BRAFV600E 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 BRAF^V600E 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 BRAF^V600E mutations in thyroid FNAC specimens and their influence on diagnosis of TN.

Methods: This prospective study enrolled 292 nodules in 269 patients who underwent BRAF^V600E 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 BRAF^V600E analysis using ARMS-qPCR in FNAC specimens were recorded, with reference to the results of BRAF^V600E mutation analysis using ARMS-qPCR in FFPE tissue sample. Diagnostic performances of FNAC, BRAF^V600E mutation analysis in FNAC specimens, BRAF^V600E mutation analysis in FFPE tissue sample, and the combination of FNAC and BRAF^V600E mutation analysis for predicting thyroid malignancy were assessed.

Results: The false-positive and false-negative mutations for BRAF^V600E analysis using ARMS-qPCR in FNAC specimens were 10.1% (19/189) and 7.1% (7/98), respectively. FNAC combined with preoperative BRAF^V600E 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 BRAF^V600E mutation analysis in FNAC specimens and the combination of FNAC and BRAF^V600E 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 BRAF^V600E mutation analysis can significantly increase the diagnostic performance in comparison with FNAC alone. False-positive and false-negative BRAF^V600E mutation results are found in preoperative FNAC specimens, whereas it does not affect the overall auxiliary diagnosis of TNs.

Keywords: BRAFV600E mutation; diagnosis; fine-needle aspiration cytology; polymerase chain reaction; thyroid nodule.