A Rapid and Simple Detection Method for theBRAF^T1796AMutation in Fine-Needle Aspirated Thyroid Carcinoma Cells

Abstract

Fine-needle aspiration biopsy (FNAB) samples from thyroid tumor tissues were analyzed for the presence of the BRAF(T1796A) mutation by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) analysis. This assay utilized a specific mismatched primer and has proved to be a relatively simple, accurate, and highly sensitive method. The analysis of 130 aspirated samples from thyroid tumors (18 follicular adenomas, 72 papillary carcinomas [PTCs], 8 follicular carcinomas, 2 undifferentiated carcinomas, 1 medullary carcinoma, 2 malignant lymphomas, and 27 adenomatous goiters) revealed BRAF(T1796A) mutations in 37 (51.4%) of 72 PTCs, supporting the usefulness of this method. We examined BRAF(T1796A) in 21 patients with thyroid tumors using leftover cells in the needle at the preoperative FNAB. BRAF(T1796A) was detected in 4 patients, of which 3 cases were diagnosed as positive and 1 case as suspicious by cytologic examination. Furthermore, BRAF(T1796A) mutations were found to occur more often in tumors of 3 cm or larger in size. Our results indicate that the preoperative determination of the presence of a BRAF(T1796A) mutation by conventional PCR-RFLP may be potentially useful in the diagnosis of the most common thyroid malignancies.

Surgical Perspective of T1799A BRAF Mutation Diagnostic Value in Papillary Thyroid Carcinoma

“…PCR RFLP that was used for mutation analysis in this study is reference to experienced in Japan. This method is considered sensitive in detecting BRAF mutation from FNAB specimen (Hayashida et al, 2004).…”

BRAF mutation in thyroid cancer

“…As the T1799A BRAF mutation occurs exclusively in PTC with a high prevalence, but not in benign thyroid neoplasms (Table 1), it is a specific diagnostic marker for thyroid cancer. Several studies have been conducted to evaluate the diagnostic applicability of BRAF mutation detection on FNAB specimens (Baloch et al 2004, Cohen et al 2004, Hayashida et al 2004, Xing et al 2004c. Most of these studies were retrospective, in which BRAF mutation was analyzed on FNAB specimens retrieved from existing cytological slides and in which the BRAF mutation status was correlated with the pre-established histopathological diagnoses of the tumors.…”

Molecular analysis of thyroid tumors

“…The results of BRAF testing in 2766 FNA samples have been reported in 18 prospective and retrospective studies. 65,66,69,70,[79][80][81][82][83][84][85][86][87][88][89][90][91][92] Among 581 BRAF-positive nodules tested in FNA samples in these studies, 580 were papillary carcinomas on pathological examination of the resected nodules, whereas one was diagnosed as a benign nodule, 92 resulting in the false-positive rate of 0.2%. This reportedly benign nodule had a histopathological diagnosis of 'atypical nodular hyperplasia' and was not examined using modern immunohistochemical techniques that are helpful in the diagnosis of thyroid malignancy in difficult cases.…”