title: Is immunohistochemistry of BRAF V600E useful as a screening tool and during progression disease of melanoma patients?
abstract: In clinical practice the gold standard method to assess BRAF status in patients with metastatic melanoma is based on molecular assays. Recently, a mutation-specific monoclonal antibody (VE1), which detects the BRAF V600E mutated protein, has been developed. With this study we aimed to confirm the clinical value of the VE1 Ventana® antibody, as today a univocal validated and accredited immunohistochemical procedure does not exist, to preliminary detect BRAF status in our routine diagnostic procedures. Moreover, we explored the biological meaning of BRAF immunohistochemical labeling both as a predictor marker of response to target therapy and, for the first time, as a player of acquired tumor drug resistance.
  
  
  
  We analyzed a retrospective series of 64 metastatic melanoma samples, previously investigated for molecular BRAF status, using a fully automatized immunohistochemical method. We correlated the data to the clinicopathologic characteristics of patients and their clinical outcome.
  
  
  
  The sensitivity and the specificity of the Ventana® VE1 antibody were 89.2 and 96.2% respectively, while the positive predictive value and negative predictive value were 97.1 and 86.2%, respectively. For six mutated patients the histological sample before treatment and when disease progressed was available. The immunohistochemical BRAF V600E expression in the specimens when disease progressed was less intense and more heterogeneous compared to the basal expression. Multivariate analysis revealed that a less intense grade of positive expression is an independent predictor of a less aggressive stage at diagnosis (p = 0.0413).
  
  
  
  Our findings encourage the introduction of immunohistochemistry as a rapid screening tool for the assessment of BRAF status in melanoma patients in routine diagnostic procedures and prepare the ground for other studies to highlight the role of immunohistochemical BRAF V600E expression in patients at the time of progression.
authors.affiliation: Functional Biomorphology Laboratory, IRCCS Istituto Tumori "Giovanni Paolo II", Viale Orazio Flacco 65, 70124, Bari, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Schirosi
authors.affiliation: Medical Oncology Department, IRCCS Istituto Tumori "Giovanni Paolo II", Viale Orazio Flacco 65, 70124, Bari, Italy.
authors.forename: Sabino
authors.initials: S
authors.lastname: Strippoli
authors.affiliation: Functional Biomorphology Laboratory, IRCCS Istituto Tumori "Giovanni Paolo II", Viale Orazio Flacco 65, 70124, Bari, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Gaudio
authors.affiliation: Scientific Direction, IRCCS Istituto Tumori "Giovanni Paolo II", Viale Orazio Flacco 65, 70124, Bari, Italy.
authors.forename: Giusi
authors.initials: G
authors.lastname: Graziano
authors.affiliation: Pathology Department, IRCCS Istituto Tumori "Giovanni Paolo II", Viale Orazio Flacco 65, 70124, Bari, Italy.
authors.forename: Ondina
authors.initials: O
authors.lastname: Popescu
authors.affiliation: Medical Oncology Department, IRCCS Istituto Tumori "Giovanni Paolo II", Viale Orazio Flacco 65, 70124, Bari, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Guida
authors.affiliation: Pathology Department, IRCCS Istituto Tumori "Giovanni Paolo II", Viale Orazio Flacco 65, 70124, Bari, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Simone
authors.affiliation: Functional Biomorphology Laboratory, IRCCS Istituto Tumori "Giovanni Paolo II", Viale Orazio Flacco 65, 70124, Bari, Italy. a.mangia@oncologico.bari.it.
authors.forename: Anita
authors.initials: A
authors.lastname: Mangia
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D018450:Disease Progression; D055088:Early Detection of Cancer / Q000379:methods*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D008297:Male; D008545:Melanoma / Q000175:diagnosis / Q000235:genetics / Q000378:metabolism*; D008875:Middle Aged; D009154:Mutation; D009362:Neoplasm Metastasis; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics / Q000378:metabolism*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D048493:Proto-Oncogene Proteins B-raf
keywords: BRAF; Immunohistochemistry; Melanoma; Progression; VE1