Molecular Markers in Thyroid Fine-needle Aspiration Biopsy: A Prospective Study

Immunocytochemistry Profile of Benign Thyroid Nodules Not Responding to Thermal Ablation: A Retrospective Study

Purpose

Thermal ablations (TA) are gaining ground as alternative options to conventional therapies for symptomatic benign thyroid nodules. Little is known about the impact of nodule biology on the outcomes of TA. The aim of our study was to evaluate the baseline immunocytochemistry profile of thyroid nodules that were poorly responsive to TA in order to identify potential predictors of the treatment response.

Methods

From a cohort of 406 patients with benign thyroid nodules treated with TA and followed for 5 years, we retrospectively selected two groups of patients: NONRESPONDERS (patients who did not respond to TA and were later surgically treated) and RESPONDERS (patients who responded to TA). The fine-needle aspiration cytology (FNAC) slides obtained before TA were stained for Galectin-3, HBME-1, CK-19, and Ki-67.

Results

Benign nodules of NONRESPONDERS (n = 19) did not express CK-19 (p = 0.03), as compared to RESPONDERS (n = 26). We combined the absence of CK-19 and the presence of Ki-67 to obtain a composite biomarker of resistance to TA, which discriminated between likelihood of retreatment and no retreatment with an AUC of 0.68 (95%CI: 0.55-0.81) and a sensitivity, specificity, PPV, and NPV of 29%, 91%, 71%, and 64%, respectively.

Conclusion

In benign thyroid nodules, the absence of CK-19 was associated with resistance to TA, while the presence of CK-19 was predictive of response to TA. If confirmed, this finding could provide rapid and inexpensive information about the potential outcome of TA on benign thyroid nodules. In addition, as CK-19 can be expressed in adenomatous hyperplasia, it could be speculated that these nodules, rather than follicular adenomas, might be better candidates for TA.

Systematic Review and Meta-Analysis to Identify the Immunocytochemical Markers Effective in Delineating Benign from Malignant Thyroid Lesions in FNAC Samples

Conventional cytology-based diagnosis for thyroid cancer is limited with more than 30-45% of nodules categorized as indeterminate, necessitating surgery for confirming or refuting the diagnosis. This systematic review and meta-analysis were aimed at identifying immunocytochemical markers effective in delineating benign from malignant thyroid lesions in fine needle aspiration cytology (FNAC) samples, thereby improving the accuracy of cytology diagnosis. A systematic review of relevant articles (2000-2021) from online databases was carried out and the search protocol registered in PROSPERO database (CRD42021229121). The quality of studies was assessed using QUADAS-2. Review Manager 5.4.1 from Cochrane collaboration and MetaDisc Version 1.4 was used to conduct the meta-analysis. Bias in the studies were visually analyzed using funnel plots, and statistical significance was evaluated by Egger's test. Systematic review identified 64 original articles, while meta-analysis in eligible articles (n = 41) identified a panel of 5 markers, Galectin-3, HBME-1, CK-19, CD-56, and TPO. Assessment of the diagnostic performance revealed that Gal-3 (sensitivity: 0.81; CI: 0.79-0.83; specificity: 0.84; CI: 0.82-0.85) and HBME-1 (sensitivity: 0.83; Cl: 0.81-0.86; specificity: 0.85; CI: 0.83-0.86) showed high accuracy in delineating benign from malignant thyroid nodules. Efficacy analysis in indeterminate nodules showed Gal-3 and HBME-1 have high specificity of 0.86 (CI 0.84-0.89) and 0.82 (CI 0.78-0.86), respectively, and low sensitivity of 0.76 (CI 0.72-0.80) and 0.75 (CI 0.70-0.80), respectively. Diagnostic odds ratio (DOR) of Galectin-3 and HBME-1 were 39.18 (CI 23.38-65.65) and 24.44 (CI 11.16-53.54), respectively. Significant publication bias was observed for the markers Galectin-3 and CK-19 (p < 0.05). The panel of 5 markers identified from this meta-analysis are high-confidence candidates that need to be validated in thyroid cytology to establish their efficacy and enable clinical applicability.

Galectin-3 and CD117 immunocytochemistry in the diagnosis of indeterminate thyroid lesions: A pilot study

BACKGROUND

Indeterminate thyroid lesions have always been a grey zone in the field of thyroid cytopathology. Immunocytochemistry (ICC) has emerged as a promising tool to correctly classify these indeterminate thyroid lesions into benign and malignant. Hence we planned to assess a panel of immune markers in the diagnosis of indeterminate thyroid lesions consisting of Galectin-3, considered positive for malignancy and CD117 which is positive in benign follicular epithelial cells and negative in malignant lesions.

METHODS

All the thyroid aspirates reported as indeterminate lesions over a period of 3 years were evaluated. Galectin-3 and CD117 immunocytochemistry was done in 50 alcohol fixed Pap stained smears of AUS/FLUS, FN/SFN and SM category lesions. The expression of both immune markers was assessed by semi-quantitative method and ICC score was calculated.

RESULT

Of 50 indeterminate lesions, 29 were positive for Galectin-3 and 21 were negative. CD117 was positive in 19 cases and rests 31 were negative. With the use of this ICC panel 29/30 indeterminate lesions in which histopathological correlation was available could be recategorized correctly into benign and malignant. The combined sensitivity and specificity of Galectin-3 and CD117 for categorising the indeterminate lesions into malignant category was 100%.

CONCLUSION

The combined use of positive and negative immune markers for thyroid malignancy increases the sensitivity and specificity of ICC to categorise the indeterminate thyroid lesions into benign and malignant. In cases with discordant ICC results we propose that inclusion of one additional positive and/or negative marker may resolve the diagnostic dilemma.

FAM172A promotes follicular thyroid carcinogenesis and may be a marker of FTC

Our aims were to uncover the role of FAM172A (Family with sequence similarity 172 member A) in the pathogenesis of follicular thyroid carcinoma (FTC) and to evaluate its value in the differential diagnosis between malignant and benign thyroid follicular lesions. FAM172A expression was evaluated by q-PCR, immunoblotting and immunohistochemistry (IHC). The ability of proliferation, migration and invasion of cells were assessed by Cell Counting Kit-8 assay (CCK8), clone-formation and Transwell assays. Nude mouse tumorigenicity assays were used to investigate the role of FAM172A in the pathogenesis of FTC in vivo. The value of FAM172A in the differential diagnosis for FTC was assessed using 120 formalin-fixed paraffin-embedded (FFPE) tissues after the operation and 81 fine-needle aspiration biopsy (FNAB) samples before the operation. FAM172A was highly expressed in FTC tissues and FTC cell lines. Downregulation of FAM172A inhibited the proliferation, invasion and migration of FTC cells through Erk1/2 and JNK pathways. Subcutaneous tumorigenesis in nude mice showed that knockdown of FAM172A inhibited tumor growth and progression in vivo. The FAM172A IHC scores of 3.5 had 92% sensitivity and 63% specificity to separate FTC from benign/borderline thyroid follicular lesions, and 92% sensitivity and 80% specificity to discriminate FTC from benign thyroid follicular lesions in postoperative FFPE samples. The corresponding values were 75 and 78%, and 75 and 89% in preoperative FNA samples, respectively. FAM172A plays an important role in the pathogenesis of FTC through Erk1/2 and JNK pathways. FAM172A may be a potential marker for the preoperative diagnosis of FTC based on the IHC results of thyroid FNAB samples.

Beyond immunohistochemistry and immunocytochemistry: a current perspective on galectin-3 and thyroid cancer

Introduction: Thyroid nodules are very common in the general population, most are benign, and do not require any intervention. However, often a challenge exists in discriminating benign thyroid nodules from cancer, without performing a biopsy or operation. Galectin-3 is a beta-galactoside binding protein that is involved in diverse biological processes and has been found to have increased expression in many human cancer types including thyroid cancer. As a result, recent studies have investigated its utility as a serum biomarker for thyroid cancer, as well as a novel target for in vivo molecular imaging of cancer. Additionally, given its role in tumorigenesis and cancer progression, galectin-3 targeting is currently under investigation for its potential utility as treatment for thyroid cancer.Areas covered: Recent studies of galectin-3 as a serum marker for thyroid cancer diagnosis, and in the preclinical setting as a target for cancer imaging and therapy.Expert opinion: Even though current studies evaluating galectin-3 as a serum marker and target for cancer imaging and therapy are promising, further research is required before it can be adopted into routine clinical use.

Molecular testing in the diagnosis of differentiated thyroid carcinomas

Different genetic mutations and other molecular alterations in papillary thyroid cancer (PTC) and follicular thyroid cancer (FTC) can be detected in fine-needle aspiration (FNA) of thyroid nodules, and can be used successfully to ameliorate cancer diagnosis and management of patients with thyroid nodules. The greatest experience has been obtained with the diagnostic use of BRAF mutation that is strongly specific for malignancy when detected using well-validated techniques. The strongest diagnostic result can be obtained testing FNA samples for a panel of mutations that typically involve TERT, BRAF, PAX8/PPARγ, RAS, and RET/PTC. Finding any of these mutations in a thyroid nodule provides strong indication for malignancy and helps to refine clinical management for a significant proportion of patients with indeterminate cytology. The use of molecular markers, as TERT, BRAF, PAX8/PPARγ, RAS, and RET/PTC, may be considered for patients with indeterminate FNA cytology (FNAC) to help guide management. In patients with indeterminate TIR3 FNA, the combination of precise molecular marker expression analysis with molecular mutations evaluations could ameliorate significantly the accuracy of cancer diagnosis. However other prospective studies are needed to identify more accurate molecular markers. Finally, the knowledge of these molecular pathways has permitted the development of new targeted therapies for aggressive TC.

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.

Molecular Signature of Indeterminate Thyroid Lesions: Current Methods to Improve Fine Needle Aspiration Cytology (FNAC) Diagnosis

Fine needle aspiration cytology (FNAC) represents the gold standard for determining the nature of thyroid nodules. It is a reliable method with good sensitivity and specificity. However, indeterminate lesions remain a diagnostic challenge and researchers have contributed molecular markers to search for in cytological material to refine FNAC diagnosis and avoid unnecessary surgeries. Nowadays, several "home-made" methods as well as commercial tests are available to investigate the molecular signature of an aspirate. Moreover, other markers (i.e., microRNA, and circulating tumor cells) have been proposed to discriminate benign from malignant thyroid lesions. Here, we review the literature and provide data from our laboratory on mutational analysis of FNAC material and circulating microRNA expression obtained in the last 6 years.

Inverse expression of caveolin-1 and EGFR in thyroid cancer patients

Cytological analysis of fine-needle aspiration (FNA) is the first step in evaluation of patients with nodular thyroid disease with the primary goal to exclude thyroid malignancy. Its improvement by combining cytology with molecular markers is still a matter of investigation. In this study, 2 molecular markers were used: caveolin-1 and epidermal growth factor receptor (EGFR), along with the well-established genetic marker BRAF V600E mutation. We set out to determine the expression signatures of EGFR and caveolin-1 in patients with thyroid malignancy as well as to determine their possible association with disease severity. In FNA biopsy samples (n=186), immunocytochemical expression of caveolin-1 and BRAF V600E mutation coincided with malignancy. The patients were sorted according to 3 parameters: final histopathological diagnosis, caveolin-1 expression, and BRAF V600E mutation status before measurement of EGFR mRNA expression. EGFR upregulation was detected in the group of patients with malignant diagnosis, no caveolin-1 expression, and wild-type BRAF. Spearman rank correlation yielded a statistically significant negative correlation of EGFR and caveolin-1. Double immunofluorescence confirmed colocalization and inverse expression of EGFR and caveolin-1. Our data demonstrated that EGFR overexpression is associated with malignancy but not with tumor aggressiveness. Furthermore, high-caveolin-1/low-EGFR cases were associated with an advanced pT status and had a greater degree of neoplastic infiltration than low-caveolin-1/high-EGFR cases. Combining caveolin-1 and BRAF V600E with EGFR might help in recognizing more aggressive thyroid lesions in a pool of relatively indolent tumors in FNA biopsies and thus be useful for early risk stratification of thyroid cancer patients.

Thyroid nodule update on diagnosis and management

Thyroid nodules are common. The clinical importance of thyroid nodules is related to excluding malignancy (4.0 to 6.5% of all thyroid nodules), evaluate their functional status and assess for the presence of pressure symptoms. Incidental thyroid nodules are being diagnosed with increasing frequency in the recent years with the use of newer and highly sensitive imaging techniques. The high prevalence of thyroid nodules necessitates that the clinicians use evidence-based approaches for their assessment and management. New molecular tests have been developed to help with evaluation of malignancy in thyroid nodules. This review addresses advances in thyroid nodule evaluation, and their management considering the current guidelines and supporting evidence.

Critical Pitfalls in the use of BRAF Mutation as a Diagnostic Tool in Thyroid Nodules: a Case Report

Thyroid fine-needle aspiration (FNA) cytology is the primary tool for the diagnostic evaluation of thyroid nodules. BRAF mutation analysis is employed as an ancillary tool in indeterminate cases, as recommended by the American Thyroid Association management guidelines. Hereby, we report the case of a 73-year-old woman who presented an 8-mm-size, ill-defined, left thyroid nodule. FNA resulted "suspicious for papillary thyroid carcinoma". BRAF mutation status was analyzed, and somatic BRAF (V600E) mutation identified. The patient underwent a total thyroidectomy. At histological examination, the nodule was composed of Langerhans cells, admixed with many eosinophils. A final diagnosis of Langerhans cell histiocytosis of the thyroid was made. Our case emphasizes the critical diagnostic pitfalls due to the use of BRAF (V600E) mutation analysis in thyroid FNA. Notably, BRAF (V600E) mutation is common in melanoma, colorectal carcinoma, lung carcinoma, ovarian carcinoma, brain tumors, hairy cell leukemia, multiple myeloma, and histiocytoses. Therefore, in cases of indeterminate FNA with unclassifiable atypical cells BRAF (V600E) mutated, the possibility of a localization of hystiocytosis or a secondary thyroid malignancy should be taken into account.

A Pilot Study of Galectin-3, HBME-1, and p27 Triple Immunostaining Pattern for Diagnosis of Indeterminate Thyroid Nodules in Cytology With Correlation to Histology

Supplemental Digital Content is available in the text.

Indeterminate thyroid nodules form a heterogenous group of lesions that constitute 5% to 30% of thyroid cytology diagnoses. We introduce a triple immunostaining protocol for subtyping. Galectin-3, HBME-1, and p27 triple immunostaining, performed on destained cytology slides and formalin-fixed paraffin-embedded tissue, was developed and applied to 51 patients retrospectively with preoperative cytologic diagnoses of follicular lesion of undetermined significance (n=40), atypia of undetermined significance (n=6), and suspicious for follicular neoplasm (n=5). The malignant rate in this series was 43.1% (22/51). A hierarchal evaluation algorithm was generated based on digital image quantitation of triple-stained histologic sections, and applied to both cytology and histology specimens. Fifty of 51 cytology cases have triple staining validated by internal controls. In cytology specimens, the individual sensitivities and specificities of p27, Galectin3, and HBME1 for cancer with 95% confidence interval are: 86.2% (0.674, 0.955)/66.7% (0.431, 0.845); 77.3% (0.542, 0.913)/72.4% (0.525, 0.866); and 72.7% (0.496, 0.884)/93.1% (0.758, 0.988), respectively. Sensitivity is increased to 95.5% (0.751, 0.998), but specificity is decreased to 69.0% (0.490, 0.840), if Galectin3 and HBME1 are both used in combination as markers for malignancy. However, the level of specificity is increased to 86.2% (0.674, 0.955) and sensitivity remains high 100% (0.808, 1) if in addition, using the Galectin3/HBME1:p27 ratio (ratio ≥2 indicating malignancy) for 2 or 3 markers positive cases. Thus, the triple staining method on cytology slides and histology sections shows a similar sensitivity/specificity/positive predictive value/negative predictive value of 100.0%/86.2%/84.0%/100.0% and 95.5%/86.2%/84.0%/96.2%, respectively (P=0.92). Overall, p27 is the most frequent single positive marker (19/50, 38% in cytology), consistent with benign nature of most indeterminate thyroid nodules. Galectin-3 and HBME-1 colocalization (positive in the same cell) was demonstrated in thyroid cancer in 45.5% (10/22) of histology sections, but in none of the normal thyroid tissues and benign thyroid lesions. This supports the notion that synchronous activation of Galectin-3 and HBME-1 occurs in thyroid malignancy and is highly specific for malignancy. We have demonstrated the performance and pattern of triple immunostaining for subtyping indeterminate thyroid nodules. Further studies and validation in different larger populations are warranted.

2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer

BACKGROUND

Thyroid nodules are a common clinical problem, and differentiated thyroid cancer is becoming increasingly prevalent. Since the American Thyroid Association's (ATA's) guidelines for the management of these disorders were revised in 2009, significant scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, researchers, and health policy makers on published evidence relating to the diagnosis and management of thyroid nodules and differentiated thyroid cancer.

METHODS

The specific clinical questions addressed in these guidelines were based on prior versions of the guidelines, stakeholder input, and input of task force members. Task force panel members were educated on knowledge synthesis methods, including electronic database searching, review and selection of relevant citations, and critical appraisal of selected studies. Published English language articles on adults were eligible for inclusion. The American College of Physicians Guideline Grading System was used for critical appraisal of evidence and grading strength of recommendations for therapeutic interventions. We developed a similarly formatted system to appraise the quality of such studies and resultant recommendations. The guideline panel had complete editorial independence from the ATA. Competing interests of guideline task force members were regularly updated, managed, and communicated to the ATA and task force members.

RESULTS

The revised guidelines for the management of thyroid nodules include recommendations regarding initial evaluation, clinical and ultrasound criteria for fine-needle aspiration biopsy, interpretation of fine-needle aspiration biopsy results, use of molecular markers, and management of benign thyroid nodules. Recommendations regarding the initial management of thyroid cancer include those relating to screening for thyroid cancer, staging and risk assessment, surgical management, radioiodine remnant ablation and therapy, and thyrotropin suppression therapy using levothyroxine. Recommendations related to long-term management of differentiated thyroid cancer include those related to surveillance for recurrent disease using imaging and serum thyroglobulin, thyroid hormone therapy, management of recurrent and metastatic disease, consideration for clinical trials and targeted therapy, as well as directions for future research.

CONCLUSIONS

We have developed evidence-based recommendations to inform clinical decision-making in the management of thyroid nodules and differentiated thyroid cancer. They represent, in our opinion, contemporary optimal care for patients with these disorders.

Downregulation of long noncoding RNA NONHSAT037832 in papillary thyroid carcinoma and its clinical significance

Long noncoding RNA (lncRNA) is a kind of RNA that is longer than 200 nucleotides with limited or no protein-coding potential. Studies have proved that lncRNAs play important regulatory roles in gene expression and contribute to oncogenesis and cancer metastasis. However, the expression level of lncRNAs and their clinicopathologic significance in papillary thyroid carcinoma (PTC) have not been well studied. In this study, we investigated the expression level of a novel lncRNA NONHSAT037832 in PTC and paired noncancerous thyroid tissues as well as some cell lines by quantitative real-time polymerase chain reaction. The association between the expression level of NONHSAT037832 and clinicopathologic characteristics of patients with PTC was further analyzed. Three receiver operating characteristic curves (ROCs) were established to evaluate the diagnostic value of NONHSAT037832. The results suggested that the expression level of NONHSAT037832 was significantly decreased in PTC compared with paired noncancerous tissues (P < 0.01). And, NONHSAT037832 was also significantly downregulated in two PTC cell lines (K1 and IHH-4) compared to normal thyroid follicular epithelial cell line Nthy-ori 3-1 (P < 0.01). Downregulated NONHSAT037832 was significantly associated with lymph node metastasis (P = 0.015) and tumor size (P = 0.032). The ROCs revealed that NONHSAT037832 had a high diagnostic value for differentiating between PTC and noncancerous diseases as well as identifying PTC with lymph node metastasis and larger tumors (≥3 cm). The area under curve was up to 0.897 (95%CI = 0.852-0.942, P = 0.000), 0.641 (95%CI = 0.519-0.762, P = 0.033), and 0.702 (95%CI = 0.567-0.827, P = 0.008), respectively. This study indicated that NONHSAT037832 might serve as a potential biomarker of PTC.

Shear-Wave Elastography for the Preoperative Risk Stratification of Follicular-patterned Lesions of the Thyroid: Diagnostic Accuracy and Optimal Measurement Plane

PURPOSE

To evaluate the diagnostic accuracy of shear-wave elastography (SWE) for the diagnosis of malignancy in follicular lesions and to identify the optimal SWE measurement plane.

MATERIALS AND METHODS

The institutional review board approved this HIPAA-compliant, single-institution, prospective pilot study. Subjects scheduled for surgery after a previous fine-needle aspiration report of "atypia of undetermined significance" or "follicular lesion of undetermined significance," "suspicion for follicular neoplasm," or "suspicion for Hurthle cell neoplasm," were enrolled after obtaining informed consent. Subjects underwent conventional ultrasonography (US), Doppler evaluation, and SWE preoperatively, and their predictive value for thyroid malignancy was evaluated relative to the reference standard of surgical pathologic findings.

RESULTS

Thirty-five patients (12 men, 23 women) with a mean age of 55 years (range, 23-85 years) and a fine-needle aspiration diagnosis of atypia of undetermined significance or follicular lesion of undetermined significance (n = 16), suspicion for follicular neoplasm (n = 14), and suspicion for Hurthle cell neoplasm (n = 5) were enrolled in the study. Male sex was a statistically significant (P = .02) predictor of malignancy, but age was not. No sonographic morphologic parameter, including nodule size, microcalcification, macrocalcification, halo sign, taller than wide dimension, or hypoechogenicity, was associated with malignancy. Similarly, no Doppler feature, including intranodular vascularity, pulsatility index, resistive index, or peak-systolic velocity, was associated with malignancy. Higher median SWE tissue Young modulus estimates from the transverse insonation plane were associated with malignancy, yielding an area under the receiver operating characteristic curve of 0.81 (95% confidence interval: 0.62, 1.00) for differentiation of malignant from benign nodules. At a cutoff value of 22.3 kPa, sensitivity, specificity, positive predictive value, and negative predictive value of 82%, 88%, 75%, and 91%, respectively, were observed.

CONCLUSION

This prospective pilot study indicates that SWE may be a valuable tool in preoperative malignancy risk assessment of follicular-patterned thyroid nodules.

Imaging, genetic testing, and biomarker assessment of follicular cell-derived thyroid cancer

Thyroid carcinoma is the most common endocrine malignancy worldwide, and its incidence continues to increase. As such the approach to a recently identified thyroid nodule is important to understand. The relevant imaging, examination, and need for fine-needle aspiration biopsy (FNA) are discussed. In approximately 25% of nodules, the diagnosis cannot be established with FNA-based cytology, and surgical excision is necessary for definitive diagnosis. Recent advances in genetic and molecular testing may increase the diagnostic accuracy of FNA in managing thyroid nodules.

Role of molecular diagnostic markers in the management of indeterminate and suspicious thyroid nodules

Incidental thyroid nodules are commonly found during routine neck examination. Fine needle aspiration (FNA) followed by cytological examination is currently considered as the most reliable method for evaluation of thyroid nodules. However, 10–40% of FNA results are inconclusive, and are reported as indeterminate or suspicious. Approximately 20% of indeterminate or suspicious nodules are malignant. Therefore, there has been an increasing trend in use of molecular markers as an adjunctive measure for more accurate preoperative diagnosis of indeterminate or suspicious nodules. Molecular markers can be used alone or as a part of molecular panels. Although some investigations revealed promising findings regarding the potential use of molecular markers in the management of thyroid nodules, their true impact on management of patients with indeterminate nodules is still unclear.

Role of ancillary testing in thyroid fine needle aspiration: Review and update

Thyroid nodules are common, and ultrasound-guided fine needle aspiration identifies 70-75% as benign, and 4% as malignant. The remainder falls into categories of "indeterminate" with a widely ranging malignancy rate from 10-75%. The diagnosis and clinical management of indeterminate lesions is evolving, and we will review ancillary testing as an aid to diagnosis.

Immunohistochemical expression of HBME-1 and galectin-3 in the differential diagnosis of follicular-derived thyroid nodules

BACKGROUND

Thyroid nodules are common among adults with only a small percentage being malignant and histologically mimic benign nodules. Accurate diagnosis of these thyroid nodules is critical for the proper clinical management. The determination of malignancy in follicular patterned thyroid lesions is based on postoperative histological findings. Therefore, affected patients are referred for surgery, although only 10% will have a final diagnosis of malignancy. The aim of this study was to investigate the ability of two immunohistochemical (IHC) markers; galectin-3 and Hector Battifora mesothelial-1 (HBME-1) individually or in combination, to distinguish between benign (non-neoplastic and neoplastic) and malignant (follicular and papillary carcinomas) thyroid lesions removed by surgical resection.

METHODS

We investigated the immunoexpression of galectin-3 and HBME-1 in 50 cases of benign and malignant thyroid nodules. The benign group included 13 cases of thyroid nodular goiter (NG) and 9 cases of follicular adenoma (FA). The malignant group included 5 cases of follicular thyroid carcinomas (FC), 18 cases of classic papillary thyroid carcinoma and 5 cases of follicular variant papillary carcinoma (FVPC).

RESULTS

The staining results showed that malignant tumors expressed galectin-3 and HBME-1 significantly more than benign nodules. The sensitivity of these markers for the distinction between benign and malignant lesions ranged from 89.3% to 92.9%. Co-expression of galectin-3 and HBME-1 was seen in 82.1% of carcinomas, but in none of the benign nodules. Immunoexpression was usually diffuse in malignant tumors, and focal in the benign lesions.

CONCLUSION

Our findings indicate that these immunohistochemical markers are significantly more expressed in malignant tumors compared to benign lesions and may be of additional diagnostic value when combined with routine histology. Galectin-3 has higher sensitivity and specificity of immunoexpression in thyroid malignancy than HBME-1, and the combined use of galectin-3 and HBME-1 can increase the specificity of immunoexpression in malignant tumors.

Molecular diagnostics of fine needle aspiration for the presurgical screening of thyroid nodules

"The incidence of thyroid cancer, the most common endocrine malignancy, is rising. The two most common types of thyroid cancer are papillary and follicular" thyroid carcinomas. "Fine-needle aspiration (FNA) of thyroid nodules" can permit to detect many genetic mutations and other molecular alterations, including RAS and BRAF point mutations, PAX8/peroxisome proliferator-activated receptor (PPAR)γ and "RET/PTC rearrangements, occurring in thyroid papillary and follicular carcinomas" (more than 70% of cases), which can be used successfully to improve the diagnosis "and the management of patients with thyroid nodules". The most extensive experience has been accumulated with "the diagnostic use of BRAF mutation", which is highly specific for malignancy. "Testing FNA samples for a panel of mutations" that typically includes RAS, BRAF, PAX8/PPARγ and RET/PTC could permit to achieve the biggest diagnostic impact. "The accuracy of cancer diagnosis in thyroid nodules could be improved significantly using these and other emerging molecular markers".

Predictive factors of malignancy in thyroid nodules with a cytological diagnosis of follicular neoplasm

In cases of follicular neoplasm identified by thyroid fine-needle aspiration (FNA), surgery is required to achieve a precise diagnosis. We investigated potential clinical factors for the preoperative prediction of malignancy in thyroid nodules with a cytological diagnosis of follicular neoplasm. We retrospectively reviewed the data of 97 patients who were diagnosed with follicular neoplasm by FNA and had undergone surgery at the Korea Cancer Center Hospital between April 2010 and April 2012. Age, sex, laboratory data (such as thyroid-stimulating hormone, free T4, thyroglobulin (Tg), and Tg antibody), and ultrasonographic findings were reviewed from the electronic medical records. Of 97 patients, 50 (51.5 %) were diagnosed with benign nodules, 16 (16.5 %) with follicular thyroid carcinoma (FTC), and 31 (32.0 %) with papillary thyroid carcinoma (PTC). In comparison with the features of benign nodules, FTC presented with a large nodule size, high serum Tg level, isoechogenicity, calcifications, and peripheral halo, whereas PTC exhibited traits similar to those of benign nodules, except for high serum Tg level and the presence of calcifications on ultrasonography. Therefore, a high serum Tg level (≥75 ng/mL) and calcification were the only significant predictive factors for malignancy in case of follicular neoplasm (p < 0.01). Serum Tg levels and the presence of calcification on ultrasonography are important clinical features to predict malignancy in thyroid nodules with cytological diagnosis of follicular neoplasm.

Molecular diagnosis for indeterminate thyroid nodules on fine needle aspiration: advances and limitations

Indeterminate thyroid lesions are diagnosed in up to 30% of fine needle aspirations. These nodules harbor malignancy in more than 25% of cases, and hemithyroidectomy or total thyroidectomy has therefore been advocated in order to achieve definitive diagnosis. Recently, many molecular markers have been investigated in an attempt to increase diagnostic accuracy of indeterminate fine needle aspiration cytology and thereby avoid unnecessary complications and costs associated with thyroid surgery. Somatic mutation testing, mRNA gene expression platforms, protein immunocytochemistry and miRNA panels have improved the diagnostic accuracy of indeterminate thyroid nodules, and although no test is perfectly accurate, in the authors' opinion, these methods will most certainly become an important part of the diagnostic tools for clinicians and cytopathologists in the future.

Progress in molecular-based management of differentiated thyroid cancer

Substantial developments have occurred in the past 5-10 years in clinical translational research of thyroid cancer. Diagnostic molecular markers, such as RET-PTC, RAS, and BRAF(V600E) mutations; galectin 3; and a new gene expression classifier, are outstanding examples that have improved diagnosis of thyroid nodules. BRAF mutation is a prognostic genetic marker that has improved risk stratification and hence tailored management of patients with thyroid cancer, including those with conventionally low risks. Novel molecular-targeted treatments hold great promise for radioiodine-refractory and surgically inoperable thyroid cancers as shown in clinical trials; such treatments are likely to become a component of the standard treatment regimen for patients with thyroid cancer in the near future. These novel molecular-based management strategies for thyroid nodules and thyroid cancer are the most exciting developments in this unprecedented era of molecular thyroid-cancer medicine.

Diagnostic use of molecular markers in the evaluation of thyroid nodules

OBJECTIVE

To describe the molecular markers thus far evaluated for use in the care of patients with clinically relevant thyroid nodules.

METHODS

We review the currently available molecular tests that have been applied to patients with thyroid nodules.

RESULTS

In the United States, approximately 450 000 diagnostic fine-needle aspirates will be performed on patients with thyroid nodules this year in an effort to identify thyroid cancer. Unfortunately, this test is imprecise and, at times, inaccurate. Because of this, novel diagnostic testing modalities have been pursued, the most promising of which involve molecular analysis of thyroid tissue. Immunohistochemical staining, analysis for mutations and gene rearrangements, and microarray analysis have all been investigated with regard to their performance characteristics in targeted patient populations.

CONCLUSIONS

Molecular tests to evaluate thyroid nodules demonstrate variable performance characteristics. Further evaluation of available and emerging molecular tests will necessarily rely on prospective real-world test validation in the clinical setting.

Controversies in the management and followup of differentiated thyroid cancer: beyond the guidelines

Thyroid cancer is among the most common endocrine malignancies. Genetic and environmental factors play an important role in the pathogenesis of differentiated thyroid cancer. Both have good prognosis but with frequent recurrences. Cancer staging is an essential prognostic part of cancer management. There are multiple controversies in the management and followup of differentiated thyroid cancer. Debate still exists with regard to the optimal surgical approach but trends toward a more conservative approach, such as lobectomy, are being more favored, especially in papillary thyroid cancer, of tumor sizes less than 4 cm, in the absence of other high-risk suggestive features. Survival of patients with well-differentiated thyroid cancer was adversely affected by lymph node metastases. Prophylactic central LN dissection did improve accuracy in staging and decrease postop TG level, but it had no effect on small-sized tumors. Conservative approach was more applied with regard to the need and dose of radioiodine given postoperatively. There have been several advancements in the management of radioiodine resistant advanced differentiated thyroid cancers. Appropriate followup is required based on risk stratification of patients postoperatively. Many studies are still ongoing in order to reach the optimal management and followup of differentiated thyroid cancer.

Absence of galectin-3 immunostaining in fine-needle aspiration cytology specimens from papillary thyroid carcinoma is associated with favorable pathological indices

BACKGROUND

Galectin-3 (G3) immunostaining of fine-needle aspiration (FNA) samples from thyroid nodules is very useful for the diagnosis of malignancy. The objective of the present study was to determine whether the absence of G3 immunostaining in preoperative FNA samples is associated with favorable clinicopathological parameters, including lymph node (LN) metastasis, in papillary thyroid carcinoma (PTC).

METHODS

The records of 868 patients with PTC who had prethyroidectomy ultrasonography-guided FNA with G3 immunostaining between January 2006 and December 2009 were retrospectively reviewed. G3 immunostaining was considered positive if the percentage of tumor cells showing definite cytoplasmic immunostaining exceeded 5%. Patients who had negative G3 immunostaining of FNA samples were assigned to the G3-negative (G3N) group; whereas those who had positive G3 immunostaining were assigned to the G3-positive (G3P) group.

RESULTS

There were 92 patients who were assigned to the G3N group (10.6%) because of the negative staining for G3 in the preoperative FNA samples from their thyroid nodules. The proportion of PTC subtypes in the G3N and G3P groups was similar (p=0.376). There was less frequent thyroid capsular invasion (46.7% vs. 66.5%, p<0.001), extrathyroidal extension (28.3% vs. 48.5%, p<0.001), and LN metastasis (22.2% vs. 48.7%, p<0.001) in the G3N group than the G3P group. In multivariate regression analysis, G3N expression predicted a lower risk of LN metastasis (odds ratio=0.37, 95% confidence interval 0.18-0.78) after adjustment for other clinicopathological parameters. Over a median follow-up of 33 months, no association was observed between G3N and disease-free survival.

CONCLUSION

The absence of G3 expression in FNA samples from PTC is associated with pathological parameters considered less aggressive than is the case for PTCs with G3 expression, including being a negative predictor of negative LN involvement. Long-term follow-up studies, however, are needed to verify whether G3N patients have lower recurrence and mortality rates.

Expression of CK-19, galectin-3 and HBME-1 in the differentiation of thyroid lesions: systematic review and diagnostic meta-analysis

Background

To distinguish between malignant and benign lesions of the thyroid gland histological demonstration is often required since the fine-needle aspiration biopsy method applied pre-operatively has some limitations. In an attempt to improve diagnostic accuracy, markers using immunocytochemistry and immunohistochemistry techniques have been studied, mainly cytokeratin-19 (CK-19), galectin-3 (Gal-3) and Hector Battifora mesothelial-1 (HBME-1). However, current results remain controversial. The aim of the present article was to establish the diagnostic accuracy of CK-19, Gal-3 and HBME-1 markers, as well as their associations, in the differentiation of malignant and benign thyroid lesions.

Methods

A systematic review of published articles on MEDLINE and The Cochrane Library was performed. After establishing inclusion and exclusion criteria, 66 articles were selected. The technique of meta-analysis of diagnostic accuracy was employed and global values of sensitivity, specificity, area under the summary ROC curve, and diagnostic odds ratio (dOR) were calculated.

Results

For the immunohistochemistry technique, the positivity of CK-19 for the diagnosis of malignant thyroid lesions demonstrated global sensitivity of 81% and specificity of 73%; for Gal-3, sensitivity of 82% and specificity of 81%; and for HBME-1, sensitivity of 77% and specificity of 83%. The association of the three markers determined sensitivity of 85%, specificity of 97%, and diagnostic odds ratio of 95.1. Similar results were also found for the immunocytochemistry assay.

Conclusion

This meta-analysis demonstrated that the three immunomarkers studied are accurate in pre- and postoperative diagnosis of benign and malignant thyroid lesions. Nevertheless, the search for other molecular markers must continue in order to enhance this diagnostic accuracy since the results found still show a persistency of false-negative and false-positive tests.

Virtual slides

Http://www.diagnosticpathology.diagnomx.eu/vs/3436263067345159

The quest for diagnostic molecular markers for thyroid nodules with indeterminate or suspicious cytology

Thyroid nodules are very common and fine needle aspiration (FNA) is a very sensitive means of diagnosis. However, its limitations include the fact that the cytology reports are often indeterminate or suspicious only. The quest for adjunctive measures to improve its specificity has been ongoing for decades, but significant results have remained elusive. The potential use of diagnostic molecular markers appears to be the most promising area of research at this time.

Toward the reliable diagnosis of indeterminate thyroid lesions: a HRMAS NMR-based metabolomics case of study

Cytological analysis of thyroid nodules detected using ultrasound-guided fine-needle aspiration technique is an efficient method for the diagnosis of well-differenciated tumors such as papillary thyroid carcinoma. However, for between 10 to 30% of all the nodules, the cytological analysis based on fine-needle aspiration biopsies leads to an "indeterminated" identification. Consequently, a surgical excision is then necessary for a definite histological diagnosis of the lesions, resulting in 85% of the patient with indeterminated nodules undergoing unnecessary surgery since their tumor is finally diagnosed as benign. In this work, we discuss how HRMAS (1)H NMR-based metabolomics could be a complementary tool for the diagnosis of these elusive cases. We first showed that our approach was able to discriminate clearly any types of thyroid lesions from healthy tissues. Then we proceeded to demonstrate that the information produced by (1)H HRMAS NMR spectra differentiate tumors according to their malignancy grade, even when they belong to the "indeterminate" category. Analysis of the discriminating spectral area in this last case points out toward a possible increase of phenylalanine, taurine, and lactate and a decrease of choline and choline derivatives, myo- and scyllo-inositol in the malignant tumors compared to the benign ones.

Thyroid nodules

Thyroid nodules are common entities, clinically important primarily because of their malignant potential. Serum thyrotropin and thyroid ultrasonography are pivotal in evaluating thyroid nodules. Fine-needle aspiration biopsy is the most accurate tool for diagnosing malignancy and selecting candidates for surgery. An approach to the initial evaluation and management of single nodules, functioning nodules, multinodular glands, incidental nodules, and cysts is discussed, as are therapeutic interventions for benign nodules. Thyroid cancer discovered during pregnancy is also discussed.

Pediatric thyroid cancer

Thyroid cancer is an uncommon childhood malignancy that presents primarily in young children or adolescent females and may be related to radiation exposure or genetic predisposition. Gene alterations, such as RET mutation or RET/PTC rearrangement, are not uncommon. Recent studies have lead to an increased understanding of the role of these particular gene alterations in the diagnosis, prognosis, and treatment of thyroid cancer. Surgery remains the mainstay of treatment for thyroid cancer followed by radioactive iodine when appropriate. In patients with MEN2, prophylactic thyroidectomy is recommended, although a delay in the initial diagnosis is common. With early aggressive treatment and long-term follow-up, these patients generally have excellent outcomes. Recent research suggests potential usefulness of novel therapies directed at oncogenic signaling pathways, modulators of growth, angiogenesis inhibitors, immunomodulators, and gene therapy.

Pyrosequencing cut-off value identifying BRAFV600E mutation in fine needle aspiration samples of thyroid nodules

CONTEXT

Recently, tremendous efforts have been made towards the development of sensitive techniques to detect the BRAF(V600E) mutation in fine needle aspiration biopsy (FNAB) samples. However, newly developed quantitative and semi-quantitative methods, such as dual-priming oligonucleotide (DPO)-based multiplex polymerase chain reaction (PCR), have the potential to generate false-positive (FP) results.

OBJECTIVES

To eliminate the possibility of FP results, we generated a receiver operating characteristic (ROC) curve to investigate the diagnostic accuracy of pyrosequencing using quantitative data.

DESIGN

Cytological diagnoses of 983 thyroid nodules were made according to the Bethesda System 2007. The BRAF(V600E) mutation was analysed by pyrosequencing, and statistical analyses were performed.

RESULTS

Of the 983 nodules, 902 were adopted to evaluate the diagnostic value of pyrosequencing. The number of pathologically confirmed malignancies was 192, of which 182 were papillary thyroid cancer (PTC). By generating an ROC curve, we defined the optimal cut-off value of the mutant allele peak as 5·95% (area under the curve, 0·849; sensitivity, 0·55; 1-specificity, 0). When we applied this selective cut-off value, the number of PTCs positive for BRAF(V600E) was 99 (54·4% of the total number of PTCs). With cytology alone, the diagnostic sensitivity and specificity of detecting malignancy were 71·2% and 100%, respectively. Pyrosequencing improved the diagnostic sensitivity from 71·2% to 78·5% (McNemar's test, P < 0·001), without any change in the diagnostic specificity. When 'suspicious for malignancy' was considered a positive cytological outcome, pyrosequencing increased the diagnostic sensitivity of cytology from 95·8% to 96·9%; however, this improvement did not show statistical significance (McNemar's test, P > 0·05).

CONCLUSIONS

Pyrosequencing is an effective method for detecting the BRAF(V600E) mutation in FNAB samples. By allowing the optimal cut-off value to be determined, pyrosequencing improves the diagnostic sensitivity while eliminating the possibility of FP results.

Elastic light-scattering spectroscopy for discrimination of benign from malignant disease in thyroid nodules

BACKGROUND

Thyroid cancer is the most common endocrine malignancy. The current standard of diagnosis, fine-needle aspiration biopsy, yields approximately 10-25% of indeterminate results leading to twice as many thyroidectomies for further diagnosis. Elastic scattering spectroscopy (ESS) is a new, minimally invasive optical-biopsy technique mediated by fiber-optic probes that is sensitive to cellular and subcellular morphological features. We assessed the diagnostic potential of ESS in the thyroid to differentiate benign from malignant thyroid nodules as determined by histology.

METHODS

Under an IRB approved protocol, 36 surgical patients (n = 21 benign thyroid nodules, n = 15 malignant tumors) had collection of ESS data from their fresh ex vivo thyroidectomy specimens. Using surgical pathology as our gold standard, spectral analyses were performed using a training set; these data were used to assess the ESS diagnostic potential using the leave-one-out technique.

RESULTS

Our test set was 75% sensitive and 95% specific in differentiating benign from malignant thyroid lesions, with a positive predictive value (PPV) of 0.92 and a negative predictive value (NPV) of 0.83.

CONCLUSIONS

The ESS can accurately distinguish benign vs malignant thyroid lesions with high PPV and NPV. With further validation ESS could potentially be used as an in situ real-time diagnostic tool or as an adjunct to conventional cytology.

CXC chemokine receptor 4 immunodetection in the follicular variant of papillary thyroid carcinoma: comparison to galectin-3 and hector battifora mesothelial cell-1

BACKGROUND

The cytological discrimination between benign and malignant follicular-patterned lesions of the thyroid can represent a diagnostic challenge, even for experienced pathologists. We evaluated the diagnostic use of protein expression of CXC chemokine receptor 4 (CXCR4) and galectin-3 (gal-3) that were found to be upregulated in papillary thyroid carcinoma compared to normal thyroid and of mesothelial cell surface protein recognized by monoclonal antibody Hector Battifora Mesothelial cell (HBME)-1 in thyroid tumors.

METHODS

Expression of CXCR4, HBME-1, and gal-3 was examined immunohistochemically in total of 100 aspirates of thyroid lesions, categorized as benign (n = 22), indeterminate lesion (n = 43), suspicious of papillary thyroid carcinoma (n = 10), or malignant (n = 25) by preoperative cytology.

RESULTS

Expression of each individual marker was significantly associated with malignancy (p < 0.0001), although the sensitivity of detection ranged from 56% for gal-3 to 94% for HBME-1. When focusing on the indeterminate lesions, only CXCR4 and HBME-1 expression was associated with malignancy; moreover, these two markers either used individually or in combination showed good values of diagnostic accuracy (88.4% and 90.7%, respectively). Further, the combination of CXCR4 plus HBME-1 or the simultaneous use of all the three markers provided absolute value of sensitivity and negative predictive value in the same group of lesions.

CONCLUSIONS

An immunohistochemical panel, including CXCR4, could be useful in the differential diagnosis between benign and malignant well-differentiated follicular-patterned thyroid lesions.

Diagnostic utility of galectin-3 in thyroid cancer

Galectin-3 (Gal-3), which has received significant recent attention for its utility as a diagnostic marker for thyroid cancer, represents the most well-studied molecular candidate for thyroid cancer diagnosis. Gal-3 is a protein that binds to beta-galactosidase residues on cell surface glycoproteins and has also been identified in the cytoplasmic and nuclear compartment. This marker has been implicated in regulation of normal cellular proliferation and apoptosis, as well as malignant transformation and the metastasis of cancer cells. We here present a mechanistic review of Gal-3 and its role in cancer development and progression. Gal-3 expression studies in thyroid tissue and cytologic tumor specimens and their methodological considerations are also discussed in this article. Despite great variance in their methodology, the majority of immunohistochemical studies found that Gal-3 was differentially expressed in thyroid carcinoma compared with benign and normal thyroid specimens, suggesting that Gal-3 is a good diagnostic marker for thyroid cancer. Recent studies have also demonstrated improved methodological reliability. On the other hand, Gal-3 genomic expression studies have shown inconsistent results for diagnostic utility and are not recommended. Overall, the development of Gal-3 as a diagnostic marker for thyroid cancer represents a promising avenue for future study, and its clinical application could significantly reduce the number of diagnostic thyroid operations performed for cases of indeterminant fine needle aspiration biopsy cytology, and thus positively impact the current management of thyroid nodular disease.

Evaluation of a thyroid nodule

The thyroid specialist frequently evaluates thyroid nodules because they may represent malignancy. Nodules are typically found on physical examination or incidentally when other imaging studies are performed. Malignant or symptomatic nodules that compress nearby structures warrant surgical excision. Yet, the majority of thyroid nodules are asymptomatic and benign, so the thyroid surgeon must rely on diagnostic studies to determine when surgery is indicated. Ultrasound is the preferred imaging modality for thyroid nodules, and the ultrasound guided fine-needle aspiration biopsy (FNAB) is the preferred method of tissue sampling. Nodules 1 cm or larger or nodules with suspicious sonographic appearance warrant cytologic analysis to better quantify the risk for malignancy. Molecular biomarkers are a powerful adjunct to cytology. Detecting malignancy preoperatively allows total thyroidectomy in a single operation without the need for frozen section or a second operation for completion of a thyroidectomy if malignancy is found during the initial thyroid lobectomy.

Revised American Thyroid Association management guidelines for patients with thyroid nodules and differentiated thyroid cancer

BACKGROUND

Thyroid nodules are a common clinical problem, and differentiated thyroid cancer is becoming increasingly prevalent. Since the publication of the American Thyroid Association's guidelines for the management of these disorders was published in 2006, a large amount of new information has become available, prompting a revision of the guidelines.

METHODS

Relevant articles through December 2008 were reviewed by the task force and categorized by topic and level of evidence according to a modified schema used by the United States Preventative Services Task Force.

RESULTS

The revised guidelines for the management of thyroid nodules include recommendations regarding initial evaluation, clinical and ultrasound criteria for fine-needle aspiration biopsy, interpretation of fine-needle aspiration biopsy results, and management of benign thyroid nodules. Recommendations regarding the initial management of thyroid cancer include those relating to optimal surgical management, radioiodine remnant ablation, and suppression therapy using levothyroxine. Recommendations related to long-term management of differentiated thyroid cancer include those related to surveillance for recurrent disease using ultrasound and serum thyroglobulin as well as those related to management of recurrent and metastatic disease.

CONCLUSIONS

We created evidence-based recommendations in response to our appointment as an independent task force by the American Thyroid Association to assist in the clinical management of patients with thyroid nodules and differentiated thyroid cancer. They represent, in our opinion, contemporary optimal care for patients with these disorders.

Diagnostic markers and prognostic factors in thyroid cancer

There has been considerable progress identifying biomarkers in thyroid tumors that improve the accuracy of fine-needle aspiration biopsy and also help predict tumor aggressiveness or behavior. In this review we address both the clinical potential of molecular biomarkers and their usefulness, based on the most recent literature. We describe the current best clinical staging systems and the common somatic mutations in thyroid cancer. The BRAF mutation is the most common mutation in papillary thyroid cancer and has recently been reported to be associated with disease aggressiveness; it is also an independent predictor of tumor behavior. Combined testing of RET/PTC, NTRK, RAS and PAX8–PPARγ, which are mutually exclusive mutations, helps improve the accuracy of fine-needle aspiration biopsy. Gene-expression profiling studies have identified a variety of potential molecular markers to help distinguish benign from malignant thyroid neoplasms. Expression analysis of differentially expressed microRNAs also appears to be a promising diagnostic approach for distinguishing benign from malignant thyroid neoplasm. It is especially useful for indeterminate nodules by fine-needle aspiration biopsy.