Extracellular vesicle-derived DNA for performing EGFR genotyping of NSCLC patients

Jae Young Hur,Chang-Min Choi,Jae Cheol Lee,Hee Joung Kim,Chan Gi Pack,Kye Young Lee,Min Kyo Jung,Jong Sik Lee

doi:10.1186/s12943-018-0772-6

Abstract

Tumor cells shed an abundance of extracellular vesicles (EVs) to body fluids containing bioactive molecules including DNA, RNA, and protein. Investigations in the field of tumor-derived EVs open a new horizon in understanding cancer biology and its potential as cancer biomarkers as well as platforms for personalized medicine. This study demonstrates that successfully isolated EVs from plasma and bronchoalveolar lavage fluid (BALF) of non-small cell lung cancer (NSCLC) patients contain DNA that can be used for EGFR genotyping through liquid biopsy. In both plasma and BALF samples, liquid biopsy results using EV DNA show higher accordance with conventional tissue biopsy compared to the liquid biopsy of cfDNA. Especially, liquid biopsy with BALF EV DNA is tissue-specific and extremely sensitive compared to using cfDNA. Furthermore, use of BALF EV DNA also demonstrates higher efficiency in comparison to tissue rebiopsy for detecting p.T790 M mutation in the patients who developed resistance to EGFR-TKIs. These finding demonstrate possibility of liquid biopsy using EV DNA potentially replacing the current diagnostic methods for more accurate, cheaper, and faster results.

Highlights

Lung cancer results in the largest number of cancerrelated deaths worldwide and non-small-cell lung cancer (NSCLC) accounts for more than 85% of all lung cancer cases [1]
We demonstrated for the first time that extracellular vesicle (EV) isolated from bronchoalveolar lavage fluid (BALF) of NSCLC patients carry genomic Double-stranded Extracellular vesicle-derived DNA (DNA) (dsDNA) and specific mutant EGFR DNA inside the double layered membranous vesicles (Fig. 2b)
The present study did not include a large sample size, preliminary findings of this study suggest that liquid biopsy of BALF EV-derived DNA (EV DNA) can overcome limitations associated with tissue rebiopsy, which is widely performed for detecting p.T790 M mutation

Summary

Introduction

Lung cancer results in the largest number of cancerrelated deaths worldwide and non-small-cell lung cancer (NSCLC) accounts for more than 85% of all lung cancer cases [1]. We compared the sensitivity of EGFR mutation testing between BALF EV DNA and cfDNA by performing PCR. Results showed higher sensitivity of EGFR mutation testing when using EV DNA compared to using cfDNA.

Results

Conclusion