BRAF V600E Mutation Analysis from May-Grünwald Giemsa-Stained Cytological Samples as an Adjunct in Identification of High-Risk Papillary Thyroid Carcinoma

摘要

The BRAF V600E mutation is specific for thyroid papillary cancer (PTC) and correlates with PTCs invasiveness. This study investigated whether detection of BRAF V600E mutation can be performed on routinely stained FNABs. We also examined if establishment of the BRAF V600E mutation could help in identification of patients at higher risk for metastatic disease. DNA was isolated from 134 FNABs samples (20 follicular neoplasm, ten suspicious for malignancy, and 104 malignant) using Pinpoint Slide DNA Isolation System. BRAF V600E mutation was detected by PCR followed by sequencing. DNA was successfully extracted from all examined FNABs samples. In follicular neoplasm, suspicious for malignancy and malignant FNABs, BRAF V600E mutation was found in 0/20 (0%), 2/10 (20%), and 47/104 (45.2%) of cases, respectively. Extra-thyroidal extension was detected in 35/47 (74.4%) BRAF V600E positive and in 24/57 (42.1%) wild-type BRAF cases (p = 0.001). Metastases were detected in 37/47 (78.7%) BRAF V600E positive and in 28/57 (49.1%) wild-type BRAF cases (p = 0.002). Our results showed that stained FNAB specimens can be used for DNA extraction and assessment of BRAF V600E mutation. Detection of BRAF V600E mutation had limited value in diagnoses of malignancy in follicular neoplasms but can ascertain malignancy in subset of suspicious for malignancy FNABs. In malignant FNABs, BRAF V600E mutation was significantly associated with presence of extra-thyroidal extension and metastases after surgery.