BRAF^V600E mutation testing in fine needle aspirates of thyroid nodules: Potential value of real-time PCR

The BRAF^V600E mutation is a valuable adjunctive diagnostic tool to ultrasound (US)-guided fine-needle aspiration (US-FNA). The objective of this study was to investigate the potential value of realtime PCR to detect BRAF^V600E mutation. This study included 447 thyroid nodules in 420 patients who underwent US-FNA and BRAF^V600E mutation analysis using dual priming oligonucleotide-based multiplex polymerase chain reaction (DPO-PCR) and real-time PCR. We calculated and compared the diagnostic performances of DPO-PCR and real-time PCR to detect BRAF^V600E mutation in the thyroid nodules. Receiver operating characteristic (ROC) analysis was used to quantify the cut-off value of the Ct values of BRAF^V600E mutation on real-time PCR. Optimal thresholds were determined (Youden index). We also compared the diagnostic performances between DPO-PCR and real-time PCR after applying the cut-off value on real-time PCR. Sensitivity, accuracy, and NPV were significantly higher in real-time PCR than DPO-PCR. When the optimal cut-off value of 32.4 at Ct values of BRAF^V600E mutation was adjusted on real-time PCR, sensitivity was 66.2% and specificity was 100%. Sensitivity, accuracy, and NPV of real-time PCR were also significantly higher than DPO-PCR. In contrast, specificity and PPV were not significantly different between DPO-PCR and real-time PCR. Real time PCR can be a promising diagnostic method in detecting BRAF^V600E mutation using optimal cut-off value.