title: A sensitive method for detecting EGFR mutations in non-small cell lung cancer samples with few tumor cells.
abstract: BACKGROUND
  Detection of epidermal growth factor receptor (EGFR) mutations in advanced non-small cell lung cancer (NSCLC) patients has relied on DNA purification from biopsies, amplification, and sequencing. However, the number of tumor cells in a sample is often insufficient for EGFR assessment.
  
  
  METHODS
  We prospectively screened 1380 NSCLC patients for EGFR mutations but found that 268 were not evaluable because of insufficient tumor tissue. We therefore developed and validated a method of detecting EGFR mutations in these samples. Tumor cells were microdissected into polymerase chain reaction buffer and amplified. EGFR mutations were detected by length analysis of fluorescently labeled polymerase chain reaction products and TaqMan assay.
  
  
  RESULTS
  We determined EGFR status in 217 (81%) of the 268 primary NSCLC samples not evaluable in our original study-fresh and paraffin-embedded with less than 150 cells. Exon 19 deletions were detected in 11.5% of patients and exon 21 L858R mutations in 5.5%. In addition, the exon 20 T790M mutation was detected in 6 of 15 (40%) patients at the time of progression to erlotinib. The primary, sensitive mutation was present in all tumor cells, whereas the T790M mutation was absent in some groups.
  
  
  CONCLUSIONS
  The method presented here eliminates the need for DNA purification and allows for detection of EGFR mutations in samples containing as few as eight cancer cells.
authors.affiliation: Catalan Institute of Oncology, Medical Oncology Service, Hosptial Germans Trias i Pujol, Badalona, Spain.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Molina-Vila
authors.forename: Jordi
authors.initials: J
authors.lastname: Bertran-Alamillo
authors.forename: Noemí
authors.initials: N
authors.lastname: Reguart
authors.forename: Miquel
authors.initials: M
authors.lastname: Taron
authors.forename: Eva
authors.initials: E
authors.lastname: Castellà
authors.forename: Mariona
authors.initials: M
authors.lastname: Llatjós
authors.forename: Carlota
authors.initials: C
authors.lastname: Costa
authors.forename: Clara
authors.initials: C
authors.lastname: Mayo
authors.forename: Anna
authors.initials: A
authors.lastname: Pradas
authors.forename: Cristina
authors.initials: C
authors.lastname: Queralt
authors.forename: Mónica
authors.initials: M
authors.lastname: Botia
authors.forename: María
authors.initials: M
authors.lastname: Pérez-Cano
authors.forename: Esther
authors.initials: E
authors.lastname: Carrasco
authors.forename: Mireia
authors.initials: M
authors.lastname: Tomàs
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Mate
authors.forename: Teresa
authors.initials: T
authors.lastname: Moran
authors.forename: Rafael
authors.initials: R
authors.lastname: Rosell
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy / Q000235:genetics / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D004273:DNA, Neoplasm / Q000235:genetics; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000235:genetics*; D000069347:Erlotinib Hydrochloride; D005091:Exons; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D009367:Neoplasm Staging; D016133:Polymerase Chain Reaction / Q000379:methods*; D011379:Prognosis; D011446:Prospective Studies; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use; D011799:Quinazolines / Q000627:therapeutic use; D012680:Sensitivity and Specificity; D015996:Survival Rate
chemical_list: D004273:DNA, Neoplasm; D047428:Protein Kinase Inhibitors; D011799:Quinazolines; D000069347:Erlotinib Hydrochloride; D066246:ErbB Receptors