Immunohistochemistry is highly sensitive and specific for the detection of V600E BRAF mutation in melanoma

Am J Surg Pathol. 2013 Jan;37(1):61-5. doi: 10.1097/PAS.0b013e31826485c0.

Abstract

This study investigated the sensitivity and specificity of immunohistochemical (IHC) analysis using an anti-BRAF antibody to detect the presence of the BRAF V600E mutation in patients with metastatic melanoma. A total of 100 patients with American Joint Committee on Cancer stage IIIC unresectable or stage IV melanoma and who underwent tumor DNA BRAF mutation testing were selected. Paraffin-embedded, formalin-fixed melanoma biopsies were analyzed for the BRAF mutation status by independent, blinded observers using both conventional DNA molecular techniques and IHC with the novel BRAF V600E mutant-specific antibody, VE1. The antibody had a sensitivity of 97% (37/38) and a specificity of 98% (58/59) for detecting the presence of a BRAF V600E mutation. Of the BRAF-mutated cases, none of the non-V600E cases (including V600K) stained positive with the antibody (0/11). There were 5 cases with discordant BRAF mutation results. Additional molecular analysis confirmed the immunohistochemically obtained BRAF result in 3 cases, suggesting that the initial molecular testing results were incorrect. Two of these patients would not have received a BRAF inhibitor on the basis of the initial false-negative mutation testing result. Two cases remained discordant. The reported IHC method is an accurate, rapid, and cost-effective method for detecting V600E BRAF mutations in melanoma patients. Clinical use of the V600E BRAF antibody should be a valuable supplement to conventional mutation testing and allow V600E mutant metastatic melanoma patients to be triaged rapidly into appropriate treatment pathways.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Monoclonal / metabolism
  • Biomarkers, Tumor / genetics*
  • Biomarkers, Tumor / metabolism
  • DNA Mutational Analysis
  • Humans
  • Immunohistochemistry / methods*
  • Melanoma / genetics*
  • Melanoma / metabolism
  • Melanoma / pathology
  • Mutation*
  • Neoplasm Staging
  • Predictive Value of Tests
  • Proto-Oncogene Proteins B-raf / genetics*
  • Proto-Oncogene Proteins B-raf / metabolism
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Skin Neoplasms / genetics*
  • Skin Neoplasms / metabolism
  • Skin Neoplasms / pathology

Substances

  • Antibodies, Monoclonal
  • Biomarkers, Tumor
  • BRAF protein, human
  • Proto-Oncogene Proteins B-raf