title: Detection and characterization of classical and "uncommon" exon 19 Epidermal Growth Factor Receptor mutations in lung cancer by pyrosequencing.
abstract: BACKGROUND
  The management of advanced stage non-small cell lung cancer is increasingly based on diagnostic and predictive analyses performed mostly on limited amounts of tumor tissue. The evaluation of Epidermal Growth Factor Receptor (EGFR) mutations have emerged as the strongest predictor of response to EGFR-tyrosine kinase inhibitors mainly in patients with adenocarcinoma. Several EGFR mutation detection techniques are available, having both sensitivity and specificity issues, being the Sanger sequencing technique the reference standard, with the limitation of a relatively high amount of mutated cells needed for the analysis.
  
  
  METHODS
  A novel nucleotide dispensation order for pyrosequencing was established allowing the identification and characterization of EGFR mutation not definable with commercially and clinically approved kits, and validated in a consecutive series of 321 lung cancer patients (246 biopsies or cytology samples and 75 surgical specimens).
  
  
  RESULTS
  61/321 (19%) mutated cases were detected, 17 (27.9%) in exon 21 and 44 (72.1%) in exon 19, these latter corresponding to 32/44 (72.7%) classical and 12/44 (27.3%) uncommon mutations. Furthermore, a novel, never reported, point mutation, was found, which determined a premature stop codon in the aminoacidic sequence that resulted in a truncated protein in the tyrosine kinase domain, thus impairing the inhibitory effect of specific therapy.
  
  
  CONCLUSIONS
  The novel dispensation order allows to detect and characterize both classical and uncommon EGFR mutations. Although several phase III studies in genotypically defined groups of patients are already available, further prospective studies assessing the role of uncommon EGFR mutations are warranted.
authors.affiliation: Divisions of Pathology, University of Torino, Regione Gonzole 10, Torino, Orbassano 10043, Italy. luisella.righi@unito.it
authors.forename: Luisella
authors.initials: L
authors.lastname: Righi
authors.forename: Alessandra
authors.initials: A
authors.lastname: Cuccurullo
authors.forename: Simona
authors.initials: S
authors.lastname: Vatrano
authors.forename: Susanna
authors.initials: S
authors.lastname: Cappia
authors.forename: Daniela
authors.initials: D
authors.lastname: Giachino
authors.forename: Paolo
authors.initials: P
authors.lastname: De Giuli
authors.forename: Mara
authors.initials: M
authors.lastname: Ardine
authors.forename: Silvia
authors.initials: S
authors.lastname: Novello
authors.forename: Marco
authors.initials: M
authors.lastname: Volante
authors.forename: Giorgio V
authors.initials: GV
authors.lastname: Scagliotti
authors.forename: Mauro
authors.initials: M
authors.lastname: Papotti
mesh_terms: D000704:Analysis of Variance; D000970:Antineoplastic Agents / Q000627:therapeutic use; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics*; D045744:Cell Line, Tumor; D004252:DNA Mutational Analysis / Q000379:methods*; D066246:ErbB Receptors / Q000378:metabolism*; D005091:Exons / Q000235:genetics*; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000235:genetics*; D009154:Mutation; D011446:Prospective Studies; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use
chemical_list: D000970:Antineoplastic Agents; D047428:Protein Kinase Inhibitors; D066246:ErbB Receptors