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Updated: May 4, 2026
Detection of Rare Mutations in CtDNA Using Next Generation Sequencing
Published on: August 24, 2017
Detection of mutations in EGFR in circulating lung-cancer cells
Shyamala Maheswaran1, Lecia V Sequist, Sunitha Nagrath
1Massachusetts General Hospital Cancer Center, Boston 02129, USA.
Background:
The use of tyrosine kinase inhibitors to target the epidermal growth factor receptor gene (EGFR) in patients with non-small-cell lung cancer is effective but limited by the emergence of drug-resistance mutations. Molecular characterization of circulating tumor cells may provide a strategy for noninvasive serial monitoring of tumor genotypes during treatment.
Methods:
We captured highly purified circulating tumor cells from the blood of patients with non-small-cell lung cancer using a microfluidic device containing microposts coated with antibodies against epithelial cells. We performed EGFR mutational analysis on DNA recovered from circulating tumor cells using allele-specific polymerase-chain-reaction amplification and compared the results with those from concurrently isolated free plasma DNA and from the original tumor-biopsy specimens.
Results:
We isolated circulating tumor cells from 27 patients with metastatic non-small-cell lung cancer (median number, 74 cells per milliliter). We identified the expected EGFR activating mutation in circulating tumor cells from 11 of 12 patients (92%) and in matched free plasma DNA from 4 of 12 patients (33%) (P=0.009). We detected the T790M mutation, which confers drug resistance, in circulating tumor cells collected from patients with EGFR mutations who had received tyrosine kinase inhibitors. When T790M was detectable in pretreatment tumor-biopsy specimens, the presence of the mutation correlated with reduced progression-free survival (7.7 months vs. 16.5 months, P<0.001). Serial analysis of circulating tumor cells showed that a reduction in the number of captured cells was associated with a radiographic tumor response; an increase in the number of cells was associated with tumor progression, with the emergence of additional EGFR mutations in some cases.
Conclusions:
Molecular analysis of circulating tumor cells from the blood of patients with lung cancer offers the possibility of monitoring changes in epithelial tumor genotypes during the course of treatment.
Insights
Monitoring lung cancer genotypes noninvasively is possible using circulating tumor cells. This method aids in tracking epidermal growth factor receptor (EGFR) mutations during treatment, improving patient management.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Tyrosine kinase inhibitors targeting EGFR are effective for non-small-cell lung cancer but face resistance from mutations.
- Noninvasive monitoring of tumor genotypes during treatment is crucial for managing drug resistance.
Purpose of the Study:
- To evaluate the utility of circulating tumor cells (CTCs) for monitoring EGFR mutations in non-small-cell lung cancer (NSCLC).
- To compare EGFR mutational analysis in CTCs with plasma DNA and tumor biopsies.
Main Methods:
- CTCs were isolated from NSCLC patients' blood using a microfluidic device with antibody-coated microposts.
- EGFR mutational analysis was performed on CTC DNA using allele-specific PCR.
- Results were compared with concurrently isolated free plasma DNA and original tumor biopsy specimens.
Main Results:
- CTCs were successfully isolated from 27 metastatic NSCLC patients.
- EGFR activating mutations were detected in 92% of CTCs vs. 33% of plasma DNA (P=0.009).
- The T790M resistance mutation was detected in CTCs from patients on tyrosine kinase inhibitors; its presence correlated with reduced progression-free survival.
Conclusions:
- Molecular analysis of CTCs enables noninvasive monitoring of epithelial tumor genotypes during lung cancer treatment.
- CTCs provide a valuable tool for tracking treatment response and resistance mutations in NSCLC.
- Serial CTC analysis can correlate with tumor progression or response and reveal emerging mutations.
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