title: BRAFV600E mutation in the diagnosis of unicystic ameloblastoma.
abstract: BACKGROUND
  Unicystic ameloblastoma, an odontogenic neoplasm, presents clinical and radiographic similarities with dentigerous and radicular cysts, non-neoplastic lesions. It is not always possible to reach a final diagnosis with the incisional biopsy, leading to inappropriate treatment. The BRAFV600E activating mutation has been reported in a high proportion of ameloblastomas. The purpose of the study was to assess the utility of the detection of the BRAFV600E mutation in the differential diagnosis of unicystic ameloblastoma with dentigerous and radicular cysts.
  
  
  METHODS
  Twenty-six archival samples were included, comprising eight unicystic ameloblastomas (UAs), nine dentigerous and nine radicular cysts. The mutation was assessed in all samples by anti-BRAFV600E (clone VE1) immunohistochemistry (IHC) and by TaqMan mutation detection qPCR assay. Sanger sequencing was further carried out when samples showed conflicting results in the IHC and qPCR.
  
  
  RESULTS
  Although all UAs (8/8) showed positive uniform BRAFV600E staining along the epithelial lining length, the mutation was not confirmed by qPCR and Sanger sequencing in three samples. Positive staining for the BRAFV600E protein was observed in one dentigerous cyst, but it was not confirmed by the molecular methods. Furthermore, 2/9 dentigerous cysts and 2/9 radicular cysts showed non-specific immunostaining of the epithelium or plasma cells. None of the dentigerous or radicular cysts cases presented the BRAFV600E mutation in the qPCR assay.
  
  
  CONCLUSIONS
  The BRAFV600E antibody (clone VE1) IHC may show non-specific staining, but molecular assays may be useful for the diagnosis of unicystic ameloblastoma, in conjunction with clinical, radiological and histopathological features.
authors.affiliation: Department of Oral Surgery and Pathology, School of Dentistry, Universidade Federal de Minas Gerais-UFMG, Belo Horizonte, Brazil.
authors.forename: Núbia Braga
authors.initials: NB
authors.lastname: Pereira
authors.affiliation: School of Dentistry, Universidade Federal do Ceará-UFC, Ceará, Brazil.
authors.forename: Karuza Maria Alves
authors.initials: KM
authors.lastname: Pereira
authors.affiliation: Department of Oral Surgery and Pathology, School of Dentistry, Universidade Federal de Minas Gerais-UFMG, Belo Horizonte, Brazil.
authors.forename: Bruna Pizziolo
authors.initials: BP
authors.lastname: Coura
authors.affiliation: Department of Oral Surgery and Pathology, School of Dentistry, Universidade Federal de Minas Gerais-UFMG, Belo Horizonte, Brazil.
authors.forename: Marina Gonçalves
authors.initials: MG
authors.lastname: Diniz
authors.affiliation: Department of Oral Surgery and Pathology, School of Dentistry, Universidade Federal de Minas Gerais-UFMG, Belo Horizonte, Brazil.
authors.forename: Wagner Henriques
authors.initials: WH
authors.lastname: de Castro
authors.affiliation: Department of Pathology, Biological Sciences Institute, Universidade Federal de Minas Gerais-UFMG, Belo Horizonte, Brazil.
authors.forename: Carolina Cavalieri
authors.initials: CC
authors.lastname: Gomes
authors.affiliation: Department of Oral Surgery and Pathology, School of Dentistry, Universidade Federal de Minas Gerais-UFMG, Belo Horizonte, Brazil. rsgomez@ufmg.br.
authors.forename: Ricardo Santiago
authors.initials: RS
authors.lastname: Gomez
mesh_terms: D000293:Adolescent; D000328:Adult; D000564:Ameloblastoma / Q000175:diagnosis* / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D001483:Base Sequence; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007573:Jaw Neoplasms / Q000175:diagnosis* / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009808:Odontogenic Tumors / Q000175:diagnosis / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D011842:Radicular Cyst / Q000175:diagnosis* / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D060888:Real-Time Polymerase Chain Reaction; D055815:Young Adult
chemical_list: C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf
keywords: BRAF V600E mutation; ameloblastoma; dentigerous cyst; odontogenic tumours; radicular cyst