Clinical implication of highly sensitive detection of the BRAF V600E mutation in fine-needle aspirations of thyroid nodules: a comparative analysis of three molecular assays in 4585 consecutive cases in a BRAF V600E mutation-prevalent area

Evaluation of Droplet Digital PCR for the Detection of BRAF V600E in Fine-Needle Aspiration Specimens of Thyroid Nodules

Background

Droplet digital (dd)PCR is a new-generation PCR technique with high precision and sensitivity; however, the positive and negative droplets are not always effectively separated because of the "rain" phenomenon. We aimed to develop a practical optimization and evaluation process for the ddPCR assay and to apply it to the detection of BRAF V600E in fine-needle aspiration (FNA) specimens of thyroid nodules, as an example.

Methods

We optimized seven ddPCR parameters that can affect "rain." Analytical and clinical performance were analyzed based on histological diagnosis after thyroidectomy using a consecutive prospective series of 242 FNA specimens.

Results

The annealing time and temperature, number of PCR cycles, and primer and probe concentrations were found to be more important considerations for assay optimization than the denaturation time and ramp rate. The limit of blank and 95% limit of detection were 0% and 0.027%, respectively. The sensitivity of ddPCR for histological papillary thyroid carcinoma (PTC) was 82.4% (95% confidence interval [CI], 73.6%-89.2%). The pooled sensitivity of BRAF V600E in FNA specimens for histological PTC was 78.6% (95% CI, 75.9%-81.2%, I2=60.6%).

Conclusions

We present a practical approach for optimizing ddPCR parameters that affect the separation of positive and negative droplets to reduce rain. Our approach to optimizing ddPCR parameters can be expanded to general ddPCR assays for specific mutations in clinical laboratories. The highly sensitive ddPCR can compensate for uncertainty in cytological diagnosis by detecting low levels of BRAF V600E.

Expression of RASSF1A, DIRAS3, and AKAP9 Genes in Thyroid Lesions: Implications for Differential Diagnosis and Prognosis of Thyroid Carcinomas

Thyroid carcinoma is the primary endocrine malignancy worldwide. The preoperative examination of thyroid tissue lesion is often unclear. Approximately 25% of thyroid cancers cannot be diagnosed definitively without post-surgery histopathological examination. The assessment of diagnostic and differential markers of thyroid cancers is needed to improve preoperative diagnosis and reduce unnecessary treatments. Here, we assessed the expression of RASSF1A, DIRAS3, and AKAP9 genes, and the presence of BRAF V600E point mutation in benign and malignant thyroid lesions in a Polish cohort (120 patients). We have also performed a comparative analysis of gene expression using data obtained from the Gene Expression Omnibus (GEO) database (307 samples). The expression of RASSF1A and DIRAS3 was decreased, whereas AKAP9's was increased in pathologically changed thyroid compared with normal thyroid tissue, and significantly correlated with e.g., histopathological type of lesion papillary thyroid cancer (PTC) vs follicular thyroid cancer (FTC), patient's age, tumour stage, or its encapsulation. The receiver operating characteristic (ROC) analysis for the more aggressive FTC subtype differential marker suggests value in estimating RASSF1A and AKAP9 expression, with their area under curve (AUC), specificity, and sensitivity at 0.743 (95% CI: 0.548-0.938), 82.2%, and 66.7%; for RASSF1A, and 0.848 (95% CI: 0.698-0.998), 54.8%, and 100%, for AKAP9. Our research gives new insight into the basis of the aggressiveness and progression of thyroid cancers, and provides information on potential differential markers that may improve preoperative diagnosis.

Advances in Molecular Profiling and Their Potential Influence on the Extent of Surgery in Well-Differentiated Thyroid Carcinoma (WDTC)

Thyroid cancer surgery has evolved dramatically with advances in our understanding of the biological behaviour of WDTC. Molecular profiling is shedding light on the subset that may behave aggressively. In an era when thyroid cancer management is becoming increasingly conservative, decision making regarding the extent of surgery must be objectively guided by molecular markers. The aim of the present article is to summarise the current published literature and provide possible practice recommendations. An online search for relevant published articles was performed using several databases. Title, abstract, and full-text screening, along with data extraction, was performed by two independent reviewers after the inclusion and exclusion criteria were defined. A total of 1241 articles were identified, and 82 relevant articles were extracted and scrutinised. BRAF V600E and TERT promoter mutations were found to be associated with an increased risk of disease recurrence and distant metastases. Several other mutations have been identified that enhance disease aggressiveness (such as RET/PTC, PTEN, and TP53). One of the most important determinants of the outcome in WDTC is the extent of surgical resection. The evolution of molecular testing has reached a stage of personalised incorporation into surgical practice. Guidelines for molecular testing and surgery in WDTC will need to be clearly defined, arguably representing the next chapter in the management of the disease.

Improving the Accuracy of Single-Nucleotide Variant Diagnosis Using On-Off Discriminating Primers

Early detection of rare mutations through liquid biopsy can provide real-time information related to cancer diagnosis, prognosis, and treatment outcomes. Cell-free DNA samples used in liquid biopsies contain single-nucleotide variants (SNVs) with a variant allele frequency (VAF) of approximately ≤1%. Droplet digital polymerase chain reaction (ddPCR) is considered the gold standard of sequencing using liquid samples, generating amplicons from samples containing mutations with 0.001-0.005% VAF; however, it requires expensive equipment and time-consuming protocols. Therefore, various PCR methods for discriminating SNVs have been developed; nonetheless, non-specific amplification cannot be avoided even in the absence of mutations, which hampers the accurate diagnosis of SNVs. In this study, we introduce single-nucleotide variant on-off discrimination-PCR (Soo-PCR), a highly accurate and practical method that uses a 3'-end tailing primer for the on-off discrimination of low-abundance mutant-type targets, including SNVs. Soo-PCR minimizes the chance of incorrect judgments owing to its high discriminating power. Cancer markers, such as KRAS G12D, EGFR L858R, and EGFR T790M mutations, containing 0.1% VAF, were clearly detected in under 2 h with a high reliability comparable with that of ddPCR. This new method serves as a practical approach to accurately detect and evaluate low-abundance mutations in a user-friendly manner.

BRAFV600E mutation test on fine-needle aspiration specimens of thyroid nodules: Clinical correlations for 4600 patients

Background

The BRAF^V600E mutation is valuable for the diagnosis, prognosis, and therapy of papillary thyroid cancer (PTC). However, studies related to this mutation have involved only a small number of patients. Therefore, we performed a large‐scale analysis from a single institute to evaluate the accuracy of combined fine‐needle aspiration (FNA) and BRAF^V600E mutation tests for PTC diagnosis.

Methods

A total of 4600 patients with thyroid nodules who underwent both FNA cytology and BRAF^V600E mutation analysis on FNA specimens were enrolled. The association between the BRAF^V600E mutation and clinicopathological features was analyzed. A separate analysis was performed for the 311 patients who underwent repeated FNA for comparison of cytological evaluation and BRAF^V600E mutation results. The diagnostic efficacy of the BRAF^V600E mutation test and cytologic diagnoses was evaluated for 516 patients who underwent preoperative FNA tests in comparison with conclusive postoperative histopathologic results.

Results

The cytology results of all 4600 FNA samples were categorized according to The Bethesda System for Reporting Thyroid Cytology (TBSRTC) stages I–VI, which accounted for 11.76%, 60.02%, 6.46%, 3.61%, 6.71%, and 11.43% of the samples, respectively. The BRAF^V600E mutation was detected in 762 (16.57%) FNA samples, with rates of 1.48%, 0.87%, 20.20%, 3.01%, 66.02%, and 87.81% for TBSRTC I–VI lesions, respectively. Among the 311 repeat FNA cases, 81.0% of the BRAF^V600E‐positive and 4.3% of the BRAF^V600E‐negative specimens with an initial indication of cytological non‐malignancy were ultimately diagnosed as malignant by repeat FNA (p < 0.001). Among the 516 patients who underwent thyroidectomy, the sensitivity and specificity of the BRAF^V600E mutation test alone for PTC diagnosis were 76.71% and 100.0%, respectively, which increased to 96.62% and 88.03%, respectively, when combining the BRAF^V600E mutation test with cytology. BRAF^V600E mutation was significantly associated with lymph node metastasis (p < 0.001), but not with age, gender, or tumor size.

Conclusions

The BRAF^V600E mutation test in FNA samples has potential to reduce false negatives in PTC diagnosis, and therefore plays an important role in the diagnosis of thyroid nodules, especially those with an indeterminate or nondiagnostic cytology, which should be considered for repeat FNA.

Improving the diagnosis of AUS/FLUS thyroid nodules using an algorithm with combination of BRAFV600E mutation analysis and ultrasound pattern-based risk stratification

PURPOSE

To propose a diagnostic algorithm for improving the diagnosis of atypia of undetermined significance or follicular lesion of undetermined significance (AUS/FLUS) thyroid nodules.

METHODS

This study retrospectively enrolled 77 consecutive patients with 81 AUS/FLUS nodules who underwent preoperative BRAFV600E mutation analysis. A new diagnostic algorithm was proposed that BRAFV600E mutation analysis for the Fine-needle aspiration cytology specimen was firstly carried out, in which positive BRAFV600E mutation indicated malignancy and classification of the nodules with negative BRAFV600E mutation was further performed based on ultrasound pattern-based risk stratification of American Thyroid Association Guidelines. The diagnostic performance of the new diagnostic algorithm was evaluated.

RESULTS

The sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and area under the receiver operating characteristic curve (AUROC) of new diagnostic algorithm were 94.6%, 84.0%, 91.4%, 86.9%, 90.1%, and 0.893, respectively. The proposed diagnostic algorithm significantly increased the diagnostic performances (AUROC: 0.893 vs. 0.837 and 0.795), sensitivity (94.6% vs. 71.4% and 75.0%), and accuracy (90.1% vs. 79.0% and 77.8%) compared with BRAFV600E mutation analysis alone and ultrasound pattern-based risk stratification alone (all P < 0.05).

CONCLUSION

The proposed diagnostic algorithm is helpful for improving the diagnosis of AUS/FLUS nodules, which might be as a routine approach.

Preoperative molecular testing in thyroid nodules with Bethesda VI cytology: Clinical experience and review of the literature

Risk assessment is critical to determine the timing of elective surgeries and preserve valuable resources in time of pandemic. This study was undertaken to better understand the potential value of molecular testing to risk‐stratify thyroid nodules with malignant cytology (Bethesda VI). Systematic review of the literature contributed 21 studies representing 2036 preoperative specimens. The BRAF p.V600E substitution was detected in 46% to 90% of cases with a pooled positivity rate of 70% (95% confidence intervals: 64%‐76%). None of the studies used comprehensive oncogene panels. Retrospective analysis of 531 clinical specimens evaluated with the next‐generation sequencing ThyGeNEXT Thyroid Oncogene Panel identified a total of 436 gene alterations. BRAF mutation rate was 64% in specimens tested as part of standard clinical care and 75% in specimens from cross‐sectional research studies (P = .022). Testing for additional actionable gene alterations such as TERT promoter mutations or RET and NTRK gene rearrangements further increased the diagnostic yield to 78%‐85% and up to 95% when including the ThyraMIR Thyroid miRNA Classifier. These data support the role of molecular cytopathology in surgical and therapeutic decision‐making and warrant additional studies.

BRAF Status in Papillary Microcarcinomas of the Thyroid Gland: a Brief Review

Papillary thyroid microcarcinoma (PTMC) is defined by the World Health Organization as papillary cancer measuring 10 mm or less in diameter. Generally, PTMC shows an indolent clinical behavior with a good prognosis, although a minority of PTMC is characterized by an aggressive course. However, efforts to identify this aggressive subset of PTMC after surgery remain inconclusive. Several oncogenic pathways have been identified in thyroid cancer and have been applied translationally to improve prognosis and clinical management. In particular, the BRAFV600E mutation was found more frequently in large, aggressive, recurrent and advanced tumors. We aimed at reviewing studies on BRAFV600E mutation as a prognostic factor in PTMC.

Molecular markers for the classification of cytologically indeterminate thyroid nodules

BACKGROUND

The diagnosis of indeterminate lesions of the thyroid is a challenge in cytopathology practice. Indeed, up to 30% of cases lack the morphological features needed to provide definitive classification. Molecular tests have been developed to assist in the diagnosis of these indeterminate cases. The first studies dealing with the preoperative molecular evaluation of FNA samples focused on the analysis of BRAF^V600E or on the combined evaluation of two or three genetic alterations. The sensitivity of molecular testing was then improved through the introduction of gene panels, which became available for clinical use in the late 2000s. Two different categories of molecular tests have been developed, the 'rule-out' methods, which aim to reduce the avoidable treatment of benign nodules, and the 'rule-in' tests that have the purpose to optimize surgical management. The genetic evaluation of indeterminate thyroid nodules is predicted to improve patient care, particularly if molecular tests are used appropriately and with the awareness of their advantages and weaknesses. The main disadvantage of these tests is the cost, which makes them rarely used in Europe. To overcome this limitation, customized panels have been set up, which are able to detect the most frequent genetic alterations of thyroid cancer.

CONCLUSIONS

In the present review, the most recent available versions of commercial molecular tests and of custom, non-commercial panels are described. Their characteristics and accuracy in the differential diagnosis of indeterminate nodules, namely Bethesda classes III (Atypical follicular lesion of undetermined significance, AUS/FLUS) and IV (Suspicious for follicular neoplasm, FN/SFN) are fully analyzed and discussed.

Evaluation of the expression levels of BRAFV600E mRNA in primary tumors of thyroid cancer using an ultrasensitive mutation assay

Background

The BRAF^V600E gene encodes for the mutant BRAF^V600E protein, which triggers downstream oncogenic signaling in thyroid cancer. Since most currently available methods have focused on detecting BRAF^V600E mutations in tumor DNA, there is limited information about the level of BRAF^V600E mRNA in primary tumors of thyroid cancer, and the diagnostic relevance of these RNA mutations is not known.

Methods

Sixty-two patients with thyroid cancer and non-malignant thyroid disease were included in the study. Armed with an ultrasensitive technique for mRNA-based mutation analysis based on a two step RT-qPCR method, we analysed the expression levels of the mutated BRAF^V600E mRNA in formalin-fixed paraffin-embedded samples of thyroid tissues. Sanger sequencing for detection of BRAF^V600E DNA was performed in parallel for comparison and normalization of BRAF^V600E mRNA expression levels.

Results

The mRNA-based mutation detection assay enables detection of the BRAF^V600E mRNA transcripts in a 10,000-fold excess of wildtype BRAF counterparts. While BRAF^V600E mutations could be detected by Sanger sequencing in 13 out of 32 malignant thyroid cancer FFPE tissue samples, the mRNA-based assay detected mutations in additionally 5 cases, improving the detection rate from 40.6 to 56.3%. Furthermore, we observed a surprisingly large, 3-log variability, in the expression level of the BRAF^V600E mRNA in FFPE samples of thyroid cancer tissue.

Conclusions

The expression levels of BRAF^V600E mRNA was characterized in the primary tumors of thyroid cancer using an ultrasensitive mRNA-based mutation assay. Our data inspires further studies on the prognostic and diagnostic relevance of the BRAF^V600E mRNA levels as a molecular biomarker for the diagnosis and monitoring of various genetic and malignant diseases.

Solid-Phase Microextraction Enables Isolation of BRAF V600E Circulating Tumor DNA from Human Plasma for Detection with a Molecular Beacon Loop-Mediated Isothermal Amplification Assay

Circulating tumor DNA (ctDNA) is a promising biomarker that can provide a wealth of information regarding the genetic makeup of cancer as well as provide a guide for monitoring treatment. Methods for rapid and accurate profiling of ctDNA are highly desirable in order to obtain the necessary information from this biomarker. However, isolation of ctDNA and its subsequent analysis remains a challenge due to the dependence on expensive and specialized equipment. In order to enable widespread implementation of ctDNA analysis, there is a need for low-cost and highly accurate methods that can be performed by nonexpert users. In this study, an assay is developed that exploits the high specificity of molecular beacon (MB) probes with the speed and simplicity of loop-mediated isothermal amplification (LAMP) for the detection of the BRAF V600E single-nucleotide polymorphism (SNP). Furthermore, solid-phase microextraction (SPME) is applied for the successful isolation of clinically relevant concentrations (73.26 fM) of ctDNA from human plasma. In addition, the individual effects of plasma salts and protein on the extraction of ctDNA with SPME are explored. The performed work expands the use of MB-LAMP for SNP detection as well as demonstrates SPME as a sample preparation tool for nucleic acid analysis in plasma.

Molecular Variants and Their Risks for Malignancy in Cytologically Indeterminate Thyroid Nodules

Background: Gene panels are routinely used to assess predisposition to hereditary cancers by simultaneously testing multiple susceptibility genes and/or variants. More recently, genetic panels have been implemented as part of solid tumor malignancy testing assessing somatic alterations. One example is targeted variant panels for thyroid nodules that are not conclusively malignant or benign upon fine-needle aspiration (FNA). We systematically reviewed published studies from 2009 to 2018 that contained genetic data from preoperative FNA specimens on cytologically indeterminate thyroid nodules (ITNs) that subsequently underwent surgical resection. Pooled prevalence estimates per gene and variant, along with their respective positive predictive values (PPVs) for malignancy, were calculated. Summary: Our systematic search identified 540 studies that were supplemented by 18 studies from bibliographies or personal files. Sixty-one studies met all inclusion criteria and included >4600 ITNs. Overall, 26% of nodules contained at least 1 variant or fusion. However, half of them did not include details on the specific gene, variant, and/or complete fusion pair reported for inclusion toward PPV calculations. The PPVs of genomic alterations reported at least 10 times were limited to BRAF^V600E (98%, 95% confidence interval [CI 96-99%]), PAX8/PPARG (55% [CI 34-78%]), HRAS^Q61R (45% [CI 22-72%]), BRAF^K601E (42% [CI 19-68%]), and NRAS^Q61R (38% [CI 23-55%]). Excluding BRAF^V600E, the pooled PPV for all other specified variants and fusions was 47%. Multiple variants within the same nodule were identified in ∼1% of ITN and carried a cumulative PPV of 77%. Conclusions: The chance that a genomic alteration predicts malignancy depends on the individual variant or fusion detected. Only five alterations were reported at least 10 times; BRAF^V600E had a PPV of 98%, while the remaining four had individual PPVs ranging from 38% to 55%. The small sample size of most variants and fusion pairs found among ITNs, however, limits confidence in their individual PPV point estimates. Better specific reporting of genomic alterations with cytological category, histological subtype, and cancer staging would facilitate better understanding of cancer prediction, and the independent contribution of the genomic profile to prognosis.

A new primer construction technique that effectively increases amplification of rare mutant templates in samples

Background

In personalized medicine, companion diagnostic tests provide additional information to help select a treatment option likely to be optimal for a patient. Although such tests include several techniques for detecting low levels of mutant genes in wild-type backgrounds with fairly high sensitivity, most tests are not specific, and may exhibit high false positive rates. In this study, we describe a new primer structure, named ‘stuntmer’, to selectively suppress amplification of wild-type templates, and promote amplification of mutant templates.

Results

A single stuntmer for a defined region of DNA can detect several kinds of mutations, including point mutations, deletions, and insertions. Stuntmer PCRs are also highly sensitive, being able to amplify mutant sequences that may make up as little as 0.1% of the DNA sample.

Conclusion

In conclusion, our technique, stuntmer PCR, can provide a simple, low-cost, highly sensitive, highly accurate, and highly specific platform for developing companion diagnostic tests.

Electronic supplementary material

The online version of this article (10.1186/s12896-019-0555-1) contains supplementary material, which is available to authorized users.

BRAFV600E mutation analysis in fine-needle aspiration cytology specimens for diagnosis of thyroid nodules: The influence of false-positive and false-negative results

Background

The accurate evaluation of BRAF^V600E mutation in preoperative fine‐needle aspiration cytology (FNAC) specimens is important for making management decisions in thyroid nodules (TNs). The aim of this study was to assess the false‐positive and false‐negative BRAF^V600E mutations in thyroid FNAC specimens and their influence on diagnosis of TN.

Methods

This prospective study enrolled 292 nodules in 269 patients who underwent BRAF^V600E mutation analysis using amplification refractory mutation system‐quantitative real‐time polymerase chain reaction (ARMS‐qPCR) both in FNAC specimens and formalin‐fixed, paraffin‐embedded (FFPE) tissue samples after surgery. The false‐positive and false‐negative mutations for BRAF^V600E analysis using ARMS‐qPCR in FNAC specimens were recorded, with reference to the results of BRAF^V600E mutation analysis using ARMS‐qPCR in FFPE tissue sample. Diagnostic performances of FNAC, BRAF^V600E mutation analysis in FNAC specimens, BRAF^V600E mutation analysis in FFPE tissue sample, and the combination of FNAC and BRAF^V600E mutation analysis for predicting thyroid malignancy were assessed.

Results

The false‐positive and false‐negative mutations for BRAF^V600E analysis using ARMS‐qPCR in FNAC specimens were 10.1% (19/189) and 7.1% (7/98), respectively. FNAC combined with preoperative BRAF^V600E mutation analysis significantly increased the diagnostic sensitivity from 75.7% to 92.3%, and accuracy from 78.7% to 90.6% in comparison with FNAC alone (both P < .001). No significant differences were found between the combination of FNAC and BRAF^V600E mutation analysis in FNAC specimens and the combination of FNAC and BRAF^V600E mutation analysis in FFPE tissue sample (sensitivity: 92.3% vs 91.9%; accuracy: 90.6% vs 91.3%; both P > .05).

Conclusions

FNAC combined with preoperative BRAF^V600E mutation analysis can significantly increase the diagnostic performance in comparison with FNAC alone. False‐positive and false‐negative BRAF^V600E mutation results are found in preoperative FNAC specimens, whereas it does not affect the overall auxiliary diagnosis of TNs.

Update on Molecular Testing for Cytologically Indeterminate Thyroid Nodules

Fine needle aspiration biopsy (FNAB) and ultrasonography are the most common modalities for the diagnosis and follow up of thyroid nodules. FNAB is able to distinguish benign from malignant nodules with high sensitivity and specificity; however, 20% to 30% of nodules are diagnosed as indeterminate with a risk of malignancy varying from 10% to 75% based on the 2017 revision of the Bethesda System for Reporting Thyroid Cytopathology. Molecular tests are being increasingly used to triage this group of nodules. Several molecular tests are commercially available and newer upgrades are being developed to either "rule in" or "rule out" malignancy with greater accuracy. The Afirma gene expression classifier and its recent upgrade (the Afirma gene sequencing classifier), Thryoseq v2, a next generation sequencing test and its recent upgrade (the v3), RosettaGX Reveal based on microRNA alterations, and ThyGenX/ThyraMIR, a combination test, are currently on the market. Familiarity with these tests, their performance, and postvalidation publications will enable appropriate test selection and improve triage of patients for appropriate therapy. The underlying rate of malignancy at different institutions and the interobserver variability in cytologic and histologic diagnosis of thyroid lesions are important factors that impact the performance of the various molecular tests.

Predictive Value of BRAFV600E Mutation for Lymph Node Metastasis in Papillary Thyroid Cancer: A Meta-analysis

BRAF^V600E mutation has been thought to be a valuable molecular marker that may predict a worse prognosis for papillary thyroid cancer (PTC). But whether BRAF^V600E mutation is associated with lymph node metastasis (LNM) remains controversial. Different surgical strategies may bring a bias in demonsstrating the association between them. In order to delineate a risk stratification to guide a tailored initial approach to tumors that express BRAF^V600E mutation, we performed this meta-analysis by using the articles in which total or near-total thyroidectomy plus bilateral central lymph node dissection was routinely performed to avoid the bias from the surgical strategy. We searched the Medline, Embase and CNKI database for eligible studies from January 2003 to May 2018. Meta-analysis was performed using the STATA 12.0 software. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated under fixed-effects or randomeffects models. Fifteen clinical studies were included with a total of 4909 PTC patients. Our meta-analysis results reported that BRAFV600E mutation was associated with LNM (OR=1.34; 95% CI: 1.09-1.65; P=0.005), as well as central LNM (OR=1.59; 95% CI: 1.35-1.88; P<0.00001). Moreover, in patients with papillary thyroid microcarcinoma, we also confirmed the predictive value of BRAF^V600E mutation for LNM (OR=3.49; 95% CI: 2.02-6.02; P<0.00001). This meta-analysis demonstrates that BRAF^V600E mutation is closely related to LNM in PTC patients. The results suggest that BRAF^V600E mutation can be considered as a risk factor for LNM in PTC. Moreover, combining BRAF^V600E mutation with other risk factors to determine the initial surgical treatment may bring benefits for PTC patients.

Diagnostic Utility of Molecular and Imaging Biomarkers in Cytological Indeterminate Thyroid Nodules

Indeterminate thyroid cytology (Bethesda III and IV) corresponds to follicular-patterned benign and malignant lesions, which are particularly difficult to differentiate on cytology alone. As ~25% of these nodules harbor malignancy, diagnostic hemithyroidectomy is still custom. However, advanced preoperative diagnostics are rapidly evolving.This review provides an overview of additional molecular and imaging diagnostics for indeterminate thyroid nodules in a preoperative clinical setting, including considerations regarding cost-effectiveness, availability, and feasibility of combining techniques. Addressed diagnostics include gene mutation analysis, microRNA, immunocytochemistry, ultrasonography, elastosonography, computed tomography, sestamibi scintigraphy, [18F]-2-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET), and diffusion-weighted magnetic resonance imaging.The best rule-out tests for malignancy were the Afirma® gene expression classifier and FDG-PET. The most accurate rule-in test was sole BRAF mutation analysis. No diagnostic had both near-perfect sensitivity and specificity, and estimated cost-effectiveness. Molecular techniques are rapidly advancing. However, given the currently available techniques, a multimodality stepwise approach likely offers the most accurate diagnosis, sequentially applying one sensitive rule-out test and one specific rule-in test. Geographical variations in cytology (e.g., Hürthle cell neoplasms) and tumor genetics strongly influence local test performance and clinical utility. Multidisciplinary collaboration and implementation studies can aid the local decision for one or more eligible diagnostics.

Update on Molecular Testing for Cytologically Indeterminate Thyroid Nodules

CONTEXT

- Approximately 15% to 30% of thyroid nodules that undergo fine-needle aspiration are classified as cytologically indeterminate, presenting management challenges for patients and clinicians alike. During the past several years, several molecular tests have been developed to reduce the diagnostic uncertainty of indeterminate thyroid fine-needle aspirations.

OBJECTIVE

- To review the methodology, clinical validation, and recent peer-reviewed literature for 4 molecular tests that are currently marketed for cytologically indeterminate thyroid fine-needle aspiration specimens: Afirma, ThyroSeq, ThyGenX/ThyraMIR, and RosettaGX Reveal.

DATA SOURCES

- Peer-reviewed literature retrieved from PubMed search, data provided by company websites and representatives, and authors' personal experiences.

CONCLUSIONS

- The 4 commercially available molecular tests for thyroid cytology offer unique approaches to improve the risk stratification of thyroid nodules. Familiarity with data from the validation studies as well as the emerging literature about test performance in the postvalidation setting can help users to select and interpret these tests in a clinically meaningful way.

Comparative analysis of diagnostic performance, feasibility and cost of different test-methods for thyroid nodules with indeterminate cytology

Since it is impossible to recognize malignancy at fine needle aspiration (FNA) cytology in indeterminate thyroid nodules, surgery is recommended for all of them. However, cancer rate at final histology is <30%. Many different test-methods have been proposed to increase diagnostic accuracy in such lesions, including Galectin-3-ICC (GAL-3-ICC), BRAF mutation analysis (BRAF), Gene Expression Classifier (GEC) alone and GEC+BRAF, mutation/fusion (M/F) panel, alone, M/F panel+miRNA GEC, and M/F panel by next generation sequencing (NGS), FDG-PET/CT, MIBI-Scan and TSHR mRNA blood assay.We performed systematic reviews and meta-analyses to compare their features, feasibility, diagnostic performance and cost. GEC, GEC+BRAF, M/F panel+miRNA GEC and M/F panel by NGS were the best in ruling-out malignancy (sensitivity = 90%, 89%, 89% and 90% respectively). BRAF and M/F panel alone and by NGS were the best in ruling-in malignancy (specificity = 100%, 93% and 93%). The M/F by NGS showed the highest accuracy (92%) and BRAF the highest diagnostic odds ratio (DOR) (247). GAL-3-ICC performed well as rule-out (sensitivity = 83%) and rule-in test (specificity = 85%), with good accuracy (84%) and high DOR (27) and is one of the cheapest (113 USD) and easiest one to be performed in different clinical settings.In conclusion, the more accurate molecular-based test-methods are still expensive and restricted to few, highly specialized and centralized laboratories. GAL-3-ICC, although limited by some false negatives, represents the most suitable screening test-method to be applied on a large-scale basis in the diagnostic algorithm of indeterminate thyroid lesions.

The Genetics of Papillary Microcarcinomas of the Thyroid: Diagnostic and Prognostic Implications

Papillary microcarcinoma of the thyroid (mPTC) is defined by the WHO as a papillary thy-roid cancer measuring 10mm or less in diameter and it is nowadays a topic of intense debate among the members of the medical community due to its apparent “epidemic” rise. Although these tumors follow almost always an indolent clinical course and carry an excellent prognosis, it is known that a small sub-set may display a potentially aggressive behavior. Nevertheless, we still lack an accurate way of predict-ing those which will cause significant disease. In an attempt to address this problem, a number of clini-co-pathologic features have been studied as poor prognostic markers in mPTC, and their association with known genetic alterations in thyroid cancer has been evaluated. Herein we review the present knowledge concerning mPTC’s genetic profile, namely the prevalence of BRAF (V600E), RAS and TERT promoter mutations and RET/PTC and PAX8-PPARG rearrangements and report the results of the evaluation in the putative prognostic value of these genetic alterations in mPTC.

Iodine intake as a risk factor for BRAF mutations in papillary thyroid cancer patients from an iodine-replete area

PURPOSE

Both deficient and excessive iodine intake leads to thyroid disease, which shows U-shaped curves. Our previous study showed that a relatively low [urinary iodine concentration (UIC) <300 μg/L] and extremely excessive (UIC ≥ 2500 μg/L) iodine intake were associated with thyroid cancer in Korea, an iodine-replete area. Papillary thyroid cancer (PTC) accounts for more than 97 % of thyroid cancer and 80% or more PTC cases harbor the BRAF mutation in Korea. We aimed to investigate the relationship between iodine intake and the prevalence of the BRAF mutation in PTC in Korea.

METHODS

UIC was measured by inductively coupled plasma mass spectrometry. The BRAF mutation was detected using both allele-specific polymerase chain reaction and mutant enrichment with 3'-modified oligonucleotide sequencing. Risk factors for the occurrence of BRAF mutations in PTC were evaluated using multivariate logistic regression models.

RESULTS

The median UIC in all patients with PTC was 287 μg/L (range from 7 to 7, 426 μg/L). Nearly half of the patients (102/215, 47%) belonged to the excessive iodine intake category (UIC ≥ 300 μg/L) according to the WHO iodine recommendations. The frequency of BRAF mutations was lowest in the 300-499 μg/L UIC group; it was significantly different compared to the relatively low (UIC < 300 μg/L) and more than excessive (UIC ≥ 500 μg/L) iodine intake groups. UIC was an independent predictor for BRAF mutations in PTC. The multivariate-adjusted odds ratios (95% confidence intervals) in the relatively low and more than excessive iodine intake groups for the BRAF mutation were 4.761 (1.764-12.850) and 6.240 (2.080-18.726), respectively, compared to the 300-499 μg/L UIC group.

CONCLUSION

Relatively low iodine intake and more than excessive iodine intake seem to be significant risk factors for the occurrence of BRAF mutations in the thyroid and, therefore, may be risk factors for the development of PTC in an iodine-replete area.

Comprehensive screening for PD-L1 expression in thyroid cancer

PD-L1 expression is being considered a potential biomarker for response of anti-PD-1 or anti-PD-L1 agents in various tumors. The reported frequency of PD-L1 positivity varies in thyroid carcinomas, and multiple factors may contribute to the variability in PD-L1 positivity. We evaluated the PD-L1 expression in various thyroid cancers on a large scale. A total of 407 primary thyroid cancers with a median 13.7-year of follow-up were included. We evaluated the frequency of PD-L1 expression using a rabbit monoclonal antibody (clone SP142). In addition, we analyzed the relationships between PD-L1 expression and clinicopathologic factors, including TERT promoter, BRAF status and disease progression. Tumoral PD-L1 was expressed in 6.1% of papillary thyroid carcinomas, 7.6% of follicular thyroid carcinomas and 22.2% of anaplastic thyroid carcinomas. The distribution of PD-L1 positivity was different according to cancer histology types (P < 0.001). All PD-L1-positive cases of follicular thyroid carcinoma and anaplastic thyroid carcinoma showed strong intensity. The proportions of positivity in PD-L1 positive anaplastic thyroid carcinomas were more than 80%. PD-L1 in immune cells was positive in 28.5% of papillary thyroid carcinoma, 9.1% of follicular thyroid carcinomas and 11.1% of anaplastic thyroid carcinomas. There was no significant association between clinicopathologic variables, disease progression, oncogenic mutation and PD-L1 expression. PD-L1 was highly expressed in a subset of patients with advanced thyroid cancer, such as follicular and anaplastic thyroid carcinoma. Identification of PD-L1 expression may have direct therapeutic relevance to patients with refractory thyroid cancer.

Evaluation of the Anyplex BRAF V600E real-time detection assay using dual-priming oligonucleotide technology in fine-needle aspirates of thyroid nodules

Background

Several molecular assays have been developed to detect the BRAF V600E mutation in fine needle aspirates (FNAs) for the diagnosis of papillary thyroid cancer. Using a multiplex PCR technique, we evaluated the Anyplex BRAF V600E Real-time Detection (Anyplex) assay and compared its efficacy with that of the Seeplex BRAF V600E ACE Detection (Seeplex) method.

Methods

We tested 258 consecutive FNA specimens using the Seeplex and Anyplex assays. Any conflicting results between the two assays were confirmed by using mutant enrichment with 3'-modified oligonucleotide (MEMO) sequencing. The limits of detection (LODs) and reproducibility for each assay were evaluated with serially diluted DNA from a BRAF V600E-positive cell line.

Results

The BRAF V600E mutation was detected in 36.4% (94/258) FNA specimens by either the Seeplex or Anyplex assay. Results for the two assays showed 93.4% (241/258) agreement, with a kappa value of 0.861 (95% confidence interval, 0.798-0.923). Of the eight specimens that were BRAF V600E-positive by the Anyplex assay but not by the Seeplex assay, five were found to be BRAF V600E-positive by MEMO sequencing. The mutation detection rate of the Seeplex and Anyplex assays was 79.0% and 84.0%, respectively, in the FNA specimens diagnosed as malignant (n=81). The LOD as determined by probit analysis was 0.046% (95% confidence interval, 0.019-0.532%).

Conclusions

The Anyplex assay performed better than the Seeplex assay with respect to the detection of the BRAF V600E mutation.

BRAFV600E mutation as a predictor of thyroid malignancy in indeterminate nodules: A systematic review and meta-analysis

BACKGROUND

Thyroid nodules are usually diagnosed using fine-needle aspiration (FNA). The sensitivity limitations of FNA result in 10-30% of nodules being classified as "indeterminate". The BRAF^V600E mutation is associated with papillary thyroid carcinoma (PTC). We conducted a systemic review and meta-analysis to evaluate the diagnostic utility of the BRAF^V600E mutation in indeterminate nodules.

METHOD

PUBMED and EMBASE were searched for studies testing for the BRAF^V600E involving indeterminate nodules (Thy3a, Thy3f, Thy4) and containing information on final surgical histopathology. Thirty two studies involving 3150 indeterminate nodules were included in the analysis.

RESULTS

The overall sensitivity and specificity for BRAF^V600E for the diagnosis of thyroid malignancy was 0.40 (95% CI: 0.32-0.48) and 1.00 (95% CI: 0.98-1.00) respectively. The diagnostic odds ratio (DOR) was 205.4 (95% CI: 40.1-1052). With a Fagan plot, the post-test probability of thyroid cancer, given a negative mutation was 6%, but this rose to 92% with a positive result. On subgroup analysis, for Thy3a nodules, the pooled sensitivity and specificity for thyroid malignancy was 0.21 (95% CI: 0.13-0.34) and 1.00 (95% CI: 0.98-1.00). For Thy3f nodules, the pooled sensitivity and specificity was 0.09 (95% CI: 0.03-0.20) and 1.00 (95% CI: 0.05-1.00) respectively. For Thy4 nodules, the corresponding sensitivity and specificity was 0.58 (95% CI: 0.5-0.64) and 0.99 (95% CI: 0.95-1.00) respectively.

CONCLUSIONS

Despite a high specificity for thyroid cancer, BRAF^V600E mutation has a low overall sensitivity and therefore has a limited diagnostic value as a single screening test.

TERT promoter mutations and long-term survival in patients with thyroid cancer

TERT promoter mutations are emerging prognostic biomarkers in multiple cancers and are found in highly aggressive thyroid cancer. Our aim is to investigate the prognostic value of these mutations for the outcome of thyroid cancer-related mortality in a large cohort of thyroid cancer patients. This was a retrospective study of 409 patients (393 with differentiated thyroid cancer) with a median age of 44 years (range 16-81 years) and median follow-up of 13 years (interquartile range 11-16 years). Analyses of associations between mutational status and various clinicopathological variables were performed. TERT promoter mutations were identified in 32 (9.8%) papillary, 11 (16.7%) follicular and seven (43.8%) poorly differentiated/anaplastic thyroid cancer patients. The presence of TERT promoter mutations was associated with factors such as increased age (P < 0.001), extrathyroidal invasion (P = 0.01), increased stage at diagnosis (P < 0.001) and dedifferentiated histological type (P = 0.001). A TERT promoter mutation was independently associated with poorer overall survival in patients with differentiated thyroid cancer (10-year survival rate, 66.2% vs 98.3% for wild type; adjusted HR, 7.18; 95% CI: 2.77-18.59) and in patients with papillary cancer (74.2% vs 99.3%; 14.20; 3.03-66.68). Concomitant TERT and BRAF mutations worsened the survival rate of patients with papillary cancer (82.6% vs 99.4% for exclusively BRAF mutation alone; 5.62; 1.85-17.09). In conclusion, the presence of TERT promoter mutations is independently associated with increased mortality in patients with differentiated thyroid cancer. The results suggest that inclusion of TERT promoter mutation analysis with conventional clinicopathological evaluation can lead to better prognostication and management for individual patients.

Detection of MYD88 L265P in patients with lymphoplasmacytic lymphoma/Waldenstrom macroglobulinemia and other B-cell non-Hodgkin lymphomas

Background

Recent studies have identified a high prevalence of the MYD88 L265P mutation in lymphoplasmacytic lymphoma (LPL)/Waldenstrom macroglobulinemia (WM) cases, whereas low frequencies have been observed in other B cell non-Hodgkin lymphomas (NHLs).

Methods

We evaluated the sensitivity of the mutant enrichment 3'-modified oligonucleotide (MEMO)-PCR technique, a new detection method. We examined the MYD88 L265P mutation in a series of Korean patients with LPL/WM and other B cell NHLs in bone marrow aspirates, using the MEMO-PCR technique.

Results

The sensitivity of MEMO-PCR was estimated to be approximately 10-16.7%. MYD88 L265P was detected in 21 of 28 LPL cases (75%) and only three of 69 B cell NHL cases (4.3%).

Conclusion

Although MEMO-PCR had relatively low sensitivity, we confirmed the high prevalence of the MYD88 L265P mutation in Korean LPL patients. Our study suggests the diagnostic value of MYD88 L265P for differentiating B-cell NHLs.

A combination of immunohistochemistry and molecular approaches improves highly sensitive detection of BRAF mutations in papillary thyroid cancer

The optimal method for BRAF mutation detection remains to be determined despite advances in molecular detection techniques. The aim of this study was to compare, against classical Sanger sequencing, the diagnostic performance of two of the most recently developed, highly sensitive methods: BRAF V600E immunohistochemistry (IHC) and peptide nucleic-acid (PNA)-clamp qPCR. BRAF exon 15 mutations were searched in formalin-fixed paraffin-embedded tissues from 86 papillary thyroid carcinoma using the three methods. The limits of detection of Sanger sequencing in borderline or discordant cases were quantified by next generation sequencing. BRAF mutations were found in 74.4 % of cases by PNA, in 71 % of cases by IHC, and in 64 % of cases by Sanger sequencing. Complete concordance for the three methods was observed in 80 % of samples. Better concordance was observed with the combination of two methods, particularly PNA and IHC (59/64) (92 %), while the combination of PNA and Sanger was concordant in 55 cases (86 %). Sensitivity of the three methods was 99 % for PNA, 94.2 % for IHC, and 89.5 % for Sanger. Our data show that IHC could be used as a cost-effective, first-line method for BRAF V600E detection in daily practice, followed by PNA analysis in negative or uninterpretable cases, as the most efficient method. PNA-clamp quantitative PCR is highly sensitive and complementary to IHC as it also recognizes other mutations besides V600E and it is suitable for diagnostic purposes.

Diagnostic value of BRAF (V600E)-mutation analysis in fine-needle aspiration of thyroid nodules: a meta-analysis

Fine-needle aspiration (FNA) is a reliable method for preoperative diagnosis of thyroid nodules; however, about 10%–40% nodules are classified as indeterminate. The BRAF^V600E mutation is the most promising marker for thyroid FNA. This meta-analysis was conducted to investigate the diagnostic value of BRAF^V600E analysis in thyroid FNA, especially the indeterminate cases. Systematic searches were performed in PubMed, Web of Science, Scopus, Ovid, Elsevier, and the Cochrane Library databases for relevant studies prior to June 2015, and a total of 88 studies were ultimately included in this meta-analysis. Compared with FNA cytology, the synergism of BRAF^V600E testing increased the diagnostic sensitivity from 81.4% to 87.4% and decreased the false-negative rate from 8% to 5.2%. In the indeterminate group, the mutation rate of BRAF^V600E was 23% and varied in different subcategories (43.2% in suspicious for malignant cells [SMC], 13.77% in atypia of undetermined significance/follicular lesion of undetermined significance [AUS/FLUS], and 4.43% in follicular neoplasm/suspicious for follicular neoplasm [FN/SFN]). The sensitivity of BRAF^V600E analysis was higher in SMC than that in AUS/FLUS and FN/SFN cases (59.4% vs 40.1% vs 19.5% respectively), while specificity was opposite (86.1% vs 99.5% vs 99.7% respectively). The areas under the summary receiver-operating characteristic curve also confirmed the diagnostic value of BRAF^V600E testing in SMC and AUS/FLUS rather than FN/SFN cases. Therefore, BRAF^V600E analysis can improve the diagnostic accuracy of thyroid FNA, especially indeterminate cases classified as SMC, and select malignancy to guide the extent of surgery.

Initial clinical experience with BRAF(V600E) mutation analysis of core-needle biopsy specimens from thyroid nodules

OBJECTIVE

The accurate diagnosis of thyroid nodules is important for making management decisions. The purpose of this study was to evaluate the feasibility of core-needle biopsy with BRAF(V600E) mutation analysis (CNB + BRAF(V600E) ) and to compare the clinical usefulness of CNB + BRAF(V600E) and fine-needle aspiration with BRAF(V600E) mutation analysis (FNA + BRAF(V600E) ) in the diagnosis of thyroid malignancy.

DESIGN, PATIENTS AND MEASUREMENTS

The results of BRAF(V600E) mutation analyses of 820 nodules from 820 patients (153 men, 667 women; mean age, 51·1 years), who underwent CNB + BRAF(V600E) (n = 256) or FNA + BRAF(V600E) (n = 564) between January 2011 and March 2012 were retrospectively evaluated. The feasibility of CNB + BRAF(V600E) was assessed by comparing its rate of detection of BRAF(V600E) mutations and positive predictive value with those of FNA + BRAF(V600E) . The clinical usefulness of CNB + BRAF(V600E) was determined by comparing rates of inconclusive results, the additional value of BRAF(V600E) mutation analysis, diagnostic surgery and diagnostic performance with those of FNA + BRAF(V600E) .

RESULTS

CNB + BRAF(V600E) and FNA + BRAF(V600E) had similar rates of BRAF(V600E) mutation detection (66·3% vs 64·4%, P = 0·883) and positive predictive value (100·0% vs 96·6%, P = 0·135). CNB + BRAF(V600E) had a significantly higher diagnostic accuracy rate (95·7% vs 85·9%, P < 0·001), and significantly lower rates of inconclusive results (8·2% vs 51·8%, P < 0·001), and diagnostic surgery (8·9% vs 22·3%, P = 0·006), than FNA + BRAF(V600E) .

CONCLUSIONS

The greater diagnostic performance of CNB + BRAF(V600E) and its lower rate of inconclusive results than FNA + BRAF(V600E) suggest that CNB + BRAF(V600E) can reduce rates of preventable diagnostic surgery.

Clinical impact of BRAF mutation on the diagnosis and prognosis of papillary thyroid carcinoma: a systematic review and meta-analysis

BACKGROUND

The possible role of BRAF(V) (600E) mutation in the diagnosis and prognosis of papillary thyroid carcinoma (PTC) remains controversial. A systematic review to investigate the diagnostic and prognostic role of BRAF(V) (600E) mutation in patients with PTC is urgently needed.

METHODS

A systematic review of relevant literatures was performed in PubMed, EMBASE and CENTRAL. The incremental accuracy (IA) of fine needle aspiration biopsy plus BRAF(V) (600E) mutation analysis over fine needle aspiration biopsy alone, and the statistical data about the association of BRAF(V) (600E) mutation and the prognosis of PTC (risk ratios (RR) for dichotomous data, standard mean differences for continuous data and hazard ratios (HRs) for disease-free survival (DFS) were pooled. Subgroup analysis was performed to explain the heterogeneities.

RESULTS

A total of 67 studies were included. The pooled IA was 2% (95% confidence interval (CI): 0·5-4%). The pooled RR for gender, multifocality, lymph node metastasis, extrathyroidal invasion and pathological stage was 1·11 (95% CI: 0·98-1·25), 1·17 (95% CI: 1·09-1·24), 1·36 (95% CI: 1·20-1·53), 1·60 (95% CI: 1·41-1·82), and 1·49 (95% CI: 1·33-1·68), respectively. The pooled standard mean differences for age and tumour size were 0·14 (95% CI: 0·04-0·23) and 0·21 (95% CI: 0·1-0·32), respectively. The pooled HR for DFS was 1·96 (95% CI: 1·62-2·37). Subgroup analysis showed that these statistical results were affected by the geographical background of patients, study design and detection methods.

CONCLUSIONS

BRAF(V) (600E) mutation analysis can not only be used in the diagnosis of PTC, but can also predict its prognosis.

Triage of patients with AUS/FLUS on thyroid cytopathology: effectiveness of the multimodal diagnostic techniques

The management of patients with thyroid cytopathologic diagnosis of atypia (or follicular lesion) of undetermined significance (AUS/FLUS) is a complex clinical problem. The purpose of this study was to develop a practical triage scheme based on multiple diagnostic tests in general use. We performed a retrospective cohort study involving 15,335 consecutive patients with a referral diagnosis of thyroid nodule between April 2011 and March 2015 using an institutional database. We obtained 904 patients with an initial cytopathologic diagnosis of AUS/FLUS who underwent repeat fine‐needle aspiration or core needle biopsy, 388 of whom had a corresponding histopathological diagnosis for excised index lesions. The diagnostic performance of ultrasound (US) findings, repeat biopsy, and BRAF^V600E mutation in cytopathologic specimens were evaluated individually or as a set. Of the 388 resected AUS/FLUS cases, 338 (87.1%) were thyroid cancer. The positive likelihood ratios (LRs) for BRAF^V600E mutation and repeat biopsy result of suspicious for malignant cell (SMC) or worse were 11.6 (95% CI = 1.7–77.8) and 13.7 (95% CI = 4.6–41.0), respectively. The absence of suspicious findings on US combined with cytologic result of less than SMC or negative BRAF^V600E mutation produced negative LRs ranging from 0.06 to 0.15, corresponding to negative predictive values of over 90% in both primary and referral settings. For patients with AUS/FLUS cytopathology, clinical decision making can be guided by a simple triage scheme based on US findings, repeat biopsy, or BRAF^V600E mutation.

Molecular cytopathology for thyroid nodules: A review of methodology and test performance

Advances in the molecular characterization of thyroid cancers have fueled the development of genetic and gene expression-based tests for thyroid fine-needle aspirations. Collectively, these tests are designed to improve the diagnostic certainty of thyroid cytology. This review summarizes the early published experience with the commercially available versions of these tests: the Afirma Gene Expression Classifier, ThyGenX (formerly miRInform)/ThyraMIR, and ThyroSeq. Key differences in testing approaches and issues regarding test performance and interpretation are also discussed.

Chronic lymphocytic thyroiditis and BRAF V600E in papillary thyroid carcinoma

It has been reported that papillary thyroid carcinoma (PTC) with chronic lymphocytic thyroiditis (CLT) is less associated with extrathyroidal extension (ETE), advanced tumor stage and lymph node (LN) metastasis. Other studies have suggested that concurrent CLT could antagonize PTC progression, even in BRAF-positive patients. Since the clinical significance of the BRAF mutation has been particularly associated with conventional PTC, the purpose of this study was to determine the clinical significance of CLT according to BRAF mutation status in conventional PTC patients. We retrospectively reviewed the medical records of 3332 conventional PTC patients who underwent total thyroidectomy with bilateral central neck dissection at the Thyroid Cancer Center of Samsung Medical Center between January 2008 and June 2015. In this study, the prevalence of BRAF mutation was significantly less frequent in conventional PTC patients with CLT (76.9% vs 86.6%). CLT was an independent predictor for low prevalence of ETE in both BRAF-negative (OR=0.662, P=0.023) and BRAF-positive (OR=0.817, P=0.027) conventional PTC patients. In addition, CLT was an independent predictor for low prevalence of CLNM in both BRAF-negative (OR=0.675, P=0.044) and BRAF-positive (OR=0.817, P=0.030) conventional PTC patients. In conclusion, BRAF mutation was significantly less frequent in conventional PTC patients with CLT. However, CLT was an independent predictor for less aggressiveness in conventional PTC patients regardless of BRAF mutation status.

Evidence-based evaluation of the thyroid nodule

This article reviews the most current literature on thyroid nodule evaluation, with particular attention to the problem of the incidentally identified thyroid nodule. Although traditional risk factors for thyroid cancer, such as age, gender, and familial syndromes, are still important, the manner in which a thyroid nodule comes to attention is of great importance these days when considering how to proceed in a workup. Most thyroid nodules today are discovered through radiologic imaging tests performed for other reasons. This article covers the key considerations that are vital in balancing the risks and benefits of thyroid nodule workup and treatment.

Evaluation of the VE1 Antibody in Thyroid Cytology Using Ex Vivo Papillary Thyroid Carcinoma Specimens

Background:

Recently, VE1, a monoclonal antibody against the BRAFV600E mutant protein, has been investigated in terms of its detection of the BRAFV600E mutation. Although VE1 immunostaining and molecular methods used to assess papillary thyroid carcinoma in surgical specimens are in good agreement, evaluation of VE1 in thyroid cytology samples is rarely performed, and its diagnostic value in cytology has not been well established. In present study, we explored VE1 immunoexpression in cytology samples from ex vivo papillary thyroid carcinoma specimens in order to minimize limitations of low cellularity and sampling/targeting errors originated from thyroid fineneedle aspiration and compared our results with those obtained using the corresponding papillary thyroid carcinoma tissues.

Methods:

The VE1 antibody was evaluated in 21 cases of thyroid cytology obtained directly from ex vivo thyroid specimens. VE1 immunostaining was performed using liquid-based cytology, and the results were compared with those obtained using the corresponding tissues.

Results:

Of 21 cases, 19 classic papillary thyroid carcinomas had BRAFV600E mutations, whereas two follicular variants expressed wild-type BRAF. VE1 immunoexpression varied according to specimen type. In detection of the BRAFV600E mutation, VE1 immunostaining of the surgical specimen exhibited 100% sensitivity and 100% specificity, whereas VE1 immunostaining of the cytology specimen exhibited only 94.7% sensitivity and 0% specificity.

Conclusions:

Our data suggest that VE1 immunostaining of a cytology specimen is less specific than that of a surgical specimen for detection of the BRAFV600E mutation, and that VE1 immunostaining of a cytology specimen should be further evaluated and optimized for clinical use.

Significance of Subcategory Atypia of Undetermined Significance/Follicular Lesion of Undetermined Significance Showing Both Cytologic and Architectural Atypia in Thyroid Aspiration Cytology

OBJECTIVE

The Bethesda System for Reporting Thyroid Cytopathology is now widely used as the standard reporting system for fine-needle aspiration cytology (FNAC). Recently, several studies have attempted to subcategorize the atypia of undetermined significance (AUS)/follicular lesion of undetermined significance (FLUS) category. We aimed to analyze the significance of a subcategory of AUS/FLUS showing both cytologic and architectural atypia (AUS/FLUS-C&amp;A).

STUDY DESIGN

From April 2011 to May 2014, 18,091 patients underwent FNAC at Samsung Medical Center. For those patients we analyzed the clinical significance of the subcategory AUS/FLUS-C&amp;A.

RESULTS

One hundred and sixty-three patients were diagnosed as AUS/FLUS-C&amp;A. Of 71 cases with subsequent histologic confirmation, 47 (66.2%) were diagnosed with papillary thyroid carcinoma (PTC). Of the 47 PTC cases, 32 (68.1%) were follicular variant-PTC. A significant difference in the PTC rate (58.3 vs. 82.6%) and PTC size (average: 1.8 and 0.9 cm) was noted between circumscribed lesions and infiltrative lesions on ultrasonography.

CONCLUSION

We demonstrated that the subcategory of AUS/FLUS-C&amp;A has considerable clinical implications and one should be aware of the cytological and ultrasonographic features.

Tumor genotype determines phenotype and disease-related outcomes in thyroid cancer: a study of 1510 patients

OBJECTIVES

To correlate thyroid cancer genotype with histology and outcomes.

BACKGROUND

The prognostic significance of molecular signature in thyroid cancer (TC) is undefined but can potentially change surgical management.

METHODS

We reviewed a consecutive series of 1510 patients who had initial thyroidectomy for TC with routine testing for BRAF, RAS, RET/PTC, and PAX8/PPARG alterations. Histologic metastatic or recurrent TC was tracked for 6 or more months after oncologic thyroidectomy.

RESULTS

Papillary thyroid cancer (PTC) was diagnosed in 97% of patients and poorly differentiated/anaplastic TC in 1.1%. Genetic alterations were detected in 1039 (70%); the most common mutations were BRAFV600E (644/1039, 62%), and RAS isoforms (323/1039, 31%). BRAFV600E-positive PTC was often conventional or tall cell variant (58%), with frequent extrathyroidal extension (51%) and lymph node metastasis (46%). Conversely, RAS-positive PTC was commonly follicular variant (87%), with infrequent extrathyroidal extension (4.6%) and lymph node metastasis (5.6%). BRAFV600E and RET/PTC-positive PTCs were histologically similar. Analogously, RAS and PAX8/PPARG-positive PTCs were histologically similar. Compared with RAS or PAX8/PPARG-positive TCs, BRAFV600E or RET/PTC-positive TCs were more often associated with stage III/IV disease (40% vs 15%, P < 0.001) and recurrence (10% vs 0.7%, P < 0.001; mean follow-up 33 ± 21 mo). Distant metastasis was highest in patients with RET/PTC-positive TC (10.8%, P = 0.02).

CONCLUSIONS

In this large study of prospective mutation testing in unselected patients with TC, molecular signature was associated with distinctive phenotypes including cancers, with higher risks of both distant metastasis and early recurrence. Preoperative genotype provides valuable prognostic data to appropriately inform surgery.

BRAF V600E mutation: Differential impact on central lymph node metastasis by tumor size in papillary thyroid carcinoma

BACKGROUND

The necessity of prophylactic central neck dissection is one of debating issues in the treatment of papillary thyroid carcinoma (PTC). In a previous study, the predictive value of BRAF mutation for lymph node metastasis was only significant in 0.5 to 1.0 cm PTC. Thus, we assess the predictive value of BRAF mutation for central lymph node metastasis according to tumor size.

METHODS

Medical records of 3107 patients with PTC who underwent thyroidectomy with central neck dissection were retrospectively reviewed.

RESULTS

BRAF mutation was a predictor for central lymph node metastasis in 2.0 to 4.0 cm PTC (odds ratio [OR] = 3.494; p = .002). Although BRAF mutation was associated with central lymph node metastasis in 0.5 to 1.0 cm PTC in univariate analysis (OR = 1.334; p = .047), this significance was not observed in multivariate analysis (OR = 1.232; p = .163). BRAF mutation was not associated with central lymph node metastasis in other tumor sizes.

CONCLUSION

Prophylactic central neck dissection could be considered in 2.0 to 4.0 cm PTC with positive BRAF mutation. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1203-E1209, 2016.

Evaluation of the Clinical Usefulness of BRAFV600E Mutation Analysis of Core-Needle Biopsy Specimens in Thyroid Nodules with Previous Atypia of Undetermined Significance or Follicular Lesions of Undetermined Significance Results

BACKGROUND

The accurate diagnosis of thyroid nodules is important for making management decisions. The purpose of this study is to evaluate the clinical usefulness of BRAF(V600E) mutation analysis with core-needle biopsy (CNB+BRAF(V600E)) in thyroid nodules with previous atypia of undetermined significance (AUS) or follicular lesions of undetermined significance (FLUS) results.

MATERIALS AND METHODS

From January 2011 to December 2012, 590 CNB+BRAF(V600E) mutation analyses were performed. We analyzed 200 nodules from 200 patients with previous AUS/FLUS results (22 men, 178 women; mean age, 48.6 years). The clinical usefulness of CNB+BRAF(V600E) was assessed by comparing the rates of conclusive results, the additional value of BRAF(V600E) mutation analysis, diagnostic performances, and therapeutic/diagnostic surgery results with those of CNB alone. For the subgroup analysis, the study patients were divided into those with nodules with previous AUS results and those with previous FLUS results.

RESULTS

All CNB+BRAF(V600E) procedures were well-tolerated. CNB+BRAF(V600E) did not show significantly better diagnostic performance than CNB alone in thyroid nodules with previous AUS/FLUS results. However, the conclusive result rate of CNB+BRAF(V600E) was improved in thyroid nodules with previous AUS/FLUS results (76.5% vs. 73.0%, p=0.016), especially with previous AUS results (81.1% vs. 76.4%, p=0.031). Of the 56 previous AUS result thyroid nodules with surgical management, BRAF(V600E) mutation analysis led to therapeutic surgery in 5.4% by decreasing unnecessary diagnostic surgery.

CONCLUSIONS

In general, CNB+BRAF(V600E) did not show significantly higher diagnostic accuracy than CNB alone. Although CNB+BRAF(V600E) may add additional value in nodules with previous AUS results, routinely adding BRAF(V600E) mutation analysis to CNB is not recommended.

Potential relationship between Hashimoto's thyroiditis and BRAF(V600E) mutation status in papillary thyroid cancer

BACKGROUND

The purpose of this study was to evaluate the potential relationship between Hashimoto's thyroiditis and BRAF(V600E) mutation status in patients with papillary thyroid carcinoma (PTC).

METHODS

A total of 619 patients with PTC who underwent total thyroidectomy with lymph node dissection were enrolled in this study. Univariable and multivariate analyses were used.

RESULTS

Hashimoto's thyroiditis was present in 35.9% (222 of 619) of PTCs. Multivariate logistic regressions showed that BRAF(V600E) mutation, sex, extrathyroidal extension, and lymph node metastasis were independent factors for Hashimoto's thyroiditis. Female sex, more frequent extrathyroidal extension, and a higher incidence of lymph node metastasis were significantly associated with PTCs accompanied by BRAF(V600E) mutation without Hashimoto's thyroiditis compared with PTCs accompanied by BRAF(V600E) mutation with Hashimoto's thyroiditis.

CONCLUSION

Hashimoto's thyroiditis was negatively associated with BRAF(V600E) mutation, extrathyroidal extension, and lymph node metastasis. In addition, Hashimoto's thyroiditis was related to less lymph node metastasis and extrathyroidal extension in PTCs with BRAF(V600E) mutation. Therefore, Hashimoto's thyroiditis is a potentially protective factor in PTC. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1019-E1025, 2016.

Cytomorphologic features in thyroid nodules read as "suspicious for malignancy" on cytology may predict thyroid cancers with the BRAF mutation

Some morphologic parameters have been studied to help predict the BRAF(V600E) mutation using cytopathologic specimens, which can indicate which nodules should undergo further testing. The aim of this study was to investigate the value of cytomorphologic parameters to predict the BRAF(V600E) mutation in nodules read as "suspicious for malignancy" on cytology. This study included 142 resected nodules which were diagnosed as "suspicious for malignancy" on cytology in 142 patients. At our institution, BRAF(V600E) mutation analysis was performed at the request of the referring clinicians based on the clinical features of the patients, or the judgment of the radiologists performing US-FNA because suspicious US features were observed on the targeted nodule during this study period. Cytology smears were re-reviewed to assess the presence and amount of polygonal eosinophilic (plump) cells and microfollicles, and the presence of intranuclear pseudoinclusions, irregular nuclear membranes, nuclear grooves, sickles cells, psammoma bodies, and cystic changes. We evaluated the diagnostic performances of the cytomorphologic features to predict the BRAF(V600E) mutation. Polygonal eosinophilic (plump) cells, microfollicles, intranuclear pseudoinclusions, sickle cells, and cystic changes were significantly associated with the BRAF(V600E) mutation. The mutation was not present in all 6 thyroid nodules with microfollicles larger than 20% on cytology. Additionally, polygonal eosinophilic (plump) cells larger than 20%, cystic changes, and sickle cells on cytology had a high specificity of 95%, 96.7%, and 81.7%, respectively. Excluding 6 nodules with microfollicles larger than 20% on cytology, there were 82 (60.3%) nodules with the BRAF(V600E) mutation among the 136 nodules. Among the 136 nodules, there were 95 nodules with polygonal eosinophilic (plump) cells larger than 20%, cystic changes, or sickle cells on cytology. Of the 95 nodules, 69 (72.6%) had the mutation. Cytomorphologic features can help select nodules for the BRAF(V600E) mutation test among nodules read as "suspicious for malignancy" on cytology.

Real-Time PCR Cycle Threshold Values for the BRAFV600E Mutation in Papillary Thyroid Microcarcinoma May Be Associated With Central Lymph Node Metastasis: A Retrospective Study

Papillary thyroid microcarcinoma (PTMC) usually has excellent prognosis, but a small subset shows aggressive behavior. Although the B-Raf proto-oncogene, serine/threonine kinase (BRAF)V600E mutation is the most common oncogenic alteration in PTMCs, it is frequently heterogeneously distributed within tumors. The aim of this study was to investigate the association of the BRAFV600E mutation found in fine needle aspirates from PTMCs with known clinicopathologic prognostic factors, based on both its presence and a quantitative approach that uses cycle threshold (Ct) values obtained by a real-time PCR technique. The 460 PTMC patients were included, with 367 patients having the BRAFV600E mutation. Clinicopathologic variables were compared between patients with and without the BRAFV600E mutation. BRAFV600E Ct values were compared according to clinicopathologic prognostic factors. Multivariate analyses were performed to evaluate factors predicting extrathyroidal extension and central and lateral lymph node metastasis (LNM). Each analysis used either the BRAFV600E mutation status or the Ct value as an independent variable for all the study patients and the 367 BRAFV600E-positive patients. Receiver-operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic performance of BRAFV600E Ct values in predicting central and lateral LNM. The BRAFV600E mutation status was not associated with clinicopathologic prognostic factors among the 460 PTMC patients. Of the 367 BRAFV600E-positive patients, Ct values were significantly lower in patients with central and lateral LNM (P < 0.001, P = 0.007). The Ct value was the only independent factor to predict central LNM (OR 0.918, P = 0.025). The area under the ROC curve (AUC) for diagnosing central LNM was 0.623 (sensitivity, 50.0%; specificity, 71.9%) and for diagnosing lateral LNM, it was 0.796 (sensitivity, 71.4%; specificity, 94.7%). In conclusion, real-time PCR Ct values for the BRAFV600E mutation obtained from fine needle aspirates can be associated with central LNM in PTMC patients. Although BRAFV600E Ct values did not reach statistical significance for predicting lateral LNM in our study, further validation through larger studies can be used to overcome any possible type-II errors. With further studies, Ct values for the BRAFV600E mutation obtained from fine needle aspirates may have important implications for predicting both central and lateral LNM in patients with PTMCs.

RAS Mutations in AUS/FLUS Cytology: Does it Have an Additional Role in BRAFV600E Mutation-Negative Nodules?

The object of this study is to evaluate the additional role of RAS mutation in detecting thyroid malignancy among BRAF mutation-negative nodules diagnosed as atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) on cytology.From December 2009 to December 2011, 202 BRAF mutation-negative thyroid nodules diagnosed as AUS/FLUS cytology in 201 patients were included in this study. RAS mutation analysis was performed using residual material from ultrasonography-guided fine needle aspiration (US-FNA) cytology testing for K-RAS, N-RAS, and H-RAS codons 12/13 and 61 point mutations. The authors evaluated the association between RAS mutation status and cytopathologic characteristics.Of the 202 BRAF mutation-negative thyroid nodules with AUS/FLUS cytology, 4 were considered insufficient for mutation analysis. Of the 198 thyroid nodules, 148 (74.7%) were confirmed as benign and 50 (25.3%) as malignant. Thirty-one (15.7%) of the 198 thyroid nodules were positive for any RAS mutation, 4 positive for K-RAS 12/13, 26 for N-RAS 61, and 1 positive for H-RAS 61. Seven (22.6%) of the RAS mutation positive nodules were malignant, 1 with K-RAS 12/13, 6 with N-RAS 61. Twenty-four (77.4%) of the 31 nodules positive for K-RAS 12/13 (N = 3), N-RAS 61 (N = 20), or H-RAS 61 (N = 1) mutations were proven benign. None of the 198 thyroid nodules were positive for K-RAS 61, N-RAS 12/13, or H-RAS 12/13 mutations.N-RAS 61 mutation is the most common mutation detected among BRAF mutation-negative nodules with AUS/FLUS cytology. RAS mutation has limited value in predicting malignancy among BRAF mutation-negative thyroid nodules with AUS/FLUS cytology and further, investigation is anticipated to evaluate the true role of RAS mutation in thyroid malignancy.

Prediction Table and Nomogram as Tools for Diagnosis of Papillary Thyroid Carcinoma: Combined Analysis of Ultrasonography, Fine-Needle Aspiration Biopsy, and BRAF V600E Mutation

Although ultrasonography (US)-guided fine-needle aspiration biopsy (FNAB) is the most reliable diagnostic modality for evaluating thyroid nodules, 10% to 40% of FNAB samples yield indeterminate findings. The BRAF V600E mutation, a highly specific molecular marker for papillary thyroid carcinoma (PTC), well known for its prognostic value, has dubious diagnostic value because of its low sensitivity. Novel strategies are clearly needed to distinguish PTC, which represents the majority of thyroid malignancies, from other thyroid nodules. The records of 3297 patients with surgically proven PTC were retrospectively reviewed. A prediction table and nomogram were designed using a combination of diagnostic parameters for US, FNAB, and the BRAF V600E mutation. For the nomogram, parameters were proportionally assigned 0 to 100 points according to their regression coefficient for PTC. The probability of PTC for thyroid nodules with intermediate-risk (IR) US and atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) FNAB was significantly dependent on BRAF V600E mutation status based on our prediction table (negative, 29.2% vs positive, 87.5%; P < 0.001). By our nomogram, the probability of PTC for thyroid nodules with IR US, AUS/FLUS FNAB, and positive BRAF V600E mutation was approximately 85% to 90%. We strongly recommend preoperative evaluation of the BRAF V600E mutation in indeterminate thyroid nodules. The prediction table and nomogram developed in this study could help clinicians and patients easily assess the probability of PTC in the preoperative period.

Evaluation of the Real-Q BRAF V600E Detection Assay in Fine-Needle Aspiration Samples of Thyroid Nodules

Recently, several molecular assays for detecting the BRAF V600E mutation in fine-needle aspiration (FNA) specimens have been developed. Herein, we tested 294 consecutive FNA samples from patients with thyroid nodules with the Real-Q BRAF V600E detection assay (Real-Q). These results were compared with an allele-specific PCR-based kit using dual-priming oligonucleotides (AS-PCR). Any discordant results between the two tests were also analyzed by mutant enrichment with 3'-modified oligonucleotide sequencing. A total of 128 cases were confirmed histologically; of these, 121 were diagnosed as papillary thyroid carcinoma (PTC). The BRAF mutation was detected by Real-Q and AS-PCR testing in 80.2% (95% CI, 71.9%-86.9%) and 76.9% (95% CI, 68.3%-84.0%), respectively, of FNA specimens with PTC. Combining the BRAF V600E molecular assays (Real-Q and AS-PCR) with cytological diagnoses of malignant and suspicious for malignant cells, the detection rates (sensitivity) of Real-Q and AS-PCR for diagnosis of PTC increased to 94.2% (95% CI, 88.4%-97.6%) and 92.6% (95% CI, 86.4%-96.5%), respectively. In conclusion, the detection of BRAF V600E mutations in PTC by Real-Q is compatible to that of AS-PCR.

What to do with thyroid nodules showing benign cytology and BRAF(V600E) mutation? A study based on clinical and radiologic features using a highly sensitive analytic method

BACKGROUND

BRAF(V600E) mutation analysis has been used as a complementary diagnostic tool to ultrasonography-guided, fine-needle aspiration (US-FNA) in the diagnosis of thyroid nodule with high specificity reported up to 100%. When highly sensitive analytic methods are used, however, false-positive results of BRAF(V600E) mutation analysis have been reported. In this study, we investigated the clinical, US features, and outcome of patients with thyroid nodules with benign cytology but positive BRAF(V600E) mutation using highly sensitive analytic methods from US-FNA.

METHODS

This study included 22 nodules in 22 patients (3 men, 19 women; mean age, 53 years) with benign cytology but positive BRAF(V600E) mutation from US-FNA. US features were categorized according to the internal components, echogenicity, margin, calcifications, and shape. Suspicious US features included markedly hypoechogenicity, noncircumscribed margins, micro or mixed calcifications, and nonparallel shape. Nodules were considered to have either concordant or discordant US features to benign cytology. Medical records and imaging studies were reviewed for final cytopathology results and outcomes during follow-up.

RESULTS

Among the 22 nodules, 17 nodules were reviewed. Fifteen of 17 nodules were malignant, and 2 were benign. The benign nodules were confirmed as adenomatous hyperplasia with underlying lymphocytic thyroiditis and a fibrotic nodule with dense calcification. Thirteen of the 15 malignant nodules had 2 or more suspicious US features, and all 15 nodules were considered to have discordant cytology considering suspicious US features. Five nodules had been followed with US or US-FNA without resection, and did not show change in size or US features on follow-up US examinations.

CONCLUSION

BRAF(V600E) mutation analysis is a highly sensitive diagnostic tool in the diagnosis of papillary thyroid carcinomas. In the management of thyroid nodules with benign cytology but positive BRAF(V600E) mutation, thyroidectomy should be considered in nodules which have 2 or more suspicious US features and are considered discordant on image-cytology correlation.

[Clinical guideline for management of patients with low risk differentiated thyroid carcinoma]

Incidence of thyroid cancer is increasing in Spain and worldwide. Overall thyroid cancer survival is very high, and stratification systems to reliably identify patients with worse prognosis have been developed. However, marked differences exist between the different specialists in clinical management of low-risk patients with thyroid carcinoma. Almost half of all papillary thyroid carcinomas are microcarcinomas, and 90% are tumors < 2 cm that have a particularly good prognosis. However, they are usually treated more aggressively than needed, despite the lack of adequate scientific support. Surgery remains the gold standard treatment for these tumors. However, lobectomy may be adequate in most patients, without the need for total thyroidectomy. Similarly, prophylactic lymph node dissection of the central compartment is not required in most cases. This more conservative approach prevents postoperative complications such as hypoparathyroidism or recurrent laryngeal nerve injury. Postoperative radioiodine remnant ablation and strict suppression of serum thyrotropin, although effective for the more aggressive forms of thyroid cancer, have not been shown to be beneficial for the treatment of low risk patients, and may impair their quality of life. This guideline provides recommendations from the task force on thyroid cancer of the Spanish Society of Endocrinology and Nutrition for adequate management of patients with low-risk thyroid cancer.