[Clinical role of BRAF V600E mutation testing in thyroid nodules]

To evaluate the clinical role of BRAF V600E mutation testing in fine-needle aspirates (FNA) of thyroid nodules.

This study included 83 nodules in 80 patients who underwent FNA from March 2013 to September 2013. Cytological specimens were collected and BRAF exon 15 was examined by polymerase chain reaction (PCR). DNA sequencing and analysis were performed. Diagnostic performances of cytology and cytology with BRAF V600E mutation analysis were compared according to postoperative pathological diagnosis. The relation of BRAF V600E mutation with clinical factors including sex and age of patients, tumor size, lymph node metastasis, multifocality, and AJCC stage were analyzed.

Of 83 nodules, 33 nodules were clinically observed, and 48 nodules underwent surgery, and suggestions of surgery were refused in 2 nodules. Among 48 nodules with surgery, BRAF V600E mutation was found in 25 nodules with histologic confirmation of papillary thyroid carcinoma after thyroidectomy, 13 of the 25 nodules were cytologically diagnosed as carcinoma and 12 were indeterminate. Among the 23 BRAF V600E negative noodles, 5 were cytologically diagnosed as carcinoma, 2 were benign, and 16 were indeterminate; 15 nodules were histologic confirmation of papillary thyroid carcinoma after thyroidectomy, 1 nodule was medullary thyroid carcinoma, and 7 nodules were benign. Biomolecular analysis significantly increased cytology sensitivity for papillary thyroid carcinoma from 43.9% to 73.2% (P < 0.05). Direct DNA sequencing showed that the presence of BRAF V600E mutation was 62.5% in 40 thyroid papillary nodules. There were 16 BRAF-positive nodules (80.0%) among 20 papillary thyroid nodules with extrathyroidal extension, however there were 9 BRAF-negative nodules (45.0%) among 20 papillary thyroid nodules without extrathyroidal extension. Univariate analysis indicated the BRAF V600E mutation was associated with extrathyroidal extension (χ² = 5.227, P = 0.022), but not with sex, age, tumor size, lymph node metastasis, multifocality and AJCC stage.

BRAF V600E mutation analysis can significantly improve FNA diagnostic accuracy and maybe useful for prediction of high-risk of thyroid carcinoma.