Diagnostic value of microRNAs in discriminating malignant thyroid nodules from benign ones on fine-needle aspiration samples

A Scoping Review of Patient Health-Related Quality of Life Following Surgery or Molecular Testing for Individuals with Indeterminate Thyroid Nodules

BACKGROUND

Molecular testing can reduce the need for diagnostic thyroidectomy in cytologically indeterminate thyroid nodules. However, the health-related quality of life in patients managed with molecular testing is not well studied.

OBJECTIVE

The objective of this scoping review was to identify and analyze the health-related quality of life outcomes in patients with indeterminate thyroid nodules who are expected to undergo or have undergone surgery or molecular testing.

METHODS

A comprehensive search was conducted on PubMed, Scopus, PsychINFO, and Embase to identify relevant studies. The search terms included "thyroid neoplasms" or "thyroid nodule" and "molecular testing" or "surgery" and "quality of life". The included articles were analyzed for their main study objective, study design, participant characteristics, and main results.

RESULTS

Eight studies were included in this scoping review. Four evaluated the quality-adjusted life years for patients with indeterminate thyroid nodules. Three of these studies found that molecular testing slightly improved quality-adjusted life years compared to surgery, while one study found no difference. Two studies assessed surgical health-related quality of life outcomes and reported that patients with indeterminate thyroid nodules who were expected to undergo surgery favored surgical procedures, while those who underwent surgery experienced impaired health-related quality of life. Two studies evaluated molecular testing in patients with indeterminate thyroid nodules and found that the final molecular test result significantly impacted health-related quality of life outcomes. Patients with suspicious/positive molecular test results had worse symptoms of goiter, anxiety, and depression, while those with benign results had preserved health-related quality of life scores. Patients with benign results from molecular testing experience better health-related quality of life within the first year compared to those with benign surgical outcomes.

CONCLUSIONS

This scoping review highlights the importance of considering health-related quality of life outcomes in the management of patients with indeterminate thyroid nodules. Benign molecular testing results yield better quality of life than benign surgical outcomes within the first year, suggesting molecular testing as a preferable option. Further research comparing the impact of surgery and molecular testing on health-related quality of life is needed to improve shared decision-making and patient outcomes.

High expression of RNF169 is associated with poor prognosis in pancreatic adenocarcinoma by regulating tumour immune infiltration

Background: Pancreatic adenocarcinoma (PAAD) is a highly deadly and aggressive tumour with a poor prognosis. However, the prognostic value of RNF169 and its related mechanisms in PAAD have not been elucidated. In this study, we aimed to explore prognosis-related genes, especially RNF169 in PAAD and to identify novel potential prognostic predictors of PAAD. Methods: The GEPIA and UALCAN databases were used to investigate the expression and prognostic value of RNF169 in PAAD. The correlation between RNF169 expression and immune infiltration was determined by using TIMER and TISIDB. Correlation analysis with starBase was performed to identify a potential regulatory axis of lncRNA-miRNA-RNF169. Results: The data showed that the level of RNF169 mRNA expression in PAAD tissues was higher than that in normal tissues. High RNF169 expression was correlated with poor prognosis in PAAD. In addition, analysis with the TISIDB and TIMER databases revealed that RNF169 expression was positively correlated with tumour immune infiltration in PAAD. Correlation analysis suggested that the long non-coding RNA (lncRNA) AL049555.1 and the microRNA (miRNA) hsa-miR-324-5p were involved in the expression of RNF169, composing a potential regulatory axis to control the progression of PAAD. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses indicated that RNF169 plays a role in PAAD through pathways such as TNF, Hippo, JAK-STAT and Toll-like receptor signaling. Conclusion: In summary, the upregulation of RNF169 expression mediated by ncRNAs might influence immune cell infiltration in the microenvironment; thus, it can be used as a prognostic biomarker and a potential therapeutic target in PAAD.

Molecular Characterization of Thyroid Follicular Lesions in the Era of "Next-Generation" Techniques

It is unequivocally recognized that thyroid nodules are frequently detected in the adult population and mostly characterized by benign lesions (up to 70% of them), with only 5%-15% malignant lesions. The evaluation of thyroid lesions with fine-needle aspiration cytology (FNAC) represents one of the first and most useful diagnostic tools in the definition of their nature. Despite the fact that the majority of thyroid lesions are correctly diagnosed as either benign (70%-75%) or malignant (5%-10%) entities, the remaining nodules (20%-25%) represent the "gray zone" of follicular lesions, which belong to indeterminate categories, according to the different classification systems. This indeterminate group of lesions includes both benign and malignant entities, which cannot be easily discriminate with morphology alone. In these last decades, the increasing role of molecular testings, feasibly performed on cytological material combined with the discoveries of specific genetic alterations in the field of thyroid pathology, has opened the pace to their more accurate and specific contribution on cytology. In fact, in 2015, in the revised management guidelines for patients with thyroid nodules and well-differentiated thyroid cancers (WDTCs), the American Thyroid Association (ATA) confirmed the performance of molecular testing in thyroid indeterminate cytology, and the same performance was addressed in recent update of the management of thyroid nodules in the second edition of the Bethesda system for reporting thyroid cytopathology (TBSRTC). In the current review, we discuss the role of molecular tests for the different thyroid diagnostic categories of the Bethesda system for reporting thyroid cytopathology, mostly focusing our attention on the follicular and indeterminate lesions.

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.

Identification of Potential lncRNAs and miRNAs as Diagnostic Biomarkers for Papillary Thyroid Carcinoma Based on Machine Learning

BACKGROUND

Papillary thyroid carcinoma (PTC) accounts for most of the proportion of thyroid cancer (TC). The objective of this study was to identify diagnostic, differentially expressed long noncoding RNAs (lncRNAs) and microRNAs (miRNAs), contributing to understanding the epigenetics mechanism of PTC.

METHODS

The data of lncRNA, miRNA, and mRNA were downloaded from the Cancer Genome Atlas (TCGA) dataset, followed by functional analysis of differentially expressed mRNAs. Optimal diagnostic lncRNA and miRNA biomarkers were identified via random forest. The regulatory network between optimal diagnostic lncRNA and mRNAs and optimal diagnostic miRNA and mRNAs was identified, followed by the construction of ceRNA network of lncRNA-mRNA-miRNA. Expression validation and diagnostic analysis of lncRNAs, miRNAs, and mRNAs were performed. Overexpression of ADD3-AS1 was performed in PTC-UC3 cell lines, and cell proliferation and invasion assay were used for investigating the role of ADD3-AS1 in PTC.

RESULTS

A total of 107 differentially expressed lncRNAs, 81 differentially expressed miRNAs, and 515 differentially expressed mRNAs were identified. 11 lncRNAs and 6 miRNAs were regarded as the optimal diagnostic biomarkers for PTC. The epigenetic modifications via the above diagnostic lncRNAs and miRNAs were identified, including MIR181A2HG-FOXP2-hsa-miR-146b-3p, BLACAT1/ST7-AS1-RPS6KA5-hsa-miR-34a-5p, LBX2-AS1/MIR100HG-CDHR3-hsa-miR-34a-5p, ADD3-AS1-PTPRE-hsa-miR-9-5p, ADD3-AS1-TGFBR1-hsa-miR-214-3p, LINC00506-MMRN1-hsa-miR-4709-3p, and LOC339059-STK32A-hsa-miR-199b-5p. In the functional analysis, MMRN1 and TGFBR1 were involved in cell adhesion and endothelial cell migration, respectively. Overexpression of ADD3-AS1 inhibited cell growth and invasion in PTC cell lines.

CONCLUSION

The identified lncRNAs/miRNAs/mRNA were differentially expressed between normal and cancerous tissues. In addition, identified altered lncRNAs and miRNAs may be potential diagnostic biomarkers for PTC. Additionally, epigenetic modifications via the above lncRNAs and miRNAs may be involved in tumorigenesis of PTC.

miR‑592 acts as an oncogene and promotes medullary thyroid cancer tumorigenesis by targeting cyclin‑dependent kinase 8

Medullary thyroid carcinoma (MTC) is a relatively rare subtype of thyroid cancer, accounting for 5‑10% of all cases of thyroid cancer worldwide. Due to the current lack of knowledge regarding the tumorigenesis of MTC, the clinical treatment of MTC remains a challenge. It has been reported that microRNAs (miRNAs) regulate the progression of MTC; however, the regulatory network of miRNAs and the exact underlying mechanisms are not completely understood. In the present study, an miRNA expression profile (GSE40807), consisting of 80 samples, was downloaded and analyzed using Gene Expression Omnibus‑2R to identify differentially expressed miRNAs between MTC and normal samples. miR‑592 expression levels were significantly increased in MTC tissues and cell lines compared with normal tissues and cell lines. Patients with high miR‑592 expression levels exhibited a less favorable prognosis compared with patients with low miR‑592 expression. The results suggested that miR‑592 overexpression promoted TT and MZ‑CRC‑1 cell proliferation in vitro. In addition, miR‑592 negatively regulated cyclin‑dependent kinase 8 (CDK8) via targeted binding in MTC cells. Moreover, co‑transfection of CDK8 overexpression plasmid and miR‑592 mimic reversed miR‑592‑mediated MTC cell proliferation. In conclusion, miR‑592 may serve as an oncogene in MTC by decreasing the expression of CDK8, indicating that the miR‑592/CDK8 axis might serve as a promising therapeutic target for MTC.

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.

Blood circulating miRNAs as biomarkers of Alzheimer's disease: a systematic review and meta-analysis

Aim: It is already known that miRNAs can be differentially expressed in Alzheimer's disease (AD). We aimed to evaluate the performance of miRNAs from blood as potential biomarkers for AD. Materials & methods: MEDLINE, PubMed and Embase were searched for studies about peripheral blood miRNAs that could discriminate patients with AD from cognitively normal controls. The data regarding the specificity and sensitivity were extracted. STATA 14.0 was used to analyze the data. Results: Ten studies containing 770 AD and 664 normal controls. The analysis showed that miRNAs presented excellent diagnostic performance and the overall sensitivity was 0.80 (95% CI: 0.75-0.83), specificity was 0.83 (95% CI: 0.78-0.87) and diagnostic odds ratio was 14 (95% CI: 11-19). Subgroup analysis suggested that the Caucasian group and blood group showed a better performance in AD diagnosis and the diagnostic odds ratio was 42 and 34, respectively. Conclusion: This meta-analysis showed that miRNAs may be a promising biomarkers for AD.

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.

Current methodologies for molecular screening of thyroid nodules

Several molecular tests have been developed for thyroid cytology with the main purpose to define the nature of indeterminate nodules in presurgical phase thus overcoming the limitations of cytological analysis. Molecular tests currently available for thyroid nodules are based on a variety of methodologies and display peculiar strengths and limitations: in this review of the literature they are summarized and critically discussed. The use of molecular diagnostics for thyroid cytology is increasingly widespread and accepted, however large, prospective validation studies are still needed to ultimately demonstrate the clinical efficacy of a wide incorporation of molecular tests into clinical practice.

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.

miRNA expression and function in thyroid carcinomas: a comparative and critical analysis and a model for other cancers

As in many cancer types, miRNA expression profiles and functions have become an important field of research on non-medullary thyroid carcinomas, the most common endocrine cancers. This could lead to the establishment of new diagnostic tests and new cancer therapies. However, different studies showed important variations in their research strategies and results. In addition, the action of miRNAs is poorly considered as a whole because of the use of underlying dogmatic truncated concepts. These lead to discrepancies and limits rarely considered. Recently, this field has been enlarged by new miRNA functional and expression studies. Moreover, studies using next generation sequencing give a new view of general miRNA differential expression profiles of papillary thyroid carcinoma. We analyzed in detail this literature from both physiological and differential expression points of view. Based on explicit examples, we reviewed the progresses but also the discrepancies and limits trying to provide a critical approach of where this literature may lead. We also provide recommendations for future studies. The conclusions of this systematic analysis could be extended to other cancer types.

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.

MiR-324-5p assists ultrasonography in predicting lymph node metastasis of unifocal papillary thyroid microcarcinoma without extracapsular spread

Ultrasonography is the first choice of lymph node metastasis (LNM) detection which is crucial for therapeutic options of papillary thyroid cancer (PTC). However, the sensitivity of ultrasonography in detecting LNM of PTC is relatively low; especially in central LNM. MiR-324-5p has been reported to play important roles in the metastasis of various cancers. To explore the relationship between miR-324-5p and LNM in PTC, quantitative real-time polymerase chain reaction was performed in PTC tissue and fine needle aspiration (FNA) washout successively. Its correlation with LNM of PTC was analyzed. The clinicopathological and sonographic factors relating to LNM were also studied. Additionally, the function assay of miR-324-5p in PTC cells was conducted. Current study demonstrated that age was an independent protective factor and multifocality, advanced TNM stage, increased transverse diameter of thyroid nodule, ultrasound suspected LNM were independent risk factors of LNM. MiR-324-5p promoted proliferation, migration and invasion of PTC cell line. MiR-324-5p could serve as a candidate predictor along with ultrasonography in predicting LNM, especially central LNM of unifocal papillary thyroid microcarcinoma without extracapsular spread.

Diagnostic accuracy of ELISA for detecting serum Midkine in cancer patients

Midkine (MK) has been reported as the potential novel diagnostic biomarker for cancer in several studies, but their results were controversial. Therefore, we performed a diagnostic meta-analysis to assess the diagnostic value of serum MK in cancer patients. A systematic electronic and manual search was performed for relevant literatures through several databases up to June 1, 2017. The quality of the studies included in the meta-analysis was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. All analyses were conducted using stata12.0 software. Ten studies collectively included 1119 cancer patients and 1441 controls met the eligible criteria. The summary estimates were: sensitivity 0.78 (95% CI = 0.68-0.85), specificity 0.83 (95% CI = 0.72-0.90), positive likelihood ratio 4,54 (95% CI = 2.64-7.80), negative likelihood 0.27 (95% CI = 0.18-0.40), diagnostic odds ratio 16.79 (95% CI = 7.17-39.33), and area under the curve 0.87 (95% CI = 0.84-0.89). Publication bias was suggested by Deeks' funnel plot asymmetry test (P = 0.92). According to our results, serum MK has greater diagnostic value in diagnosing cancer, however, more reliable studies in larger cohort should be conducted to evaluate the diagnostic accuracy of serum MK.

Systematic reviews of diagnostic tests in endocrinology: an audit of methods, reporting, and performance

BACKGROUND

Systematic reviews provide clinicians and policymakers estimates of diagnostic test accuracy and their usefulness in clinical practice. We identified all available systematic reviews of diagnosis in endocrinology, summarized the diagnostic accuracy of the tests included, and assessed the credibility and clinical usefulness of the methods and reporting.

METHODS

We searched Ovid MEDLINE, EMBASE, and Cochrane CENTRAL from inception to December 2015 for systematic reviews and meta-analyses reporting accuracy measures of diagnostic tests in endocrinology. Experienced reviewers independently screened for eligible studies and collected data. We summarized the results, methods, and reporting of the reviews. We performed subgroup analyses to categorize diagnostic tests as most useful based on their accuracy.

RESULTS

We identified 84 systematic reviews; half of the tests included were classified as helpful when positive, one-fourth as helpful when negative. Most authors adequately reported how studies were identified and selected and how their trustworthiness (risk of bias) was judged. Only one in three reviews, however, reported an overall judgment about trustworthiness and one in five reported using adequate meta-analytic methods. One in four reported contacting authors for further information and about half included only patients with diagnostic uncertainty.

CONCLUSION

Up to half of the diagnostic endocrine tests in which the likelihood ratio was calculated or provided are likely to be helpful in practice when positive as are one-quarter when negative. Most diagnostic systematic reviews in endocrine lack methodological rigor, protection against bias, and offer limited credibility. Substantial efforts, therefore, seem necessary to improve the quality of diagnostic systematic reviews in endocrinology.

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.

Plasma exosomal miR-21 and miR-181a differentiates follicular from papillary thyroid cancer

Thyroid cancer (TC) is the most common endocrine malignancy and its incidence has increased over the last few decades. As has been revealed by a number of studies, TC tissue's micro-RNA (miRNA) profile may reflect histological features and the clinical behavior of tumor. However, alteration of the miRNA profile of plasma exosomes associated with TC development has to date not been explored. We isolated exosomes from plasma and assayed their characteristics using laser diffraction particle size analysis, atomic force microscopy, and western blotting. Next, we profiled cancer-associated miRNAs in plasma exosomes obtained from papillary TC patients, before and after surgical removal of the tumor. The diagnostic value of selected miRNAs was evaluated in a large cohort of patients displaying different statuses of thyroid nodule disease. MiRNA assessment was performed by RT-qPCR. In total, 60 patients with different types of thyroid nodal pathology were included in the study. Our results revealed that the development of papillary TC is associated with specific changes in exosomal miRNA profiles; this phenomenon can be used for differential diagnostics. MiRNA-31 was found to be over-represented in the plasma exosomes of patients with papillary TC vs. benign tumors, while miRNA-21 helped to distinguish between benign tumors and follicular TC. MiRNA-21 and MiRNA-181a-5p were found to be expressed reciprocally in the exosomes of patients with papillary and follicular TC, and their comparative assessment may help to distinguish between these types of TC with 100 % sensitivity and 77 % specificity.

The diagnostic and prognostic role of liquid-based cytology: are we ready to monitor therapy and resistance?

Here, we evaluate the diagnostic and prognostic role of liquid-based cytology (LBC) in different body lesions, including thyroid, lung, effusions and malignant breast lesions. LBC has gained consensus after being applied to both non-gynecologic and fine-needle aspiration cytology. Although some remain sceptical regarding the diagnostic efficacy of LBC, mainly when used alone, in recent years, good results have been obtained as long as it showed a high diagnostic accuracy. Here, we discuss the additional possibility of storing material for the application of ancillary techniques (immunocytochemistry-molecular analysis) with several diagnostic and prognostic advantages, which may pave the way for the challenging evaluation of both monitoring responses to treatment and resistance to targeted therapies in thyroid, lung, breast carcinoma or malignant effusions. Furthermore, it provides the use of several molecular spots as specific targets for personalized therapy.

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.

MicroRNA-17 family as novel biomarkers for cancer diagnosis: a meta-analysis based on 19 articles

Cancer remains as the leading cause of death all over the world due to the lack of efficient diagnostic techniques and therapeutic methods. Many studies have reported the potential diagnostic value of microRNA-17 (miRNA-17, miR-17) family members as biomarkers for cancer detection. However, inconsistent results were revealed from a wide range of studies. As a result of this, a meta-analysis based on 19 studies was conducted to assess the diagnostic performance of miR-17 family for cancer detection. A total of 1772 patients with certain types of cancer and 1320 healthy controls were involved in these studies. The overall diagnostic accuracy was measured by the following: sensitivity, 0.67 (95 % confidence interval (CI) 0.60-0.74); specificity, 0.83 (95 % CI 0.74-0.85); positive likelihood ratio (PLR), 3.9 (95 % CI 2.6-5.9); negative likelihood ratio (NLR), 0.40 (95 % CI 0.34-0.48); and diagnostic odds ratio (DOR), 10 (95 % CI 6-16), respectively. Additionally, the pooled area under the summary receiver operator characteristic (SROC) curve (area under the curve (AUC)) was 0.79 (95 % CI 0.75-0.82), indicating a relatively low accuracy of miR-17 family as biomarkers for cancer detection. Subgroup analysis further showed that miR-17 family had more reliable performance in cancer diagnosis for Asian than that for Caucasian. Moreover, multiple miRNAs containing miR-17, -20a/b, and -93 reflected higher diagnostic accuracy than both miR-106a/b (single miRNA) and the overall miR-17 family assay. Therefore, appropriate combinations of miR-17 family may be used as non-invasive screening biomarkers for cancer, and it is necessary to carry out a large-scale population-based study to further assess the potential diagnostic value of miR-17 family.

New global analysis of the microRNA transcriptome of primary tumors and lymph node metastases of papillary thyroid cancer

Background

Papillary Thyroid Cancer (PTC) is the most prevalent type of endocrine cancer. Its incidence has rapidly increased in recent decades but little is known regarding its complete microRNA transcriptome (miRNome). In addition, there is a need for molecular biomarkers allowing improved PTC diagnosis.

Methods

We performed small RNA deep-sequencing of 3 PTC, their matching normal tissues and lymph node metastases (LNM). We designed a new bioinformatics framework to handle each aspect of the miRNome: whole expression profiles, isomiRs distribution, non-templated additions distributions, RNA-editing or mutation. Results were validated experimentally by qRT-PCR on normal samples, tumors and LNM from 14 independent patients and in silico using the dataset from The Cancer Genome Atlas (small RNA deepsequencing of 59 normal samples, 495 PTC, and 8 LNM).

Results

We performed small RNA deep-sequencing of 3 PTC, their matching normal tissues and lymph node metastases (LNM). We designed a new bioinformatics framework to handle each aspect of the miRNome: whole expression profiles, isomiRs distribution, non-templated additions distributions, RNA-editing or mutation. Results were validated experimentally by qRT-PCR on normal samples, tumors and LNM from 14 independent patients and in silico using the dataset from The Cancer Genome Atlas (small RNA deep-sequencing of 59 normal samples, 495 PTC, and 8 LNM). We confirmed already described up-regulations of microRNAs in PTC, such as miR-146b-5p or miR-222-3p, but we also identified down-regulated microRNAs, such as miR-7-5p or miR-30c-2-3p. We showed that these down-regulations are linked to the tumorigenesis process of thyrocytes. We selected the 14 most down-regulated microRNAs in PTC and we showed that they are potential biomarkers of PTC samples. Nevertheless, they can distinguish histological classical variants and follicular variants of PTC in the TCGA dataset. In addition, 12 of the 14 down-regulated microRNAs are significantly less expressed in aggressive PTC compared to non-aggressive PTC. We showed that the associated aggressive expression profile is mainly due to the presence of the BRAF V600E mutation. In general, primary tumors and LNM presented similar microRNA expression profiles but specific variations like the down-regulation of miR-7-2-3p and miR-30c-2-3p in LNM were observed. Investigations of the 5p-to-3p arm expression ratios, non-templated additions or isomiRs distributions revealed no major implication in PTC tumorigenesis process or LNM appearance.

Conclusions

Our results showed that down-regulated microRNAs can be used as new potential common biomarkers of PTC and to distinguish main subtypes of PTC. MicroRNA expressions can be linked to the development of LNM of PTC. The bioinformatics framework that we have developed can be used as a starting point for the global analysis of any microRNA deep-sequencing data in an unbiased way.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-2082-3) contains supplementary material, which is available to authorized users.

Downregulation of serum microRNA-205 as a potential diagnostic and prognostic biomarker for human glioma

OBJECT Circulating microRNAs (miRNAs) are a new class of highly promising cancer biomarkers. Malignant glioma is one of the most devastating and lethal forms of intrinsic CNS tumor. Here, the authors evaluated serum miRNA 205 (miR-205) levels in patients with glioma. METHODS Sixty-four patients in whom glioma was diagnosed and 45 healthy controls were recruited between October 2011 and March 2012 and randomly assigned to the screening cohort or the validation cohort. Cohorts of patients with other brain tumors, including meningioma (n = 8), primary diffuse large B-cell lymphoma of the CNS (n = 6), and pituitary adenoma (n = 5), were investigated and compared. miR-205 extraction from serum was detected by real-time quantitative reverse-transcription polymerase chain reaction. The Kaplan-Meier method was applied to perform survival analysis, the risk factors were analyzed by using a Cox regression model, and the receiver operating characteristic working curve was used to analyze the value of miR-205 in the prognostic evaluation of the patients. RESULTS The authors first demonstrated that serum miR-205 expression was significantly lower in patients with glioma than in healthy controls (p < 0.001). It is important to note that serum miR-205 expression demonstrated a stepwise decrease with ascending pathological grades. The serum miR-205 biomarker had high sensitivity, specificity, and accuracy in patients with glioma. Serum levels of miR-205 were identified as an individual diagnostic marker and were significantly lower in the glioma cohort than in the other brain tumor cohorts. Serum miR-205 levels were significantly increased in postoperative samples over those in the preoperative samples and were reduced again during glioblastoma recurrences. Statistical analysis revealed a significant correlation between low serum miR-205 expression and both ascending pathological grades (p = 0.002) and low Karnofsky Performance Scale scores (p = 0.01). Patients with glioma at an advanced pathological grade (Grade III or IV) and a higher miR-205 serum level showed longer overall survival than those with a lower miR-205 serum concentration (p < 0.01). Furthermore, Cox regression analysis revealed that miR-205 serum levels were independently associated with overall survival. CONCLUSIONS These data indicate that serum miR-205 expression is a novel and valuable biomarker for the diagnosis of glioma and a prognostic factor for those with a tumor at an advanced pathological grade.

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.

Circulating MicroRNA as Potential Source for Neurodegenerative Diseases Biomarkers

An increasing number of circulating micro-ribonucleic acids (microRNAs, miRNAs) have been discovered its potential as biomarkers to diagnose neurodegenerative diseases (NDs) by many researchers. However, there were obvious inconsistencies among previous studies, and thus we performed this meta-analysis to evaluate whether miRNA is an effective biomarker with high accuracy to diagnose the NDs. PubMed, MEDLINE, EMBASE, the Cochrane Library, and other related databases were used to search eligible articles. The data of sensitivity and specificity were employed to plot the summary receiver operator characteristic (SROC) curve and calculate the area under the SROC curve (AUC). I (2) test were used to estimate the heterogeneity among different studies. In addition, the possible sources of heterogeneity were further explored by subgroup analyses and meta-regression. All analyses were performed by STATA 12.0 software. In this meta-analysis, eight publications with 459 NDs patients and 340 healthy controls were included to investigate the diagnostic performance of circulating miRNAs for NDs. The overall sensitivity and specificity, positive likelihood ratio (PLR), negative likelihood ration (NLR), and diagnostic odds ratio (DOR) were 0.83 (95% confidence interval (CI) 0.77-0.88), 0.87 (95% CI 0.83-0.89), 6.2 (95% CI 4.9-7.9), 0.19 (95% CI 0.14-0.27), 33 (95% CI 20-52), and 0.91 (95% CI: 0.88-0.93), respectively. The overall SROC curve was plotted with AUC of 0.91 (95% CI 0.88-0.93), which indicated an excellent diagnostic performance of circulating miRNA for NDs. Subgroup analysis based on miRNA profile demonstrated that multiple-miRNA assay had higher diagnostic accuracy for NDs when compared with single-miRNA assay. In conclusion, the circulating miRNAs may be the potential biomarkers in the clinical diagnosis of NDs, and the diagnostic accuracy would be better by using multiple-miRNA assay. However, large-scale studies are still needed to explore the relation between the circulating miRNA dysregulation and the pathological mechanism of NDs.