BRAF p.V600E status in epithelial areas of ameloblastoma with different histological aspects: Implications to the clinical practice

Abstract

Background: BRAF p.V600E is reported in up to 80% of ameloblastomas. Despite the high frequency, the presence of this mutation in different histopathological areas of the tumour has not been investigated. This information has an important role in the use of BRAF p.V600E assessment as an auxiliary tool in the differential diagnosis between unicystic ameloblastoma and other odontogenic cystic lesions, especially when only incisional biopsies are available. Therefore, the purpose of the present study was to investigate BRAF p.V600E heterogeneity in unicystic ameloblastoma.Methods: Five cases of ameloblastoma and two dentigerous cysts were analysed.The regions exhibiting different microscopic characteristics were selected from each ameloblastoma case and manually dissected. TaqMan allele-specific qPCR or Sanger sequencing was performed to determine BRAF p.V600E status. Results:We screened the mutation in a small cohort of UA and no molecular heterogeneity was found. Four cases of ameloblastoma (80%) exhibited BRAF p.V600E in all different areas evaluated. One case did not harbour the mutation in any microscopic region analysed. The BRAF mutation was absent in the dentigerous cysts. Conclusion:Ameloblastomas appear to exhibit a homogeneous profile regarding the BRAF p.V600E no matter what histological feature is observed under light microscopy, suggesting that this molecular test may contribute to establish the correct diagnosis in cases microscopically resembling other odontogenic lesions.

A conservative approach for unicystic ameloblastoma: Retrospective clinic‐pathologic analysis of 12 cases

“…[4][5][6][7] From the demographic point of view, our unicystic ameloblastoma cases were predominantly observed in patients between the second and third decades of life, which is similar to other studies, 8,9 and in female individuals, contrary to what is observed in the literature. 2,10,11 This difference regarding gender can be explained by the reduced sample size.…”

“…First described as a distinct entity by Robinson and Martinez in 1977, 1 unicystic ameloblastoma (UAM) is an encapsulated lesion which comprises 5 to 22% of all the diagnosed ameloblastoma cases. 2 It is often observed in patients between the second to third decades of life and presents a slight male predilection. Radiographically, it is mostly found at the posterior region of the mandible and usually presents as a unilocular image that may mimic some odontogenic cysts.…”

“…First described as a distinct entity by Robinson and Martinez in 1977, 1 unicystic ameloblastoma (UAM) is an encapsulated lesion which comprises 5 to 22% of all the diagnosed ameloblastoma cases 2 . It is often observed in patients between the second to third decades of life and presents a slight male predilection.…”

Does BRAF mutation status and related clinicopathological factors affect the recurrence rate of ameloblastoma? A systematic review, meta‐analysis and metaregression

“…It plays a crucial role in regulating biological events such as apoptosis, differentiation and cell proliferation 6 . There is now increasingly robust evidence demonstrating that most ameloblastomas of all types harbour the activating v600e variant mutation of BRAF 7–10 . The role of BRAFv600e in ameloblastoma has gained clinical interest with the emergence of targeted therapy in the neoadjuvant setting 11–13 .…”

The Changing Clinicopathological Profile of Ameloblastoma: An update

“…Solid/multicystic shows diverse subtypes. Although evidence on the molecular involvement of BRAF V600E mutant gene in the oncogenesis of mandibular AM and SMO in maxillary AM can be accepted now, surgical resection is the standard treatment because molecular-based therapy is still lagging [2][3][4]. Synchronous association of AM with other syndromes were observed in Gorlin syndrome, Gardner syndromes, epidermal nevus syndrome, Simpson-Golabi-Behmel Syndrome and Williams' syndrome [5,6].…”