Investigation of BRAF V600E detection approaches in papillary thyroid carcinoma

Objective

The detection of BRAF V600E mutation in papillary thyroid carcinoma (PTC) may be helpful to offer diagnostic confirmation. Additionally, such detection may provide a targeted therapeutic approach for the radioactive iodine resistant patients to predict adverse outcomes. To compare the results of immunohistochemistry (IHC) method using the anti-BRAF V600E (VE1) antibody with the Quantitative real-time polymerase chain reaction (qPCR) approach in examining BRAF V600E mutation in PTC, we investigated the sensitivity and specificity of BRAF V600E (clone VE1) mouse monoclonal antibody in detecting the BRAF V600E mutation and correlated BRAF V600E mutation with clinicopathologic features in PTC.

The Relationship of the BRAFV600E Mutation and the Established Prognostic Factors in Papillary Thyroid Carcinomas

It has been shown that BRAF(V600E) mutation in papillary thyroid carcinomas (PTC) is associated both with pathogenesis and poor prognosis. In this study, we aimed to investigate the relationship of the BRAF(V600E) mutation and the established prognostic factors in a cohort of Turkish patients with PTC. Forty-six cases of papillary thyroid carcinoma have been evaluated for the presence of BRAF(V600E) mutation. BRAF(V600E) has been examined by restriction fragment length polymorphism. BRAF(V600E) mutation status has been compared with well-known histopathological and clinical prognostic parameters such as invasion of thyroid capsule, extrathyroidal extension, and the presence of lymph node and/or distant metastasis. We have found that BRAF(V600E) mutation was present in the majority of our cases (40/46). Considering the stage of the disease, five of the negative cases were in stage 1 while the remaining one was in stage 2. Only one BRAF(V600E) negative case has shown extrathyroidal extension and lymph node metastasis. All four patients with distant metastasis had BRAF(V600E) mutation. Statistical analyses revealed that there are no significant relationship between the BRAF(V600E) mutation and the established prognostic factors. We found a relatively higher BRAF(V600E) mutation rate in classical type PTC than in other similar studies. We think that the limited number of our cases may either weaken or mask some potentially important relationship between BRAF(V600E) mutation and the established prognostic factors.     

Immunohistochemical detection of the BRAF V600E mutation in melanoma patients with monoclonal antibody VE1

A novel mutation‐specific monoclonal antibody VE1 was generated to detect BRAF V600E mutation with immunohistochemistry. This study aims to investigate the sensitivity and specificity of immunohistochemistry compared with conventional Sanger sequencing and to evaluate whether IHC would become the routine screening method of BRAF V600E mutation. A total of 84 cases of melanoma lesion specimens were selected to make the tissue microarray and to perform IHC with VE1 antibody. Simultaneously Sanger sequencing was applied to test and verify. VE1 has a high specificity (100%) and sensitivity (72.2%), and the concordance between the two techniques is excellent (93.8% cases coherent and kappa = 0.801). As a rapid, cost‐effective method, IHC may become the routine diagnostic means for the detection of BRAF V600E mutation of malignant melanomas in the near future, and the recommended detection process is initial immunohistochemical staining for positive cases, followed by molecular techniques for negative or ambiguous cases.     

BRAFV600E 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.     

LIMD2 Is Overexpressed in BRAF V600E-Positive Papillary Thyroid Carcinomas and Matched Lymph Node Metastases

We previously described that LIM domain containing 2 (LIMD2) overexpression was closely correlated with metastatic process in papillary thyroid carcinoma (PTC). We here evaluated the expression of LIMD2 in a series of non-metastatic and metastatic PTC and their matched lymph node metastases via immunohistochemistry. LIMD2 was expressed in 74 (81%) of primary PTC and 35 (95%) of lymph node metastases. Sub-analysis performed in 37 matched samples demonstrated that in four cases, LIMD2 is expressed in lymph node metastases, while it is not expressed in primary tumors. Moreover, in eight cases, the staining intensity of LIMD2 was stronger in the patient-matched lymph node metastases than in the primary tumors. Next, the expression of LIMD2 was correlated with clinical pathological parameters and BRAF V600E and RET/PTC mutational status. The expression of LIMD2 in primary tumors was correlated with the presence of BRAF V600E mutation (P =?0.0338). Western blot analysis in thyroid cell lines demonstrated that LIMD2 is expressed in two PTC cell lines, while it is not expressed in normal thyroid and follicular thyroid carcinoma cell lines. Importantly, its expression was higher in a PTC cell line that harbors BRAF V600E mutation than in a PTC cell line that harbors RET/PTC1. The available genomic profiling data generated by The Cancer Genome Atlas Research Network confirmed that LIMD2 expression is higher in BRAF-like PTC samples. Our data suggest that LIMD2 may play an important role in the metastatic process of PTC, predominantly in BRAF V600E-positive tumors.     

BRAF mutations are associated with some histological types of papillary thyroid carcinoma

Mutations in the BRAF gene have recently been detected in a wide range of neoplastic lesions with a particularly high prevalence in melanoma and papillary thyroid carcinoma (PTC). The hot-spot mutation BRAF(V599E) is frequently detected in PTC (36-69%), in contrast to its absence in other benign or malignant thyroid lesions. In order to unravel whether there is any association between the occurrence of the BRAF mutation and the histological pattern of PTC, in this study a previous series of 50 PTCs was extended to 134 cases, including ten cases of PTC-related entities-hyalinizing trabecular tumour (HTT) and mucoepidermoid carcinoma (MEC). Using PCR/SSCP and sequencing, the BRAF(V599E) mutation was detected in 45 of the 124 PTCs (36%). No mutations were detected in any case of HTT and MEC. BRAF(V599E) was present in 75% of Warthin-like PTCs and 53% of conventional PTCs, whereas no BRAF(V599E) mutations were detected in any of the 32 cases of the follicular variant of PTC. BRAF(V599E) was also detected in 6 of 11 cases of the oncocytic variant of PTC that displayed a papillary or mixed follicular-papillary growth pattern and in none of the four oncocytic PTCs with a follicular growth pattern. A distinct mutation in BRAF (codon K600E) was detected in three cases of the follicular variant of PTC. This study has confirmed the high prevalence of BRAF(V599E) in PTC and has shown that the mutation is almost exclusively seen in PTC with a papillary or mixed follicular-papillary growth pattern, regardless of the cytological features of the neoplastic cells. The results support the existence of an oncocytic variant of PTC that should be separated from the oncocytic variant of follicular carcinoma and suggest that the follicular variant of PTC may be genetically different from conventional PTC.     

甲状腺乳头状癌中BRAFV599E点突变与RET/PTC融合基因的检测

目的检测甲状腺乳头状癌(PTC)及其他类型甲状腺良恶性肿瘤中BRAFV599E的点突变及 RET/PTC1、3融合基因的表达状况,探讨二者与PTC临床病理学特征的关系.方法用聚合酶链反应(PCR)及逆转录(RT)-PCR分别检测95例石蜡与新鲜甲状腺病变组织中BRAFV599E点突变和RET/PTC1、3融合基因.结果 (1)仅在PTC中检测到BRAFV599E的突变,突变率56%(37/66),在经典型PTC和高细胞型PTC中突变率分别为70%(29/41)和2/3,在滤泡型PTC及其他类型甲状腺病变中未检测到BRAFV599E的突变.统计学分析BRAF突变与性别、年龄、伴慢性淋巴细胞浸润及淋巴结转移无明显关系(P>0.05).(2)PTC中RET/PTC检出率21.2%(14/66),其中5例RET/PTC1阳性(7.6%),9例RET/PTC3阳性(13.6%).RET/PTC融合基因阳性的14例PTC中未检测到BRAFV599E突变.其余29例良恶性病例中未检测到RET/PTC融合基因.RET/PTC融合基因的表达与PTC的临床病理学特征无明显关系(P>0.05).结论 (1)BRAFV599E突变和RET/PTC融合基因是PTC较特征性的遗传学改变,可作为PTC诊断和鉴别诊断提供分子学的依据,BRAFV599E突变可能是甲状腺乳头状癌表型的重要决定因素之一;(2)BRAFV599E突变与PTC的经典型和高细胞型两种主要亚型密切相关;(3)BRAFV599E突变与RET/PTC融合基因可能在PTC中是独立事件.     

实时剪切波弹性成像杨氏模量最大值诊断甲状腺乳头状癌BRAF V600E基因突变的价值

目的:探究实时剪切波弹性成像（SWE）杨氏模量最大值诊断甲状腺乳头状癌（PTC）鼠类肉瘤滤过性毒菌致癌同源体B1（BRAF）V600E基因突变的价值。方法:回顾性分析2018年1月~2019年6月宿迁市第一人民医院收治的110例PTC患者共124个结节的临床及超声影像学资料。患者经病理学检查均确诊为PTC,并完成了BRAF V600E基因检测以及SWE检查,临床资料完整。通过比较V600E基因突变型与野生型PTC的SWE检查结果,并绘制患者Emax值的ROC曲线,分析Emax值对PTC患者BRAF V600E基因突变的诊断效能。结果:BRAF基因检测结果显示:124个PTC结节BRAF基因检测V600E野生型共37个,V600E突变型共87个。野生型PTC结节的SWE图像多以蓝色为主,而突变型主要表现为红橙相间彩色混杂的图像。突变组PTC结节Emax、Emean、Eratio值均明显大于野生组,比较差异具有统计学意义（P<0.05）,ROC曲线分析显示:Emax值诊断V600E突变的AUC=0.846>0.5（95%CI:0.808~0.885, P<0.01）;Cut-off值为43.65 kPa,此时敏感度为91.45%,特异性为68.23%。以Emax≥43.65 kPa为临界值对124个结节进行诊断,结果显示:SWE诊断PTC结节为V600E基因突变型90个,野生型34个,正确率为86.29%;SWE诊断结果与基因检测结果一致性显著（Kappa值=0.665, P<0.01）。结论:PTC BRAF V600E基因突变型与野生型的SWE影像学特征具有明显差异,应用SWE的Emax值诊断PTC结节V600E基因突变的正确率和敏感性均较高,诊断价值显著,值得在临床上推广应用。     

mRNA BRAF expression helps to identify papillary thyroid carcinomas in thyroid nodules independently of the presence of BRAFV600E mutation

Literature has consistently shown associations of BRAFV600E mutation with papillary thyroid cancer clinical features. However, the clinical utility of BRAF expression has not been clinically explored so far. We studied 67 thyroid nodules (32 benign nodules and 35 PTC cases). BRAF mRNA expression levels measured by a quantitative real-time PCR and a PCR-RFLP were used to identify BRAFV600E mutation. BRAF mRNA expression was significantly higher in malignant (198.2±373.9 AU) than in benign (4.1±6.9 AU) nodules (p<0.0001). BRAF expression identified malignancy with a sensitivity of 80.6%, specificity of 77.1%, positive predictive value of 75.8%, and negative predictive value of 81.8%. A cut-point of 4.712, identified by the ROC curve, was able to sort out malignant nodules with an accuracy of 78.8%. Although we did not find any correlation between the presence of BRAF V600E mutation and clinical or tumor features such as age (p=0.309), gender (p=0.5453), ethnicity (p=0.9820), tumor size (p=1.000), multifocality (p=0.2530) or mRNA levels (p=0.7510), the study power for BRAF expression and diagnosis (99%; FPRP=0.85) indicated that data is noteworthy despite the relative small number of patients investigated. We concluded that BRAF mRNA expression may help to identify PTC among thyroid nodules independently of the presence of BRAFV600E mutation.     

甲状腺乳头状癌中TROP-2表达的临床意义及其诊断价值

目的观察人类滋养层细胞表面抗原2(TROP-2)在甲状腺乳头状癌(papillary thyroid carcinoma,PTC)中的表达,探讨TROP-2在PTC中表达的临床意义及其诊断价值。方法采用免疫组化EnVision法检测100例甲状腺恶性病变(PTC 75例、滤泡性癌10例、髓样癌10例、差分化癌5例)、45例良性病变(正常甲状腺10例、结节性甲状腺肿10例、桥本甲状腺炎15例、滤泡性腺瘤10例),5例具有乳头样核特征的非浸润性甲状腺滤泡性肿瘤(non-invasive folliculaRthyroid neoplasms with papillary-like nucleaRfeatures,NIFTP)中TROP-2的表达;ARMS法检测PTC中BRAF V600E基因突变。分析TROP-2对PTC诊断的敏感性和特异性,及其与PTC临床病理特征以及BRAF V600E基因突变的关系。结果TROP-2在PTC中的阳性率为81.3%(61/75),在其他甲状腺恶性肿瘤和良性病变中均阴性,TROP-2对PTC诊断的敏感性为81.3%,特异性为100%。TROP-2表达与PTC淋巴结转移有关(P<0.05),与患者年龄、性别、肿瘤部位及临床分期无关(P>0.05),经典型PTC中TROP-2表达高于滤泡亚型PTC(P<0.05)。PTC中TROP-2表达与BRAF V600E基因突变呈正相关(P<0.05)。结论TROP-2是一种具有高度特异性和敏感性的诊断PTC的标志物,TROP-2检测可预测PTC的临床生物学行为和BRAF V600E基因突变状态,并对于形态学变形的PTC、微小型PTC和PTC的甲状腺内扩散的诊断和识别具有重要价值。     

分化型甲状腺癌中BRAF V600E突变分析

目的探讨分化型甲状腺癌中BRAF V600E突变与临床病理特征的关系。方法收集甲状腺乳头状癌(papillary thyroid carcinoma,PTC)80例(其中经典型67例、滤泡亚型8例、嗜酸细胞亚型3例、高细胞亚型2例)、滤泡癌5例,其中30例PTC取相应癌旁组织,全部送基因检测室检测BRAF V600E突变情况。结果 80例PTC中BRAF V600E突变率为65.0%,5例滤泡癌及30例癌旁组织中未发现BRAF V600E突变;BRAF V600E突变与患者年龄、肿瘤包膜侵犯、淋巴结转移及TNM分期有关。PTC亚型中,经典型和高细胞亚型的BRAF V600E突变率较高(70.1%、100.0%),滤泡亚型的突变率较低(33.3%)。结论PTC中BRAF V600E突变可能与患者年龄有一定相关性,还与包膜侵犯、淋巴结转移及TNM分期有关,经典型和高细胞亚型的BRAF V600E突变率较高,明显高于滤泡亚型。     

A new BRAF gene mutation detected in a case of a solid variant of papillary thyroid carcinoma

BRAF gene mutations have been frequently detected in papillary thyroid carcinoma (PTC). Moreover, there is a close association between the type of mutation and the PTC histotype: BRAF(V600E) is associated with conventional PTC and with histological variants of PTC displaying a prominent papillary growth pattern, whereas BRAF(K601E) is associated with the follicular variant of PTC. We report the detection of a novel BRAF triplet deletion in a case of PTC displaying a predominantly solid growth pattern. The deletion leads to the replacement of a valine and a lysine by a glutamate in the BRAF activation segment (BRAF(VK600-1E)), thus mimicking partially the 2 BRAF mutations previously described. Our study reinforces the existence of a close relationship between the occurrence of some types of BRAF mutation and some PTC histotypes. The genetic study of more cases of the solid variant of PTC is necessary to find whether there exists a significant association between the occurrence of BRAF(VK600-1E) and such PTC histotype.     

BRAF V600E mutation does not predict recurrence after long-term follow-up in TNM stage I or II papillary thyroid carcinoma patients

The BRAF V600E mutation may serve as a marker of disease recurrence in well-differentiated papillary thyroid cancer (PTC). Our aim was to study if TNM stage I or II PTC patients, with and without recurrence after long-term follow-up would differ in BRAF status. BRAF status was retrospectively determined in tumour tissue from a cohort of low-risk PTC patients (n = 461) with and without recurrence after 16 years of follow-up. Initial treatment was total thyroidectomy (TTE) and radioiodine remnant ablation (RRA). Forty-six patients (9.9%) experienced disease recurrence. BRAF mutation was positive in 66% (17/26) of patients with and 68% (17/25) without recurrence (p = NS). Fifty per cent of BRAF positive and 53% of BRAF negative patients experienced disease recurrence (p = NS). Time to recurrence was 52 (range 18-144) and 36 (range 16-71) months, respectively (p = NS). Primary tumour size, nodal metastasis and local infiltration at presentation did not differ between BRAF positive and negative patients (2.0 vs 2.2 cm, 21% vs 35% and 6% vs 12%, respectively, all p = NS). Taken together, BRAF V600E is common in Finnish patients with low-risk PTC but does not predict recurrence after long-term follow-up after initial treatment with TTE and RRA.     

Most multifocal papillary thyroid carcinomas acquire genetic and morphotype diversity through subclonal evolution following the intra-glandular spread of the initial neoplastic clone

Papillary thyroid carcinoma (PTC) is frequently multifocal (mPTC), with synchronous tumour foci often showing varied morphology. The genetic mechanisms underlying the development of multiple and histologically diverse tumour foci remain uncertain. Different tumour foci might develop either through intrathyroidal dissemination of a single malignant clone, with morphotype differentiation occurring as a result of subclonal progression, or they may stem from independent transformational events involving multiple progenitor clones. To determine the clonal derivation of multiple tumour foci and to map their clonal relationships and genetic progression in mPTC, we evaluated genome-wide allelic imbalances (AI) and BRAF V600E mutation status in 55 synchronous tumour foci from 18 mPTC patients. For apparently monoclonal tumours, we calculated the probabilities of monoclonal derivation and used phylogenetic analysis to model clonal evolution. Genome-wide allelotyping and BRAF mutation analysis showed genetic alterations consistent with monoclonal origin in 83% of cases, mostly with evidence of subclonal evolution. BRAF V600E mutations were early events during clonal evolution of most, but not all cases. MPTC with morphologically diverse tumour foci also arose through monoclonal derivation in 75% of cases, demonstrating that morphotype-determining genetic changes can be acquired during clonal diversification, subsequent to the spread of the original malignant progenitor clone. In 17% of patients, discordant AI or BRAF V600E profiles implied that mPTCs can occasionally develop from distinct transformation events. This study suggests that mPTC originates usually from neoplastic transformation and subsequent intrathyroidal spread of a single malignant progenitor clone. Clonal progression and morphotype differentiation occur through progressive acquisition of genetic alterations subsequent to the initial intra-glandular spread. In monoclonal BRAF V600E-positive mPTCs, BRAF V600E is not always present in all tumour foci, indicating that other tumour-genetic factors in the primary progenitor clone can also trigger PTC neoplastic transformation.     

Immunohistochemical analysis using a BRAF V600E mutation specific antibody is highly sensitive and specific for the diagnosis of hairy cell leukemia

Hairy cell leukemia (HCL) is usually diagnosed by morphology and flow cytometry studies. However, it is challenging sometimes to distinguish HCL from its mimics. Recently, the BRAF V600E mutation has been described as a disease-defining molecular marker for HCL which is present in nearly all cases of HCL but virtually absent in mimics of HCL. In this study, we investigated the possibility of using immunohistochemical detection of the BRAF V600E mutant protein to differentiate HCL from its mimics. A total of twenty-eight FFPE tissue specimens were studied, including HCL (n=12), HCL variant (HCL-v, n=3), splenic marginal zone lymphoma (SMZL, n=6), and other marginal zone lymphomas (MZL, n=7). Immunohistochemical studies were performed using a mouse monoclonal antibody (clone VE1, Spring Bioscience, CA) specific for BRAF V600E mutation. Molecularly confirmed BRAF V600E mutation positive and negative cases were used as the positive and negative controls respectively. All 12 cases of HCL showed cytoplasmic BRAF V600E protein expression in leukemia cells by immunohistochemical study regardless of tumor burden, whereas all cases of HCL mimics including HCL-v, SMZL, and MZL were negative for BRAF V600E protein. Using this BRAF V600E mutation specific antibody, this immunohistochemical study has 100% sensitivity and 100% specificity for the diagnosis of HCL in our cohort. In conclusion, immunohistochemical detection of the BRAF V600E mutant protein is highly sensitive and specific for the diagnosis of HCL. Compared to PCR or sequencing-based methodologies, immunohistochemistry is a relatively rapid and inexpensive alternative for the differential diagnosis between HCL and its mimics.     

BRAF mutation in sporadic colorectal cancer and Lynch syndrome

The aim of the study was to detect mutations of BRAF oncogene in colorectal cancer and to use this information to identify Lynch syndrome patients. Consecutive cases of primary colorectal cancer (n?=?137) were analyzed for MLH1 protein expression using immunohistochemistry (IHC). BRAF V600E mutation was detected by IHC using a specific monoclonal antibody (VE1) and by qPCR. All MLH1 protein-negative cases were subjected to microsatellite instability analysis and MLH1 promoter methylation assay. MLH1 protein expression deficiency and high microsatellite instability (MSI-H) were detected in 18 of the 137 (13.1 %) consecutive colorectal cancer specimens. Detection of the BRAF V600E mutation by IHC was 100 % sensitive and specific as compared to qPCR, and this mutation was frequently present in the MSI-H group (77.8 %; 14/18) and less frequently in the microsatellite-stable group (7.6 %; 9/118). All BRAF V600E mutated cases of the MSI-H group presented with a MLH1 promoter methylation (14/14) as detected by methylation-specific multiplex ligation-dependent probe amplification. When BRAF was wild type in the MSI-H group, only one MLH1 promoter methylation was detected (1/4), and of the remaining three cases without MLH1 methylation, two were identified to harbor an MLH1 mutation consistent with Lynch syndrome. Finally, 11 previously confirmed Lynch syndrome cases were analyzed for BRAF V600E mutation, and all of them were wild type. In conclusion, detection of BRAF V600E in colorectal cancer specimens by IHC is sensitive and specific and may help to identify Lynch syndrome patients.     

Effect of BRAF V600E mutation detection of fine-needle aspiration biopsy on diagnosis and treatment guidance of papillary thyroid carcinoma

ObjectiveThe aim of this study was to evaluate the diagnostic value of detection of BRAF V600E mutation in the fine-needle aspiration cytology (FNAC) specimens of thyroid nodules and the relationship between BRAF V600E mutation and the clinicopathological characteristics of papillary thyroid carcinoma (PTC).MethodsA total of 252 patients who underwent initial thyroid surgery were retrospectively analysed. All the patients underwent a preoperative FNAC at our institution, and the thyroid puncture cell fluid was used for both the cytological diagnosis and BRAF V600E mutational analysis using quantitative polymerase chain reaction. The Cochran-Mantel-Haenszel test was used to evaluate the diagnostic value of BRAF V600E mutation in FNAC fluid in diagnosing PTC. The association between BRAF V600E mutation and the clinicopathological parameters of PTC was analysed using the χ² test.ResultsThrough FNAC, 21 (8%), 60 (24%), and 171 (68%) cases were cytologically diagnosed as benign, indeterminate, and malignant, respectively. Postoperatively, 242 cases were histopathologically diagnosed as PTCs and 10 as goitre nodules. In the FNAC samples, 12 (57 %) of the 21 benign, 48 (80 %) of the 60 indeterminate, and 152 (88.9 %) of the 171 malignant cases showed BRAF V600E mutation. The histopathological diagnosis was used as the gold standard. The sensitivity and specificity of BRAF V600E mutational analysis in the FNAC samples for the diagnosis of PTC were 91.7 % and 100 % in benign, 82.8 % and 100 % in the indeterminate, and 89.4 % and 100 % in the malignant cases, respectively.ConclusionBRAF V600E mutational analysis in FNAC samples of thyroid nodules can be used an effective supplementary diagnostic method at our institution. However, BRAF V600E mutation was not associated with aggressive characteristics in PTC.     

Association between BRAF V600E mutation and regional lymph node metastasis in papillary thyroid carcinoma

Background: BRAF V600E is the most frequent genetic alteration in papillary thyroid carcinoma (PTC); there are ongoing conflicts on its association with regional lymph node metastasis. And we aimed to test this association in a referred sample in a single institute in China. Methods: We analyzed BRAF V600E mutational status in the primary lesion of 150 PTC cases in Peking Union Medical College Hospital (PUMCH) and their corresponding lymph node metastasis (if present and available) using a validated Amplification Refractory Mutation System Polymerase Chain Reaction (ARMS-PCR) method. Results: Among 150 PTC cases, 121 (80.6%) primary tumors harbored BRAF V600E mutation, 66.9% (81/121) and 79.3% (23/29) had regional lymph node metastasis (LNM) in cases detected with and without BRAF V600E mutation, respectively (P = 0.195). The BRAF V600E mutational status of most of the metastatic lesions was not different to that of their primary foci (73 out of 76 cases, 96.1%, Kappa value = 0.893). The 3 inconsistent cases were all mutation positive for primary tumors and mutation negative for LNM. Conclusion: No association was established between BRAF V600E mutation and regional lymph node metastasis in PTC in Chinese patients.