Extracellular vesicle-based EGFR genotyping in bronchoalveolar lavage fluid from treatment-naive non-small cell lung cancer patients
Jae Young Hur, Jong Sik Lee, In Ae Kim, Hee Joung Kim, Wan Seop Kim, Kye Young Lee, Jae Young Hur, Jong Sik Lee, In Ae Kim, Hee Joung Kim, Wan Seop Kim, Kye Young Lee
Abstract
Background: Extracellular vesicles (EV) have been proven to contain double-stranded DNA reflecting the mutational status of the parental tumor cells in non-small cell lung cancer (NSCLC), which can be translated into clinically useful EV-based liquid biopsy for Epidermal growth factor receptor (EGFR) genotyping using bronchoalveolar lavage fluid (BALF) obtained from tumor site.
Methods: Patients subjected for an initial lung cancer work-up underwent bronchoscopy and BALF was obtained from tumor site. After isolating EVs from BALF by ultracentrifugation, EV-derived DNA (EV DNA) was extracted for subsequent EGFR genotyping performed through peptide nucleic acid (PNA)-mediated Real-Time PCR. The sensitivity, specificity, and concordance rate of BALF EV-based EGFR genotyping were calculated in comparison to tissue genotyping.
Results: The average sensitivity and specificity of BALF EV-based EGFR genotyping were 76% and 87%, respectively, while the sensitivity significantly increased as the stage progressed. Especially, in stage IV, BALF EV-based EGFR typing identified all tissue-proven EGFR mutant cases (n=31) and detected 6 additional mutant cases. The concordance rate was 79% in stage I, 100% in stage II, 74% in stage III, and 92% in stage IV. As TNM stage advanced, especially in the presence of metastasis, concordance rate significantly increased (P<0.05).
Conclusions: The use of BALF for the collection of EV DNA in lung cancer patients resulted in a highly accurate diagnosis. The establishment of a fast and reliable method to identify target genes using EV DNA illustrated that it can overcome the problems of low sensitivity and instability in using cell-free DNA (cfDNA).
Keywords: EGFR genotyping; Extracellular vesicles (EV); bronchoalveolar lavage fluid (BALF); liquid biopsy; non-small cell lung cancer (NSCLC).
Conflict of interest statement
Conflicts of Interest: The authors have no conflicts of interest to declare.
2019 Translational Lung Cancer Research. All rights reserved.
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Source: PubMed