BRAF^V600E mutation analysis in fine‐needle aspiration cytology specimens for diagnosis of thyroid nodules: The influence of false‐positive and false‐negative results

Abstract

Background The accurate evaluation of BRAFV600E mutation in preoperative fine‐needle aspiration cytology (FNAC) specimens is important for making management decisions in thyroid nodules (TNs). The aim of this study was to assess the false‐positive and false‐negative BRAFV600E mutations in thyroid FNAC specimens and their influence on diagnosis of TN. Methods This prospective study enrolled 292 nodules in 269 patients who underwent BRAFV600E mutation analysis using amplification refractory mutation system‐quantitative real‐time polymerase chain reaction (ARMS‐qPCR) both in FNAC specimens and formalin‐fixed, paraffin‐embedded (FFPE) tissue samples after surgery. The false‐positive and false‐negative mutations for BRAFV600E analysis using ARMS‐qPCR in FNAC specimens were recorded, with reference to the results of BRAFV600E mutation analysis using ARMS‐qPCR in FFPE tissue sample. Diagnostic performances of FNAC, BRAFV600E mutation analysis in FNAC specimens, BRAFV600E mutation analysis in FFPE tissue sample, and the combination of FNAC and BRAFV600E mutation analysis for predicting thyroid malignancy were assessed. Results The false‐positive and false‐negative mutations for BRAFV600E analysis using ARMS‐qPCR in FNAC specimens were 10.1% (19/189) and 7.1% (7/98), respectively. FNAC combined with preoperative BRAFV600E mutation analysis significantly increased the diagnostic sensitivity from 75.7% to 92.3%, and accuracy from 78.7% to 90.6% in comparison with FNAC alone (both P < .001). No significant differences were found between the combination of FNAC and BRAFV600E mutation analysis in FNAC specimens and the combination of FNAC and BRAFV600E mutation analysis in FFPE tissue sample (sensitivity: 92.3% vs 91.9%; accuracy: 90.6% vs 91.3%; both P > .05). Conclusions FNAC combined with preoperative BRAFV600E mutation analysis can significantly increase the diagnostic performance in comparison with FNAC alone. False‐positive and false‐negative BRAFV600E mutation results are found in preoperative FNAC specimens, whereas it does not affect the overall auxiliary diagnosis of TNs.

Comment on: BRAF mutation analysis by ARMS‐PCR refines thyroid nodule management

“…Unfortunately, it is not clear if the poor performance of the assay is due to the FNA samples since the mutational analysis has not been confirmed on the matched FFPE slides. Despite other papers reported a better specificity of the same assay on thyroid FNAs, this study raises doubts on the reliability of this methodology, suggesting the need for further investigations before clinical applicability. To date, other robust technologies, such as next‐generation sequencing, have been extensively tested with a very high analytical sensitivity and specificity for BRAF mutation detection in patients with different ethnic background.…”

Impact of the Italian Society of Anatomic Pathology and Diagnostic Cytology Classification of Thyroid Nodules in the Treatment of Indeterminate Follicular Lesions: Five-Year Results at a Single Center

“…We found only one false-positive mutation case, confirmed as adenomatous hyperplasia with underlying lymphocytic thyroiditis by surgical pathology. Surgically proven benign cases of falsepositive BRAF V600E mutation have been documented in the literature [55][56][57]. False-positive results can be mainly explained by the trade-off of improved sensitivity by sacrificing specificity.…”

Thyroid Nodules with Preoperative Benign Cytology and BRAF V600E Mutations: the Role of Conventional Ultrasound and Shear Wave Elastography

“…one nodule had an unde ned boundary, and the other nodule extended from the isthmus but had a clear boundary. There were two reasons for this situation in the analysis, one was that the FNA BRAF V600E test was false positive before surgery; the other was that the nodule gene was mutated, but the cellular tissue morphology had not changed signi cantly and cannot be diagnosed malignant by histology [29].…”