title: EGFR mutations detected on cytology samples by a centralized laboratory reliably predict response to gefitinib in non-small cell lung carcinoma patients.
abstract: BACKGROUND
  Epidermal growth factor receptor (EGFR) mutations are reliably detected by referral laboratories, even if most lung cancer cytology specimens sent to such laboratories contain very few cells. However, EGFR mutations may be distributed heterogeneously within tumors, thereby raising concerns that mutations detected on cytology are not representative of the entire tumor and, thus, are less reliable in predicting response to tyrosine kinase inhibitor (TKI) treatment than mutations detected on histology. To address this issue, the authors reviewed their clinical practice archives and compared the outcome of TKI treatment among patients who were selected by cytology versus patients who were selected by histology.
  
  
  METHODS
  From July 2010 to July 2012, 364 cytology samples and 318 histology samples were received. Exon 19 deletions and the L858R point mutation in exon 21, detected by fragment assay and TaqMan assay, respectively, were confirmed by direct sequencing; discrepancies were resolved by cloning polymerase chain reaction products. The response rate (RR) and progression-free survival (PFS) at 12 months (range, 3-34 months) were evaluable in 13 EGFR-mutated patients who were selected for treatment by cytology and 13 patients who were selected by histology.
  
  
  RESULTS
  The mutation rate was similar in histology samples (8.5%) and cytology samples (8.8%). The RR (54%) and PFS (9.2 months) were similar in histologically selected patients and cytologically selected patients (RR, 62%; PFS, 8.6 months; P = .88). The disease control rate (responsive plus stable disease) was 92% in histologically selected patients and 100% in cytologically selected patients.
  
  
  CONCLUSIONS
  EGFR mutations detected on cytology specimens by a centralized laboratory can predict TKI treatment response equally well as mutations identified on histology samples.
authors.affiliation: Department of Public Health, University of Naples Federico II, Naples, Italy.
authors.forename: Umberto
authors.initials: U
authors.lastname: Malapelle
authors.forename: Claudio
authors.initials: C
authors.lastname: Bellevicine
authors.forename: Caterina
authors.initials: C
authors.lastname: De Luca
authors.forename: Maria
authors.initials: M
authors.lastname: Salatiello
authors.forename: Alfonso
authors.initials: A
authors.lastname: De Stefano
authors.forename: Danilo
authors.initials: D
authors.lastname: Rocco
authors.forename: Nicla
authors.initials: N
authors.lastname: de Rosa
authors.forename: Fabiana
authors.initials: F
authors.lastname: Vitiello
authors.forename: Stefania
authors.initials: S
authors.lastname: Russo
authors.forename: Francesco
authors.initials: F
authors.lastname: Pepe
authors.forename: Antonino
authors.initials: A
authors.lastname: Iaccarino
authors.forename: Pietro
authors.initials: P
authors.lastname: Micheli
authors.forename: Alfonso
authors.initials: A
authors.lastname: Illiano
authors.forename: Chiara
authors.initials: C
authors.lastname: Carlomagno
authors.forename: Franco Vito
authors.initials: FV
authors.lastname: Piantedosi
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Troncone
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics / Q000401:mortality / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000401:mortality / Q000473:pathology; D003581:Cytodiagnosis; D066246:ErbB Receptors / Q000235:genetics*; D005260:Female; D000077156:Gefitinib; D005838:Genotype; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D009367:Neoplasm Staging; D016133:Polymerase Chain Reaction; D011379:Prognosis; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use; D011799:Quinazolines / Q000627:therapeutic use*; D015996:Survival Rate
chemical_list: D047428:Protein Kinase Inhibitors; D011799:Quinazolines; C512478:EGFR protein, human; D066246:ErbB Receptors; D000077156:Gefitinib
keywords: adenocarcinoma; cytopathology; epidermal growth factor receptor; gefitinib; lung cancer; molecular testing