title: Comparison of epidermal growth factor receptor mutations between primary tumors and lymph nodes in non-small cell lung cancer: a review and meta-analysis of published data.
abstract: BACKGROUND
  Epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancer (NSCLC) can predict the clinical response to tyrosine kinase inhibitor (TKI) therapy. However, EGFR mutations may be different in primary tumors (PT) and metastatic lymph nodes (MLN). The aim of this study was to compare EGFR mutations between PT and the corresponding MLN in NSCLC patients, and provide some guidelines for clinical treatment using TKI therapy.
  
  
  METHODS
  A systematic review and meta-analysis was performed with several research databases. Relative risk (RR) with the 95% confidence interval (CI) were used to investigate the EGFR mutation status between PT and the corresponding MLN. A random-effects model was used.
  
  
  RESULTS
  9 publications involving 707 patients were included in the analysis. It was found that activation of EGFR mutations identified in PT and the corresponding MLN was 26.4% (187/707) and 19.9% (141/707), respectively. The overall discordance rate in our meta-analysis was 12.2% (86/707). The relative risk (RR) for EGFR mutation in PT relative to MLN was 1.33 (95%CI: 1.10-1.60; random-effects model). There was no significant heterogeneity between the studies (I2=5%, p=0.003).
  
  
  CONCLUSIONS
  There exists a considerable degree of EGFR mutation discrepancy in NSCLC between PT and corresponding MLN, suggesting that tumor heterogeneity might arise at the molecular level during the process of metastasis.
authors: Department of Respiratory Disease, Tongling People's Hospital, Tongling, China E-mail : sycaolejie@163.com.
authors: Feng
authors: F
authors: Wang
authors: Ping
authors: P
authors: Fang
authors: Dan-Yang
authors: DY
authors: Hou
authors: Zai-Jun
authors: ZJ
authors: Leng
authors: Le-Jie
authors: LJ
authors: Cao
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D066246:ErbB Receptors / Q000235:genetics*; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000235:genetics*; D008198:Lymph Nodes / Q000473:pathology; D008207:Lymphatic Metastasis / Q000235:genetics* / Q000473:pathology; D009154:Mutation / Q000235:genetics*; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use
chemical_list: D047428:Protein Kinase Inhibitors; C512478:EGFR protein, human; D066246:ErbB Receptors