MicroRNA signature in thyroid fine needle aspiration cytology applied to "atypia of undetermined significance" cases

Investigation of the alterations in miRNA expression levels in thyroid nodules and malignancies

The relationship between preoperative miR-146b and miR-155 expression levels and postoperative pathology results in patients operated on for nodular thyroid disease and thyroid malignancy was investigated. Sixty three patients who were operated on for thyroid nodules diagnosed as benign, malignant and atypia of undetermined significance (AUS) were included in the study. Preoperative miR-146b and miR-155 expression levels of these patients were compared according to postoperative pathology results. Twenty three of the patients were male (36.5%) and 40 patients were female (63.5%). According to the results of fine needle aspiration biopsy (FNAB) taken from the patients in the preoperative period, The number of benign patients was 26 (41.2%), the number of malignant patients was 17 (26.9%), the number of patients reported as suspicion of malignancy was 10 (15.8%), and the number of AUS patients reported was 10 (15.8%). The postoperative pathology of 58.7% (n = 37) of the patients was benign, and the postoperative pathology of 41.3% (n = 26) was malignant. Compared to the group with benign postoperative pathology results, miR-146b expression level significantly increased by 8.08-fold in the group with malignant postoperative pathology results (p < 0.01). Additionally, miR-146b expression level was significantly upregulated by 3.23-fold in AUS patients compared with benign pathology results (p < 0.01). Although a 1.88-fold increase in miR-155 expression level was detected in malignant patients compared to the benign group, it was determined that the expression level of miR-155 significantly increased by 2.36-fold in AUS patients (p < 0.001). Circulating miRNA could discriminate between patients with benign and malignant nodules. Our results suggest that both miR-146b and miR-155 expression levels increased in the group with malignant postoperative pathology results. Additionally, increased miR-155 expression level could be associated with AUS progression. Therefore, miRNAs could be used as preoperative malignancy biomarkers to determine the characteristics of nodules and the decision to undergo surgery.

Effective Use of microRNA, BRAF and Sonographic Risk Assessment in Bethesda III Thyroid Nodules Requires a Different Approach to Nodules with Features of Nuclear Atypia and Other Types of Atypia

The aim of the study was to analyze the diagnostic usefulness of the combined assessment of the ultrasound risk category of the nodule (evaluated with EU-TIRADS system), the presence of BRAF V600E mutation and the expression of selected microRNAs (miR-146b, miR-221 and miR-222) in Bethesda category III thyroid nodules, separately for cases with nuclear atypia (AUS-nuclear) and cases with other types of atypia (AUS-other). We evaluated 161 nodules (66 AUS-nuclear and 95 AUS-other) with known results of postoperative histopathological examination. The rate of cancer and the rate of PTC among cancers were nearly three times higher in the AUS-nuclear than the AUS-other group. For AUS-nuclear nodules, the most effective diagnostic panel included, in addition to repeat FNA, the assessment of BRAF V600E mutation and the expression of miR-146b and miR-222 (sensitivity: 93.5%, specificity: 80.0%). For AUS-other nodules, a two-step procedure was most effective: at the first stage, forgoing surgical treatment in subjects with a benign repeat FNA outcome, and, at the second stage, the assessment of miR-222 expression and the EU-TIRADS category (sensitivity: 92.3%, specificity: 76.8%). The optimal use of molecular methods in the diagnostics of category III thyroid nodules requires a separate approach for nodules with nuclear atypia and nodules with other types of atypia.

New biomarkers: prospect for diagnosis and monitoring of thyroid disease

After the metabolic syndrome and its components, thyroid disorders represent the most common endocrine disorders, with increasing prevalence in the last two decades. Thyroid dysfunctions are distinguished by hyperthyroidism, hypothyroidism, or inflammation (thyroiditis) of the thyroid gland, in addition to the presence of thyroid nodules that can be benign or malignant. Thyroid cancer is typically detected via an ultrasound (US)-guided fine-needle aspiration biopsy (FNAB) and cytological examination of the specimen. This approach has significant limitations due to the small sample size and inability to characterize follicular lesions adequately. Due to the rapid advancement of high-throughput molecular biology techniques, it is now possible to identify new biomarkers for thyroid neoplasms that can supplement traditional imaging modalities in postoperative surveillance and aid in the preoperative cytology examination of indeterminate or follicular lesions. Here, we review current knowledge regarding biomarkers that have been reliable in detecting thyroid neoplasms, making them valuable tools for assessing the efficacy of surgical procedures or adjunctive treatment after surgery. We are particularly interested in providing an up-to-date and systematic review of emerging biomarkers, such as mRNA and non-coding RNAs, that can potentially detect thyroid neoplasms in clinical settings. We discuss evidence for miRNA, lncRNA and circRNA dysregulation in several thyroid neoplasms and assess their potential for use as diagnostic and prognostic biomarkers.

An institutional experience with DICER1 mutated thyroid nodules-evaluating the cytomorphology and molecular phenotype

INTRODUCTION

DICER1 mutated thyroid nodules are commonly seen in pediatric populations often, as part of DICER1 syndrome. We seek to evaluate DICER1 mutated thyroid nodules in adult populations to assess whether there exists distinctive clinical, cytologic, histologic, and molecular characteristics that underline our institutional cohort.

MATERIALS AND METHODS

Retrospective analysis was performed on all fine-needle aspiration (FNA) specimens with a corresponding ThyroSeq panel, to select a cohort of cases with DICER1 mutations. Clinical, radiologic, and cytology materials were reviewed, and histology was reviewed for corresponding resection cases were available. ThyroSeq panel was further scrutinized for additional molecular alterations and variant allele frequency.

RESULTS

DICER1 mutated thyroid nodules (n = 8), more commonly occurred in younger adults (P = 0.01) with larger (P = 0.01) nodules and only in female patients in our cohort. FNA commonly demonstrates cellular specimens with banal cytomorphologic cues including regular nuclei, inconspicuous nucleoli, smooth nuclear membranes, and abundant colloid. On retrospective review by 2 cytopathologists, the lesions were frequently diagnosed as Bethesda II (5 of 8) by both reviewers. Histology, when available, showed that all nodules were categorized as follicular adenomas (5 of 5), often demonstrating macrofollicles with papillary excrescences demonstrating bland nuclei (4 of 5). DICER1 mutational profile revealed a variant allele frequency of &gt;40% in 25% of cases (2 of 8) and &gt;30% in an additional 4 cases, highlighting a possible germline association.

CONCLUSIONS

DICER1 mutated nodules may be under-reported due to banal cytomorphologic features and may be associated with an underlying germline alteration.

Diagnostic Significance of FNAB miRNA Expression in Papillary Thyroid Carcinoma

The aim of the study was to evaluate the diagnostic utility of specific miRNAs in the preoperative assessment of thyroid nodules. One hundred and sixty thyroid fine needle aspiration biopsy (FNAB) samples with suspected thyroid carcinoma were collected. To detect the levels of miRNA expression in FNAB, next generation small RNA sequencing was performed in 60 samples. Based on the results obtained, three miRNAs (miR125A, miR200B, miR4324) were selected for further analysis. Based on the most frequently reported miRNAs in the literature associated with thyroid papillary carcinoma (PTC), two more miRNA (miR146B, miR221) were selected for further validation, using real-time reverse transcriptase polymerase chain reaction (RT-PCR) in 36 benign and 64 PTC samples. Expression of miR125A, miR146B, miR221, and miR4324 was significantly higher in patients with PTC compared with benign thyroid nodules (p ˂ 0.05). miR125A and miR4324 were also significantly more highly expressed in patients with extrathyroidal tumor extension compared to those without extrathyroidal PTC extension (p < 0.001). We also found a significantly higher expression of miR221 (p = 0.043) in patients with multifocal carcinomas compared to patients with single foci carcinomas. This prospective study showed that the expression analysis of four miRNAs (miR125A, miR146B, miR221, and miR4324) improve accuracy of FNAB, which could allow a better pre-operative diagnostic and prognostic assessment of thyroid malignancies.

Correlation between Ultrasonographic Appearance of Papillary Thyroid Microcarcinoma and BRAF V600E Mutation

The study was conducted to investigate the correlation between the ultrasonographic appearance of a thyroid nodule and the BRAF V600E mutation. Patients with thyroid nodules (n = 186), for which BRAF V600E testing and cytopathology analysis were performed, and who underwent subsequent surgery for nodule resection were enrolled in this study. For each patient, color Doppler ultrasonography was performed to observe the variables of the nodules. The nodules were then characterized using the thyroid imaging reporting and data system classification TI-RADS. Furthermore, the ultrasonographic appearance of the control group, encompassing patients with nodular thyroid goiters, and the case group, encompassing patients with papillary thyroid microcarcinoma (PTMC), was statically analyzed. Similarly, a statistical analysis of the ultrasonographic appearance of the BRAF V600E-positive and BRAF V600E-negative subgroups was also performed. The accuracy was significantly different for the corresponding values when color Doppler ultrasonography, BRAF V600E testing, or cytopathology alone was used for diagnosis. There were significant differences in the ultrasonographic appearance variables between the control and case groups. Comparing with the BRAF V600E-negative subgroup of the case group, the ultrasonographic appearances of the BRAF V600E-positive subgroup showed less circumscribed and more irregularly shaped nodules, with significantly different aspect ratios of >1. The combination of BRAF V600E testing and color Doppler ultrasonography or cytopathology improved the accuracy of the PTMC diagnose. We found that the ultrasonographic appearance of thyroid nodules was related to PTMC.

Thyroid and Molecular Testing. Advances in Thyroid Molecular Cytopathology

Thyroid nodules are a common finding in the adult population including the fact that more than 50% of individuals, over the age of 60, have thyroid nodules. The majority have been mostly detected with ultrasonography and 10% by palpation. The majority of these nodules are benign, whereas 5–15% of them are malignant. The pre-operative diagnosis of cancer is a critical challenge in order to ensure that each patient can be treated with the best tailored management with a reduction of unnecessary surgery for benign lesions. Fine needle aspiration cytology (FNAC) represents the first and most important diagnostic tool for the evaluation of thyroid lesions. According to the literature, FNAC is able to render a conclusive diagnosis in up to 70–80% of all cases. For the remaining 20–30% of nodules, cytological diagnoses fall into the category of indeterminate lesions mostly due to the lack of specific morphological features. According to the Bethesda system for reporting thyroid cytopathology (TBSRTC), indeterminate lesions can be sub-stratified into three different subcategories including “atypia of undetermined significance/follicular lesion of undetermined significance-AUS/FLUS”; “follicular or Hürthle cell neoplasm/suspicious for follicular or Hürthle cell neoplasm-FN/SFN”; and “suspicious for malignancy-SFM”. Many of these indeterminate lesions undergo repetition or diagnostic lobectomy. Nonetheless, the majority of these cases will have a benign diagnosis due to the fact that the rate of cancer ranges between 6 and 30%. It stands to reason that the application of ancillary technique, mostly molecular testing, emerged as a critical additional tool for those thyroid indeterminate lesions. Since the early 1990s, material collected from cytological samples yields sufficient and adequate cells for the detection of point mutation or gene fusions. Nonetheless, the further availability of new sequencing technologies such as next-generation sequencing (NGS) has led to more comprehensive molecular applications adopted now in clinical use. The current review investigates the multiple advances in the field of molecular testing applied in thyroid cytology.

Genetic alterations in cfDNA of benign and malignant thyroid nodules based on amplicon-based next-generation sequencing

Background

Circulating cell-free DNA (cfDNA) serves as a biomarker in multiple malignant diseases. However, controversy still surrounds the role of cfDNA detection in the diagnosis and monitoring of papillary thyroid carcinoma (PTC). This study set out to identify the role of cfDNA detection in distinguishing between benign and malignant thyroid nodules.

Methods

Tissue, blood cell, and plasma samples were collected from 10 patients with benign nodules and 10 patients with malignant nodules. The DNA isolated from these samples was subject to PCR-based amplification using primers designed for 50 proto-oncogenes and tumor suppressor genes. PCR products were sequenced using Illumina technology, and the mutations were detected with varScan among sequencing data for each sample and comparative analysis was carried out.

Results

Through amplicon sequencing, we found one non-synonymous somatic mutation in the benign nodules and three in the malignant nodules. Among these four mutations, BRAF^V600E mutation was detected in the tissue samples of 8 out of the 10 PTC patients, but it was not detected in the benign nodules. However, no BRAF^V600E mutation was detected in cfDNA. Further differential analysis of cfDNA indicated that some genes had more mutations in benign patients than in malignant patients, such as MET and IDH, and some genes had more mutations in malignant patients, such as PIK3CA and EZH2.

Conclusions

We found that BRAF^V600E mutation was a credible disease-related mutation in PTC; however, it could not be detected in cfDNA. Moreover, there was a large difference in mutation gene distribution between benign and malignant thyroid nodules.

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.

Diagnostic value of the candidate microRNAs in thyroid fine-needle aspiration biopsy (FNAB) samples

Background Thyroid cancer (TC) is known to be the most common endocrine malignancy with an incidence rate which has increased by 2.3-fold over the past 30 years. Approximately, 30% of the thyroid fine-needle aspiration biopsy (FNAB) outcomes are indecisive. Moreover, researchers recognized multiple differentially expressed microRNAs (miRNAs) as candidate diagnostic markers for thyroid nodules. The purpose of this study was to identify thyroid tumor-associated miRNAs in FNAB with the capacity to be developed as unique biomarkers. Materials and methods According to the study design, a quantitative real time reverse transcription polymerase chain reaction (qRT-PCR) was applied to evaluate the expression levels of nine miRNAs (Let7, miR-34a, miR-146b, miR-221, miR-151, miR-155, miR-181b, miR-222 and miR-375) among 224 FNA samples as the training set. Results The findings of this study revealed that miR-181b and miR-146b are the best predictors to diagnose benign thyroid FNA samples from malignant samples. However, the remaining miRNAs were co-expressed and had no significant effect on the predictor model. On the other hand, sensitivity and specificity of miR-181b and miR-146b were reported at 83.0%-83.0% and 83.0%-66.0%, respectively. Conclusions According to the results of this study, miR-146b and miR-181b might be considered as adjunct markers contributing to thyroid FNAB in tumor types. In addition, miR-146b and miR-181b were recognized as biomarkers for discriminating benign thyroid nodules from malignant ones. It is suggested that further prospective clinical trials be conducted to evaluate the accuracy of such findings in a larger cohort and determine the clinical uses.

Ancillary molecular testing of indeterminate thyroid nodules

Cytological specimens from thyroid nodules are increasingly being adopted as the first available material for cost effectively managing patients in the era of personalized medicine. Cytology aspirates not only play a central role in providing accurate diagnoses, but are also being collected for ancillary molecular testing. Molecular analysis, including the evaluation of somatic mutations and other genomic alterations, has accordingly become well integrated in the cytological workup of thyroid lesions. Appropriately handled thyroid cytology preparations provide well-preserved and adequately cellular material with improved DNA/RNA quantity. The recent publication of the 2nd edition of The Bethesda System for Reporting Thyroid Cytopathology and the American Thyroid Association guidelines confirm the relevant role of molecular testing in the management of the different subcategories of indeterminate thyroid lesions. This review discusses the role of molecular testing for indeterminate thyroid nodules, including the recent introduction of the noninvasive, encapsulated follicular variant of papillary thyroid carcinoma (FVPTC), known also as noninvasive follicular neoplasm with papillary-like nuclear features (NIFTP).

The Role of Molecular Testing for the Indeterminate Thyroid FNA

Thyroid nodules are common in the adult population where a majority are benign and only 4.0% to 6.5% are malignant. Fine needle aspiration (FNA) is a key method used in the early stages to evaluate and triage patients with thyroid nodules. While a definitive cytological diagnosis is provided in more than 70–75% of all thyroid FNA cases, the group of indeterminate lesions offers a challenge in terms of interpretation and clinical management. Molecular testing platforms have been developed, are recognized as an option by the 2015 American Thyroid Association Guidelines, and are frequently used in conjunction with FNA as an integral part of the cytologic evaluation. In this review, the utility of molecular testing options for nodules assigned to the group of indeterminate thyroid FNAs is described.

Altered Serum MicroRNA Profile May Serve as an Auxiliary Tool for Discriminating Aggressive Thyroid Carcinoma from Nonaggressive Thyroid Cancer and Benign Thyroid Nodules

Thyroid cancers are the most common malignancy of the endocrine system; however, there is no reliable blood biomarkers for thyroid cancer diagnosis and even for aggressive and nonaggressive thyroid cancers as well as benign nodule discrimination. The present study is aimed at evaluating whether circulating microRNA (miRNA) can differentiate aggressive and nonaggressive thyroid cancer from benign thyroid nodules. In this study, we performed a multiphase, case-control study to screen serum miRNA expression profile in 100 patients with papillary thyroid cancer (PTC), 15 patients with aggressive medullary thyroid carcinoma (MTC), 91 patients with benign nodules, and 89 healthy controls using TaqMan low-density array followed by extensive reverse transcription quantitative real-time PCR validation. The results showed that the serum levels of miR-222-3p, miR-17-5p, and miR-451a were markedly increased, while miR-146a-5p, miR-132-3p, and miR-183-3p were significantly decreased in the PTC and benign nodule groups compared with the control group. There was no difference in the miRNA expression profile between the PTC group and the benign nodule group. Nevertheless, the serum levels of miR-222-3p and miR-17-5p were significantly increased in the MTC group than the benign nodule and control group. Moreover, receiver operating characteristic curve analyses demonstrated that the 2 miRNAs and their panel can accurately discriminate MTC from the benign nodule group and healthy controls. These findings indicated that the altered circulating miRNAs may discriminate PTC and benign thyroid nodules from controls, and serum miR-222-3p and miR-17-5p have the potential to serve as auxiliary tools for diagnosing more aggressive thyroid carcinomas, such as MTC.

BRAF V600E mutation and microRNAs are helpful in distinguishing papillary thyroid malignant lesions: Tissues and fine needle aspiration cytology cases

AIMS

Mutations of BRAF oncogene are considered to contribute in the invasiveness and poor clinicopathologic features of papillary thyroid cancer (PTC). As a step towards understanding the underlying molecular mechanisms of this contribution, we aimed to examine the association of four microRNAs' (miR-222, -137, -214, -181b) levels with BRAFV600E and clinicopathological features in PTC tissues and fine needle aspiration (FNA) specimens.

METHODS

In total, 56 PTC and 27 benign with multinodular goiter tissue samples, 95 FNA samples, and B-CPAP and HEK293 cell lines were examined. BRAFV600E mutation was examined in PTC tissues and FNA samples. Expression of microRNAs was assessed by real-time quantitative reverse transcription-PCR.

KEY FINDINGS

The frequency of BRAFV600E in PTC tissues and FNA samples "suspicious for PTC" was 41.1 and 36.8%, respectively. MiR-222, -137, -214, and -181b were significantly upregulated in PTC tumors (P < 0.05) and in B-CPAP cell line (P < 0.001). In FNA, the expressions of miR-222, -181b and -214 were significantly elevated in patients suspected for PTC (P < 0.05), while there was no significant difference in miR-137. After adjustment for age and sex, miR-181b was associated with an increased risk of bearing BRAFV600E mutation (OR: 1.27; 95% CI: 1.01-1.61; P = 0.045) and risk of lymphovascular invasion (OR: 1.66; 95% CI: 1.01-2.72; P = 0.045); miR-137 was associated with the risk of larger tumor size (OR: 1.31; 95% CI: 1.04-1.65; P = 0.022); miR-222 was related to increase in extracapsular invasion (OR: 1.28; 95% CI: 1.04-1.57; P = 0.018).

SIGNIFICANCE

Upregulation of miR-222, -214 and -181b has been confirmed in PTC tumors, FNA samples and cell line. MiR-137 upregulation has been confirmed in PTC tumors and cell line, but not in FNA samples. MiR-222, -137 and -181b showed an association with the degree of malignancy in PTC tumors.

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.

To Obtain More With Less: Cytologic Samples With Ancillary Molecular Techniques-The Useful Role of Liquid-Based Cytology

CONTEXT

- Fine-needle aspiration cytology has been increasingly used as the first tool in the evaluation of several diseases. Although cytology has a relevant role in the discrimination between benign and malignant lesions, conventional slides cannot lead to 100% conclusive results. It was hoped that the introduction of liquid-based cytology (LBC) would improve the efficacy of cytology through standardization, quality improvement, and the possibility of carrying out ancillary techniques on the residual stored material. In recent decades, the application of genomic alterations has been studied on cytologic samples with feasible and reliable results. The molecular analysis offers a powerful aid to define the best clinical or surgical approaches and follow-up for patients. In recent years, the application of different ancillary techniques has been carried out on conventional slides even though LBC represents a useful additional and alternative method for molecular testing.

OBJECTIVE

- To demonstrate the relevance of LBC as a valid aid to overcoming the difficulties encountered in the application of ancillary techniques on conventional slides.

DATA SOURCES

- We examined and reviewed our experience with the application of ancillary techniques on LBC performed on different body sites.

CONCLUSIONS

- We emphasize that LBC achieves significant and accurate results. It represents a valid method for cytologic evaluation and it provides highly reproducible and informative molecular yields.

MicroRNA-302c modulates peritoneal dialysis-associated fibrosis by targeting connective tissue growth factor

Long‐term peritoneal dialysis (PD) can lead to the induction of mesothelial/epithelial‐mesenchymal transition (MMT/EMT) and fibrosis; these effects eventually result in ultrafiltration failure and the discontinuation of PD. MicroRNA‐302c (miR‐302c) is believed to be involved in regulating tumour cell growth and metastasis by suppressing MMT, but the effect of miR‐302c on MMT in the context of PD is unknown. MiR‐302c levels were measured in mesothelial cells isolated from the PD effluents of continuous ambulatory peritoneal dialysis patients. After miR‐302c overexpression using lentivirus, human peritoneal mesothelial cell line (HMrSV5) and PD mouse peritoneum were treated with TGF‐β1 or high glucose peritoneal dialysate respectively. MiR‐302c expression level and MMT‐related factors alteration were observed. In addition, fibrosis of PD mouse peritoneum was alleviated by miR‐302c overexpression. Furthermore, the expression of connective tissue growth factor (CTGF) was negatively related by miR‐302c, and LV‐miR‐302c reversed the up‐regulation of CTGF induced by TGF‐β1. These data suggest that there is a novel TGF‐β1/miR‐302c/CTGF pathway that plays a significant role in the process of MMT and fibrosis during PD. MiR‐302c might be a potential biomarker for peritoneal fibrosis and a novel therapeutic target for protection against peritoneal fibrosis in PD patients.

MiRNA-221/222 in thyroid cancer: A meta-analysis

OBJECTIVES

A meta-analysis was performed to observe whether a difference in miRNA-221/222 expression exists in thyroid cancer with normal thyroid or BTLs (benign thyroid lesions) and, under this premise, assess its diagnostic efficacy for thyroid cancer.

METHODS

Systematic electronic literature searches were conducted to include PubMed, the Cochrane Central Register of Controlled Trials, and Web of Science. The combined fold change (FC) was calculated, and pooled estimates of sensitivity, specificity, diagnostic odds ratio (DOR) and summary receiver operating characteristic (SROC) curves were calculated.

RESULTS

Twenty-seven articles were included in this meta-analysis. The combined FC of miRNA-221/222 were 13.85 and 13.75 in thyroid cancer with normal control. For miRNA-221/222, the pooled sensitivity was 0.79 (95% CI = 0.73-0.85), specificity was 0.84 (95% CI = 0.76-0.90) and AUC (area under the curve) value was 0.88 (0.85-0.91). For miRNA-221, the pooled sensitivity was 0.82 (95% CI = 0.76-0.86) and specificity was 0.84 (95%CI = 0.74-0.91). For miRNA-222, the pooled sensitivity was 0.78 (95%CI = 0.68-0.85) and specificity was 0.83 (95% CI = 0.70-0.92).

CONCLUSION

Differences in expression levels of miRNA-221/222 can provide clues for exploring the etiology of thyroid cancer. In addition, miRNA-221/222 were promising molecular biomarkers that may significantly improve the diagnostic accuracy of thyroid cancer.

Morphology combined with ancillary techniques: An algorithm approach for thyroid nodules

INTRODUCTION

Several authors have underlined the limits of morphological analysis mostly in the diagnosis of follicular neoplasms (FN). The application of ancillary techniques, including immunocytochemistry (ICC) and molecular testing, contributes to a better definition of the risk of malignancy (ROM) and management of FN. According to literature, the application of models, including the evaluation of ICC, somatic mutations (ie, BRAF^V600E ), micro RNA analysis is proposed for FNs. This study discusses the validation of a diagnostic algorithm in FN with a special focus on the role of morphology then followed by ancillary techniques.

METHODS

From June 2014 to January 2016, we enrolled 37 FNs with histological follow-up. In the same reference period, 20 benign nodules and 20 positive for malignancy were selected as control. ICC, BRAF^V600E mutation and miR-375 were carried out on LBC.

RESULTS

The 37 FNs included 14 atypia of undetermined significance/follicular lesion of undetermined significance and 23 FN. Specifically, atypia of undetermined significance/follicular lesion of undetermined significance resulted in three goitres, 10 follicular adenomas and one NIFTP whereas FN/suspicious for FN by seven follicular adenomas and 16 malignancies (nine non-invasive follicular thyroid neoplasms with papillary-like nuclear features, two invasive follicular variant of papillary thyroid carcinoma [PTC] and five PTC). The 20 positive for malignancy samples included two invasive follicular variant of PTC, 16 PTCs and two medullary carcinomas. The morphological features of BRAF^V600E mutation (nuclear features of PTC and moderate/abundant eosinophilic cytoplasms) were associated with 100% ROM. In the wild type cases, ROM was 83.3% in presence of a concordant positive ICC panel whilst significantly lower (10.5%) in a negative concordant ICC. High expression values of MirR-375 provided 100% ROM.

CONCLUSIONS

The adoption of an algorithm might represent the best choice for the correct diagnosis of FNs. The morphological detection of BRAF^V600E represents the first step for the identification of malignant FNs. A significant reduction of unnecessary thyroidectomies is the goal of this application.

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.

microRNA-302c-3p inhibits renal cell carcinoma cell proliferation by targeting Grb2-associated binding 2 (Gab2)

The expression and biological function of Grb2-associated binding 2 (Gab2) in renal cell carcinoma (RCC) cells was tested here. We showed that Gab2 expression was significantly elevated in human RCC tissues and RCC cells. It was correlated with over-activation of Akt and downregulation of microRNA-302c-3p ("miR-302c-3p"), a putative Gab2-targeting microRNA. Knockdown of Gab2 inhibited Akt activation and 786-O RCC cell proliferation. Reversely, forced over-expression of Gab2 led to Akt hyper-activation to facilitate 786-O cell proliferation. Exogenous expression of miR-302c caused Gab2 downregulation, Akt inhibition and 786-O cell proliferation inhibition. On the other hand, miR-302c-3p depletion by expressing its anti-sense ("antagomiR-302c") led to Gab2 upregulation, Akt activation and increased 786-O cell proliferation. Significantly, miR-302c-3p failed to affect the proliferation of 786-O cells with shRNA-depleted Gab2. Together, we suggest that miR-302c-3p depletion in human RCC cells leads to Gab2 over-expression, Akt hyper-activation and cell proliferation.

MicroRNAs as Biomarkers in Thyroid Carcinoma

Optimal management of patients with thyroid cancer requires the use of sensitive and specific biomarkers. For early diagnosis and effective follow-up, the currently available cytological and serum biomarkers, thyroglobulin and calcitonin, present severe limitations. Research on microRNA expression in thyroid tumors is providing new insights for the development of novel biomarkers that can be used to diagnose thyroid cancer and optimize its management. In this review, we will examine some of the methods commonly used to detect and quantify microRNA in biospecimens from patients with thyroid tumor, as well as the potential applications of these techniques for developing microRNA-based biomarkers for the diagnosis and prognostic evaluation of thyroid cancers.

Meta-analysis of microRNAs expression in head and neck cancer: uncovering association with outcome and mechanisms

Head and neck squamous cell carcinoma (HNSCC) is often diagnosed at advanced stages, incurring significant high mortality and morbidity. This review explored the risk stratification of miRNAs, and investigated the impact of miRNA networking in HNSCC prognostication. We performed a meta-analysis and a systematic literature search on online databases for papers published prior to December 1, 2016. The list of miRNAs was uploaded to MetacoreTM to construct a protein-protein interaction network, which was used to identify targets of the miRNAs and potential drugs. In addition, a representative network was further validated by immunohistochemistry in a cohort of 100 patients. We found 116 studies that included 8,194 subjects, in which the relationship between miRNA expression and prognosis of HNSCC were analyzed. Significant elevated expressions of 27 miRNAs and decreased expression of 26 miRNAs were associated with poor outcome. After excluding the studies causing heterogeneity, a fixed model was applied, which showed a statistically significant association between increased expression of miR-21 and poor survival (Pooled HR = 1.81,95% CI = 0.66-2.95, P < 0.005). We identified four networks affected by the miRNAs expression and enriched in genes related to metabolic processes and regulation of cell mitogenesis in response to extracellular stimuli. One network point out to 16 miRNAs directly or indirectly involved in the regulation of androgen-receptor (AR). Evaluation of AR protein expression in our cohort revealed that patients with upregulation of AR had poor survival rates (log-rank test, P < 0.005). This study showed that miRNAs have potential prognostic value to serve as screening tool for HNSCC during the follow-up. In addition, the implementation of a network-based analysis may reveal proteins with potential to be used as a biomarker.

The lncRNA XIST regulates the tumorigenicity of renal cell carcinoma cells via the miR-302c/SDC1 axis

Long non-coding RNAs (LncRNAs) are thought to be involved in several biological processes in carcinomas. The aim of this study is to evaluate the roles of lncRNA-XIST in the tumorigenicity of renal cell carcinoma (RCC) cells via the miR-302c/SDC1 axis. In this study, the expression levels of miR-302c and XIST in RCC tissues and cells were analyzed by qRT-PCR. Cell proliferation was measured using MTT and colony formation assays, and cell apoptosis was detected using flow cytometry. The interaction between XIST and miR-302c was analyzed using a luciferase reporter gene assay. RCC tissues and cells exhibited decreased miR-302c expression and increased lncRNA-XIST expression. Furthermore, XIST negatively regulated miR-302c by directly binding regulatory sites in RCC cells. In addition, XIST silencing with siRNAs significantly inhibited the proliferation and promoted the apoptosis of 786-O and Caki-1 cells. Knockdown of Syndecan-1 (SDC1), a miR-302c target gene, yielded similar results as XIST silencing. In summary, XIST regulated the development and progression of RCC by inhibiting the miR302c/SDC1 axis.

MicroRNA-146b: A Novel Biomarker and Therapeutic Target for Human Papillary Thyroid Cancer

Papillary thyroid cancer (PTC) is the most common tumor subtype of thyroid cancer. However, not all PTCs are responsive to current surgical and radioiodine treatment. The well-established clinical prognostic factors include tumor size, lymph node/distal metastasis, and extrathyroidal invasion. The RET/PTC-RAS-BRAF linear molecular signaling cascade is known to mediate PTC pathogenesis. However, whether presence of BRAF mutation, the most common genetic alteration in PTC, can affect PTC behavior and prognosis is controversial. MicroRNAs (miRNAs) have been labeled as promising molecular prognostic markers in several tumor types. Our recent studies demonstrated that microRNA-146b (miR-146b) deregulation is associated with PTC aggressiveness and prognosis. Here we summarize the current knowledge related to the functional roles, regulated target genes, and clinical applications of miR-146b in PTC and discuss how these studies provide insights into the key role of miR-146b as an oncogenic regulator promoting cellular transformation as well as a prognosis marker for tumor recurrence in PTC. In conjunction with the current perspectives on miRNAs in a wide variety of human cancers, this review will hopefully translate these updated findings on miR-146b into more comprehensive diagnostic or prognostic information regarding treatment in PTC patients before surgical intervention and follow up strategies.

Nodular thyroid disease in the elderly: novel molecular approaches for the diagnosis of malignancy

Epithelial thyroid cancers (TC) comprise two differentiated histotypes (DTC), the papillary (PTC) and the follicular (FTC) thyroid carcinomas which, following dedifferentiation, are assumed to give rise to the poorly differentiated thyroid carcinomas and the rare, but highly aggressive and invariably fatal, anaplastic thyroid carcinomas. Although thyroid cancer mortality has not been changed, its annual incidence has increased over the last two decades, mainly because of the improved ability to diagnose malignant transformation in small non-palpable thyroid nodules. Despite DTC patients have a favorable prognosis, aggressive disease is more frequently observed in the elderly showing a higher disease-specific mortality. Of relevance is the high prevalence of nodular thyroid disease in aged patients being higher than 90%, in women older than 60 year, and 60% in men older than 80 year. This implies a careful evaluation of thyroid nodules in this group of patients in order to exclude malignancy. In fact, despite the tremendous progress in the comprehension of the underlying molecular mechanisms deregulated in DTC progression, several aspects of their clinical management remain to be solved and novel diagnostic strategies are sorely needed. Here, we will attempt to review new molecular approaches, which are currently being exploited in order to ameliorate the diagnosis of thyroid nodules.

The role of miRNAs in the evaluation of follicular thyroid neoplasms: an overview of literature

MicroRNA (miRNA) deregulation has been frequently associated with different human cancers. Not only have miRNAs been involved in almost every cellular function but they have also been linked with a significant number of cancers including thyroid carcinomas. Specifically, thyroid tumors encompass several different miRNA profiles based on the histotypes. Furthermore, thyroid lesions with their broad spectrum of neoplasms (from benign to malignant entities) offer the possibility of studying and recognizing specific subsets of different up-and downregulated miRNAs in each different entity. To date, the majority of authors completed their evaluation mostly by including histologic samples of thyroid tumors. Nonetheless, in the last years, a few studies are focusing on the role of miRNA expression in thyroid fine-needle aspiration cytology (FNAC) regardless of the cytologic preparation, including liquid-based cytology. This growing interest is driven by the possible role of miRNAs in the malignant risk stratification, especially for the indeterminate categories of follicular neoplasms (FNs). In this review we overview the reliability of analyzing miRNAs on thyroid lesions, including those diagnosed as FNs, to identify whether their profiles are likely to distinguish benign from malignant lesions, providing a predictive molecular diagnosis on FNAC.

Cytopathology of Follicular Cell Nodules

The detection of thyroid nodules, consisting of different diseases, represents a common finding in population. Their evaluation and diagnosis are mostly achieved with fine-needle aspiration cytology (FNAC). Even though the majority of thyroid nodules are correctly diagnosed, a total of 25% to 30% of them are classified "indeterminate" comprising lesions with varying risk of malignancy and different types of management. Although the number of thyroid FNACs, including small lesions, is increasing due to the reliance upon sonographic and cytologic interpretations, there are issues concerning cytomorphologic interpretation and interobserver reproducibility. Different classification systems have tried to better define the criteria for inclusion in specific categories and to therefore reduce the rate of indeterminate diagnoses such as atypia of undetermined significance, follicular neoplasms, and suspicious for malignancy. However, the support of ancillary techniques (eg, immunocytochemistry and molecular analysis) are reshaping morphologic diagnoses made on materials obtained from FNAC.

The evaluation of miRNAs on thyroid FNAC: the promising role of miR-375 in follicular neoplasms

Fine needle aspiration cytology (FNAC) plays an essential role in the evaluation of thyroid nodules especially for the category of follicular neoplasms (FN) representing 25 % of all thyroid cases including different neoplastic entities. Hence, one of the most promising areas is the application of molecular tests to FNAC. Among them, microRNAs (miRNA),identified as negative (post-transcriptional) gene expression regulators involved in tumor development, are likely to discriminate among FNs. Limited data explored the use of miRNAs on FNAC as well as their role in the malignant risk stratification. We aimed to define whether liquid-based cytology (LBC) is a valid method for miRNA evaluation. From June 2014 to March 2015, we enrolled 27FNs with histological follow-up. In the same reference period, 13 benign nodules (BN) and 20 positive for malignancy (PM) were selected as controls. Histologically, FNs resulted in 14 malignancies (3 papillary thyroid carcinoma-PTC and 11 follicular variant of PTC-FVPC) and 13 follicular adenomas (FA). The 20 PMs included two FVPC, 16 PTC and two medullary thyroid carcinoma (MTC). Five miRNAs (10b, 92a, 221/222 cluster, and 375) were studied on LBC and quantified by real-time PCR. Only miR-375 was over-expressed in the FNs diagnosed as carcinomas and in the PMs. A cut-off of 12 miR-375/U6 relative ratio recognized all BNs and 95 % PMs. Specifically, in each category, FVPCs and PTCs did not show any difference while MTCs had the highest value. miR-375 shows 97.1 % sensitivity, 100 % specificity, 96.3 % negative predictive value (NPV), 100 % positive predictive value (PPV), and 98.3 % diagnostic accuracy. LBC is suitable for miRNAs evaluation. miR-375 resulted over-expressed in all malignant FNs and 95 % PMs. It may represent a valid aid in ruling out BNs and supporting PTCs and/or FVPCs.

Multicentre validation of a microRNA-based assay for diagnosing indeterminate thyroid nodules utilising fine needle aspirate smears

AIMS

The distinction between benign and malignant thyroid nodules has important therapeutic implications. Our objective was to develop an assay that could classify indeterminate thyroid nodules as benign or suspicious, using routinely prepared fine needle aspirate (FNA) cytology smears.

METHODS

A training set of 375 FNA smears was used to develop the microRNA-based assay, which was validated using a blinded, multicentre, retrospective cohort of 201 smears. Final diagnosis of the validation samples was determined based on corresponding surgical specimens, reviewed by the contributing institute pathologist and two independent pathologists. Validation samples were from adult patients (≥18 years) with nodule size >0.5 cm, and a final diagnosis confirmed by at least one of the two blinded, independent pathologists. The developed assay, RosettaGX Reveal, differentiates benign from malignant thyroid nodules, using quantitative RT-PCR.

RESULTS

Test performance on the 189 samples that passed quality control: negative predictive value: 91% (95% CI 84% to 96%); sensitivity: 85% (CI 74% to 93%); specificity: 72% (CI 63% to 79%). Performance for cases in which all three reviewing pathologists were in agreement regarding the final diagnosis (n=150): negative predictive value: 99% (CI 94% to 100%); sensitivity: 98% (CI 87% to 100%); specificity: 78% (CI 69% to 85%).

CONCLUSIONS

A novel assay utilising microRNA expression in cytology smears was developed. The assay distinguishes benign from malignant thyroid nodules using a single FNA stained smear, and does not require fresh tissue or special collection and shipment conditions. This assay offers a valuable tool for the preoperative classification of thyroid samples with indeterminate cytology.

Value of Molecular Tests in Cytologically Indeterminate Lesions of Thyroid

CONTEXT

Fine-needle aspiration has been the initial step in the workup of thyroid nodular lesions and has successfully reduced the number of unnecessary surgeries and improved preoperative malignancy detection. However, up to one-third of cases fall in the diagnostically "indeterminate group," which poses a patient-management challenge. objective: To review the characteristics of molecular tests useful for stratifying the malignancy risk of indeterminate thyroid lesions, including their advantages and limitations.

DATA SOURCES

PubMed.

CONCLUSIONS

Molecular tests are useful for triage of indeterminate thyroid nodules initially diagnosed by using fine-needle aspiration. Immunocytochemistry is readily available with the shortest turnaround time among the molecular tests but suffers from poor reproducibility and low interpretation concordance. Gene mutation analysis is superior in detecting malignancies as a rule-in test, despite low specificity. Next-generation sequencing seems promising but needs more validations before widespread use. Gene expression profiling is more suitable for detecting benign lesions as a rule-out test to avoid unnecessary surgeries but is not reliable in excluding malignancies. MicroRNA profiling has great potential for both risk stratification and predicting prognosis but is limited by significant variations in sensitivity and specificity. Although many questions still need to be answered, taken together, molecular tests are a promising option for classifying cytologically indeterminate thyroid nodular lesions.

MicroRNA Expression Profiles in Papillary Thyroid Carcinoma, Benign Thyroid Nodules and Healthy Controls

MicroRNAs (miRNAs) represent a class of short endogenous non-coding RNAs that negatively regulate gene expression at the post-transcriptional level in many biological processes, including proliferation, differentiation, stress response and apoptosis. In this study we analyzed a set of seven miRNA molecules in sera of patients with papillary thyroid cancer, multinodular goiter and healthy controls to identify miRNA molecules that may have utility as markers for PTC. MiR-21 serum levels in the preoperative PTC and MG groups were significantly higher than the control group. Likewise, postoperative levels of miR-151-5p, miR-221 and miR-222 were significantly lower in patients with PTC. When serum miRNA levels were evaluated according to stage, postoperative levels of miR-151-5p and miR-222 were significantly lower in patients with advanced stages of the disease. The miRNA levels were also found associated with the size of the primary tumor. Our data imply that specific miRNA molecules which are differentially expressed in thyroid tumors may play role in the development of papillary thyroid carcinoma.

Molecular Aberrance in Papillary Thyroid Microcarcinoma Bearing High Aggressiveness: Identifying a "Tibetan Mastiff Dog" From Puppies

Today the most common differentiated thyroid cancer in many countries is papillary thyroid microcarcinoma (PTMC). Although the majority of PTMCs exhibit an indolent clinical course, a few possess high risk for aggressiveness with tumor invasion, metastasis, and even patient mortality. This imposes significant confusion and often dilemma in the clinical management of PTMC. The present review summarizes the molecular pathogenesis, particularly the major genetic alterations, of PTMC that may have prognostic values in assisting risk stratification of this cancer and identification of the most aggressive cases from the many well-behaving cases. J. Cell. Biochem. 117: 1491-1496, 2016. © 2016 Wiley Periodicals, Inc.

Pathobiology of MicroRNAs and Their Emerging Role in Thyroid Fine-Needle Aspiration

OBJECTIVE

MicroRNAs (miRs) are noncoding, single-stranded regulatory RNA molecules involved in the posttranscriptional regulation of gene expression. They control the development and maintenance of the diverse cellular processes including proliferation, differentiation, motility and apoptosis. Expression of miRs is tissue-specific and each alteration of the tissue miR profile is associated with a distinct disease status.

STUDY DESIGN

We reviewed the literature on the expression of miRs in thyroid tumors, focusing on methodology and diagnostic and prognostic output. Separately, we analyzed 11 studies on miR profiles in thyroid cytological material.

RESULTS

Numerous studies have evaluated the miR profiles of thyroid tumors in an attempt to find a possible diagnostic and prognostic role. Both downregulation and upregulation of numerous miRs was found, but differences between the surgical pathology specimens and corresponding fine-needle aspirates in the expression of the same miRs were also reported.

CONCLUSIONS

The results from surgically resected material cannot be extrapolated into preoperative use without validation. For diagnostic use, the strong overlap between follicular adenoma and follicular carcinoma miR profiles is challenging. In summary, miR-221 and miR-222 are consistently upregulated in different types of thyroid carcinomas and might be used as markers of malignancy.

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.

MicroRNAs as a potential tool in the differential diagnosis of thyroid cancer: a systematic review and meta-analysis

OBJECTIVE

Thyroid cancer is the most common endocrine malignancy, and its incidence has been increasing over the last 30 years. Several studies have suggested that miRNAs may play a significant role in the differential diagnosis of indeterminate thyroid nodules. To systematically evaluate the utility of miRNAs in discriminating malignant thyroid nodules from benign ones on fine-needle aspiration biopsy (FNAB) samples, a systematic review and meta-analysis of the published literatures were carried out.

PATIENTS AND DESIGN

Three hundred and sixty-one samples, obtained from 341 patients, were included in the research, and summary sensitivities (SEN), specificities (SPE), positive likelihood ratios, negative likelihood ratios and diagnostic odds ratio were calculated. Then, summary receiver operating characteristic curves (SROCs) and areas under the SROC curves (AUCs) were calculated to further estimate the overall diagnostic value of miRNAs in thyroid cancer.

RESULTS

The overall pooled SEN, SPE and AUC are 0·75, 0·81 and 0·89, respectively. For multiple miRNAs assays, the pooled SEN, SPE and AUC are 0·87, 0·75 and 0·68, respectively. For single miRNA assays, the corresponding results are 0·71, 0·84 and 0·87, respectively. The corresponding statistical results for differentiating indeterminate FNAB samples are 0·92, 0·68 and 0·86, respectively.

CONCLUSION

Our current meta-analysis suggests that miRNAs may serve as a novel diagnostic tool in distinguishing malignant thyroid nodules from benign ones on FNAB specimens. In addition, subgroup analysis suggests that a panel of miRNAs may have a higher sensitivity but a relatively lower specificity than that of single miRNA in distinguishing thyroid nodules.

The management of thyroid nodules and cancer in the molecular era

The incidence of thyroid cancer is increasing worldwide. Current standards in the diagnosis and management of thyroid cancer are limited by the uncertainty of fine-needle aspiration samples that are indeterminate in nature. Molecular markers have the potential to improve the accuracy of thyroid fine-needle aspiration and to aid the physician in giving a more accurate diagnosis and prognosis. This paper summarizes the various molecular markers currently available.

Evaluation and management of thyroid nodules with atypia/follicular lesion of undetermined significance on fine-needle aspiration

Since the introduction of the Bethesda System for Reporting Thyroid Cytopathology in 2008, the management of thyroid nodules has become more standardized, with clearly defined algorithms based on risk of malignancy for each of the six cytologic categories. However, the management of a thyroid nodule with a fine-needle aspiration biopsy classified as Bethesda III, or atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS), remains controversial due to the cytologic heterogeneity and the variability in the reported rates of malignancy. In this review, the history and rationale for the new Bethesda III category is examined, the reported incidence and risk of malignancy from published studies is reviewed and recommendations for management of patients with a thyroid nodule and AUS/FLUS are provided. Recent advances in molecular analysis and their role in the evaluation of patients with AUS/FLUS are also discussed.

The utility of molecular markers in pre-operative assessment of thyroid nodules

The pre-operative diagnosis of thyroid tumors is determined by gold standard fine needle aspiration (FNA) biopsy. This has been widely accepted and offers the most cost-effective approach for evaluation of thyroid nodules. However, its diagnostic accuracy can pose a challenging scenario to surgeons. These diagnostic difficulties may subject patients to unnecessary thyroidectomies for benign thyroid nodules. Thus, additional molecular tests are needed to improve the sensitivity and specificity of FNA. The role of molecular markers is being proposed to predict the type and risk of malignancy to abate the need for diagnostic thyroidectomies. This review discusses their utility and validity in pre-operative diagnosis of thyroid nodules and how these markers can enhance the accuracy of FNA cytology.

Molecular Assays in Cytopathology for Thyroid Cancer

Background

Despite lack of adequate, validated, independently performed clinical studies, several molecular tests are commercially available on the market and are being used on indeterminate thyroid nodules to guide patient-care decisions.

Methods

We summarize the current evidence on the role and limitations of molecular tests used in combination with thyroid cytopathology to refine the presurgical diagnosis of thyroid nodules.

Results

The clinical performance of molecular tests depends on the pretest risk of malignancy within the specific cytological group being assessed. This risk is variable and should be assessed at each institution to optimize the selection of the molecular test and the interpretation of its results. Next-generation sequencing has increased the sensitivity of oncogene panels while maintaining high specificity. Tests assessing the gene expression pattern have shown promising results, with high sensitivity but low specificity. The impacts of molecular markers on clinical practice remains in flux and their effect on health care costs remains poorly understood.

Conclusions

Further large, independent, confirmatory, clinical validation studies and real-world, cost-effectiveness studies are necessary before the widespread adoption of these tests can be endorsed as standard of care.

Differential expression profiling of circulation microRNAs in PTC patients with non-131I and 131I-avid lungs metastases: a pilot study

INTRODUCTION

Loss of the ability to concentrate (131)I is one of the important causes of radioiodine-refractory disease in papillary thyroid carcinoma (PTC). Recent advantages of serum microRNAs (miRNAs) open a new realm of possibilities for noninvasive diagnosis and prognosis of many cancers. The aim of the current study was to identify differential expression profiling of circulation miRNAs in PTC patients with non-(131)I and (131)I-avid lungs metastases.

METHODS

The expressions of miRNAs were examined using miRNA microarray chip. The most significantly changed miRNAs from microarray were verified by using qRT-PCR. The potential miRNAs regulating target genes and their preliminary biological functions were forecasted by Bioinformatic analysis.

RESULTS

Compared to (131)I-avid lung metastases, 13 kinds of significantly differential serum miRNAs including 5 upregulated miRNAs (miR-1249, miR-106a, miR-503, miR-34c-5p, miR-1281) and 8 downregulated miRNAs (miR-1915, miR-2861, miR-3196, miR-500, miR-572, miR-33b, miR-554, miR-18a) in PTC patients with non-(131) I-avid lung metastases were identified. Bioinformatic analysis demonstrated that miR-106a was the core miRNA regulating 193 genes in the network. The results of validation confirmed the up-regulation of miR-106a in non-(131)I-avid lungs metastatic PTC patients.

CONCLUSION

Differentially expressed serum miRNA profiles between PTC patients with non-(131)I and (131)I-avid lungs metastases were analyzed. These findings in our present study could represent new clues for the diagnostic and therapeutic strategy in PTC patients with non-(131)I-avid metastatic disease.

MicroRNA expression profiles in the management of papillary thyroid cancer

Papillary thyroid cancer (PTC) is the major contributor to the dramatically increasing incidence of thyroid cancer. Low-risk PTC shows the most rapid rate of increase because of changing trends in neck imaging and the use of fine needle aspiration to investigate thyroid nodules. The need for a paradigm shift in the management of these patients, to provide personalized treatment and surveillance plans, has led to the focus on molecular biomarker research. MicroRNAs (miRNAs) compose a class of molecules with promising applications for every stage of PTC management, including diagnosis, prognosis, treatment, and surveillance. Although most of the miRNA studies are currently preclinical, given the rapid progress of scientific discovery, clinical trials will not be far away. Thyroid clinicians will be expected to have good insights into the current status of PTC-related molecular translational research. This article focuses on the potential roles of miRNA in PTC management in the context of contemporary recommended clinical practice.

Thyroid atypia of undetermined significance or follicular lesion of undetermined significance: an indispensable Bethesda 2010 diagnostic category or waste garbage?

OBJECTIVE

The Bethesda System for Reporting Thyroid Cytopathology (BSRTC) was introduced in thyroid cytology in 2007 and is now generally accepted. BSRTC categories include a morphologic description and risk of malignancy as well as follow-up suggestions in each group. However, the category entitled 'atypia of undetermined significance or follicular lesion of undetermined significance' (AUS/FLUS) is problematic. This category is heterogeneous and has been overused so far.

STUDY DESIGN

Twenty-six studies were included in a meta-analysis. In addition to AUS/FLUS percentage, we analysed repeated AUS/FLUS percentage, cytological and histological correlations, and risk of malignancy and neoplasm for AUS/FLUS. Furthermore, stratification, inter- and intra-observer variability, and the possibility of a switch to another category and its clinical consequences were reviewed.

RESULTS

Out of a total of 81,833 cases, AUS/FLUS accounted for 10.9%, with a 34% risk of malignancy. Persistent AUS/FLUS was found in 21.6% in repeated cytology. Cytohistological correlation was analysed from 16 studies (4,964 cases), revealing 10.4% as AUS/FLUS and a 21.5% risk of malignancy.

CONCLUSIONS

An AUS/FLUS category seems to be currently reasonable with clearly defined cytomorphological criteria which do not correspond unequivocally with those of the other categories. An AUS/FLUS category is justified and possible means of its improvement with immunohistochemistry, molecular analysis and imaging are discussed.

MiR-302c inhibits tumor growth of hepatocellular carcinoma by suppressing the endothelial-mesenchymal transition of endothelial cells

Endothelial cells (ECs) are critical for angiogenesis, and microRNA plays important roles in this process. In this study, we investigated the function and mechanism of miR-302c in the process of endothelial-mesenchymal transition (EndMT) in ECs. When miR-302c was overexpressed in HUVECs, the motility of the HUVECs was weakened; the expression levels of EndMT markers were also changed: vascular endothelial (VE)-cadherin was up-regulated, whereas β-catenin, FSP1, and α-SMA were down-regulated. Further in vivo and in vitro experiments showed that the growth of HCC was inhibited when co-cultured or co-injected with HUVECs overexpressing miR-302c. On the contrary, when miR-302c was suppressed in HUVECs, the opposite results were observed. Reporter assays showed that miR-302c inhibited metadherin (MTDH) expression through directly binding to its 3'UTR. In addition, compared to ECs isolated from normal liver tissues of HCC patients, ECs isolated from tumor tissues expressed markedly low levels of miR-302c but high levels of MTDH. These results suggest that EC-specific miR-302c suppresses tumor growth in HCC through MTDH-mediated inhibition of EndMT. MTDH and miR-302c might provide a new strategy for anti-angiogenic therapy in HCC.

Molecular diagnostics for thyroid nodules: the current state of affairs

Molecular diagnostics offers great promise for the evaluation of cytologically indeterminate thyroid nodules. Numerous molecular genetic and immunohistochemical tests have been developed that may be performed on thyroid specimens obtained during standard fine-needle aspiration, some of which may greatly improve diagnostic yield. A sound understanding of the diagnostic performance of these tests, and how they can enhance clinical practice, is important. This article reviews the diagnostic utility of immunohistochemical and molecular testing for the clinical assessment of thyroid nodules, and makes recommendations about how these tests can be integrated into clinical practice for patients with cytologically indeterminate thyroid nodules.

Differential miRNA expression defines migration and reduced apoptosis in follicular thyroid carcinomas

The objective of the study was to identify microRNAs (miRs) characteristic for follicular thyroid carcinoma (FTC) and to define their role in tumorigenesis. A miR-microarray study was conducted to identify miRs differentially expressed between FTCs and their surrounding tissues. Selection was further reinforced by a literature review. Four miRs were selected and confirmed by RT-qPCR: miR-146b, -183, -221 were up-regulated, whereas miR-199b down-regulated in FTCs. The influence of these miRs on cell proliferation, cell cycle, apoptosis and migration was studied in HTori and FTC-133 cells. Functional characterization suggests an impact of miR-183 and miR-146b in FTC development. Overexpression of both miRs significantly induces migration. Moreover, overexpression of miR-183 significantly represses apoptosis. MiR-199b and -221 do not have significant effects on proliferation, cell cycle, apoptosis or migration in HTori and FTC-133 cells. Our data suggest that miR-146b and miR-183 may influence FTC development through the induction of migration and apoptosis inhibition.

Tyrosine kinase inhibitor treatments in patients with metastatic thyroid carcinomas: a retrospective study of the TUTHYREF network

OBJECTIVE

Tyrosine kinase inhibitors (TKIs) are used to treat patients with advanced thyroid cancers. We retrospectively investigated the efficacy of TKIs administered outside of clinical trials in metastatic sites or locally advanced thyroid cancer patients from five French oncology centers.

DESIGN AND METHODS

THERE WERE 62 PATIENTS (37 MEN, MEAN AGE: 61 years) treated with sorafenib (62%), sunitinib (22%), and vandetanib (16%) outside of clinical trials; 22 had papillary, five had follicular, five had Hürthle cell, 13 had poorly differentiated, and 17 had medullary thyroid carcinoma (MTC). Thirty-three, 25, and four patients were treated with one, two, and three lines of TKIs respectively. Primary endpoints were objective tumor response rate and progression-free survival (PFS). Sequential treatments and tumor response according to metastatic sites were secondary endpoints.

RESULTS

Among the 39 sorafenib and 12 sunitinib treatments in differentiated thyroid carcinoma (DTC) patients, partial response (PR) rate was 15 and 8% respectively. In the 11 MTC patients treated with vandetanib, 36% had PR. Median PFS was similar in second-line compared with first-line sorafenib or sunitinib therapy (6.7 vs 7.0 months) in DTC patients, but there was no PR with second- and third-line treatments. Bone and pleural lesions were the most refractory sites to treatment.

CONCLUSIONS

This is the largest retrospective study evaluating TKI therapies outside of clinical trials. DTC patients treated with second-line therapy had stable disease as best response, but had a similar median PFS compared with the first-line treatment.