title: Detection of BRAF p.V600E Mutations in Melanoma by Immunohistochemistry Has a Good Interobserver Reproducibility.
abstract: BACKGROUND
  Assessment of BRAF p.V600E mutational status has become necessary for treatment of patients with metastatic melanoma. Detection of p.V600E mutation by immunohistochemistry was recently reported in several tumor types.
  
  
  OBJECTIVE
  To evaluate the interobserver reproducibility of BRAF p.V600E detection by immunohistochemistry in melanoma.
  
  
  METHODS
  Immunohistochemistry with VE1 antibody was performed on metastatic melanomas of 67 patients. Staining interpretation was performed on digital image virtual slides of tissue microarrays. The p.V600E status was determined by 7 pathologists from 3 European laboratories, blinded for other interpretations and for molecular biology results.
  
  
  RESULTS
  Melanomas had p.V600E (n = 30), p.V600K (n = 4), p.K601E (n = 1), p.600-601delinsE (n = 1), or no p.V600 mutations (n = 31). Staining of p.V600E within mutated cells was cytoplasmic and diffuse, and for each case the staining on the 3 tissue microarray cores was similar. In 53 cases (79.1%) the 7 pathologists had perfect concordance. Agreement of interobserver reproducibility was almost perfect (κ = 0.81 [0.77-0.85]). Only 2 false-positive responses (0.9%) were obtained. The specificities reported were 100% for 5 pathologists (two of whom previously trained for p.V600E interpretation), and 97% for 2 untrained pathologists.
  
  
  CONCLUSIONS
  Detection of BRAF p.V600E mutation by immunohistochemistry in melanomas has an excellent interobserver reproducibility. Our results suggest that immunohistochemistry could be used as a first step for detection of BRAF p.V600E mutation, to identify patients with melanoma as candidates for BRAF inhibitors.
authors: From units EA4340 (Drs Marin, Julié, and Emile) and EA4339 (Drs Beauchet, Zimmermann, and Saiag), Versailles SQY University, Boulogne, France; the Departments of Pathology (Drs Marin, Zimmermann, Julié, and Emile), Public Health (Dr Beauchet), and General and Oncologic Dermatology (Dr Saiag), Ambroise Pare Hospital, APHP, Boulogne, France; the Department of Neuropathology, Ruprecht-Karls-University Heidelberg, and Clinical Cooperation Unit Neuropathology, German Cancer Research Center (DKFZ), Heidelberg, Germany (Drs Capper and Deimling); and the Laboratory of Clinical and Experimental Pathology, Pasteur Hospital and Medical School, Nice Sophia University, Nice, France (Drs Ilie and Hofman).
authors: Cristi
authors: C
authors: Marin
authors: Alain
authors: A
authors: Beauchet
authors: David
authors: D
authors: Capper
authors: Ute
authors: U
authors: Zimmermann
authors: Catherine
authors: C
authors: Julié
authors: Marius
authors: M
authors: Ilie
authors: Philippe
authors: P
authors: Saiag
authors: Andreas
authors: A
authors: von Deimling
authors: Paul
authors: P
authors: Hofman
authors: Jean-François
authors: JF
authors: Emile
mesh_terms: D004252:DNA Mutational Analysis / Q000379:methods*; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D008545:Melanoma / Q000235:genetics*; D009154:Mutation; D015588:Observer Variation; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D015203:Reproducibility of Results; D046888:Tissue Array Analysis
chemical_list: C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf