EGFR array: uses in the detection of plasma EGFR mutations in non-small cell lung cancer patients

J Thorac Oncol. 2012 Jul;7(7):1131-40. doi: 10.1097/JTO.0b013e3182558198.


Introduction: We aim to develop a simple and sensitive array-based method for the detection of epidermal growth factor receptor (EGFR) gene mutations in the plasma of non-small-cell lung cancer patients and determine its use in the follow-up of those on tyrosine-kinase inhibitor (TKI) therapy.

Method: DNA from 100 μl of plasma was amplified in the presence of peptide nucleic acid clamp to provide single-stranded template for the allele-specific arrayed primer extension reaction, incorporating cyanine-5-deoxycytidine triphosphate in the newly synthesized strands. The fluorescent product was visualized by laser at 670 nm.

Results: Eleven different types of EGFR TKI drug-sensitive mutants (SM) were identified in plasma-DNA from 46 of 51 patients. Five patients carried only wild-type sequence. Plasma-DNA finding was concordant in 36 of 37 cases with tumor-sequencing data. This method could detect as little as 62.5 copies of mutant L858R; 125 copies of E709K + G719A or 625 copies of del 746-750 in the presence of 100,000 copies of wild-type EGFR. In 21 patients on longitudinal follow-up for up to 18 months, SM was found in all initial plasma samples, except for three samples collected after recent chemotherapy. Nine of 16 patients (56%) who responded to TKI had undetectable plasma EGFR mutant. SM was present concurrently with drug-resistant mutant in 44% of patients with disease progression while on TKI, the remaining 56% might have other mechanisms of resistance.

Conclusion: The EGFR array provides a sensitive, inexpensive, and robust method for monitoring non-small-cell lung cancer patients' response to TKI, and obviates the need of repeated lung biopsy.

MeSH terms

  • Adenocarcinoma / blood
  • Adenocarcinoma / genetics
  • Adenocarcinoma / pathology
  • Adult
  • Aged
  • Aged, 80 and over
  • Biomarkers, Tumor / blood
  • Biomarkers, Tumor / genetics*
  • Carcinoma, Non-Small-Cell Lung / blood*
  • Carcinoma, Non-Small-Cell Lung / genetics*
  • Carcinoma, Non-Small-Cell Lung / pathology
  • Carcinoma, Squamous Cell / blood
  • Carcinoma, Squamous Cell / genetics
  • Carcinoma, Squamous Cell / pathology
  • Cross-Sectional Studies
  • DNA Mutational Analysis
  • DNA, Neoplasm / blood
  • DNA, Neoplasm / genetics*
  • Drug Resistance, Neoplasm / genetics
  • ErbB Receptors / genetics*
  • Female
  • Follow-Up Studies
  • Humans
  • Longitudinal Studies
  • Lung Neoplasms / blood
  • Lung Neoplasms / genetics
  • Lung Neoplasms / pathology
  • Male
  • Middle Aged
  • Mutation / genetics*
  • Polymerase Chain Reaction
  • Prognosis
  • Protein Kinase Inhibitors / therapeutic use
  • Small Cell Lung Carcinoma / blood
  • Small Cell Lung Carcinoma / genetics
  • Small Cell Lung Carcinoma / pathology


  • Biomarkers, Tumor
  • DNA, Neoplasm
  • Protein Kinase Inhibitors
  • EGFR protein, human
  • ErbB Receptors