Combination Analyses Next Generation Sequencing of Lung Adenocarcinoma ctDNA and CTCs Based on Multi-Site Immunomagnetic Beads

Background: Lung cancer is the most important disease that endangers human health worldwide. High research value exists for liquid biopsy in predicting treatment response, early diagnosis of disease recurrence, and real-time dynamic detection of tumor evolution, and each one have their own unique advantages and drawbacks. Methods: We used a novel combined Epcam immunomagnetic liposome bead (Ep-IML) and Vimentin immunomagnetic liposome bead (Vi-IML) tumor cell enrichment strategy to capture CTCs from 30 lung adenocarcinoma (LAC) patients and then performed high-throughput sequencing with Circulating tumor cell DNA (ctcDNA) and ctDNA to understand the genetic variants of the patients. Results: The modified CTC enrichment efficiency was significantly improved and the mean value of CTCs enriched when Ep-IML combined with Vi-IML is 11.78/7.5 mL. The results of genomic analysis of CTC in lung adenocarcinoma showed that the five most frequently mutated genes were EGFR, TP53, KRAS, ALK, BRAF. And results of ctDNA gene analysis in lung adenocarcinoma patients showed that the five most frequently mutated genes were EGFR, AKT1, TP53, DDR2, and FGFR3. NGS analysis demonstrated that variations in the genetic profile revealed by the liquid biopsy might be increased by combining tests with CTC and ctDNA. Conclusion: We have developed a customized CTC enrichment identification system. CTCs could be an ideal complement to ctDNA and have important clinical applications in guiding clinical dosing and individualized therapy, combined CTC and ctDNA assays could detect as many drug-available targets as possible for a patient in a single trial.