title: Peptide Nucleic Acid Clamping Versus Direct Sequencing for the Detection of EGFR Gene Mutation in Patients with Non-small Cell Lung Cancer.
abstract: OBJECTIVE
  Direct sequencing (DS) is the standard method for detection of epidermal growth factor receptor (EGFR) gene mutation in non-small cell lung cancer (NSCLC); however, low detection sensitivity is a problem. The aim of this study is to demonstrate higher detection rate of EGFR gene mutation with peptide nucleic acid (PNA) clamping compared with DS.
  
  
  METHODS
  This is a single arm, prospective study for patients with stage IIIB/IV or relapsed NSCLC. Using tumor DNA from 138 patients, both DS and PNA clamping for EGFR gene in exon 18, 19, 20, and 21 were performed. Discrepant results between the two methods were verified using Cobas and a mutant enrichment based next generation sequencing (NGS). Patients with activating mutations were treated with EGFR tyrosine kinase inhibitor (EGFR-TKI, gefitinib, or erlotinib) as first line treatment.
  
  
  RESULTS
  Of 138 paired test sets, 24 (17.4%) and 45 (32.6%) cases with activating mutations were detected by DS and PNA clamping, respectively. The difference of detection rate between the two methods was 15.2% (95% confidence interval, 8.7% to 17.8%; p < 0.001). Between the two methods, 25 cases showed discrepant results (n=23, PNA+/DS-; n=2, PNA-/DS+). Mutations were confirmed by Cobas or NGS in 22 of 23 PNA+/DS- cases. The response rates to EGFR-TKI were 72.2% in the PNA+/DS+ group and 85.0% in the PNA+/DS- group.
  
  
  CONCLUSIONS
  PNA clamping showed a significantly higher detection rate of EGFR gene mutation compared with DS. Higher sensitivity of PNA clamping was not compromised by the loss of predictive power of response to EGFR-TKI.
authors.affiliation: Lung and Esophageal Cancer Clinic, Chonnam National University Hwasun Hospital, Hwasun, Korea.|Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea.
authors.forename: Seong-Hoon
authors.initials: SH
authors.lastname: Yoon
authors.affiliation: Lung and Esophageal Cancer Clinic, Chonnam National University Hwasun Hospital, Hwasun, Korea.|Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Yoo-Duk
authors.initials: YD
authors.lastname: Choi
authors.affiliation: Lung and Esophageal Cancer Clinic, Chonnam National University Hwasun Hospital, Hwasun, Korea.|Chonnam National University Medical School, Gwangju, Korea.
authors.forename: In-Jae
authors.initials: IJ
authors.lastname: Oh
authors.affiliation: Lung and Esophageal Cancer Clinic, Chonnam National University Hwasun Hospital, Hwasun, Korea.|Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Kyu-Sik
authors.initials: KS
authors.lastname: Kim
authors.affiliation: Lung and Esophageal Cancer Clinic, Chonnam National University Hwasun Hospital, Hwasun, Korea.|Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Hayoung
authors.initials: H
authors.lastname: Choi
authors.affiliation: Lung and Esophageal Cancer Clinic, Chonnam National University Hwasun Hospital, Hwasun, Korea.|Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Jinsun
authors.initials: J
authors.lastname: Chang
authors.affiliation: Lung and Esophageal Cancer Clinic, Chonnam National University Hwasun Hospital, Hwasun, Korea.|Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Hong-Joon
authors.initials: HJ
authors.lastname: Shin
authors.affiliation: Lung and Esophageal Cancer Clinic, Chonnam National University Hwasun Hospital, Hwasun, Korea.|Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Cheol-Kyu
authors.initials: CK
authors.lastname: Park
authors.affiliation: Lung and Esophageal Cancer Clinic, Chonnam National University Hwasun Hospital, Hwasun, Korea.|Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Young-Chul
authors.initials: YC
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000201:enzymology* / Q000235:genetics*; D004252:DNA Mutational Analysis / Q000379:methods*; D066246:ErbB Receptors / Q000235:genetics*; D005260:Female; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D008175:Lung Neoplasms / Q000201:enzymology* / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D020135:Peptide Nucleic Acids / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D055815:Young Adult
chemical_list: D020135:Peptide Nucleic Acids; C512478:EGFR protein, human; D066246:ErbB Receptors
keywords: Genes; Mutation; Peptide nucleic acids; erbB-1