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W.S. Kim
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P3.01 - Advanced NSCLC (ID 621)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Advanced NSCLC
- Presentations: 1
- Moderators:
- Coordinates: 10/18/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
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P3.01-034 - Liquid Biopsy for EGFR Genotyping Using Cell-Free DNA and Extracellular Vesicular DNA of Pleural Effusion in Pulmonary Adenocarcinoma Patients (ID 9201)
09:30 - 09:30 | Author(s): W.S. Kim
- Abstract
Background:
Pleural effusion is a highly efficient sample for liquid biopsy due to cancer cell enriched components. Liquid biopsy for EGFR genotyping is mostly being done using cell-free DNA. Extracellular vesicles (EVs) are known to carry oncogenic double stranded DNA that is considered as a noble biomarker. We set up to investigate the liquid biopsy using cell-free (cf) DNA and extracellular vesicular (EV) DNA of pleural effusion for EGFR genotyping in pulmonary adenocarcinoma patients.
Method:
Forty nine pleural effusion samples of pulmonary adenocarcinoma patients were evaluated. Non-cellular components after removing cell pellets by centrifuge (400g, 10 min, 4[0]C) were used for liquid biopsy and EVs were isolated by ultracentrifuge method (200,000g, 1 hr, 4[o]C). EV DNA and cf DNA were extracted separately and EGFR genotyping was done by PNA-clamping method. For the analysis of T790M detection, cell block slides were used as rebiopsy sample, when compared with liquid samples.
Result:
Among 31 EGFR-TKI naïve patients with known tissue EGFR genotyping, liquid biopsy using effusion EV DNA showed 100% matching with tissue EGFR genotyping in 19 EGFR mutant cases and detected 3 more EGFR mutant cases in tissue wild type (WT) patients, while liquid biopsy using effusion cf DNA missed 2 cases of tissue-based EGFR mutant patients and found 2 more EGFR mutant cases in tissue WT patients. In 18 patients with acquired resistance to EGFR-TKI, EGFR genotyping using effusion EV DNA detected T790M mutation in 13 of 18 (72.2%) patients, while 11 of 18 (61.1%) patients were detected by using effusion cf DNA, respectively. In contrast, only 3 patients were found to have T790M when using cell block slides.
Conclusion:
Liquid biopsy using pleural effusion is particularly effective for EGFR genotyping than conventional cytology or cell block sample. Liquid biopsy using effusion EV DNA is highly promising for EGFR genotyping, especially detecting T790M mutation, when compared with cf DNA.
