Abstract: Background and purpose: In papillary thyroid carcinoma (PTC), the BRAF V600E mutations are reported so far to have the most important diagnostic value among genetic mutations. Detection of BRAF V600E mutation in thyroid puncture cells can improve the diagnostic accuracy of fine-needle aspiration cytology (FNAC). In this study, BRAF V600E mutation detection was performed on thyroid puncture cell fluid, compared with postoperative histopathologic diagnosis, and the preoperative diagnostic value of this mutation was evaluated according to the coincidence rate with histopathologic diagnosis. Methods: A total of 563 patients with thyroid nodules were enrolled following ultrasound-guided aspiration in Fudan University Shanghai Cancer Center from Jun. 2016 to Apr. 2017. DNA QIAamp Mini Kit was used to extract the DNA in thyroid puncture cell fluid, and amplification refractory mutation system (ARMS) method was used to detect BRAF V600E mutation. Results: Among the 563 patients who were tested for BRAF V600E, 209 cases had surgical treatment. The overall ratio of men to women was 1.0∶3.7, aged 1 to 79 years, with an average age of (45.0±0.9) years. The success rate of BRAF V600E detection was 99.3%. Histopathological diagnosis was taken as the gold standard. The sensitivity and specificity of cytology diagnosis of papillary thyroid carcinoma were 86.6% and 100.0%, respectively. The sensitivity and specificity of cytology combined with BRAF V600E test for the diagnosis of PTC were 92.1% and 100.0%, respectively. FNAC combined with BRAF V600E detection method had a higher positive detection rate than cytological diagnosis. Among the patients diagnosed by histopathology as having PTC, 11 cases had negative cytological diagnosis but positive results of BRAF V600E test. Conclusion: As to ultrasound-guided thyroid FNAC tissue, the ARMS method for BRAF V600E mutation test has a high success rate of detection, and can aid preoperative diagnosis. The combination of cytological diagnosis and BRAF V600E detection results can improve the detection rate of malignancy and the accuracy of preoperative diagnosis, and protect the patients from the delay of treatment and the progression of the disease caused by missed cytological diagnosis.

Key words: Papillary thyroid carcinoma, Fine-needle aspiration cytology, BRAF V600E mutation test