title: BRAFV600E protein expression in primary cutaneous malignant melanomas and paired metastases.
abstract: OBJECTIVE
  BRAFV600E mutations are present in approximately 50% of cutaneous malignant melanomas (CMMs). The use of BRAFV600E mutation-specific monoclonal antibody VE1 immunohistochemical analysis may facilitate rapid detection of BRAFV600E mutations in CMMs and demonstrate heterogeneity among tumors.
  
  
  OBJECTIVE
  To characterize the pattern of BRAFV600E protein expression in primary CMMs with matched metastases and to analyze the use of VE1 immunohistochemical analysis in clinical practice using formalin-fixed, paraffin-embedded tumor tissue.
  
  
  METHODS
  In this retrospective cohort study performed at Karolinska University Hospital from September 2012 to September 2013, we examined CMMs (124 primary tumors and 76 metastases) with VE1 immunohistochemical analysis, and results were compared with DNA mutation analyses.
  
  
  METHODS
  Determination of intratumoral and intertumoral heterogeneity as well as the sensitivity and specificity of VE1 immunohistochemical analysis.
  
  
  RESULTS
  Positive staining results with the VE1 antibody were detected in 94 of 200 tumors (47.0%). In general, VE1 staining was homogeneous. However, VE1 staining intensity varied among the primary tumors and corresponding metastases in 63 of 135 tumors (46.7%), but a change of mutational status based on DNA analysis was found in only 4 matched tumors (3.0%). Discordant findings between DNA mutation analysis and immunohistochemical analysis were observed in 12 tumors. The overall sensitivity and specificity of VE1 immunohistochemical analysis were 96.7% and 94.5%, respectively. A comparable sensitivity was obtained for primary and metastatic CMMs. The specificity was lower among primary CMMs (92.4%) compared with metastases (98.0%).
  
  
  CONCLUSIONS
  We found VE1 immunohistochemical analysis to be a useful and rapid assay for BRAFV600E mutations that may contribute to the detection of intratumoral and intertumoral heterogenetic subclones. Tumors with positive results, including strong staining, should be expedited for confirmatory BRAF mutation testing. If this test result is negative, a false-negative result of the mutation analysis should be considered. Validation of VE1 immunohistochemical analysis in clinical practice is needed.
authors.affiliation: Department of Oncology-Pathology, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden.
authors.forename: Hanna
authors.initials: H
authors.lastname: Eriksson
authors.affiliation: Department of Oncology-Pathology, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden.
authors.forename: Abdlsattar
authors.initials: A
authors.lastname: Zebary
authors.affiliation: Dermatologic Diagnostic Centre, Unit of Dermatology, Department of Medicine, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden.
authors.forename: Ismini
authors.initials: I
authors.lastname: Vassilaki
authors.affiliation: Department of Oncology-Pathology, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden3Department of Clinical Pathology and Cytology, Karolinska University Hospital Huddinge, Stockholm, Sweden.
authors.forename: Katarina
authors.initials: K
authors.lastname: Omholt
authors.affiliation: Department of Oncology-Pathology, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden.
authors.forename: Mehran
authors.initials: M
authors.lastname: Ghaderi
authors.affiliation: Department of Oncology-Pathology, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Hansson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D008545:Melanoma / Q000235:genetics* / Q000473:pathology; D008875:Middle Aged; D009154:Mutation; D009362:Neoplasm Metastasis / Q000235:genetics; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012878:Skin Neoplasms / Q000235:genetics* / Q000473:pathology; D055815:Young Adult; D000096142:Cutaneous Malignant Melanoma
chemical_list: C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf