EGFR was also detected in four of 18 samples (22.2%) in the negative group. Conclusions A combined test using both cell sediment DNA and supernatant ccf DNA samples increases the concordance rate of EGFR mutations between primary tumour and corresponding metastases. Our findings indicate that supernatant ccf DNA is useful even in cases where the cytological diagnosis is negative.