title: Plasma epidermal growth factor receptor mutation testing with a chip-based digital PCR system in patients with advanced non-small cell lung cancer.
abstract: Epidermal growth factor receptor (EGFR) mutation testing is a companion diagnostic to determine eligibility for treatment with EGFR tyrosine kinase inhibitors (EGFR-TKIs) in non-small cell lung cancer (NSCLC). Recently, plasma-based EGFR testing by digital polymerase chain reaction (dPCR), which enables accurate quantification of target DNA, has shown promise as a minimally invasive diagnostic. Here, we aimed to evaluate the accuracy of a plasma-based EGFR mutation test developed using chip-based dPCR-based detection of 3 EGFR mutations (exon 19 deletions, L858R in exon 21, and T790M in exon 20).
  
  
  
  Forty-nine patients with NSCLC harboring EGFR-activating mutations were enrolled, and circulating free DNAs (cfDNAs) were extracted from the plasma of 21 and 28 patients before treatment and after progression following EGFR-TKI treatment, respectively.
  
  
  
  Using reference genomic DNA containing each mutation, the detection limit of each assay was determined to be 0.1%. The sensitivity and specificity of detecting exon 19 deletions and L858R mutations, calculated by comparing the mutation status in the corresponding tumors, were 70.6% and 93.3%, and 66.7% and 100%, respectively, showing similar results compared with previous studies. T790M was detected in 43% of 28 cfDNAs after progression with EGFR-TKI treatment, but in no cfDNAs before the start of the treatment.
  
  
  
  This chip-based dPCR assay can facilitate detection of EGFR mutations in cfDNA as a minimally invasive method in clinical settings.
authors.affiliation: Division of Thoracic Oncology, Shizuoka Cancer Center, Japan; Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, 3-39-15, Showa-machi, Maebashi, Gunma 371-8511, Japan.
authors.forename: Norimitsu
authors.initials: N
authors.lastname: Kasahara
authors.affiliation: Division of Thoracic Oncology, Shizuoka Cancer Center, Japan. Electronic address: h.kenmotsu@scchr.jp.
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Kenmotsu
authors.affiliation: Drug Discovery and Development Division, Shizuoka Cancer Center Research Institute, Japan. Electronic address: m.serizawa@scchr.jp.
authors.forename: Masakuni
authors.initials: M
authors.lastname: Serizawa
authors.affiliation: Drug Discovery and Development Division, Shizuoka Cancer Center Research Institute, Japan.
authors.forename: Rina
authors.initials: R
authors.lastname: Umehara
authors.affiliation: Division of Thoracic Oncology, Shizuoka Cancer Center, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Ono
authors.affiliation: Division of Thoracic Oncology, Shizuoka Cancer Center, Japan; Department of Medical Oncology and Hematology, Oita University Faculty of Medicine, 1-1 Idaigaoka, Hasamamachi, Yufu, Oita, 879-5593, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Hisamatsu
authors.affiliation: Division of Thoracic Oncology, Shizuoka Cancer Center, Japan.
authors.forename: Kazushige
authors.initials: K
authors.lastname: Wakuda
authors.affiliation: Division of Thoracic Oncology, Shizuoka Cancer Center, Japan.
authors.forename: Shota
authors.initials: S
authors.lastname: Omori
authors.affiliation: Division of Thoracic Oncology, Shizuoka Cancer Center, Japan.
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Nakashima
authors.affiliation: Division of Thoracic Oncology, Shizuoka Cancer Center, Japan; Division of Respiratory Medicine, Minami Kyushu National Hospital, 1882 Kida, Kajiki-chou, Aira, Kagoshima, 899-5293, Japan.
authors.forename: Tetsuhiko
authors.initials: T
authors.lastname: Taira
authors.affiliation: Division of Thoracic Oncology, Shizuoka Cancer Center, Japan.
authors.forename: Tateaki
authors.initials: T
authors.lastname: Naito
authors.affiliation: Division of Thoracic Oncology, Shizuoka Cancer Center, Japan.
authors.forename: Haruyasu
authors.initials: H
authors.lastname: Murakami
authors.affiliation: Third Department of Internal Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama, Wakayama, 641-8509, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Koh
authors.affiliation: Clinical Trial Coordination Office, Shizuoka Cancer Center, Japan.
authors.forename: Keita
authors.initials: K
authors.lastname: Mori
authors.affiliation: Division of Diagnostic Radiology, Shizuoka Cancer Center, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Endo
authors.affiliation: Division of Diagnostic Pathology, Shizuoka Cancer Center, 1007 Shimonagakubo, Nagaizumi-chou, Suntou-gun, Shizuoka, 411-8777, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakajima
authors.affiliation: Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, 3-39-15, Showa-machi, Maebashi, Gunma 371-8511, Japan.
authors.forename: Masanobu
authors.initials: M
authors.lastname: Yamada
authors.affiliation: Drug Discovery and Development Division, Shizuoka Cancer Center Research Institute, Japan.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Kusuhara
authors.affiliation: Division of Thoracic Oncology, Shizuoka Cancer Center, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Takahashi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D000073888:Cell-Free Nucleic Acids / Q000235:genetics*; D018450:Disease Progression; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000097:blood / Q000235:genetics*; D005091:Exons; D005260:Female; D006801:Humans; D000073890:Liquid Biopsy; D008175:Lung Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009154:Mutation; D016133:Polymerase Chain Reaction; D011446:Prospective Studies; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use; D017384:Sequence Deletion
chemical_list: D014408:Biomarkers, Tumor; D000073888:Cell-Free Nucleic Acids; D047428:Protein Kinase Inhibitors; C512478:EGFR protein, human; D066246:ErbB Receptors
keywords: Circulating free DNA; Digital PCR; Epidermal growth factor receptor mutation; Liquid biopsy; Non-small cell lung cancer