Differential expression levels of plasma-derived miR-146b and miR-155 in papillary thyroid cancer

From sequencing to validation: NGS-based exploration of plasma miRNA in papillary thyroid carcinoma

Objective

A non-invasive method using plasma microRNAs provides new insights into thyroid cancer diagnosis. The objective of this study was to discover potential circulating biomarkers of papillary thyroid carcinoma (PTC) through the analysis of plasma miRNAs using next-generation sequencing (NGS).

Methods

Plasma miRNAs were isolated from peripheral blood samples collected from healthy individuals, patients diagnosed with PTC, and those with benign thyroid nodules. The Illumina NovaSeq 6000 platform was employed to establish the miRNA expression profiles. Candidate miRNAs for diagnostic purposes were identified utilizing the Random Forest (RF) algorithm. The selected miRNAs were subsequently validated in an independent validation set using RT-qPCR.

Results

NGS results revealed consistent plasma miRNA expression patterns among healthy individuals and patients with benign thyroid nodules in the discovery set (6 healthy cases, 17 benign cases), while differing significantly from those observed in the PTC group (17 PTC cases). Seven miRNAs exhibiting significant expression differences were identified and utilized to construct an RF classifier. Receiver operating characteristic (ROC) analysis for PTC diagnosis, and the area under the curve (AUC) was 0.978. Subsequent KEGG and GO analyses of the target genes associated with these 7 miRNAs highlighted pathways relevant to tumors and the cell cycle. Independent validation through RT-qPCR in a separate cohort (15 CONTROL, 15 PTC groups) underscored hsa-miR-301a-3p and hsa-miR-195-5p as promising candidates for PTC diagnosis.

Conclusion

In conclusion, our study established a seven-miRNA panel in plasma by Random Forest algorithm with significant performance in discriminating PTC from healthy or benign group. hsa-miR-301a-3p, hsa-miR-195-5p in plasma have potential for further study in the diagnosis of PTC in Asian ethnic.

Progress in long non-coding RNAs as prognostic factors of papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is generally recognized as a slow-growing tumor. However, a small subset of patients may still experience relapse or metastasis shortly after therapy, leading to a poor prognosis and raising concerns about excessive medical treatment. One major challenge lies in the inadequacy of effective biomarkers for accurate risk stratification. Long non-coding RNAs (lncRNAs), which are closely related to malignant characteristics and poor prognosis, play a significant role in the genesis and development of PTC through various pathways. The objective of this review is to provide a comprehensive summary of the biological functions of lncRNAs in PTC, identify prognosis-relevant lncRNAs, and explore their potential mechanisms in drug resistance to BRAF kinase inhibitors, tumor dedifferentiation, and lymph node metastasis. By doing so, this review aims to offer valuable references for both basic research and the prediction of PTC prognosis.

Exosomes; a Potential Source of Biomarkers, Therapy, and Cure for Type-1 Diabetes

The scourge of type-1 diabetes (T1D) is the morbidity and mortality it and its complications cause at a younger age. This propels the constant search for better diagnostic, treatment, and management strategies, with the ultimate quest being a cure for T1D. Recently, the therapeutic potential of exosomes has generated a lot of interest. Among the characteristics of exosomes of particular interest are (a) their regenerative capacity, which depends on their "origin", and (b) their "content", which determines the cell communication and crosstalk they influence. Other functional capacities, including paracrine and endocrine homeostatic regulation, pathogenic response ability resulting in insulin secretory defects or β-cell death under normal metabolic conditions, immunomodulation, and promotion of regeneration, have also garnered significant interest. Exosome "specificity" makes them suitable as biomarkers or predictors, and their "mobility" and "content" lend credence to drug delivery and therapeutic suitability. This review aims to highlight the functional capacities of exosomes and their established as well as novel contributions at various pathways in the onset and progression of T1D. The pathogenesis of T1D involves a complex crosstalk between insulin-secreting pancreatic β-cells and immune cells, which is partially mediated by exosomes. We also examine the potential implications for type 2 diabetes (T2D), as the link in T2D has guided T1D exploration. The collective landscape presented is expected to help identify how a deeper understanding of exosomes (and their cargo) can provide a framework for actionable solutions to prevent, halt, or change the very course of T1D and its complications.

MicroRNA-155 and cancer metastasis: Regulation of invasion, migration, and epithelial-to-mesenchymal transition

Among the leading causes of death globally has been cancer. Nearly 90% of all cancer-related fatalities are attributed to metastasis, which is the growing of additional malignant growths out of the original cancer origin. Therefore, a significant clinical need for a deeper comprehension of metastasis exists. Beginning investigations are being made on the function of microRNAs (miRNAs) in the metastatic process. Tiny non-coding RNAs called miRNAs have a crucial part in controlling the spread of cancer. Some miRNAs regulate migration, invasion, colonization, cancer stem cells' properties, the epithelial-mesenchymal transition (EMT), and the microenvironment, among other processes, to either promote or prevent metastasis. One of the most well-conserved and versatile miRNAs, miR-155 is primarily distinguished by overexpression in a variety of illnesses, including malignant tumors. It has been discovered that altered miR-155 expression is connected to a number of physiological and pathological processes, including metastasis. As a result, miR-155-mediated signaling pathways were identified as possible cancer molecular therapy targets. The current research on miR-155, which is important in controlling cancer cells' invasion, and metastasis as well as migration, will be summarized in the current work. The crucial significance of the lncRNA/circRNA-miR-155-mRNA network as a crucial regulator of carcinogenesis and a player in the regulation of signaling pathways or related genes implicated in cancer metastasis will be covered in the final section. These might provide light on the creation of fresh treatment plans for controlling cancer metastasis.

Identification of transcriptional level variations in microRNA-221 and microRNA-222 as alternate players in the thyroid cancer tumor microenvironment

Thyroid cancer (TC) is caused by genetic factors and or their cross talk with lifestyle and environment. An important role of miRNA involvement has been identified in different human diseases alongside the cancer. The growing cloud of miRNA discoveries narrates miRNA-221 and miRNA-222 as key elements of ready arsenal in the cancer micro-niches. The aim of present study was to identify the variations of miRNA-221 and miRNA-222 expression in TC tissues and their likely association with TC. miRNA-221 and miRNA-222 were investigated for their expressional alterations in TC tissue samples and healthy thyroid tissue. Expression of miRNA-221 and -222 was analyzed through real time PCR. The relative gene expression of both the miRNA was quantified and statistically evaluated. miRNA-221 and miRNA-222 were found to be highly over expressed when compared with samples of multinodular goiter (MNG) and normal controls. Interestingly, it was also noted that miRNA-221 and miRNA-222 expression is working in a cluster in thyroid cancer patients. So, it can be concluded that the expressional alterations of miRNA-221 and -222 are playing their potential role in the development of thyroid cancer.

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.

Expression Levels of MicroRNA-300/BCL2L11 in Papillary Thyroid Cancer and Their Clinical Diagnostic Values

INTRODUCTION

This research aims to explore the expression levels of microRNA (miRNA)-300/BCL-2-like protein 11 (BCL2L11) and their values in the clinical diagnosis of papillary thyroid cancer (PTC).

METHODS

Pathological tissues that were surgically removed for thyroid disease were selected. miR-300 and BCL2L11 expression levels in the samples were measured. Receiver operating characteristic (ROC) curves were plotted to analyze miR-300 and BCL2L11 predictive values for PTC. Upon silencing miR-300 and silencing BCL2L11 in PTC cells, the corresponding miR-300 and BCL2L11 expression levels were tested, followed by examining PTC cell activities. The targeting relationship of miR-300 and BCL2L11 was detected by the bioinformatics website and luciferase activity assay.

RESULTS

miR-300 expression levels were elevated and BCL2L11 expression levels were reduced in PTC tissues. miR-300 and BCL2L11 expression levels in PTC tissues had a correlation with TNM stage and lymph node metastasis. The results of ROC curve revealed that both miR-300 and BCL2L11 had clinical predictive values for PTC. Mechanistically, miR-300 negatively regulated BCL2L11. The functional assays unveiled that silencing miR-300 impeded PTC cell activities, and silencing BCL2L11 induced PTC cell activities. In the rescue experiment, silencing BCL2L11 reversed the impacts of silencing miR-300 on PTC cell development.

CONCLUSION

This study underlines that miR-300 expression is increased and BCL2L11 expression is declined in PTC. miR-300 and BCL2L11 both have clinical predictive values for diagnosing PTC.

The Diagnostic and Prognostic Value of miR-155 in Cancers: An Updated Meta-analysis

BACKGROUND

MicroRNA-155 has been discussed as a biomarker in cancer diagnosis and prognosis. Although relevant studies have been published, the role of microRNA-155 remains uncertain because of insufficient data.

METHODS

We conducted a literature search in PubMed, Embase, and Web of Science databases to obtain relevant articles and extract data to evaluate the role of microRNA-155 in cancer diagnosis and prognosis.

RESULTS

The pooled results showed that microRNA-155 presented a remarkable diagnostic value in cancers (area under the curve = 0.90, 95% confidence interval (CI 0.87-0.92; sensitivity = 0.83, 95% CI 0.79-0.87; specificity = 0.83, 95% CI 0.80-0.86), which was maintained in the subgroups stratified by ethnicity (Asian and Caucasian), cancer types (breast cancer, lung cancer, hepatocellular carcinoma, leukemia, and pancreatic ductal adenocarcinoma), sample types (plasma, serum, tissue), and sample size (n >100 and n <100). In prognosis, a combined hazard ratio (HR) showed that microRNA-155 was significantly associated with poor overall survival (HR = 1.38, 95% CI 1.25-1.54) and recurrence-free survival (HR = 2.13, 95% CI 1.65-2.76), and was boundary significant with poor progression-free survival (HR = 1.20, 95% CI 1.00-1.44), but not significant with disease-free survival (HR = 1.14, 95% CI 0.70-1.85). Subgroup analyses in overall survival showed that microRNA-155 was associated with poor overall survival in the subgroups stratified by ethnicity and sample size. However, the significant association was maintained in cancer types subgroups of leukemia, lung cancer, and oral squamous cell carcinoma, but not in colorectal cancer, hepatocellular carcinoma, and breast cancer, and was maintained in sample types subgroups of bone marrow and tissue, but not in plasma and serum.

CONCLUSIONS

Results from this meta-analysis demonstrated that microRNA-155 was a valuable biomarker in cancer diagnosis and prognosis.

Differential microRNA expression for diagnosis and prognosis of papillary thyroid cancer

Papillary thyroid cancer accounts for 85% of thyroid cancer. The diagnosis is based on ultrasound methods and tumor biopsies (FNA). In recent years, research has revealed the importance of miRNAs, non-coding RNA molecules that regulate gene expression and are involved in many diseases. The present mini review describes upregulated and downregulated miRNAs expression in papillary thyroid cancer patient samples (tissue, serum, plasma) and the genes regulated by these non-coding molecules. In addition, a bibliographic search was performed to identify the expression of miRNAs that are common in tumor tissue and blood. The miRNAs miR-146b, miR-221-3p, miRNA 222, miR-21, miR-296-5p, and miR-145 are common in both tissue and bloodstream of PTC patient samples. Furthermore, these miRNAs regulate genes involved in biological processes such as cell differentiation, proliferation, migration, invasion, and apoptosis. In conclusion, miRNAs could potentially become valuable biomarkers, which could help in the early diagnosis and prognosis of papillary thyroid cancer.

Chromatin-Accessible miRNA Regulons Driving Thyroid Tumorigenesis and Progression

BACKGROUND

Although papillary thyroid cancer can remain indolent, associated lymph node metastases and recurrence rates are approximately 50% and 20%, respectively. Omics-based medicine has led to the discovery of predictive biomarkers that can be used to predict tumor progression and clinical outcomes. We aimed to develop a noninvasive omics-driven blood test to allow accurate risk stratification and help tailor individual patient treatment plans.

STUDY DESIGN

RNA sequencing (seq) and microRNA analysis of The Cancer Genome Atlas and Gene Expression Omnibus datasets were employed to identify an epigenetic prognostic panel. Integrated bulk assay for transposase-accessible chromatin-seq and RNA-seq experiments confirmed the results. Sixty-two paired tumor and adjacent control thyroid tissues and 67 blood samples (62 papillary thyroid cancer and 5 controls) were analyzed for validation using sequencing and real-time polymerase chain reaction and correlated to clinical outcomes. A liposome-exosome fusion clustered regularly interspaced short palindromic repeats (CRISPR)-fluorescent detection system miRNA assay was developed. A predictive risk nomogram was generated and tested for performance.

RESULTS

Our miRNA panel (miR-146b-5p and miR-221-3p) from tissue and blood was associated with aggressive features and was located within accessible chromatin regions. The miRNA risk score and prognostic nomogram showed higher accuracy in predicting lymph node metastases (miR-146b: area under the curve [AUC] 0.816, sensitivity 76.9%; miR-221: AUC 0.740, sensitivity 79.5%) and recurrence (miR-146b: AUC 0.921, sensitivity 75.0%; miR-221: AUC 0.756, sensitivity 70.0%; p < 0.001) than staging and American Thyroid Association risk stratification. CRISPR-based miRNA assays showed upregulation in the blood of cancer cohorts.

CONCLUSIONS

CRISPR-based detection of miR-146b and miR-221 in the blood of thyroid cancer patients is a reliable and noninvasive tool for real-time assessment and prognostication that has great potential to provide a direct impact on the care of these patients.

Circulating microRNA as potential diagnostic and prognostic biomarkers of well-differentiated thyroid cancer: A review article

Half of all people aged 50 and over develop a thyroid nodule in their lifetime, exclusion of cancer is required in each case. Nodule tissue sampling is performed by way of fine needle aspiration biopsy (FNAB), however a definite diagnosis in possible only in 30% of cases. The discovery of a diagnostic biomarker to discriminate between thyroid cancer and benign nodules would therefore greatly improve current clinical practice. Using the databases of Medline, Embase and Pubmed we identified 21 original research papers examining various microRNA as potential biomarkers. Currently, the most evidence supporting diagnostic utility exists for miRNA-222. It has been shown repeatedly to have potential in diagnosis of PTC & MTC as well as being linked with the most prognostic factors of all microRNA. To a lesser extent, evidence seems to support the diagnostic and prognostic utility of miR-146b, Let-7 family, miR-221 for PTC and miR-21 for PTC & FTC. MicroRNA appear to show promise as potential diagnostic and prognostic biomarkers, however there is still not enough data to produce a consensus. Continued research should be undertaken with streamlined protocols.

Thyroid Cancer Persistence in Patients with Unreliable Thyroglobulin Measurement: Circulating microRNA as Candidate Alternative Biomarkers

BACKGROUND

We aimed to evaluate the role of circulating miRNAs as a biomarker of the persistence of papillary thyroid cancer (PTC) in patients with an "uninformative" thyroglobulin (Tg) measurement.

METHODS

We prospectively enrolled 49 consecutive PTC patients with Tg-positive antibodies (TgAb) who had undergone a (near)-total thyroidectomy and ¹³¹I therapy (RIT). The serum thyroid stimulating hormone (TSH), Tg, and TgAb levels were measured before and at 6 and 12 months after RIT, respectively. The serum miRNA (221, 222, 375, 155, and 146b) levels were measured simultaneously.

RESULTS

The response to the initial therapy was assessed according to the 2015 ATA criteria. A decrease in 50% or more of serum miRNA over time was observed in 41/49 PTC patients, who showed an excellent response (ER), but six and two patients were classified to have an indeterminate/incomplete biochemical or incomplete structural response to initial therapy.

CONCLUSION

Serum miRNA kinetics emerge as a promising biomarker for the early detection of a persistent disease in PTC patients with uninformative Tg results.

Circulating Biomarkers in Thyroid Cancer

Thyroid cancer is the most important endocrine cancer with increasing incidence. While thyroid cancers, especially papillary thyroid cancers, are known to exhibit generally a favorable outcome with excellent survival rates, some thyroid cancers are more aggressive with a poor prognosis. Several different biomarkers have been introduced for the diagnosis of disease, identification of tumor load, assessment of therapy response, and the detection of recurrence during follow-up of the thyroid cancer patients. This chapter gives a brief overview of the circulating biomarkers used in thyroid cancer patients.

Circulating microRNAs and Clinicopathological Findings of Papillary Thyroid Cancer: A Systematic Review

BACKGROUND/AIM

Papillary thyroid cancer (PTC) is the most common endocrine malignancy with a rising incidence. There is a need for a non-invasive preoperative test to enable better patient counselling. The aim of this systematic review was to investigate the potential role of circulating microRNAs (miRNAs) in the diagnosis and prognosis of PTC.

MATERIALS AND METHODS

A systematic literature search was performed using MEDLINE, Cochrane, and Scopus databases (last search date was December 1, 2021). Studies investigating the expression of miRNAs in the serum or plasma of patients with PTC were deemed eligible for inclusion.

RESULTS

Among the 1,533 screened studies, 39 studies met the inclusion criteria. In total, 108 miRNAs candidates were identified in the serum, plasma, or exosomes of patients suffering from PTC. Furthermore, association of circulating miRNAs with thyroid cancer-specific clinicopathological features, such as tumor size (13 miRNAs), location (3 miRNAs), extrathyroidal extension (9 miRNAs), pre- vs. postoperative period (31 miRNAs), lymph node metastasis (17 miRNAs), TNM stage (9 miRNAs), BRAF V600E mutation (6 miRNAs), serum thyroglobulin levels (2 miRNAs), ¹³¹I avid metastases (13 miRNAs), and tumor recurrence (2 miRNAs) was also depicted in this study.

CONCLUSION

MiRNAs provide a potentially promising role in the diagnosis and prognosis of PTC. There is a correlation between miRNA expression profiles and specific clinicopathological features of PTC. However, to enable their use in clinical practice, further clinical studies are required to validate the predictive value and utility of miRNAs as biomarkers.

Noncoding RNAs in Thyroid-Follicular-Cell-Derived Carcinomas

Simple Summary

Thyroid tumors represent the most common neoplastic pathology of the endocrine system. Mutations occurring in oncogenes and tumor suppressor genes are responsible for thyroid carcinogenesis; however, the complete mutational landscape characterizing these neoplasias has not been completely unveiled. It has been established that only the 2% of the human genome codes for proteins, suggesting that the vast majority of the genome has regulatory capabilities, which, if altered, could account for the onset of cancer. Hence, many scientific efforts are currently focused on the characterization of the heterogeneous class of noncoding RNAs, which represent an abundant part of the transcribed noncoding genome. In this review, we mainly focus on the involvement of microRNAs, long noncoding RNAs, and pseudogenes in thyroid cancer. The determination of the diagnosis, prognosis, and treatment of thyroid cancers based on the evaluation of the noncoding RNA network could allow the implementation of a more personalized approach to fighting these pathologies.

Abstract

Among the thyroid neoplasias originating from follicular cells, we can include well-differentiated carcinomas, papillary (PTC) and follicular (FTC) thyroid carcinomas, and the undifferentiated anaplastic (ATC) carcinomas. Several mutations in oncogenes and tumor suppressor genes have already been observed in these malignancies; however, we are still far from the comprehension of their full regulation-altered landscape. Even if only 2% of the human genome has the ability to code for proteins, most of the noncoding genome is transcribed, constituting the heterogeneous class of noncoding RNAs (ncRNAs), whose alterations are associated with the development of several human diseases, including cancer. Hence, many scientific efforts are currently focused on the elucidation of their biological role. In this review, we analyze the scientific literature regarding the involvement of microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and pseudogenes in FTC, PTC, and ATC. Recent findings emphasized the role of lncRNAs in all steps of cancer progression. In particular, lncRNAs may control progression steps by regulating the expression of genes and miRNAs involved in cell proliferation, apoptosis, epithelial–mesenchymal transition, and metastatization. In conclusion, the determination of the diagnosis, prognosis, and treatment of cancer based on the evaluation of the ncRNA network could allow the implementation of a more personalized approach to fighting thyroid tumors.

MiR-221 Regulates Suppressors of Cytokine Signaling 3-Janus Kinase 2/Signal Transducer and Activator of Transcription 3 (SOCS3-JAK2/STAT3) Pathway and Affects Thyroid Cancer Cell Proliferation and Apoptosis

Objective: Suppressors of cytokine signaling 3 (SOCS3) negatively regulates JAK-STAT signaling. Bioinformatics analysis showed a targeted relationship between miR-221 and SOCS3 mRNA 3′-UTR. This study investigated whether miR-221 regulates SOCS3 expression and affects thyroid cancer cells. Methods: Dual-luciferase reporter gene experiments verified the relationship between miR-221 and SOCS3. The tumor tissues and adjacent tissues of patients with thyroid cancer were collected to detect miR-221 and SOCS3 level. Thyroid cancer cell line KTC-1 cells were assigned into miR-NC group and miR-221 inhibitor group followed by analysis of SOCS3, p-JAK2, and p-STAT3 level by Real-time PCR, cell apoptosis and cell proliferation by flow cytometry and cell invasion by Transwell assay. Results: Compared with adjacent tissues, miR-221 level in tumor tissues was increased, and SCOS3 mRNA level was decreased. There was a targeted relationship between miR-221 and SOCS3 mRNA. MiR-221 level in KTC-1 and TPC-1 cells was increased, while SOCS3 mRNA level was decreased. MiR-221 inhibitor can significantly upregulate SOCS3 mRNA and protein in KTC-1 cells, reduce the expression of p-JAK2, p-STAT3 protein, increase cell apoptosis, and reduce cell proliferation and invasion. Conclusion: The increased miR-221 and decreased SOCS3 expression are related to thyroid cancer pathogenesis. MiR-221 can inhibit the expression of SOCS3, affect JAK-STAT signaling activity, and regulate the proliferation and apoptosis of thyroid cancer cells.

Circulating MicroRNA Profiles as Potential Biomarkers for Differentiated Thyroid Cancer Recurrence

CONTEXT

Circulating microRNAs (miRNAs) are emerging biomarkers of thyroid cancer.

OBJECTIVE

This study sought to identify the profile of circulating miRNAs and its response to human recombinant TSH (rhTSH) in thyroid cancer patients with recurrent/persistent disease.

METHODS

We obtained serum samples from 30 patients with differentiated thyroid cancer, 14 with recurrent/persistent disease and 16 with complete remission. We used next-generation sequencing to define the miRnomes along with a comprehensive quantitative PCR (qPCR) validation using 2 different platforms. We made a transversal study by comparing serum miRNA profiles of patients with or without recurrent/persistent disease and a longitudinal study looking at differences before and after rhTSH stimulation. Selected miRNAs were then studied in human thyroid cancer cell lines TPC-1, FTC-133, and OCUT-2 in response to TSH stimulation.

RESULTS

We could not demonstrate any consistent differences in serum profiles of known miRNAs between patients with and without recurrent/persistent disease or before and after rhTSH stimulation. However, our sequencing data revealed 2 putative novel miRNAs that rise with rhTSH stimulation in the serums of patients with recurrent/persistent disease. We further confirmed by qPCR the upregulation of these putative miRNAs both in serums and in TSH-stimulated cells. We also show miRNAs that are good candidates for housekeeping genes in the serum of patients independently of the levels of TSH.

CONCLUSIONS

The present study does not provide evidence that known miRNAs can be used as circulating markers for recurrence of thyroid cancer. However, we suggest that novel miRNA molecules may be related to thyroid cancer pathogenesis.

MicroRNAs in Papillary Thyroid Cancer: What Is New in Diagnosis and Treatment

Introduction

Papillary thyroid cancer (PTC) accounts for up to 80% of thyroid malignancies. New diagnostic and therapeutic options are suggested including innovative molecular methods. MicroRNAs (miRNAs) are nonprotein coding single-stranded RNAs that regulate many cell processes. The aim of the present study is to review the deregulated miRNAs associated with PTCs.

Methods

A bibliographic research was conducted, resulting in 272 articles referred to miRNAs and PTC. Regarding our exclusion criteria, 183 articles were finally included in our review.

Results

A remarkably large number of miRNAs have been found to be deregulated during PTC manifestation in the literature. The deregulated miRNAs are detected in tissue samples, serum/plasma, and FNA samples of patients with PTC. These miRNAs are related to several molecular pathways, involving genes and proteins responsible for important biological processes. MiRNA deregulation is associated with tumor aggressiveness, including larger tumor size, multifocality, extrathyroidal extension, lymphovascular invasion, lymph node and distant metastasis, and advanced tumor node metastasis stage.

Conclusion

MiRNAs are proposed as new diagnostic and therapeutic tools regarding PTC. They could be essential biomarkers for PTC diagnosis applied in serum and FNA samples, while their contribution to prognosis is of great importance.

Inflammatory Components of the Thyroid Cancer Microenvironment: An Avenue for Identification of Novel Biomarkers

The incidence of thyroid cancer in the United States is on the rise with an appreciably high disease recurrence rate of 20-30%. Anaplastic thyroid cancer (ATC), although rare in occurrence, is an aggressive form of cancer with limited treatment options and bleak cure rates. This chapter uses discussions of in vitro models that are representative of papillary, anaplastic, and follicular thyroid cancer to evaluate the crosstalk between specific cells of the tumor microenvironment (TME), which serves as a highly heterogeneous realm of signaling cascades and metabolism that are associated with tumorigenesis. The cellular constituents of the TME carry out varying characteristic immunomodulatory functions that are discussed throughout this chapter. The aforementioned cell types include cancer-associated fibroblasts (CAFs), endothelial cells (ECs), and cancer stem cells (CSCs), as well as specific immune cells, including natural killer (NK) cells, dendritic cells (DCs), mast cells, T regulatory (Treg) cells, CD8+ T cells, and tumor-associated macrophages (TAMs). TAM-mediated inflammation is associated with a poor prognosis of thyroid cancer, and the molecular basis of the cellular crosstalk between macrophages and thyroid cancer cells with respect to inducing a metastatic phenotype is not yet known. The dynamic nature of the physiological transition to pathological metastatic phenotypes when establishing the TME encompasses a wide range of characteristics that are further explored within this chapter, including the roles of somatic mutations and epigenetic alterations that drive the genetic heterogeneity of cancer cells, allowing for selective advantages that aid in their proliferation. Induction of these proliferating cells is typically accomplished through inflammatory induction, whereby chronic inflammation sets up a constant physiological state of inflammatory cell recruitment. The secretions of these inflammatory cells can alter the genetic makeup of proliferating cells, which can in turn, promote tumor growth.This chapter also presents an in-depth analysis of molecular interactions within the TME, including secretory cytokines and exosomes. Since the exosomal cargo of a cell is a reflection and fingerprint of the originating parental cells, the profiling of exosomal miRNA derived from thyroid cancer cells and macrophages in the TME may serve as an important step in biomarker discovery. Identification of a distinct set of tumor suppressive miRNAs downregulated in ATC-secreted exosomes indicates their role in the regulation of tumor suppressive genes that may increase the metastatic propensity of ATC. Additionally, the high expression of pro-inflammatory cytokines in studies looking at thyroid cancer and activated macrophage conditioned media suggests the existence of an inflammatory TME in thyroid cancer. New findings are suggestive of the presence of a metastatic niche in ATC tissues that is influenced by thyroid tumor microenvironment secretome-induced epithelial to mesenchymal transition (EMT), mediated by a reciprocal interaction between the pro-inflammatory M1 macrophages and the thyroid cancer cells. Thus, targeting the metastatic thyroid carcinoma microenvironment could offer potential therapeutic benefits and should be explored further in preclinical and translational models of human metastatic thyroid cancer.

The Importance of miRNA in the Diagnosis and Prognosis of Papillary Thyroid Cancer

In recent years, the global incidence of thyroid cancer has been increasing. Despite the significant progress in the diagnostic tools applied for papillary thyroid cancer (PTC) diagnosis, commonly used methods require undergoing invasive diagnostic procedures, such as liquid biopsy, which still, in some cases, remains imprecise. In this case, novel screening and diagnostic biomarkers are still being evaluated using highly specialized techniques, which could increase PTC detection. Currently, a number of genes and proteins associated with PTC development are currently under investigation to assess their clinical utility. Accordingly, a literature search was undertaken to collect novel information about the diagnosis of and prognosis for PTC with a particular emphasis on the role of microRNA (miRNA) evaluation. The early identification of novel biomarkers is essential for facilitating appropriate therapeutic decisions. Moreover, the evaluation of plasma- and serum-derived miRNA measurements could be considered as equivalent thyroid cancer screening tools in the future. On the other hand, the PTC pathogenesis could be evaluated further with the use of miRNA evaluation, which may bring novel insights for potential medical target determination.

Translational Utility of Liquid Biopsies in Thyroid Cancer Management

Liquid biopsies are a novel technique to assess for either circulating tumor cells (CTC) or circulating tumor DNA (ctDNA and microRNA (miRNA)) in peripheral blood samples of cancer patients. The diagnostic role of liquid biopsy in oncology has expanded in recent years, particularly in lung, colorectal and breast cancer. In thyroid cancer, the role of liquid biopsy in either diagnosis or prognosis is beginning to translate from the lab to the clinic. In this review, we describe the evolution of liquid biopsies in detecting CTC, ctDNA and miRNA in thyroid cancer patients, together with its limitations and future directions in clinical practice.

A meta-analysis of circulating microRNAs in the diagnosis of papillary thyroid carcinoma

BACKGROUND

Aim of this meta-analysis was to evaluate the overall diagnostic value of circulating mini miRNAs for papillary thyroid carcinoma (PTC) and to find the possible molecular marker with higher diagnostic value for PTC.

METHODS

We searched the Pubmed, Cochrane and Embase database until June 2020. We selected relevant literatures associated with the diagnosis of PTC with circulating miRNAs. The number of cases in experimental group and the control group, sensitivity and specificity could be extracted from the literatures.

RESULTS

We got 9 literatures including 2114 cases of PTC. Comprehensive sensitivity was 0.79, comprehensive specificity was 0.82, positive likelihood ratio was 4.3, negative likelihood ratio was 0.26, diagnostic advantage ratio was 16. The summary receiver operating characteristic curve was drawn and the Area Under the Curve was 0.87.

CONCLUSIONS

Circulating microRNAs may be promising molecular markers for the diagnosis of papillary thyroid carcinoma. Combined detection of certain serum microRNAs can improve the diagnostic accuracy of papillary thyroid carcinoma. Especially MiR-222 and miR-146b may be prime candidates for the diagnosis of PTC in Asian population.

Stem Cell Based Exosomes: Are They Effective in Disease or Health?

Exosomes are nano-sized vesicles involved in intercellular communication via delivery of molecules including lipids, nucleic acids, proteins, or other cellular components to distant or neighboring sites. Their ability to pass biological barriers, stability in physiological fluids without degradation, and distinctive affinity to target cells make exosomes very remarkable therapeutic vehicles. Virus-based approaches are some of the most widely used gene therapy methods; however, there are many issues need to be clarified such as high immunogenicity. Using of the exosomes procures the functional transfer of their cargo with minimal intervention from the immune system and it has been reported to be secure and well-tolerated. When the regenerative medicine is taken into consideration, stem cell-based approaches have been aimed to utilize but the general efficacy and safety profile of stem cell therapy has still not been enlightened. At this point, stem cell-derived exosomes exhibit a way to procure cell-free regenerative medicine with their unique characteristics. Exosomes are considered as appropriate and highly stable biological nano-vectors taking part in a wide variety of healthy and pathological processes for advanced targeted therapies. However, there are still crucial obstacles to achieve efficient isolation of large amount of specific and pure exosomes. Thus, large-scale exosome production under good manufacturing practice is required. The purpose of this review is to focus on stem cell-based exosomes for gene delivery and to introduce synthetic exosome-mimics as a potential alternative in the field of targeted gene therapies. Further, we aim to highlight the biobanking and large-scale manufacturing methods of exosomes.

lncRNA CASC2 Enhances 131I Sensitivity in Papillary Thyroid Cancer by Sponging miR-155

Long noncoding RNA cancer susceptibility candidate 2 (CASC2) has been reported to play an anticancer role in papillary thyroid cancer (PTC). Radioiodine (¹³¹I) is a common option for the treatment of PTC. However, the role and mechanism of CASC2 in ¹³¹I sensitivity remain unclear. In this study, ¹³¹I-resistant cells were constructed through continuous treatment of ¹³¹I. The expression levels of CASC2 and miR-155 were measured by qRT-PCR. The IC50 of ¹³¹I was analyzed by cell viability using MTT assay. Flow cytometry was conducted to determine cell apoptosis induced by ¹³¹I. The association between CASC2 and miR-155 was evaluated by luciferase assay and RNA immunoprecipitation. A mouse xenograft model was built to explore the effect of CASC2 on the growth of ¹³¹I-resistant PTC cells in vivo. Results showed that CASC2 expression was decreased in PTC tissues and cells, and low expression of CASC2 was associated with poor outcome of patients. CASC2 level was reduced in ¹³¹I-resistant cells. Knockdown of CASC2 inhibited ¹³¹I sensitivity in thyroid cancer cells. Overexpression of CASC2 enhanced ¹³¹I sensitivity in constructed resistant PTC cells. CASC2 was a decoy of miR-155, and CASC2-mediated promotion of ¹³¹I sensitivity was weakened by decreasing miR-155. Abundance of CASC2 inhibited the growth of ¹³¹I-resistant cells in vivo. As a conclusion, CASC2 increases ¹³¹I sensitivity in PTC by sponging miR-155, providing a novel target for the treatment of thyroid cancer patients with ¹³¹I resistance.

Diagnostic value of circulating microRNAs in thyroid carcinoma: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

Thyroid cancer (TC) is the most common endocrine system tumour. Several studies had revealed the potential of circulating microRNAs (miRNAs) as novel biomarkers for the diagnosis of TC. The purpose of this meta-analysis is to summarize published studies and evaluate the diagnostic accuracy of circulating miRNAs in TC detection.

METHODS

In this meta-analysis, we systematically searched three databases: PubMed, EMBASE and Cochrane Library. We used the bivariate mixed-effects regression model to calculate the pooled diagnostic parameters and conduct the summary receiver operator characteristic curve (SROC). All calculations were performed using stata software.

RESULTS

Thirty-five studies from 9 articles, including 663 TC patients, 519 patients with benign thyroid nodules (BTNs), and 84 healthy controls were included in this meta-analysis. The pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR) and area under the SROC curve (AUC) were 0.81 (95% CI 0.75-0.86), 0.81 (95% CI 0.75-0.86), 4.3 (95% CI 3.2-5.6), 0.24 (95% CI 0.18-0.31), 18 (95% CI 12-28) and 0.88 (95% CI 0.85-0.90), respectively in BTN controls, and 0.81 (95% CI 0.75-0.86), 0.85 (95% CI 0.75-0.91), 5.3 (95% CI 3.3-8.7), 0.23 (95% CI 0.18-0.29), 24 (95% CI 14-39), 0.89 (95% CI 0.86-0.91) in healthy controls. The subgroup analysis found that multiple miRNA assays had higher diagnostic accuracy than single miRNA assays with sensitivity of 0.88, specificity of 0.89 and AUC of 0.94.

CONCLUSION

Circulating miRNAs have good values to diagnose TC and distinguish TC patients from BTN patients. MiRNAs can assist in the diagnosis of malignancy and avoid unnecessary surgery. In summary, circulating miRNAs should be added to our current clinical tools.

Plasma-Derived miRNA-222 as a Candidate Marker for Papillary Thyroid Cancer

We analyzed five miRNA molecules (miR-221; miR-222; miR-146b; miR-21; miR-181b) in the plasma of patients with papillary thyroid cancer (PTC), nodular goiter (NG) and healthy controls (HC) and evaluated their diagnostic value for differentiation of PTC from NG and HC. Preoperative PTC plasma miRNA expression (n = 49) was compared with plasma miRNA in the HC group (n = 57) and patients with NG (n = 23). It was demonstrated that miR-221; miR-222; miR-146b; miR-21 and miR-181b were overexpressed in preoperative PTC plasma samples compared to HC (p < 0.0001; p < 0.0001; p < 0.0001; p < 0.0001; p < 0.002; respectively). The upregulation in tumor tissue of these miRNAs was consistent with The Cancer Genome Atlas Thyroid Carcinoma dataset. A significant decrease in miR-21; miR-221; miR-146b and miR-181b expression was observed in the plasma of PTC patients after total thyroidectomy (p = 0.004; p = 0.001; p = 0.03; p = 0.036; respectively). The levels of miR-222 were significantly higher in the preoperative PTC compared to the NG group (p = 0.004). ROC curve (receiver operating characteristic curve) analysis revealed miR-222 as a potential marker in distinguishing PTC from NG (AUC 0.711; p = 0.004). In conclusion; circulating miR-222 profiles might be useful in discriminating PTC from NG.

miR-146b Reverses epithelial-mesenchymal transition via targeting PTP1B in cisplatin-resistance human lung adenocarcinoma cells

Epithelial-mesenchymal transformation (EMT) is associated with drug resistance in human lung adenocarcinoma cells, but its specific mechanism has not been clarified. In this study, we investigated the effect of miRNA-146b on EMT in cisplatin (DDP) resistant human lung adenocarcinoma cells and the corresponding mechanism. Cisplatin resistant (CR) human lung adenocarcinoma cells (A549/DDP and H1299/DDP) were established, and the EMT characteristics and invasion and metastasis ability of CR cells were determined by tumor cell-related biological behavior experiments. The role of miR-146b in EMT of CR cells was determined by in vitro functional test. The targeted binding of miR-146b to protein tyrosine phosphatase 1B (PTP1B) was verified by biological information and double luciferin gene reporting experiments. The effect of miR-146b on tumor growth and EMT phenotype in vivo was investigated by establishing the xenotransplantation mouse model. Compared with the control group, H1299/DDP and A549/DDP cells showed the enhanced EMT phenotypes, invasion and migration ability. Besides, miR-146b was lowly expressed in H1299/DDP and A549/DDP cells. More importantly, overexpressed miR-146b could specifically bind to PTP1B, thus inhibiting the EMT process and ultimately reducing CR in H1299/DDP and A549/DDP cells. Finally, overexpressed miR-146b observably inhibited tumor growth in xenograft model mice and inhibited the EMT phenotype of A549/DDP cells in vivo by regulating the expressions of EMT-related proteins. Overexpressed miR-146b could reverse the EMT phenotype of CR lung adenocarcinoma cells by targeting PTP1B, providing new therapeutic directions for CR of lung adenocarcinoma cells.

Differential MicroRNA-Signatures in Thyroid Cancer Subtypes

Thyroid cancer is one of the most common endocrine cancers, with an increasing trend in the last few decades. Although papillary thyroid cancer is the most frequent subtype compared with follicular or anaplastic thyroid cancer, it can dedifferentiate to a more aggressive phenotype, and the recurrence rate is high. The cells of follicular adenomas and follicular carcinomas appear identical in cytology, making the preoperative diagnosis difficult. On the other hand, anaplastic thyroid cancer poses a significant clinical challenge due to its aggressive nature with no effective therapeutic options. In the past several years, the roles of genetic alterations of thyroid tumors have been documented, with a remarkable correlation between genotype and phenotype, indicating that distinct molecular changes are associated with a multistep tumorigenic process. Besides mRNA expression profiles, small noncoding microRNA (miRNA) expression also showed critical functions for cell differentiation, proliferation, angiogenesis, and resistance to apoptosis and finally activating invasion and metastasis in cancer. Several high-throughput sequencing studies demonstrate that miRNA expression signatures contribute clinically relevant information including types of thyroid cancer, tumor grade, and prognosis. This review summarizes recent findings on miRNA signatures in thyroid cancer subtypes.

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.

A Panel of Plasma Exosomal miRNAs as Potential Biomarkers for Differential Diagnosis of Thyroid Nodules

Background: A liquid biopsy using circulating exosomal genetic materials provides new insights for thyroid cancer diagnosis. This study aimed to identify plasma-derived exosomal biomarkers that could be used for early detection of papillary thyroid carcinoma (PTC).

Method: Exosomal miRNAs in plasma were isolated from patients with benign thyroid nodules and patients with PTC. Profiling of exosomal miRNA was performed using RNA sequencing (RNA-seq) to identify miRNA candidates and differentiate the benign from malignant. The validation cohort consisted of 30 patients with benign thyroid nodules, 35 PTC patients, and 31 healthy individuals. Real-time PCR was used to quantify the expression of miRNA candidates. The diagnostic potential of the candidates was evaluated by receiver operating characteristic (ROC) curves.

Results: After RNA-seq, eight plasma exosomal miRNAs were selected as candidates. Further validation indicated that the levels of exosomal miR-16-2-3p, miR-223-5p, miR-34c-5p, miR-182-5p, miR-223-3p, and miR-146b-5p were significantly lower in nodules compared to healthy controls (p < 0.0001), whereas miR-16-2-3p and miR-223-5p were significantly higher in the PTC cases than in those with benign nodules (p < 0.05). ROC analyses revealed that the above six miRNAs were potent indicators for detection of thyroid nodules. Meanwhile, miR-16-2-3p and miR-223-5p can be utilized for detecting PTC from benign nodules. Additionally, combined miRNA panels showed increased diagnostic sensitivities and specificities compared to single miRNA markers.

Conclusion: Six aberrantly expressed plasma exosomal miRNAs may be used as diagnostic biomarkers to differentiate thyroid nodules from healthy individuals. The panel consisting of miR-16-2-3p, miR-223-5p, miR-101-3p, and miR-34c-5p are eligible for discriminating benign from malignant thyroid nodules.

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.

Role of microRNAs in remodeling the tumor microenvironment (Review)

MicroRNAs (miRNAs) are short non-coding RNAs that are known to regulate gene expression at the post-transcriptional level. miRNA expression is often deregulated in several human cancers, affecting the communication between tumor stroma and tumor cells, among other functions. Understanding the role of miRNAs in the tumor microenvironment is crucial for fully elucidating the molecular mechanisms underlying tumor progression and exploring novel diagnostic biomarkers and therapeutic targets. The present review focused on the role of miRNAs in remodeling the tumor microenvironment, with an emphasis on their impact on tumor growth, metastasis and resistance to treatment, as well as their potential clinical applications.

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.

Noncoding RNAs in Extracellular Fluids as Cancer Biomarkers: The New Frontier of Liquid Biopsies

The last two decades of cancer research have been devoted in two directions: (1) understanding the mechanism of carcinogenesis for an effective treatment, and (2) improving cancer prevention and screening for early detection of the disease. This last aspect has been developed, especially for certain types of cancers, thanks also to the introduction of new concepts such as liquid biopsies and precision medicine. In this context, there is a growing interest in the application of alternative and noninvasive methodologies to search for cancer biomarkers. The new frontiers of the research lead to a search for RNA molecules circulating in body fluids. Searching for biomarkers in extracellular body fluids represents a better option for patients because they are easier to access, less painful, and potentially more economical. Moreover, the possibility for these types of samples to be taken repeatedly, allows a better monitoring of the disease progression or treatment efficacy for a better intervention and dynamic treatment of the patient, which is the fundamental basis of personalized medicine. RNA molecules, freely circulating in body fluids or packed in microvesicles, have all the characteristics of the ideal biomarkers owing to their high stability under storage and handling conditions and being able to be sampled several times for monitoring. Moreover, as demonstrated for many cancers, their plasma/serum levels mirror those in the primary tumor. There are a large variety of RNA species noncoding for proteins that could be used as cancer biomarkers in liquid biopsies. Among them, the most studied are microRNAs, but recently the attention of the researcher has been also directed towards Piwi-interacting RNAs, circular RNAs, and other small noncoding RNAs. Another class of RNA species, the long noncoding RNAs, is larger than microRNAs and represents a very versatile and promising group of molecules which, apart from their use as biomarkers, have also a possible therapeutic role. In this review, we will give an overview of the most common noncoding RNA species detectable in extracellular fluids and will provide an update concerning the situation of the research on these molecules as cancer biomarkers.

Evaluating pre- and post-operation plasma miRNAs of papillary thyroid carcinoma (PTC) patients in comparison to benign nodules

Background

Thyroid cancer is the most common endocrinology cancer that its incidence has increased in recent decades. miRNAs are new biomarkers in recent studies in the diagnosis and follow-up of these patients.

Methods

Blood and thyroid tissue samples were obtained from two groups of included patients (PTC and benign nodules), pre- and post-operation. miRNAs were extracted from these plasma samples and were measured quantitatively. After cDNA synthesis, qPCR was carried out. Then tissue samples were investigated, and their relation to miR expression was studied. These results were analyzed by paired- and independent samples t-test, and non-parametric tests.

Results

miR-222 and miR-181a declined in PTC patients before and after surgery, significantly (P < 0.001 for both groups), with no significant difference in control group before and after surgery (P = 0.61 for miR-222 and P = 0.06 for miR-181a). The difference between the two groups, pre-and post-operation, was statistically significant (P = 0.01 for miR-222 and P < 0.001 for miR-181a). Comparing case and control groups, pre- and post-operatively, yielded no significant difference, in miR-155-5p levels (P = 0.61 and P = 0.53, respectively). Comparing PTC and control groups before surgery showed a significant difference (P = 0.01), while no significant difference was observed comparing them after surgery, in miR146-a (P = 0.27). Our results depicted a higher miR-155-5p and miR-146a expression before surgery than after it (P < 0.001 in both groups, for both miRs). We found a significant relationship between miR-222 and BRAFV600E mutation and significantly higher levels of miR-181a with increasing tumor size in PTC patients.

Conclusion

miR-222 showed overexpression in all PTC cases, which is indicative of a relation between miRNA and PTC. Also, comparing miR-181 and miR-146a showed a significant difference between cancerous and benign cases. miR-155-5p as an inflammatory factor, showed no significant changes, comparing two groups.

Expression of miRNA-146b-5p in patients with thyroid cancer in combination with Hashimoto's disease and its clinical significance

The expression level of microRNA (miRNA)-146b in patients with thyroid carcinoma (TC) in combination with Hashimoto's thyroditis (HT) was evaluated to analyze the clinical significance. Eighty-seven patients who underwent thyroid surgery in The Third Affiliated Hospital of Southern Medical University from March 2010 to February 2013 were enrolled. Of the patients, 37 were diagnosed with TC (group A), and 50 were diagnosed with TC in combination with HT (group B). Forty patients were diagnosed with HT (group C). The expression levels of miRNA-146b-5p in cancer tissue and paracancerous tissue of patients in the two groups were measured by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Correlation between the miRNA-146b-5p levels and the clinicopathological characteristics of patients with combined TC and HT were evaluated. According to the expression of miRNA-146b-5p, patients in group B were separated into the high and low expression groups to observe the five-year cancer recurrence rate. There was no significant difference in miRNA-146b-5p expression between the papillary carcinoma group, the follicular carcinoma group and the medullary carcinoma group (P>0.05). The miRNA-146b-5p expression in the lesion tissue of group B was significantly higher than that of groups A and C, while the miRNA-146b-5p expression in the lesion tissue of group A was significantly higher than that of group C (P<0.05), and the lesion tissue of the three groups was higher than that of the corresponding parastatal tissue (P<0.05). The miRNA-146b-5p expression level was associated with tumor size, lymph node metastasis and TNM stage (P<0.05), while not associated with sex, age, lesion multiplicity, smoking history, diabetes history and pathological type in group B (P>0.05). The non-recurrence rate of group B high expression subgroup was lower than that of group B low expression subgroup (P=0.045). High expression of miRNA-146b-5p was found in the cancer tissues of patients with combined TC and HT. The expression level of miRNA-146b-5p was associated with tumor size, lymph node metastasis and TNM stage. It is a potential prognostic indicator for patients with combined TC and HT.

A three plasma microRNA signature for papillary thyroid carcinoma diagnosis in Chinese patients

Whether plasma miRNAs could be used as novel non-invasive biomarkers in diagnosing papillary thyroid carcinoma (PTC) remains unknown. In this study, we designed a four-phase study to identify differentially expressed plasma miRNAs in Chinese PTC patients. Exiqon panel was initially utilized to conduct plasma miRNA profile (3 PTC pools VS. 1 healthy control (HC) pool; each 10 samples were pooled as 1 sample). The dysregulated miRNAs were then analyzed in the training (30 PTC VS. 30 HCs), testing (57 PTC VS. 54 HCs) and external validation phases (33 PTC VS. 30HCs). The identified miRNAs were further affirmed in benign nodules (2 nodular goiter (NG) pool VS. 1 HC pool). We also verified the expression of identified miRNAs in 17 matched malignant and normal tissue samples, NG plasma samples (29 PTC VS. 29 NG) and plasma exosomes (25 PTC VS. 25 HCs). Receiver operating characteristic (ROC) curves were constructed to evaluate the diagnostic value of the identified miRNAs. As a result, the screening phase demonstrated 30 dysregulated plasma miRNAs in PTC patients compared with HCs. After multiphase experiment processes, miR-346, miR-10a-5p and miR-34a-5p were found significantly elevated in PTC plasma samples relative to HCs. The areas under the ROC curve (AUC) of the three-miRNA panel for the training, testing and validation phases were 0.926, 0.811 and 0.816, separately. The panel could also differentiate PTC from NG with the AUC of 0.877. MiR-346 and miR-34a-5p but not miR-10a-5p were up-regulated in PTC tissues. And the three miRNAs showed consistently up-regulation in PTC plasma exosomes. In conclusion, our study established a three-miRNA panel in plasma with considerable clinical value in discriminating PTC from HC or NG.

MicroRNA-1270 modulates papillary thyroid cancer cell development by regulating SCAI

PURPOSE

We intended to evaluate expression and mechanisms of human microRNA 1270 (hsa-miR-1270) in papillary thyroid cancer (PTC).

METHODS

In PTC cell lines and human PTC tumors, hsa-miR-1270 expressions were evaluated by qRT-PCR. Hsa-miR-1270 was downregulated in TPC1 and K1 cells via lentiviral transduction. Its effects on PTC cancer cell proliferation, migration and in vivo transplantation were assessed, respectively. Potential targeting of hsa-miR-1270 on downstream gene, Suppressor Of Cancer Cell Invasion (SCAI), was assessed. In hsa-miR-1270-downregulated PTC cells, SCAI was further downregulated to examine its associating role in hsa-miR-1270-mediated regulation on cancer cell proliferation and migration.

RESULTS

Hsa-miR-1270 was aberrantly upregulated in PTC cell lines and human PTC tumors. In TPC1 and K1 cells, lentivirus-mediated hsa-miR-1270 downregulation suppressed cancer cell proliferation, migration and in vivo transplantation. Hsa-miR-1270 binds SCAI and inversely regulated SCAI gene expression in PTC cells. SCAI downregulation removed the suppressing effects of hsa-miR-1270 downregulation in human PTC cells.

CONCLUSION

Hsa-miR-1270 downregulation may suppress human PTC cell development both in vitro and in vivo. The regulatory mechanism of hsa-miR-1270 in PTC may be primarily associated with SCAI.

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.

Discriminatory miRNAs for the Management of Papillary Thyroid Carcinoma and Noninvasive Follicular Thyroid Neoplasms with Papillary-Like Nuclear Features

BACKGROUND

Papillary thyroid carcinoma (PTC) variants have several overlapping clinical and pathological features. The World Health Organization recently published a new classification of thyroid tumors containing significant revisions. Encapsulated papillary thyroid carcinoma (EPTC) has been recognized as a distinctive variant of PTC. The noninvasive encapsulated follicular variant of PTC has been reclassified as noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTP). Different neoplasms are associated with different outcomes and require different clinical management. The objective of this study was to explore the miRNA expression patterns specific for classic PTC (cPTC), EPTC, follicular variant of PTC, and NIFTP in order to identify biomarkers of diagnostic and prognostic utility aiming for better clinical decisions.

METHODS

The expression of 84 miRNAs was determined by quantitative real-time polymerase chain reaction in 113 thyroid tissues of PTC (classic, encapsulated, and follicular), NIFTP, and hyperplasia lesions. Expression of the same miRNAs was tested in pre- and postoperative whole-blood samples.

RESULTS

Several miRNAs were differentially expressed in the different groups. Expression profile of miRNAs in the tissue was similarly reflected in the circulation. Receiver operating characteristic curve analysis showed that miR-7-5p, miR-222-3p, and miR-146b-5p can discriminate between the different groups with high sensitivity and specificity. Downregulation of miR-144-3p, miR-15a-5p, miR-20a-5p, miR-32-5p miR-142-5p, miR-143-3p, and miR-20b-5p is associated with aggressive behavior in cPTC. Circulating miR-146b-5p, miR-222-3p, miR-155-5p, and miR-378a-3p are potential diagnostic and follow up biomarkers for PTC.

CONCLUSION

Downregulation of miR-7-5p discriminates NIFTP from hyperplasia. Upregulation of miR-222-3p discriminates follicular variant of PTC from NIFTP. High levels of miR-146b-5p distinctively characterize cPTC. These miRNAs are useful biomarkers in the diagnosis of PTC and NIFTP, and help to avoid unnecessary thyroidectomy and improve clinical management.

Role of microRNAs in endocrine cancer metastasis

The deregulation of transcription and processing of microRNAs (miRNAs), as well as their function, has been involved in the pathogenesis of several human diseases, including cancer. Despite advances in therapeutic approaches, cancer still represents one of the major health problems worldwide. Cancer metastasis is an aggravating factor in tumor progression, related to increased treatment complexity and a worse prognosis. After more than one decade of extensive studies of miRNAs, the fundamental role of these molecules in cancer progression and metastasis is beginning to be elucidated. Recent evidences have demonstrated a significant role of miRNAs on the metastatic cascade, acting either as pro-metastatic or anti-metastatic. They are involved in distinct steps of metastasis including epithelial-to-mesenchymal transition, migration/invasion, anoikis survival, and distant organ colonization. Studies on the roles of miRNAs in cancer have focused mainly on two fronts: the establishment of a miRNA signature for different tumors, which may aid in early diagnosis using these miRNAs as markers, and functional studies of specific miRNAs, determining their targets, function and regulation. Functional miRNA studies on endocrine cancers are still scarce and represent an important area of research, since some tumors, although not frequent, present a high mortality rate. Among the endocrine tumors, thyroid cancer is the most common and best studied. Several miRNAs show lowered expression in endocrine cancers (i.e. miR-200s, miR-126, miR-7, miR-29a, miR-30a, miR-137, miR-206, miR-101, miR-613, miR-539, miR-205, miR-9, miR-195), while others are commonly overexpressed (i.e. miR-21, miR-183, miR-31, miR-let7b, miR-584, miR-146b, miR-221, miR-222, miR-25, miR-595). Additionally, some miRNAs were found in serum exosomes (miR-151, miR-145, miR-31), potentially serving as diagnostic tools. In this review, we summarize studies concerning the discovery and functions of miRNAs and their regulatory roles in endocrine cancer metastasis, which may contribute for the finding of novel therapeutic targets. The review focus on miRNAs with at least some identified targets, with established functions and, if possible, upstream regulation.

Stem cell-derived exosomes: a novel vector for tissue repair and diabetic therapy

Exosomes are extracellular vesicles (EVs) secreted from a majority of cell types. Exosomes play a role in healthy and pathogenic intercellular interactions via the transfer of proteins, lipids and RNA. The contents and effects of exosomes vary depending on the properties of the originating cell. Exosomes secreted from some cell types, including stem cells, carry biological factors implicated in the protection, regeneration and angiogenesis of damaged tissues. Due to these properties, exosomes have attracted attention as a novel vector for regenerative therapies. Exosomes as a therapeutic tool could have applications for the treatment of many disorders characterized by chronic tissue damage. Exosomes derived from stem cells could be applied to repair or prevent damage from the complications of diabetes mellitus. The immunomodulatory and reparative properties of stem cell-derived exosomes could protect or even restore an early-stage type 1 diabetic patient's original islets from autoimmune destruction. Exosomes could also possibly suppress graft rejection of pancreatic islet transplants. Therefore, it is our recommendation that the treatment of diabetes mellitus using exosome-based therapies be further explored. Development of novel therapies using exosomes is slowed by a limited understanding of their mechanisms. This hurdle must be overcome to pave the way for clinical trials and ultimately the adaptation of exosomes as a therapeutic vector.

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.

Dynamic monitoring of circulating microRNAs as a predictive biomarker for the diagnosis and recurrence of papillary thyroid carcinoma

Circulating microRNAs (miRNAs/miRs) are considered to be potential biomarkers for numerous types of cancer. However, previous investigations into the expression of miRNAs in the serum of patients with papillary thyroid carcinoma (PTC) to predict diagnosis, prognosis and recurrence have reported conflicting results, and the role of miRNAs remains unclear. The present study dynamically assessed the circulating miRNA profile in patients with PTC and determined whether miRNAs in the serum could be used as biomarkers for the diagnosis, prognosis and recurrence of PTC. The expression levels of 3 reportedly upregulated miRNAs (miR-222, miR-221 and miR-146b) were analyzed using reverse transcription-quantitative polymerase chain reaction in 106 patients with PTC, 35 patients with benign thyroid nodules (BTN) and 40 paired controls. Patients with either newly diagnosed PTC or BTN who were undergoing thyroidectomies were recruited for a dynamic analysis of preoperative and postoperative serum miRNA levels. The results indicated that the expression levels of serum miR-222, miR-221 and miR-146b were significantly increased in patients with newly diagnosed PTC compared with controls and patients with BTN. Receiver operating characteristic curve analysis indicated that these miRNAs had a high diagnostic sensitivity and specificity for PTC prior to surgery. The expression of these three miRNAs in serum was significantly associated with poorer prognostic variables, including extrathyroidal invasion, metastatic lymph nodes and high-risk or advanced tumor node metastasis stage. More notably, the present study identified 2.36-, 2.69- and 5.39-fold reductions in the serum levels of miR-222, miR-221 and miR-146b, respectively, subsequent to patients undergoing a thyroidectomy. In addition, miR-222, miR-221 and miR-146b were overexpressed in the PTC with recurrence group compared with the PTC without recurrence group. Collectively, dynamic monitoring of circulating miRNAs may serve as a non-invasive biomarker for the diagnosis of PTC and the postoperative monitoring of its progression and recurrence.

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

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

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.

Roles of microRNAs in cancer associated fibroblasts of gastric cancer

Cancer associated fibroblasts (CAFs) are a key component of the tumor microenvironment (TME). They play critical roles in the occurrence and development of gastric cancer (GC) through controlling various cytokines secretion and direct cell-to-cell interaction. However, the underlying mechanism of CAFs in tumor progression has not been entirely elucidated. MicroRNAs (miRNAs) as important factors have a central role in the interplay between tumor cell and TME. Recent studies also highlight that the aberrant expression of miRNAs in CAFs is involved in multiple functions in tumorigenesis and malignant process of GC. In this article, we shortly introduce the miRNAs biogenesis and provide an overview of the mechanisms and emerging roles of CAFs-related miRNAs. Focusing on these miRNAs as potential therapeutic targets may bring better treatment effect on GC and other diseases.

Identification of Thyroid-Associated Serum microRNA Profiles and Their Potential Use in Thyroid Cancer Follow-Up

Context:

Trends toward more conservative management of papillary thyroid cancer (PTC) diminish the primacy of serum thyroglobulin (Tg) assays as a posttreatment surveillance tool.

Objective:

To identify thyroid tumor-associated microRNAs (miRNAs) in the serum with potential for development as unique biomarkers of PTC recurrence.

Methods:

We measured expression of 754 miRNAs in serum samples collected from 11 patients with PTC before and 30 days after thyroidectomy. Major candidates were then re-evaluated by absolute quantitative polymerase chain reaction analysis in an independent cohort of patients with PTC (n = 44) or benign nodules and 20 healthy controls (HCs). The 2 miRNAs most significantly associated with thyroid tumors were then assessed in matched serum samples (before and 30 days and 1 to 2 years after surgery) from the 20 PTC patients with complete follow-up datasets and results correlated with American Thyroid Association (ATA) responses to therapy.

Results:

Eight miRNAs (miR-221-3p, miR-222-3p, miR-146a-5p, miR-24-3p, miR-146b-5p, miR-191-5p, miR-103a-3p, and miR-28-3p) displayed levels in prethyroidectomy serum samples from patients with PTC that significantly exceeded those measured after thyroidectomy and those found in samples from HCs. The 2 most promising candidates—miR-146a-5p and miR-221-3p —were further analyzed in the 20 PTC patients mentioned earlier. Serum levels of both miRNAs after 1 to 2 years of follow-up were consistent with ATA responses to therapy in all patients, including 2 with structural evidence of disease whose Tg assays remained negative (<1 ng/mL).

Conclusion:

miR-146a-5p and miR-221-3p hold remarkable promise as serum biomarkers for post-treatment monitoring of PTC patients, especially when Tg assay results are uninformative.

Expression of MicroRNAs in Thyroid Carcinoma

MicroRNA (miRNA) are negative regulators of gene expression and subsequent protein production. This method of action translates into regulatory control over cellular processes, including development, signaling, metabolism, and apoptosis. A broad range of miRNA are shown to have abnormal expressions in thyroid cancers which could explain the pathology of tumor oncogenesis and disease progression. A review is conducted of the current research on miRNA dysregulation in thyroid cancers, including papillary thyroid carcinoma (PTC), follicular thyroid carcinoma (FTC), anaplastic thyroid cancer (ATC), and medullary thyroid carcinoma (MTC). Dysregulated miRNA and their associated regulatory pathways are identified and their oncogenic and pathological significance are discussed.