ABSTRACT
BACKGROUND: The objective of this study is to evaluate the diagnostic accuracy of plasma-based liquid biopsy for the detection of the BRAF V600E mutation in circulating cell-free DNA from patients with ameloblastoma. METHODS: This is a prospective diagnostic accuracy study conducted based on the Standards for Reporting Diagnostic Accuracy recommendations. The index test was the plasma-based liquid biopsy, whereas the reference standard was the conventional tissue biopsy. The target condition was the detection of BRAF V600E mutation. The study population consisted of individuals with ameloblastoma recruited from three tertiary hospitals from Brazil. A negative control group composed of three individuals with confirmed wild-type BRAF lesions were included. The participants underwent plasma circulating cell-free DNA and tumor tissue DNA isolation, and both were submitted to using competitive allele-specific TaqMan™ real-time polymerase chain reaction technology mutation detection assays. Sensitivity and specificity measures and positive and negative predictive values were calculated. RESULTS: Twelve patients with conventional ameloblastoma were included. BRAF V600E mutation was detected in 11/12 (91.66%) ameloblastoma tissue samples. However, the mutation was not detected in any of the plasma-based liquid biopsy circulating cell-free DNA samples in both ameloblastomas and negative control group. The sensitivity and specificity of plasma-based liquid biopsy for the detection of the BRAF V600E mutation in circulating cell-free DNA was 0.0 and 1.0, respectively. The agreement between index test and reference standard results was 26.66%. CONCLUSION: Plasma-based liquid biopsy does not seem to be an accurate method for the detection of the BRAF V600E mutation in circulating circulating cell-free DNA from patients with ameloblastoma, regardless of tumor size, anatomic location, recurrence status, and other clinicopathological features.
Subject(s)
Ameloblastoma , Cell-Free Nucleic Acids , Humans , Ameloblastoma/diagnosis , Ameloblastoma/genetics , Proto-Oncogene Proteins B-raf/genetics , Prospective Studies , Mutation , Cell-Free Nucleic Acids/geneticsABSTRACT
BACKGROUND: Dysregulation of the MAPK pathway appears to exert a pivotal role in the pathogenesis of ameloblastomas, since BRAF p.V600E has been reported in over 65% of the tumors. Therefore, the purpose of this study was to investigate whether the BRAF p.V600E is related to biological behavior and disease-free survival in patients with conventional ameloblastomas. METHODS: This is a retrospective cohort study based on the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) recommendations. The study population consisted of individuals treated for conventional ameloblastomas. Clinical, imaging, histomorphological, immunohistochemical (Ki67 and CD138/syndecan-1), and molecular BRAF p.V600E mutation analyses were performed. Bivariate statistical analysis was performed through chi-square and Fisher's exact tests. Kaplan-Meier analysis with log-rank test and Cox proportional hazards regression were used to identify predictors of disease-free survival, with a significance level of 5%. RESULTS: Forty-one individuals were included, with a male-to-female ratio of 1.15:1. BRAF p.V600E mutation was identified in 75.6% of the tumors. No association between the BRAF mutational status and other clinical, imaging, histomorphological, and immunohistochemical variables was observed. Only the initial treatment modality was significantly associated with a better prognosis in univariate (p = 0.008) and multivariate (p = 0.030) analyses, with a hazard ratio of 9.60 (95%IC = 1.24-73.89), favoring radical treatment. CONCLUSION: BRAF p.V600E mutation emerges as a prevalent molecular aberration in ameloblastomas. Nevertheless, it does not seem to significantly affect the tumor proliferative activity, CD138/syndecan-1-mediated cell adhesion, or disease-free survival outcomes.
