title: Immunohistochemical detection of mutations in the epidermal growth factor receptor gene in lung adenocarcinomas using mutation-specific antibodies.
abstract: BACKGROUND
  The recent development of antibodies specific for the major hotspot mutations in the epidermal growth factor receptor (EGFR), L858R and E746_A750del, may provide an opportunity to use immunohistochemistry (IHC) as a screening test for EGFR gene mutations. This study was designed to optimize the IHC protocol and the criteria for interpretation of the results using DNA sequencing as the gold-standard.
  
  
  METHODS
  Tumor sections from fifty lung adenocarcinoma specimens from Chinese patients were immunostained using L858R and E746_A750del-specific antibodies using three different antigen retrieval solutions, and the results were evaluated using three different sets of criteria. The same specimens were used for DNA purification and analysis of EGFR gene mutations.
  
  
  RESULTS
  In this study the optimal buffer for antigen retrieval was EDTA (pH 8.0), and the optimal scoring method was to call positive results when there was moderate to strong staining of membrane and/or cytoplasm in >10% of the tumor cells. Using the optimized protocol, L858R-specific IHC showed a sensitivity of 81% and a specificity of 97%, and E746_A750del-specific IHC showed a sensitivity of 59% and a specificity of 100%, both compared with direct DNA analysis. Additionally, the mutant proteins as assessed by IHC showed a more homogeneous than heterogeneous pattern of expression.
  
  
  CONCLUSIONS
  Our data demonstrate that mutation-specific IHC, using optimized procedures, is a reliable prescreening test for detecting EGFR mutations in lung adenocarcinoma.
  The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2059012601872392.
authors: Yan
authors: Y
authors: Xiong
authors: Yun
authors: Y
authors: Bai
authors: Nufatt
authors: N
authors: Leong
authors: Todd S
authors: TS
authors: Laughlin
authors: Paul G
authors: PG
authors: Rothberg
authors: Haodong
authors: H
authors: Xu
authors: Lin
authors: L
authors: Nong
authors: Jing
authors: J
authors: Zhao
authors: Ying
authors: Y
authors: Dong
authors: Ting
authors: T
authors: Li
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics* / Q000276:immunology / Q000473:pathology; D000077192:Adenocarcinoma of Lung; D000906:Antibodies; D000918:Antibody Specificity; D002021:Buffers; D002681:China; D004252:DNA Mutational Analysis / Q000379:methods*; D066246:ErbB Receptors / Q000235:genetics* / Q000276:immunology; D005091:Exons; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000235:genetics* / Q000276:immunology / Q000473:pathology; D009154:Mutation; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013048:Specimen Handling
chemical_list: D000906:Antibodies; D002021:Buffers; C512478:EGFR protein, human; D066246:ErbB Receptors