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Updated: May 19, 2026
Detection and Monitoring of Tumor Associated Circulating DNA in Patient Biofluids
Published on: June 8, 2019
Application of a highly sensitive detection system for epidermal growth factor receptor mutations in plasma DNA
Tomomi Nakamura1, Naoko Sueoka-Aragane, Kentaro Iwanaga
1Department of Internal Medicine, Faculty of Medicine, Saga University, Saga, Japan.
Introduction:
: Detection of epidermal growth factor receptor (EGFR) mutations is indispensable to determine an appropriate lung cancer treatment. Although retreatment often prolongs survival, how to select the appropriate population for retreatment has not been clarified.
Methods:
: We used novel methods to identify EGFR mutations: wild inhibiting polymerase chain reaction (PCR) and quenched probe system (WIP-QP) for exon 19 deletions and mutation-biased PCR and quenched probe system for L858R. After the detection limits were determined, we examined DNA isolated from lung cancer specimens and circulating plasma DNA samples of 39 adenocarcinoma patients whose primary tumors harbored EGFR exon 19 deletions or L858R.
Results:
: Detection limit was 0.005 to 0.04 ng in genomic DNA and 0.1% to 0.3% in mutant plasmids. The results of cancer tissue specimens were identical to those with existing systems (nucleic acid-locked nucleic acid PCR clamp or cycleave PCR), except for two samples that showed both exon 19 deletions and L858R. One of the two samples was confirmed to harbor L858R mutation by allele-specific oligonucleotide PCR; the other one did not. Exon 19 deletions and L858R were detected in 44.7% and 8.7% of patients, using plasma DNA, among those who carried the identical abnormalities in primary tumors all of cases that evidenced pathological stage IV except for one patient, suggesting that EGFR mutations might be preferentially detected in plasma DNA obtained from patients in advanced stages. Serial monitoring of these mutations with T790M, a gate keeper mutation, demonstrated correlation with disease state.
Conclusions:
: Our novel detection systems for EGFR mutations could be useful not only at the beginning of treatment but also for monitoring using plasma DNA for deciding appropriate treatment, including rechallenge with EGFR-tyrosine kinase inhibitors.
Insights
Novel methods accurately detect epidermal growth factor receptor (EGFR) mutations in lung cancer patients using plasma DNA. This aids in selecting appropriate retreatment strategies, potentially improving patient survival.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Accurate detection of epidermal growth factor receptor (EGFR) mutations is crucial for guiding lung cancer treatment decisions.
- While retreatment can prolong survival, identifying suitable patient populations remains a challenge.
Purpose of the Study:
- To develop and validate novel methods for detecting EGFR mutations (exon 19 deletions and L858R).
- To assess the utility of these methods in identifying EGFR mutations in both tumor tissue and circulating plasma DNA.
- To evaluate the potential of plasma DNA-based mutation detection for guiding treatment, including retreatment strategies.
Main Methods:
- Utilized novel wild inhibiting polymerase chain reaction (PCR) and quenched probe system (WIP-QP) for exon 19 deletions.
- Employed mutation-biased PCR and quenched probe system for L858R detection.
- Examined DNA from lung cancer specimens and plasma of 39 adenocarcinoma patients with known EGFR mutations.
Main Results:
- Novel methods demonstrated high sensitivity, with detection limits as low as 0.005 ng in genomic DNA and 0.1% in mutant plasmids.
- EGFR exon 19 deletions and L858R mutations were detected in plasma DNA of 44.7% and 8.7% of patients, respectively.
- Plasma DNA mutation detection correlated with advanced disease stage (pathological stage IV) and showed potential for serial monitoring of mutations like T790M.
Conclusions:
- Novel EGFR mutation detection systems are effective for initial treatment selection and for monitoring treatment response using plasma DNA.
- Plasma DNA analysis offers a non-invasive approach for guiding therapeutic decisions, including rechallenge with EGFR-tyrosine kinase inhibitors.
- These advancements can optimize treatment strategies and potentially improve outcomes for lung cancer patients with EGFR mutations.