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: Núbia Braga Pereira, Karuza Maria Alves Pereira, Bruna Pizziolo Coura, Marina Gonçalves Diniz, Wagner Henriques de Castro, Carolina Cavalieri Gomes, Ricardo Santiago Gomez
• Journal: Journal of oral pathology & medicine : official publication of the International Association of Oral Pathologists and the American Academy of Oral Pathology (J Oral Pathol Med) Vol. 45 Issue 10 Pg. 780-785 (Nov 2016) ISSN: 1600-0714 [Electronic] Denmark
• PMID: 27084044 (Publication Type: Journal Article)
• Copyright: © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Chemical References

• BRAF protein, human
• Proto-Oncogene Proteins B-raf

Topics

• Adolescent
• Adult
• Ameloblastoma (diagnosis, enzymology, genetics, pathology)
• Base Sequence
• Child
• Child, Preschool
• Diagnosis, Differential
• Female
• Humans
• Immunohistochemistry
• Jaw Neoplasms (diagnosis, enzymology, genetics, pathology)
• Male
• Middle Aged
• Mutation
• Odontogenic Tumors (diagnosis, enzymology, genetics, pathology)
• Proto-Oncogene Proteins B-raf (genetics)
• Radicular Cyst (diagnosis, enzymology, genetics, pathology)
• Real-Time Polymerase Chain Reaction
• Young Adult