title: Can serum be used for analyzing the EGFR mutation status in patients with advanced non-small cell lung cancer?
abstract: BACKGROUND
  Epidermal growth factor receptor (EGFR) mutations as prognostic or predictive marker in patients with non-small cell lung cancer (NSCLC) have been used widely. However, it may be difficult to get tumor tissue for analyzing the status of EGFR mutation status in large proportion of patients with advanced disease.
  
  
  METHODS
  We obtained pairs of tumor and serum samples from 57 patients with advanced NSCLC, between March 2006 and January 2009. EGFR mutation status from tumor samples was analyzed by genomic polymerase chain reaction and direct sequence and EGFR mutation status from serum samples was determined by the peptide nucleic acid locked nucleic acid polymerase chain reaction clamp.
  
  
  RESULTS
  EGFR mutations were detected in the serum samples of 11 patients and in the tumor samples of 12 patients. EGFR mutation status in the serum and tumor samples was consistent in 50 of the 57 pairs (87.7%). There was a high correlation between the mutations detected in serum sample and the mutations detected in the matched tumor sample (correlation index 0.62; P<0.001). Twenty-two of 57 patients (38.5%) received EGFR-tyrosine kinase inhibitors as any line therapy. The response for EGFR-tyrosine kinase inhibitors was significantly associated with EGFR mutations in both tumor samples and serum samples (P<0.05). There was no significant differences in overall survival according to the status of EGFR mutations in both serum and tumor samples (P>0.05).
  
  
  CONCLUSIONS
  Serum sample might be alternatively used in the difficult time of getting tumor tissue for analyzing the status of EGFR mutation status in patients with advanced NSCLC.
authors.affiliation: Division of Hematology-Oncology, Korea University College of Medicine, Seoul, South Korea.
authors.forename: Seung Tae
authors.initials: ST
authors.lastname: Kim
authors.forename: Hae-Yun
authors.initials: HY
authors.lastname: Jung
authors.forename: Jae Sook
authors.initials: JS
authors.lastname: Sung
authors.forename: Uk Hyun
authors.initials: UH
authors.lastname: Jo
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Tanaka
authors.forename: Koichi
authors.initials: K
authors.lastname: Hagiwara
authors.forename: Kyong Hwa
authors.initials: KH
authors.lastname: Park
authors.forename: Sang Won
authors.initials: SW
authors.lastname: Shin
authors.forename: Jun Suk
authors.initials: JS
authors.lastname: Kim
authors.forename: Yeul Hong
authors.initials: YH
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood* / Q000235:genetics; D002289:Carcinoma, Non-Small-Cell Lung / Q000097:blood* / Q000235:genetics* / Q000473:pathology; D004252:DNA Mutational Analysis / Q000379:methods*; D005260:Female; D018773:Genes, erbB-1 / Q000235:genetics*; D006801:Humans; D008175:Lung Neoplasms / Q000097:blood* / Q000235:genetics* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009367:Neoplasm Staging; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity
chemical_list: D014408:Biomarkers, Tumor