Assessing the Sensitivity of Nested PCR Followed by Direct Sequencing on Exosomal DNA for EGFR Mutation Detection in NSCLC

Background: Early and minimally invasive detection of epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancer (NSCLC) patients is a promising tool to select patients for targeted therapy in order to improve their prognosis. This study aimed to identify a sensitive, cost-effective, and easily accessible noninvasive method for detecting the EGFR-targetable mutations in the plasma exosomal DNA (exoDNA)+ of patients with NSCLC. Methods: This retrospective observational study was conducted over 10 months, from December 2022 to October 2023, at Masih Daneshvari Hospital in Tehran, Iran. A total of 30 patients with stage II-IV NSCLC and targetable mutation in the EGFR gene were included in the study. Nested PCR and Sanger sequencing were used to evaluate EGFR mutations in the DNA extracted from circulating exosomes. Results: The study found a sensitivity of 76.6% for EGFR mutation detection on exoDNA compared to tissue results. No significant impact was observed based on tumor staging, histology, mutation type, smoking status, gender, or age. Conclusion: Therapeutically targetable driver mutations in the EGFR gene can be accurately detected using nested PCR followed by direct sequencing of plasma exoDNA from patients with NSCLC. This approach facilitates timely and more personalized treatment for NSCLC patients, ultimately improving patient prognosis. Additionally, this method reduces the reliance on invasive tissue biopsies and their associated complications.