title: Detection of low-level EGFR T790M mutation in lung cancer tissues.
abstract: Epidermal growth factor receptor (EGFR) gene mutation status is critical to predicting responsiveness to EGFR tyrosine kinase inhibitor (TKI) therapies in non-small cell lung cancer (NSCLC) patients. However, a vast majority of the patients experience recurrence of the cancers by a secondary mutation of EGFR (T790M). Earlier studies suggested evidence that subclones bearing EGFR T790M mutation pre-exist in NSCLCs even prior to the therapies. However, to date, the status of T790M mutation in primary NSCLC is largely known. In this study, we developed an assay using peptide nucleic acid (PNA)-clamping PCR for detection of low-level EGFR T790M mutation. We found that the assay showed the highest sensitivity (0.01% mutation detection) in the clamping condition. We analyzed 147 NSCLC tissues [70 adenocarcinomas (AD), 62 squamous cell carcinomas (SQ), 12 large cell carcinomas (LC), and three adenosquamous carcinomas] that had not been exposed to the TKI therapies, and found 12 (8.2%; 12/147) EGFR T790M mutation in eight AD (11.4%), three SQ (4.8%), and one LC (8.3%) by the PNA-clamping PCR. However, this mutation was not detected by conventional DNA sequencing. Our data indicate that EGFR T790M exists in pretreatment NSCLC at low levels irrespective of histologic types. This study provides a basis for developing an applicable protocol for detecting low-level EGFR T790M mutation in primary NSCLC, which might contribute to predicting recurrence of the tumor in response to the TKI therapies.
authors.affiliation: Department of Pathology, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Ji Eun
authors.initials: JE
authors.lastname: Oh
authors.forename: Chang Hyeok
authors.initials: CH
authors.lastname: An
authors.forename: Nam Jin
authors.initials: NJ
authors.lastname: Yoo
authors.forename: Sug Hyung
authors.initials: SH
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use; D001483:Base Sequence; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy / Q000235:genetics*; D045744:Cell Line, Tumor; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D066246:ErbB Receptors / Q000037:antagonists & inhibitors; D005260:Female; D018773:Genes, erbB-1; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009364:Neoplasm Recurrence, Local; D020135:Peptide Nucleic Acids; D016133:Polymerase Chain Reaction; D047428:Protein Kinase Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D017422:Sequence Analysis, DNA
chemical_list: D000970:Antineoplastic Agents; D020135:Peptide Nucleic Acids; D047428:Protein Kinase Inhibitors; D066246:ErbB Receptors