MicroRNAs as Biomarkers in Thyroid Carcinoma

Cyto-Histological Profile of MicroRNAs as Diagnostic Biomarkers in Differentiated Thyroid Carcinomas

INTRODUCTION

The repertoire of microRNAs (miRNAs) in thyroid carcinomas starts to be elucidated. Among differentiated thyroid carcinomas (DTCs), papillary thyroid carcinoma (PTC) is the most frequent. The assessment of miRNAs expression may contribute to refine the pre-surgical diagnosis in order to obtain a personalized and more effective treatment for patients.

AIMS

This study aims to evaluate (1) the miRNAs in a series of DTCs, and their association with the presence of selected genetic mutations in order to improve diagnosis and predict the biologic behavior of DTC/PTC. (2) The reliability of molecular tests in Ultrasound-guided Fine Needle Aspiration Cytology (US-FNAC) for a more precise preoperative diagnosis.

MATERIAL AND METHODS

This series includes 176 samples (98 cytology and 78 histology samples) obtained from 106 patients submitted to surgery, including 13 benign lesions (controls) and 93 DTCs (cases). The microRNA expression was assessed for miR-146b, miR-221, miR-222, and miR-15a through quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). The results were analyzed by the 2-ΔΔCT method, using miR16 as an endogenous control. Regarding PTC diagnosis, the discriminative ability of miRNAs expression was assessed by the area under the Receiver Operating Characteristic Curve (AUC). In PTCs, the association of miRNAs expression, clinicopathological features, and genetic mutations (BRAF, RAS, and TERTp) was evaluated.

RESULTS/DISCUSSION

All the analyzed miRNAs presented a tendency to be overexpressed in DTCs/PTCs when compared with benign lesions, both in cytology and histology samples. In cytology, miRNAs expression levels were higher in malignant tumors than in benign tumors. In histology, the discriminative abilities regarding PTC diagnosis were as follows: miR-146b (AUC 0.94, 95% CI 0.87-1), miR-221 (AUC 0.79, 95% CI 0.68-0.9), miR-222 (AUC 0.76, 95% CI 0.63-0.89), and miR-15a (AUC 0.85, 95% CI 0.74-0.97). miR-146b showed 89% sensitivity (se) and 87% specificity (sp); miR-221 se = 68.4, sp = 90; miR-222 se = 73, sp = 70; and mi-R15a se = 72, sp = 80. MicroRNAs were associated with worst-prognosis clinicopathological characteristics in PTCs (p < 0.05), particularly for miR-222. Our data reveal a significant association between higher expression levels of miR-146b, miR-221, and miR-222 in the presence of the BRAF mutation (p < 0.001) and miR-146b (p = 0.016) and miR-221 (p = 0.010) with the RAS mutation, suggesting an interplay of these mutations with miRNAs expression. Despite this study having a relatively small sample size, overexpression of miRNAs in cytology may contribute to a more precise preoperative diagnosis. The miRNAs presented a good discriminative ability in PTC diagnosis. The association between the miRNAs expression profile and genetic alterations can be advantageous for an accurate diagnosis of DTCs/PTCs in FNAC.

Clinical Impact of Androgen Receptor-Suppressing miR-146b Expression in Papillary Thyroid Cancer Aggressiveness

CONTEXT

Papillary thyroid carcinoma (PTC) is the most common thyroid malignancy. Dysregulated expression of miR-146b and androgen receptor (AR) has been shown to play critical roles in tumorigenesis in PTC. However, the mechanistic and clinical association between AR and miR-146b is not fully understood.

OBJECTIVE

The purpose was to investigate miR-146b as the potential AR target miRNA and its involvement in advanced tumor characteristics of PTC.

METHODS

Expression of AR and miR-146b were assessed in frozen and formalin-fixed paraffin-embedded tissue samples from PTC and adjacent normal thyroid specimens by quantitative real-time polymerase chain reaction, and their correlation was examined. Human thyroid cancer cell lines BCPAP and TPC-1 were used to evaluate the effect of AR on miR-146b signaling. Chromatin immunoprecipitation (ChIP) assays were performed to determine whether AR binds to the miR-146b promoter region.

RESULTS

Pearson correlation analysis confirmed significant inverse correlation between miR-146b and AR expression. Overexpressing AR BCPAP and TPC-1 cells showed relatively lower miR-146b expression. ChIP assay revealed that AR might bind to the androgen receptor element located on the promoter region of miRNA-146b gene, and overexpression of AR suppresses miR-146b-mediated tumor aggressiveness. The low AR/high miR-146b PTC patient group was associated with advanced tumor characteristics, including higher tumor stage, lymph node metastasis, and worse treatment response.

CONCLUSION

To sum up, miR-146b is a molecular target of AR transcriptional repression; therefore, AR suppresses miR-146b expression to reduce PTC tumor aggressiveness.

The role of miR-139-5p in radioiodine-resistant thyroid cancer

PURPOSE

Radioiodine I-131 (RAI) is the therapy of choice for differentiated thyroid cancer (DTC). Between 5% and 15% of DTC patients become RAI refractory, due to the loss of expression/function of iodide metabolism components, especially the Na/I symporter (NIS). We searched for a miRNA profile associated with RAI-refractory DTC to identify novel biomarkers that could be potential targets for redifferentiation therapy.

METHODS

We analyzed the expression of 754 miRNAs in 26 DTC tissues: 12 responsive (R) and 14 non-responsive (NR) to RAI therapy. We identified 15 dysregulated miRNAs: 14 were upregulated, while only one (miR-139-5p) was downregulated in NR vs. R tumors. We investigated the role of miR-139-5p in iodine uptake metabolism. We overexpressed miR-139-5p in two primary and five immortalized thyroid cancer cell lines, and we analyzed the transcript and protein levels of NIS and its activation through iodine uptake assay and subcellular protein localization.

RESULTS

The finding of higher intracellular iodine levels and increased cell membrane protein localization in miR-139-5p overexpressing cells supports the role of this miRNA in the regulation of NIS function.

CONCLUSIONS

Our study provides evidence of miR-139-5p involvement in iodine uptake metabolism and suggests its possible role as a therapeutic target in restoring iodine uptake in RAI-refractory DTC.

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.

Cell-free DNA methylation biomarker for the diagnosis of papillary thyroid carcinoma

BACKGROUND

Cell-free DNA (cfDNA) is being explored as biomarker for non-invasive diagnosis of cancer. We aimed to establish a cfDNA-based DNA methylation marker panel to differentially diagnose papillary thyroid carcinoma (PTC) from benign thyroid nodule (BTN).

METHODS

220 PTC- and 188 BTN patients were enrolled. Methylation markers of PTC were identified from patients' tissue and plasma by reduced representation bisulfite sequencing and methylation haplotype analyses. They were combined with PTC markers from literatures and were tested on additional PTC and BTN samples to verify PTC-detecting ability using targeted methylation sequencing. Top markers were developed into ThyMet and were tested in 113 PTC and 88 BTN cases to train and validate a PTC-plasma classifier. Integration of ThyMet and thyroid ultrasonography was explored to improve accuracy.

FINDINGS

From 859 potential PTC plasma-discriminating markers that include 81 markers identified by us, the top 98 most PTC plasma-discriminating markers were selected for ThyMet. A 6-marker ThyMet classifier for PTC plasma was trained. In validation it achieved an Area Under the Curve (AUC) of 0.828, similar to thyroid ultrasonography (0.833) but at higher specificity (0.722 and 0.625 for ThyMet and ultrasonography, respectively). A combinatorial classifier by them, ThyMet-US, improved AUC to 0.923 (sensitivity = 0.957, specificity = 0.708).

INTERPRETATION

The ThyMet classifier improved the specificity of differentiating PTC from BTN over ultrasonography. The combinatorial ThyMet-US classifier may be effective in preoperative diagnosis of PTC.

FUNDING

This work was supported by the grants from National Natural Science Foundation of China (82072956 and 81772850).

Expression of miR-31-5p affects growth, migration and invasiveness of papillary thyroid cancer cells

PURPOSE

In this study, we evaluated the biological role of miRNA-31-5p in papillary thyroid cancer (PTC).

METHODS

By using the real-time PCR, we measured miRNA-31-5p expression levels in 25 PTC tissues and in two human PTC cell lines (K1 and TPC-1). Then, K1 cells were transiently transfected with mirVana inhibitor or mirVana mimic to miRNA-31-5-p. Cell proliferation was determined by MTT and colony formation assays. The in vitro metastatic ability of thyroid cancer cells was evaluated by adhesion, migration and invasion assays. Epithelial mesenchymal transition (EMT) and Hippo pathway related gene and protein levels were evaluated by using the TaqMan™ Gene Expression Assays and western blot analysis, respectively.

RESULTS

We found a significant increase of miR-31-5-p expression in tumor tissue and in K1 cells harboring the BRAF p.V600E mutation. Knockdown of miR-31-5p determined a reduction of cell proliferation, associated with a significant decrease in cell adhesion, migration and invasion properties. A downregulation of EMT markers and YAP/β-catenin axis was also observed.

CONCLUSIONS

Our findings suggest that miRNA-31-5p acts as oncogenic miRNA in human thyrocytes and its overexpression may be involved in the BRAF-related tumorigenesis in PTCs, providing new understanding into its pathological role in PTC progression and invasiveness.

Significance of miRNAs on the thyroid cancer progression and resistance to treatment with special attention to the role of cross-talk between signaling pathways

Thyroid cancer (TC) is the most prevalent endocrine malignant tumor. It has many types, the Papillary thyroid cancer (PTC)(most common and follicular thyroid carcinoma (FTC). Several risk factors have been associated with TC radiation exposure, autoimmunity, and genetics. Microribonucleic acids (miRNAs) are the most important genetic determinants of TC. They are small chains of nucleic acids that are able to inhibit the expression of several target genes. They could target several genes involved in TC proliferation, angiogenesis, apoptosis, development, and even resistance to therapy. Besides, they could influence the stemness of TC. Moreover, they could regulate several signaling pathways such as WNT/β-catenin, PI3K/AKT/mTOR axis, JAK/STAT, TGF- β, EGFR, and P53. Besides signaling pathways, miRNAs are also involved in the resistance of TC to major treatments such as surgery, thyroid hormone-inhibiting therapy, radioactive iodine, and adjuvant radiation. The stability and sensitivity of several miRNAs might be exploited as an approach for the usage of miRNAs as diagnostic and/or prognostic tools in TC.

VHL tumor suppressor as a novel potential candidate biomarker in papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is the most common type of endocrine cancer, with an increasing incidence worldwide. The treatment of PTC is currently the subject of clinical controversy, making it critically important to identify molecular markers that would help improve the risk stratification of PTC patients and optimize the therapeutic approach. The VHL tumor suppressor gene has been implicated in tumorigenesis of various types of carcinoma and linked with their aggressive biological behavior. The role of VHL in the origin and development of PTC has only recently begun to be revealed. In this narrative review we attempt to summarize the existing knowledge that implicates VHL in PTC pathogenesis and to outline its potential significance as a candidate molecular biomarker for the grouping of PTC patients into high and low risk groups.

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.

Molecular testing in fine-needle aspiration of thyroid nodules

BACKGROUND

Thyroid nodules are commonly faced by clinicians as palpable nodules or incidentally identified on imaging. Nodules that are found to be suspicious by imaging can be biopsied by fine needle aspiration, which can yield material for molecular testing to refine the diagnosis.

METHODS

The current literature concerning molecular testing in thyroid nodules including available commercial assays was reviewed and summarized.

RESULTS/CONCLUSIONS

Commonly encountered alterations include mutations in RAS, BRAF, TERT promoter, PTEN, and DICER1 as well as fusions of RET, ALK, PAX8-PPARγ, and NTRK. This article provides a summary of these molecular alterations, commercially available molecular assays, and general considerations for thyroid epithelial malignancies and benign thyroid nodules.

MiR-203a-3p, miR-204-3p, miR-222-3p as useful diagnostic and prognostic tool for thyroid neoplasia spectrum

PURPOSE

The challenge in the diagnosis and treatment of thyroid carcinoma is to correctly classify neoplasias with overlapping features and to identify the high-risk patients among those with a less aggressive form, in order to personalize the treatment of thyroid carcinoma patients accordingly.

METHODS

MiR-203a-3p, miR-204-3p, and miR-222-3p levels were determined in 99 cases of thyroid neoplasias (77 papillary thyroid carcinomas (PTC) of diverse variants, 12 follicular thyroid adenomas (FTA) and 10 nodular goiters (NG)) along with 99 adjacent non-malignant thyroid tissues using quantitative RT-PCR. The results were evaluated in comparison with the clinicopathological features of the patients and available TCGA data.

RESULTS

Down-regulated miR-203a-3p indicates the presence of thyroid tumor (PTC or FTA) with high sensitivity (75%) and specificity (73%), while its up-regulation indicates NG. If miR-203a-3p is down-regulated, up-regulated miR-204-3p with high sensitivity (83.3%) and specificity (74.4%) indicates FTA presence, while up-regulated miR-222-3p, with high sensitivity (76.6%) and specificity (75.0%), points to PTC. The expression of miR-204-3p and miR-222-3p depends on the PTC subtype (P < 0.05). While the deregulated expression of tested miRs is associated with a long-range of unfavorable clinicopathological parameters of PTC, only abundant expression of miR-222-3p may be used as an independent predictive factor for the presence of extrathyroid invasion and advanced pTNM stage of PTC (P < 0.05).

CONCLUSION

Successive evaluation of miR-203a-3p, miR-204-3p, and miR-222-3p expression can help in the differential diagnosis of thyroid neoplasias. A high relative value of miR-222-3p expression is an independent predictive factor for the presence of extrathyroid invasion and advanced pTNM stage of PTC. The panel consisting of miR-203a-3p, miR-204-3p, and miR-222-3p could be used as a diagnostic and prognostic tool for personalizing the treatment of thyroid cancer patients.

Identification of Exosomal microRNAs and Their Targets in Papillary Thyroid Cancer Cells

The release of molecules in exosomal cargoes is involved in tumor development and progression. We compared the profiles of exosomal microRNAs released by two thyroid cancer cell lines (TPC-1 and K1) with that of non-tumorigenic thyroid cells (Nthy-ori-3-1), and we explored the network of miRNA–target interaction. After extraction and characterization of exosomes, expression levels of microRNAs were investigated using custom TaqMan Advanced array cards, and compared with those expressed in the total cell extracts. The functional enrichment and network-based analysis of the miRNAs’ targets was also performed. Five microRNAs (miR-21-5p, miR-31-5p, miR-221-3p, miR-222-3p, and let-7i-3p) were significantly deregulated in the exosomes of tumor cells vs. non-tumorigenic cells, and three of them (miR-31-5p, miR-222-3p, and let-7i-3p) in the more aggressive K1 compared to TPC-1 cells. The network analysis of the five miRNAs identified some genes as targets of more than one miRNAs. These findings permitted the identification of exosomal microRNAs secreted by aggressive PTC cells, and indicated that their main targets are regulators of the tumor microenvironment. A deeper analysis of the functional role of the targets of exosomal miRNAs will provide further information on novel targets of molecular treatments for these neoplasms.

Circular RNAs and thyroid cancer: closed molecules, open possibilities

Thyroid neoplasms requiring differential diagnosis between thyroid cancer and benign tumors can be detected in more than half of the healthy population. A generally accepted method that allows assessing the risk of malignant potential and determining the indications for surgical treatment of thyroid tumor is a fine-needle aspiration biopsy followed by a cytological examination. Nevertheless, in patients with indeterminate categories of cytological conclusions according to Bethesda system, the positive predictive value of the cytology result is significantly lower than desired and often leads to unjustified surgical treatment. In this regard, the search for alternative diagnostic solutions continues. Circular RNAs are a group of non-coding RNAs distinguished by a closed structure formed by covalent bonding of the nucleotide chain ends. Recent studies allow us to conclude that many different circular RNAs are involved in processes mediating oncogenesis in the thyroid gland, and their altered expression in tissue, blood, and exosomes of plasma may be a characteristic sign of thyroid cancer and certain clinicopathological features of its course. The purpose of this review is to analyze the accumulated data on the association of various circular RNAs with thyroid cancer and to discuss possible ways to improve the diagnosis and treatment of the disease based on the assessment of the expression of these molecules.

Sex Differences in Differentiated Thyroid Cancer

Background: Sex dimorphism strongly impacts tumor biology, with most cancers having a male predominance. Uniquely, thyroid cancer (TC) is the only nonreproductive cancer with striking female predominance with three- to four-fold higher incidence among females, although males generally have more aggressive disease. The molecular basis for this observation is not known, and current approaches in treatment and surveillance are not sex specific. Summary: Although TC has overall good prognosis, 6-20% of patients develop regional or distant metastasis, one third of whom are not responsive to conventional treatment approaches and suffer a 10-year survival rate of only 10%. More efficacious treatment strategies are needed for these aggressive TCs, as tyrosine kinase inhibitors and immunotherapy have major toxicities without demonstrable overall survival benefit. Emerging evidence indicates a role of sex hormones, genetics, and the immune system in modulation of both risk for TC and its progression in a sex-specific manner. Conclusion: Greater understanding of the molecular mechanisms underlying sex differences in TC pathogenesis could provide insights into the development of sex-specific, targeted, and effective strategies for prevention, diagnosis, and management. This review summarizes emerging evidence for the importance of sex in the pathogenesis, progression, and response to treatment in differentiated TC with emphasis on the role of sex hormones, genetics, and the immune system.

Analysis of serum microRNA in exosomal vehicles of papillary thyroid cancer

PURPOSE

In this study, we investigated the profile of microRNAs (miRNAs) contained in exosomes secreted in the serum of patients with papillary thyroid cancer (PTC).

METHODS

Exosome were isolated by adding ExoQuick Exosome Precipitation Solution. Dynamic light scattering (DLS) and western blotting analysis were used to ensure the quality of exosomes. The expression levels of miRNAs were investigated using custom-designed TaqMan Advanced miRNA Array Cards in the screening cohort and using specific TaqMan Advanced MicroRNA Assays in the validation cohort.

RESULTS

We identified miR24-3p, miR146a-5p, miR181a-5p and miR382-5p with different expression levels in two different series of 56 and 58 PTC patients as compared with healthy controls. Significant differences in the expression of three PTC exosomal miRNAs, depending on the presence of lymph node metastasis, were detected in only one PTC series. When comparing the expression levels of some PTC-specific exosomal miRNAs with those of the same miRNAs circulating free of any encapsulation, we found a significant correlation for only miR24-3p, suggesting that only select miRNAs are secreted in exosomes.

CONCLUSIONS

Our findings demonstrate that four miRNAs are differently secreted in the exosomes of PTC patients, whereas no conclusive results were found to characterize PTCs with lymph node metastasis, suggesting caution in the use of circulating exosomal miRNA expression levels as lymph node metastasis biomarkers. Further investigation into the mechanisms governing miRNA secretion in tumor cells are required.

Emerging Biomarkers in Thyroid Practice and Research

Simple Summary

Tumor biomarkers are molecules at genetic or protein level, or certain evaluable characteristics. These help in perfecting patient management. Over the past decade, advanced and more sensitive techniques have led to the identification of many new biomarkers in the field of oncology. A knowledge of the recent developments is essential for their application to clinical practice, and furthering research. This review provides a comprehensive account of such various markers identified in thyroid carcinoma, the most common endocrine malignancy. While some of these have been brought into use in routine patient management, others are novel and need more research before clinical application.

Abstract

Thyroid cancer is the most common endocrine malignancy. Recent developments in molecular biological techniques have led to a better understanding of the pathogenesis and clinical behavior of thyroid neoplasms. This has culminated in the updating of thyroid tumor classification, including the re-categorization of existing and introduction of new entities. In this review, we discuss various molecular biomarkers possessing diagnostic, prognostic, predictive and therapeutic roles in thyroid cancer. A comprehensive account of epigenetic dysregulation, including DNA methylation, the function of various microRNAs and long non-coding RNAs, germline mutations determining familial occurrence of medullary and non-medullary thyroid carcinoma, and single nucleotide polymorphisms predisposed to thyroid tumorigenesis has been provided. In addition to novel immunohistochemical markers, including those for neuroendocrine differentiation, and next-generation immunohistochemistry (BRAF V600E, RAS, TRK, and ALK), the relevance of well-established markers, such as Ki-67, in current clinical practice has also been discussed. A tumor microenvironment (PD-L1, CD markers) and its influence in predicting responses to immunotherapy in thyroid cancer and the expanding arena of techniques, including liquid biopsy based on circulating nucleic acids and plasma-derived exosomes as a non-invasive technique for patient management, are also summarized.

Investigating differential miRNA expression profiling using serum and urine specimens for detecting potential biomarkers for early prostate cancer diagnosis

Background/aim

MicroRNAs (miRNAs) are known up-to-date candidate biomarkers for several diseases. In addition, obtaining miRNA from different body fluids such as serum, plasma, saliva, and urine is relatively easy to handle. Herein we aimed to detect miRNAs as biomarkers for early stage prostate cancer (PC). For this purpose, we used urine and serum samples to detect any significant differences in miRNA profiles between patients and healthy controls.

Materials and methods

Total ribonucleic acid (RNA) in urine and serum samples were isolated from eight untreated PC patients, thirty healthy individuals were screened for miRNA profile, and candidate miRNAs were validated. Whole urinary and serum miRNA profile was analyzed using Affymetrix GeneChip miRNA 4.0 Arrays. Candidate miRNAs were investigated by stem-loop reverse transcription- polymerase chain reaction.

Results

When we analyzed the urinary samples of PC patients, 49 miRNAs were detected to be upregulated and 14 miRNAs were found to be downregulated when compared with healthy controls. According to the serum samples, 19 miRNAs were found to be upregulated, and 21 miRNAs were found to be downregulated when compared with healthy individuals as well. Interestingly, we detected only four overlapping miRNAs (MIR320A, MIR4535, MIR4706, MIR6750) that commonly increase or decrease in both serum and urine samples. Among them, MIR320A was found to be downregulated, and MIR4535, MIR4706, and MIR6750 were found to be upregulated for urine samples. However, only MIR6750 was upregulated and the other three miRNAs were downregulated for serum samples.

Conclusion

Notably, the expression profile of MIR320A was significantly altered in urine specimens of prostate cancer patients. We considered that MIR320A has been evaluated as a valuable biomarker that can be used in the early diagnosis of PC.

Thyroid Nodule Characterization: How to Assess the Malignancy Risk. Update of the Literature

Ultrasound (US) is the first imaging modality for thyroid parenchyma evaluation. In the last decades, the role of ultrasound has been improved with the introduction of new US software, such as contrast-enhanced ultrasound (CEUS) and US-elastography (USE). USE is nowadays recognized as an essential part of the multiparametric ultrasound (MPUS) examination, in particular for the indeterminate thyroid nodule with possible fine-needle aspiration cytology (FNAC) number reduction; even if further and larger studies are needed to validate it. More controversial is the role of CEUS in thyroid evaluation, due to its high variability in sensitivity and specificity. Semi-automatic US systems based on the computer-aided diagnosis (CAD) system are producing interesting results, especially as an aid to less experienced operators. New knowledge on the molecular mechanisms involved in thyroid cancer is allowing practitioners to identify new genomic thyroid markers that could reduce the number of "diagnostic" thyroidectomies. We have therefore drawn up an updated representation of the current evidence in the literature for thyroid nodule multiparametric ultrasound (MPUS) evaluation with particular regard to USE, the US CAD system and CEUS.

Phytochemicals in thyroid cancer: analysis of the preclinical studies

PURPOSE

In the search for novel effective compounds to use in thyroid cancer (TC) unresponsive to current treatment, attention has recently focused on plant-derived compounds with anticancer activity. In this review, we discuss the preclinical studies demonstrating phytochemical activity against thyroid cancer cells.

RESULTS/CONCLUSIONS

In particular, we describe their antiproliferative properties or ability to re-induce iodine retention, thus supporting their potential use as single agents or adjuvants in radioiodine-resistant thyroid cancer treatment.

Curcumin inhibits the viability, migration and invasion of papillary thyroid cancer cells by regulating the miR-301a-3p/STAT3 axis

Thyroid cancer is one of the most common malignant tumors, and the mortality rate associated with thyroid cancer has been increasing annually. Curcumin has been reported to exert an antitumor effect on papillary thyroid cancer (PTC), and the identification of additional mechanisms underlying the anticancer effect of curcumin on PTC requires further investigation. The present study aimed to explore the effects of curcumin on the viability, migration and invasion of PTC cells. TPC-1 cells were incubated with different concentrations of curcumin, and then, cell viability, migration and invasion, and wound healing were examined by CCK-8, Transwell and wound healing assays, respectively. Subsequently, microRNA (miR)-301a-3p mimics, miR-301a-3p inhibitors and signal transducer and activator of transcription (STAT)3 overexpression vector were transfected into TPC-1 cells, and cell viability, migration, and invasion were reassessed in these transfected cells. Matrix metallopeptidase (MMP)-2, MMP-9, epithelial-mesenchymal transition (EMT)-related markers, and Janus kinase (JAK)/STAT signaling pathway components were assessed by western blot analysis. Curcumin significantly inhibited cell viability, migration and invasion and downregulated MMP-2, MMP-9 and EMT marker expression. Additionally, curcumin decreased STAT3 expression by upregulating miR-301a-3p expression, and the inhibition of miR-301a-3p and the overexpression of STAT3 reversed the effects of curcumin on cell viability, migration and invasion, and MMP-2, MMP-9 and EMT marker expression in TPC-1 cells. Furthermore, curcumin suppressed the JAK/STAT signaling pathway through the miR-301a-3p/STAT3 axis. The data of the present study indicated that curcumin could inhibit the viability, migration and invasion of TPC-1 cells by regulating the miR-301a-3p/STAT3 axis. These findings may provide a possible strategy for the clinical treatment of PTC.

Overexpression of DDIT4 and TPTEP1 are associated with metastasis and advanced stages in colorectal cancer patients: a study utilizing bioinformatics prediction and experimental validation

BACKGROUND

Various diagnostic and prognostic tools exist in colorectal cancer (CRC) due to multiple genetic and epigenetic alterations causing the disease. Today, the expression of RNAs is being used as prognostic markers for cancer.

METHODS

In the current study, various dysregulated RNAs in CRC were identified via bioinformatics prediction. Expression of several of these RNAs were measured by RT-qPCR in 48 tissues from CRC patients as well as in colorectal cancer stem cell-enriched spheroids derived from the HT-29 cell line. The relationships between the expression levels of these RNAs and clinicopathological features were analyzed.

RESULTS

Our bioinformatics analysis determined 11 key mRNAs, 9 hub miRNAs, and 18 lncRNAs which among them 2 coding RNA genes including DDIT4 and SULF1 as well as 3 non-coding RNA genes including TPTEP1, miR-181d-5p, and miR-148b-3p were selected for the further investigations. Expression of DDIT4, TPTEP1, and miR-181d-5p showed significantly increased levels while SULF1 and miR-148b-3p showed decreased levels in CRC tissues compared to the adjacent normal tissues. Positive relationships between DDIT4, SULF1, and TPTEP1 expression and metastasis and advanced stages of CRC were observed. Additionally, our results showed significant correlations between expression of TPTEP1 with DDIT4 and SULF1.

CONCLUSIONS

Our findings demonstrated increased expression levels of DDIT4 and TPTEP1 in CRC were associated with more aggressive tumor behavior and more advanced stages of the disease. The positive correlations between TPTEP1 as non-coding RNA and both DDIT4 and SULF1 suggest a regulatory effect of TPTEP1 on these genes.

Assessment of AXL and mTOR genes expression in medullary thyroid carcinoma (MTC) cell line in relation with over expression of miR-144 and miR-34a

OBJECTIVES

The aim of the present study was to investigate the expression of AXL and mTOR genes and their targeting microRNAs (miRNAs) including miR-34a and miR-144 in Medullary Thyroid Carcinoma (MTC) cell line, TT, and determine the effect of these two miRNAs on their target genes to introduce new molecular markers or therapeutics.

METHODS

The expression of miR-34a, miR-144, and their targets genes including AXL and mTOR was evaluated by quantitative Real-time PCR. Luciferase assay was performed to confirm the interaction between miRNAs and their target mRNAs. The expression level of AXL and mTOR was evaluated before and after miRNAs induction in TT cell line compared with Cos7 as control cells.

RESULTS

The expression of AXL and mTOR were up-regulated significantly, while miR-34a and miR-144 were down-regulated in TT cell line compared to Cos7. After transduction, the overexpression of miR-34a and 144 caused down-regulation of both genes. Luciferase assay results showed that the mTOR is targeted by miR-34a and miR-144 and the intensity of luciferase decreased in the presence of miRNAs.

CONCLUSIONS

Based on the results of the present study and since AXL and mTOR genes play a critical role in variety of human cancers, suppression of these genes by their targeting miRNAs, especially miR-34a and miR-144, can be propose as a new strategy for MTC management. However, more studies are needed to approve the hypothesis.

Selective Use of Radioactive Iodine Therapy for Papillary Thyroid Cancers With Low or Lower-Intermediate Recurrence Risk

CONTEXT

Current guidelines recommend a selective use of radioiodine treatment (RAI) for papillary thyroid cancer (PTC).

OBJECTIVE

This work aimed to determine how policy changes affect the use of RAI and the short-term outcomes of patients.

METHODS

A retrospective analysis of longitudinal data was conducted in an academic referral center of patients with nonaggressive PTC variants; no extrathyroidal invasion or limited to soft tissues, no distant metastases, and 5 or fewer central-compartment cervical lymph node metastases. In cohort 1, standard treatments were total thyroidectomy and RAI (May 2005-June 2011); in cohort 2 decisions on RAI were deferred for approximately 12 months after surgery (July 2011-December 2018). Propensity score matching was used to adjust for sex, age, tumor size, lymph node status, and extrathyroidal extension. Intervention included immediate RAI or deferred choice. Main outcome measures were responses to initial treatment during 3 or more years of follow-up.

RESULTS

In cohort 1, RAI was performed in 50 of 116 patients (51.7%), whereas in cohort 2, it was far less frequent: immediately in 10 of 156 (6.4%), and in 3 more patients after the first follow-up data. The frequencies of structural incomplete response were low (1%-3%), and there were no differences between the 2 cohorts at any follow-up visit. Cohort 2 patients had higher rates of "gray-zone responses" (biochemical incomplete or indeterminate response).

CONCLUSION

Selective use of RAI increases the rate of patients with "uncertain" status during early follow-up. The rate of structural incomplete responses remains low regardless of whether RAI is used immediately. Patients should be made aware of the advantages and drawbacks of omitting RAI.

Molecular Genetics of Follicular-Derived Thyroid Cancer

Simple Summary

Thyroid tumors that derive from follicular cells are not a homogeneous entity, showing variable morphological appearance and different degrees of differentiation. Molecular markers are useful for both diagnostic purposes and prognostic stratification of patients. In presurgical setting, molecular testing of indeterminate thyroid nodules on aspirates provides useful diagnostic information; the molecular analysis on tumor tissues can also reveal the presence of genetic alterations related to patients’ prognosis. In recent years, the molecular characterization of these tumors has acquired even more importance thanks to the introduction of targeted drugs. This review summarizes the current literature on the molecular landscape of follicular-derived thyroid tumors.

Abstract

Thyroid cancer is the most common type of endocrine-related malignancy, whose incidence rates have increased dramatically in the last few decades. Neoplasms of follicular origin generally have excellent prognosis, with the exception of less differentiated tumors. Follicular-derived thyroid cancer can manifest as a variety of morphologically distinct entities, characterized by various degrees of differentiation and invasiveness. Histological evaluation is thus crucial for the definition of patients’ prognosis. However, within each histological subtype, tumor behavior can be highly variable, and, in this respect, molecular characterization can provide insightful information to refine the risk stratification of tumors. In addition to the importance of its prognostic role, molecular testing can be used to support the differential diagnosis of thyroid nodules in the absence of marked cyto-morphological aberrations. Finally, with the advent of targeted drugs, the presence of molecular alterations will guide the therapeutic strategies for patients with advanced tumors who do not respond to standard treatment. This review aims to describe the genetic landscape of follicular-derived thyroid tumors also highlighting differences across histological subtypes.

Long non-coding RNA LINC00488 facilitates thyroid cancer cell progression through miR-376a-3p/PON2

Objective: Long non-coding RNAs (lncRNAs) recently have been identified as influential indicators in a variety of malignancies. The aim of the present study was to identify a functional lncRNA LINC00488 and its effects on thyroid cancer in the view of cell proliferation and apoptosis.

Methods: In order to evaluate the effects of LINC00488 on the cellular process of thyroid cancer, we performed a series of in vitro experiments, including cell counting kit-8 (CCK-8) assay, EdU (5-ethynyl-2′-deoxyuridine) assay, flow cytometry, transwell chamber assay, Western blot and RT-qPCR. The target gene of LINC00488 was then identified by bioinformatics analysis (DIANA and TargetScan). Finally, a series of rescue experiments was conducted to validate the effect of LINC00488 and its target genes on proliferation, migration, invasion and apoptosis of thyroid cancer.

Results: Our findings revealed that LINC00488 was highly expressed in thyroid cancer cell lines (BCPAP, BHP5-16, TPC-1 and CGTH-W3) and promoted the proliferation, migration and invasion, while inhibited the apoptosis of thyroid cancer cells (BCPAP and TPC-1). The results of bioinformatics analysis and dual luciferase reporter gene assay showed that LINC00488 could directly bind to miR-376a-3p and down-regulated the expression level of miR-376a-3p. In addition, Paraoxonase-2 (PON2) was a target gene of miR-376a-3p and negatively regulated by miR-376a-3p. Rescue experiment indicated that LINC00488 might enhance PON2 expression by sponging miR-376a-3p in thyroid cancer.

Conclusion: Taken together, our study revealed that lncRNA LINC00488 acted as an oncogenic gene in the progression of thyroid cancer via regulating miR-376a-3p/PON2 axis, which indicated that LINC00488-miR-376a-3p-PON2 axis could serve as novel biomarkers or potential targets for the treatment of thyroid cancer.

MicroRNA Profile for Diagnostic and Prognostic Biomarkers in Thyroid Cancer

The challenge in managing thyroid nodules is to accurately diagnose the minority of those with malignancy. We aimed to identify diagnostic and prognostic miRNA markers for thyroid nodules. In a discovery cohort, we identified 20 candidate miRNAs to differentiate between noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTP) and papillary thyroid carcinomas (PTC) by using the high-throughput small RNA sequencing method. We then selected three miRNAs (miR-136, miR-21, and miR-127) that were differentially expressed between the PTC follicular variant and other variants in The Cancer Genome Atlas data. High expression of three miRNAs differentiated thyroid cancer from nonmalignant tumors, with an area under curve (AUC) of 0.76-0.81 in an independent cohort. In patients with differentiated thyroid cancer, the high-level expression of the three miRNAs was an independent indicator for both distant metastases and recurrent or persistent disease. In patients with PTC, a high expression of miRNAs was associated with an aggressive histologic variant, extrathyroidal extension, distant metastasis, or recurrent or persistent disease. Three miRNAs may be used as diagnostic markers for differentiating thyroid cancers from benign tumors and tumors with extremely low malignant potential (NIFTP), as well as prognostic markers for predicting the risk of recurrent/persistent disease for differentiated thyroid cancer.

Molecular analysis of fine-needle aspiration cytology in thyroid disease: where are we?

PURPOSE OF REVIEW

The prevalence of thyroid nodules in the general population is high but only about 5% are malignant lesions. Cytology is usually appropriate to rule out malignancy in sonographically suspicious nodules but in many cases, reports are indeterminate. Molecular testing is a more recent approach to rule out malignancy and guide subsequent management.

RECENT FINDINGS

Although several different molecular testing approaches have proven useful in reducing unnecessary surgery, there are still several remaining issues, such as the possible occurrence of RAS mutations (which are difficult to interpret in clinical management) and the role of molecular analysis in specific histotypes, such as Hürthle cell carcinomas. Furthermore, conclusive evidence is lacking regarding the cost-effectiveness and appropriateness of surgical options following molecular tests.

SUMMARY

To be useful in clinical practice, molecular tests should be applied to appropriate candidates. In truly uncertain thyroid nodules in which diagnostic surgery may be considered, molecular testing may change the clinical approach and 'save' a number of thyroids.

Liquid biopsy in thyroid cancer: from circulating biomarkers to a new prospective of tumor monitoring and therapy

Recently, liquid biopsy has attracted much interest as a tool for early cancer screening, prognosis, monitoring and response to treatment in many different cancer types. Indeed, liquid biopsies can be repeatedly performed in a noninvasive way, at lower cost and without the risks associated to the classic tissue biopsy. The objective of this monography was to describe the main components studied in liquid biopsy (circulating tumor nucleic acids, circulating tumor cells and extracellular vesicles) and how they have been explored in thyroid cancer, through an in-depth scientific literature review. While circulating tumor cells are the most represented component in the literature of liquid biopsy in thyroid cancer, circulating tumor nucleic acids and extracellular vesicles have also been recently explored. One important challenge in this field of research, especially for differentiated thyroid cancer, has been the low quantity of circulating components with respect to other cancer types, requiring more advanced techniques for both isolation and analysis. Despite these limitations, liquid biopsy showed promise as an additional noninvasive tool for diagnosis, prognosis, to predict outcome and therapeutic response in differentiated, medullary and anaplastic thyroid cancer.

MicroRNA in Papillary Thyroid Carcinoma: A Systematic Review from 2018 to June 2020

Simple Summary

The most common form of endocrine cancer - papillary thyroid carcinoma, has an increasing incidence. Although this disease usually has an indolent behavior, there are cases when it can evolve more aggressively. It has been known for some time that it is possible to use microRNAs for the diagnosis, prognosis and even treatment monitoring of papillary thyroid cancer. The purpose of this study is to summarize the latest information provided by publications regarding the involvement of microRNAs in papillary thyroid cancer, underling the new clinical perspectives offered by these publications.

Abstract

The involvement of micro-ribonucleic acid (microRNAs) in metabolic pathways such as regulation, signal transduction, cell maintenance, and differentiation make them possible biomarkers and therapeutic targets. The purpose of this review is to summarize the information published in the last two and a half years about the involvement of microRNAs in papillary thyroid carcinoma (PTC). Another goal is to understand the perspective offered by the new findings. Main microRNA features such as origin, regulation, targeted genes, and metabolic pathways will be presented in this paper. We interrogated the PubMed database using several keywords: “microRNA” + “thyroid” + “papillary” + “carcinoma”. After applying search filters and inclusion criteria, a selection of 137 articles published between January 2018–June 2020 was made. Data regarding microRNA, metabolic pathways, gene/protein, and study utility were selected and included in the table and later discussed regarding the matter at hand. We found that most microRNAs regularly expressed in the normal thyroid gland are downregulated in PTC, indicating an important tumor-suppressor action by those microRNAs. Moreover, we showed that one gene can be targeted by several microRNAs and have nominally described these interactions. We have revealed which microRNAs can target several genes at once.

Plasma levels of soluble HLA-G and cytokines in papillary thyroid carcinoma before and after thyroidectomy

BACKGROUND

Increasing evidence shows that chronic inflammation plays an important role in thyroid tumorigenesis. Cytokines as central mediators in inflammatory microenvironment can present both pro-tumour and anti-tumour effects and cytokine release may be influenced by soluble HLA-G (sHLA-G), an immune checkpoint molecule whose expression can also be induced by certain cytokines.

AIM

To understand the role of these soluble factors in papillary thyroid cancer (PTC).

METHODS

We evaluated plasma levels of sHLA-G and of 13 cytokines using ELISA and flow cytometry, respectively, in PTC patients at two time points: pre- and post-thyroidectomy; and control subjects.

RESULTS

Compared with controls, IL-6 levels were increased, while IL-1β, IFN-α and TGF-β1 levels were decreased in pre-thyroidectomy PTC patients. IFN-α and TGF-β1 efficiently discriminated patients from controls and were associated with extrathyroidal extension and lymph node metastasis, respectively. In addition, TNF and IL-13 were associated with male gender, lymph node metastasis and Hashimoto thyroiditis, and sHLA-G with tumour invasion. Compared with pre-thyroidectomy, IL-4, IL-10, TNF, IFN-α and TGF-β1 levels were increased in post-thyroidectomy.

CONCLUSION

There are significant changes in the cytokine profile after surgical removal of the thyroid tumour, and IFN-α e TGF-β1 showed to be promising cytokines for discriminating PTC patients from controls. We also found that different cytokines are associated with clinicohistopathological characteristics of PTC related to poor prognosis, suggesting that cytokines seem to play an important role in PTC development and management.

Molecular Markers Guiding Thyroid Cancer Management

The incidence of thyroid cancer is rapidly increasing, mostly due to the overdiagnosis and overtreatment of differentiated thyroid cancer (TC). The increasing use of potent preclinical models, high throughput molecular technologies, and gene expression microarrays have provided a deeper understanding of molecular characteristics in cancer. Hence, molecular markers have become a potent tool also in TC management to distinguish benign from malignant lesions, predict aggressive biology, prognosis, recurrence, as well as for identification of novel therapeutic targets. In differentiated TC, molecular markers are mainly used as an adjunct to guide management of indeterminate nodules on fine needle aspiration biopsies. In contrast, in advanced thyroid cancer, molecular markers enable targeted treatments of affected signalling pathways. Identification of the driver mutation of targetable kinases in advanced TC can select treatment with mutation targeted tyrosine kinase inhibitors (TKI) to slow growth and reverse adverse effects of the mutations, when traditional treatments fail. This review will outline the molecular landscape and discuss the impact of molecular markers on diagnosis, surveillance and treatment of differentiated, poorly differentiated and anaplastic follicular TC.

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.

Performance of a dual-component molecular assay in cytologically indeterminate thyroid nodules

PURPOSE

Deciding whether patients with a cytologically indeterminate thyroid nodule should be referred for surgery or for active surveillance is an important challenge for clinicians. The aim of this study was to evaluate the performance of a novel dual-component molecular assay as an ancillary molecular method for resolving indeterminate thyroid nodule cytology.

METHODS

We selected 156 thyroid nodules from those that had undergone fine-needle aspiration processed by liquid-based cytology and surgical resection between June 2016 and December 2017. The sample set included 63 nodules cytologically classified as indeterminate, and 93 other nodules randomly selected from those with non-diagnostic, benign, suspicious, or malignant cytology. Nucleic acids from each nodule were subjected to next-generation sequencing analysis for mutation detection in 23 genes and to digital polymerase chain reaction (PCR) evaluation for miR-146b-5p expression levels.

RESULTS

Used alone, mutation analysis in the indeterminate subset (cancer prevalence: 22.5%) displayed high sensitivity (89%) and NPV (96%). In contrast, the miR-146b-5p assay offered high specificity (93%) and PPV (93%). Combined use of both analyses improved panel performance by eliminating false-negative results.

CONCLUSIONS

These preliminary data suggest that a dual-component molecular test can increase the diagnostic accuracy of thyroid cytology alone by reducing the number of nodules that will be classified as indeterminate and increasing those that can be reliably classified as benign. If these findings are confirmed, this test can be considered for use in clinical practice and is expected to reduce diagnostic surgery and health care costs, and to improve patient quality of life.

Nutraceutical Boom in Cancer: Inside the Labyrinth of Reactive Oxygen Species

In recent years, epidemiological studies have shown that food is a very powerful means for maintaining a state of well-being and for health prevention. Many degenerative, autoimmune and neoplastic diseases are related to nutrition and the nutrient-organism interaction could define the balance between health and disease. Nutrients and dietary components influence epigenetic phenomena and modify drugs response; therefore, these food-host interactions can influence the individual predisposition to disease and its potential therapeutic response. Do nutraceuticals have positive or negative effects during chemotherapy? The use of nutraceutical supplements in cancer patients is a controversial debate without a definitive conclusion to date. During cancer treatment, patients take nutraceuticals to alleviate drug toxicity and improve long-term results. Some nutraceuticals may potentiate the effect of cytotoxic chemotherapy by inducing cell growth arrest, cell differentiation, and alteration of the redox state of cells, but in some cases, high levels of them may interfere with the effectiveness of chemotherapy, making cancer cells less reactive to chemotherapy. In this review, we highlighted the emerging opinions and data on the pros and cons on the use of nutraceutical supplements during chemotherapy.

Exosomes as Mediators of Cell-to-Cell Communication in Thyroid Disease

Exosomes are a type of extracellular vehicle, formed by budding cell membranes, containing proteins, DNA, and RNA. Concentrated cargoes from parent cells are enveloped in exosomes, which are cell specific and may have functions in the recipient cell, reflecting a novel physiological and pathological mechanism in disease development. As a transmitter, exosomes shuttle to different cells or tissues and mediate communications among these organelles. To date, several studies have demonstrated that exosomes play crucial roles in disease pathogenesis and development, such as breast and prostate cancer. However, studies investigating connections between exosomes and thyroid disease are limited. In this review, recent research advances on exosomes in thyroid cancer and Graves' disease are reviewed. These studies suggest that exosomes are involved in thyroid disease and appear as impressive potentials in thyroid therapeutic areas.

Update on Fundamental Mechanisms of Thyroid Cancer

The incidence of thyroid cancer (TC) has increased worldwide over the past four decades. TC is divided into three main histological types: differentiated (papillary and follicular TC), undifferentiated (poorly differentiated and anaplastic TC), and medullary TC, arising from TC cells. This review discusses the molecular mechanisms associated to the pathogenesis of different types of TC and their clinical relevance. In the last years, progresses in the genetic characterization of TC have provided molecular markers for diagnosis, risk stratification, and treatment targets. Recently, papillary TC, the most frequent form of TC, has been reclassified into two molecular subtypes, named BRAF-like and RAS-like, associated to a different range of cancer risks. Similarly, the genetic characterization of follicular TC has been proposed to complement the new histopathological classification in order to estimate the prognosis. New analyses characterized a comprehensive molecular profile of medullary TC, raising the role of RET mutations. More recent evidences suggested that immune microenvironment associated to TC may play a critical role in tumor invasion, with potential immunotherapeutic implications in advanced and metastatic TC. Several types of ancillary approaches have been developed to improve the diagnostic value of fine needle aspiration biopsies in indeterminate thyroid nodules. Finally, liquid biopsy, as a non-invasive diagnostic tool for body fluid genotyping, brings a new prospective of disease and therapy monitoring. Despite all these novelties, much work remains to be done to fully understand the pathogenesis and biological behaviors of the different types of TC and to transfer this knowledge in clinical practice.

Thyroid Cancer Patients With No Evidence of Disease: The Need for Repeat Neck Ultrasound

CONTEXT

Ultrasonography (US) is considered the most sensitive tool for imaging persistent or recurrent papillary thyroid cancer (PTC) in the neck.

OBJECTIVE

To clarify the usefulness of routine neck US in low- and intermediate-risk patients with PTC with no evidence of disease 1 year after thyroidectomy.

DESIGN

Retrospective analysis of prospectively recorded data.

SETTING

Academic center.

PATIENTS

Two hundred twenty-six patients with PTC with sonographically normal neck lymph nodes and unstimulated serum thyroglobulin (Tg) levels that were either undetectable (<0.20 ng/mL) or low (0.21 to 0.99 ng/mL) at the 1-year evaluation.

INTERVENTIONS

Yearly assessment: unstimulated serum Tg level, anti-Tg-antibody (TgAb) titer, TSH levels, and ultrasound examination of neck lymph nodes.

MAIN OUTCOME MEASURES

Rates of ultrasonographic lymph node abnormalities at the 3-year and last follow-up visits.

RESULTS

In patients with an undetectable Tg level at the 1-year evaluation, sonographically suspicious neck lymph nodes were found in 1.2% of patients at 3 years and in 1.8% at the last visit [negative predictive values (NPVs) of 1-year Tg < 0.2 ng/mL: 98.8% (95% CI 95.8% to 99.9%) and 98.2% (95% to 99.6%), respectively]. Similar NPVs emerged for low detectable 1-year Tg levels [98.2% (90.3% to 99.9%) and 94.5% (84.9% to 98.9%) at the 3-year and last visits, respectively]. Seventy-five percent of the nodal lesions were likely false positive; none required treatment.

CONCLUSIONS

Low- and intermediate-risk patients with PTC with negative ultrasound findings and unstimulated Tg levels <1 ng/mL at the 1-year evaluation can be safely followed with clinical assessments and unstimulated serum Tg determinations. Neck US might be repeated if TgAb titers rise, or unstimulated Tg levels exceed 1 ng/mL.

Down-regulation and clinical significance of miR-7-2-3p in papillary thyroid carcinoma with multiple detecting methods

Altered miRNA expression participates in the biological progress of thyroid carcinoma and functions as a diagnostic marker or therapeutic agent. However, the role of miR-7-2-3p is currently unclear. The authors' study was the first investigation of miR-7-2-3p expression level and diagnostic ability in several public databases. Potential target genes were obtained from DIANA Tools, and function enrichment analysis was then performed. Furthermore, the authors examined expression levels of potential targets in the Human Protein Atlas (HPA) and the Cancer Genome Atlas (TCGA). Finally, the potential transcription factors (TFs) were predicted by JASPAR. TCGA, GSE62054, GSE73182, GSE40807, and GSE55780 revealed that miR-7-2-3p expression in papillary thyroid carcinoma (PTC) tissues was notably lower compared with non-tumour tissues, while its expression in E-MATB-736 showed no remarkable difference. Function enrichment analysis showed that 698 genes were enriched in pathways, including pathways in cancer, and glioma. CCND1, GSK3B, and ITGAV of pathways in cancer were inverse correlations with miR-7-2-3p in both post-transcription and protein levels. According to the TF prediction, the prospective upstream TFs of miR-7-2-3p were ISX, SPI1, PRRX1, and BARX1. MiR-7-2-3p was significantly down-regulated and may act on PTC progression by crucial pathways. However, the mechanisms of miR-7-2-3p need further investigation.

MiR-599 serves a suppressive role in anaplastic thyroid cancer by activating the T-cell intracellular antigen

Anaplastic thyroid cancer (ATC) has a mean survival time of 6 months and accounts for 1-2% of all thyroid tumors. Understanding the underlying molecular mechanisms of carcinogenesis and progression in ATC would contribute to the identification of novel therapeutic targets. A previous study revealed that microRNA (miR)-599 was associated with tumor initiation and development in certain types of cancer. However, the specific functions and mechanisms of miR-599 in ATC are poorly understood. The objective of the present study was to identify its expression, function and molecular mechanism in ATC. The expression levels of miR-599 in 10 pairs of surgical specimens and human ATC cell lines were examined by reverse transcription-quantitative polymerase chain reaction. Function assays illustrated that miR-599 overexpression not only suppressed KAT-18 cell viability, proliferation and metastasis in vitro and decreased tumor growth in the tumor xenograft model but also induced cell apoptosis. Furthermore, T-cell intracellular antigen (TIA1), a tumor suppressor, was confirmed as a direct target of miR-599. It was demonstrated that TIA1 silencing rescued the inhibitory effect of migration and invasion induced by the overexpression of miR-599 in KAT-18 cells. In conclusion, the present study revealed that miR-599 inhibited ATC cell growth and metastasis via activation of TIA1. Therefore miR-599 may be a novel molecular therapeutic target for ATC.

MicroRNAs in endocrine tumors

MicroRNAs (miRNAs) are small, protein noncoding RNAs that regulate gene expression post-transcriptionally. Their role is considered to set the gene expression to the optimal level, or in other words to provide "fine tuning" of gene expression. They regulate essential physiological processes such as differentiation, cell growth, apoptosis and their role is known in tumor development too. At tissue level differential miRNA expression in endocrine disorders including endocrine malignancies has also been reported. A new era of miRNAs-related research started when miRNAs were successfully detected outside of cells, in biofluids, in cell-free environments. Their significant role has been demonstrated in cell-cell communication in tumor biology. Due to their stability circulating miRNAs can serve as potential biomarkers. In common diseases circulating miRNAs can be potentially proposed as screening biomarkers and they are also useful to detect tumor recurrence hence they can be applied in post-surgery follow-up too. MiRNAs as diagnostic markers can also be helpful at tissue level when certain histology diagnosis is challenging. Beside diagnosis, tissue miRNAs have the potential to predict prognosis. Intensive research is carried out regarding endocrine tumors as well in terms of miRNAs. However, until now miRNAs as biomarkers do not applied in routine diagnostics, probably due to the challenging preanalytics. In this review we summarized tissue and circulating miRNAs found in thyroid, adrenal, pituitary and neuroendocrine tumors. We aimed to highlight the most important, selected miRNAs with potential diagnostic and prognostic value both in tissue and circulation. Common miRNAs across different endocrine neoplasms are summarized and miRNAs enriched at 14q31 locus are also highlighted suggesting their general role in tumorigenesis of endocrine glands.

kshv-mir-k12-1-5p promotes cell growth and metastasis by targeting SOCS6 in Kaposi's sarcoma cells

Background: Kaposi’s sarcoma (KS) is a highly disseminated angiogenic tumour of endothelial cells. Many deregulated miRNAs, including kshv-mir-k12-1-5p, have been identified in KS. kshv-mir-k12-1-5p plays important roles in KS. However, the underlying mechanism is not fully understood. The aim of this study was to investigate the exact functions of kshv-mir-k12-1-5p in KS cells.

Materials and methods: The biological functions of kshv-mir-k12-1-5p were studied using CCK-8, apoptosis, migration and invasion assays. Bioinformatics software was used to identify the target gene (SOCS6) of kshv-mir-k12-1-5p. A dual luciferase assay, Western blot (WB) and quantitative real-time polymerase chain reaction (q-PCR) were performed to further verify the target gene. The underlying molecular mechanisms of kshv-mir-k12-1-5p in KS cells were also explored.

Results: kshv-mir-k12-1-5p can promote the proliferation, migration and invasion of KS cells and inhibit cell apoptosis. Suppressor of cytokine signalling 6 (SOCS6) was identified as a direct target of kshv-mir-k12-1-5p, and kshv-mir-k12-1-5p can downregulate SOCS6 expression. In addition, knockdown of SOCS6 rescued the effects of kshv-mir-k12-1-5p inhibitor. Hence, a direct relationship between kshv-mir-k12-1-5p and SOCS6 was confirmed.

Conclusions: kshv-mir-k12-1-5p promotes the malignant phenotype of KS cells by targeting SOCS6, suggesting that kshv-mir-k12-1-5p could be a potential therapeutic target for KS.

Downregulation of TSPAN13 by miR-369-3p inhibits cell proliferation in papillary thyroid cancer (PTC)

Previous studies demonstrated dysregulation of different microRNAs in thyroid cancer. Tetraspanins (TSPANs) are cell surface proteins with critical roles in many cellular processes, and implications in tumor development. Here we investigated the role of miR-369-3p in papillary thyroid cancer (PTC) and its association with TSPAN13. miR-369-3p and the TSPAN13 gene expression profiles of 513 thyroid cancer and 59 normal thyroid tissues were downloaded from the Cancer Genome Atlas database. Thyroid cancer tissues were classified according to the histological type, grouped based on low and high median miR-369-3p and TSPAN13 expression, and analyzed in relation to overall survival (OS) of patients. Human PTC cell lines (TPC-1 and GLAG-66) and human embryonic kidney 293T (HEK293T) cells were used for in vitro analysis. Transfection experiments were performed with synthetic miRNA mimics for miR-369-3p and small interfering RNAs for TSPAN13. Relative expression of miR-369-3p and TSPAN13 mRNA was determined by RT-qPCR. Protein levels of TSPAN13 were determined by western blotting. Cell proliferation (CCK-8 assay), colony formation, and apoptosis (flow cytometry) were analyzed in transfected cells. Binding sites of miR-369-3p in TSPAN13 mRNA were determined by bioinformatics analysis and dual luciferase reporter assay. miR-369-3p was downregulated and TSPAN13 upregulated in PTC, follicular thyroid cancer, and tall cell variant tissues. Both low expression of miR-369-3p and high expression of TSPAN13 were associated with shorter OS in thyroid cancer patients. Overexpression of miR-369-3p significantly suppressed proliferation and promoted apoptosis in PTC cells. TSPAN13 was a direct target of miR-369-3p, and silencing of TSPAN13 phenocopied the effect of miR-369-3p mimics in PTC cells. Overall, the downregulation of miR-369-3p and consequent upregulation of its target TSPAN13 appear to be involved in pathophysiology of PTC.

Extracellular Vesicles from Thyroid Carcinoma: The New Frontier of Liquid Biopsy

The diagnostic approach to thyroid cancer is one of the most challenging issues in oncology of the endocrine system because of its high incidence (3.8% of all new cancer cases in the US) and the difficulty to distinguish benign from malignant non-functional thyroid nodules and establish the cervical lymph node involvement during staging. Routine diagnosis of thyroid nodules usually relies on a fine-needle aspirate biopsy, which is invasive and often inaccurate. Therefore, there is an urgent need to identify novel, accurate, and non-invasive diagnostic procedures. Liquid biopsy, as a non-invasive approach for the detection of diagnostic biomarkers for early tumor diagnosis, prognosis, and disease monitoring, may be of particular benefit in this context. Extracellular vesicles (EVs) are a consistent source of tumor-derived RNA due to their prevalence in circulating bodily fluids, the well-established isolation protocols, and the fact that RNA in phospholipid bilayer-enclosed vesicles is protected from blood-borne RNases. Recent results in other types of cancer, including our recent study on plasma EVs from glioblastoma patients suggest that information derived from analysis of EVs from peripheral blood plasma can be integrated in the routine diagnostic tumor approach. In this review, we will examine the diagnostic and prognostic potential of liquid biopsy to detect tumor-derived nucleic acids in circulating EVs from patients with thyroid carcinoma.

Papillary Thyroid Cancer: Genetic Alterations and Molecular Biomarker Investigations

Papillary thyroid cancer (PTC) is the most prevalent form of malignancy among all cancers of the thyroid. It is also one of the few cancers with a rapidly increasing incidence. PTC is usually contained within the thyroid gland and generally biologically indolent. Prognosis of the cancer is excellent, with less than 2% mortality at 5 years. However, more than 25% of patients with PTC developed a recurrence during a long term follow-up. The present article provides an updated condensed overview of PTC, which focuses mainly on the molecular alterations involved and recent biomarker investigations.

MicroRNA‑663b targets GAB2 to restrict cell proliferation and invasion in hepatocellular carcinoma

Previous studies have demonstrated that numerous tumor‑specific microRNAs (miRNAs) are upregulated or downregulated in hepatocellular carcinoma (HCC), and that their dysregulation is implicated in HCC occurrence and development. Therefore, investigation of crucial miRNAs involved in HCC oncogenesis and progression may provide novel insights into the therapy of patients with this malignant tumor. In the present study, reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) assays were performed to detect tissue and cellular expression levels of miRNA‑663b (miR‑663b) in HCC. The effects of miR‑663b overexpression on the proliferation and invasion of HCC cells were examined using Cell Counting Kit‑8 and Transwell invasion assays, respectively. The direct target of miR‑663b in HCC cells was determined by bioinformatics analysis, luciferase reporter assay, RT‑qPCR and western blot analysis. It was observed that miR‑663b was expressed at low levels in HCC tissues and cell lines. miR‑663b upregulation suppressed the proliferative and invasive abilities of HCC cells. Additionally, Grb2‑associated binding 2 (GAB2) was regarded as a direct target gene of miR‑663b in HCC cells. Furthermore, GAB2 was overexpressed in HCC tissues, and overexpression of GAB2 was inversely correlated with levels of miR‑663b. GAB2 overexpression was able to rescue the suppressive effects of miR‑663b on HCC cells. These results demonstrated that this newly‑identified miR‑663b/GAB2 axis may be implicated in HCC occurrence and development.

A molecular approach combined with American Thyroid Association classification better stratifies recurrence risk of classic histology papillary thyroid cancer

BACKGROUND

Prognosis among patients with differentiated thyroid cancer is widely variable. Better understanding of biologic subtypes is necessary to stratify patients and improve outcomes.

METHODS

In patients diagnosed with classic histology papillary thyroid cancer treated from 1973 to 2009, BRAF V600E mutation status was determined on surgical tumor specimens by restriction fragment length polymorphism analysis. A tissue microarray (TMA) was constructed from tumor specimens in triplicate and stained by immunohistochemistry for RET, phospho-MEK, MAPK(dpERK), PPARγ, and phospho-AKT(pAKT). Stained slides were scored independently and blindly by two investigators and compared to tumor and patient characteristics and outcomes.

RESULTS

A total of 231 patients had archived formalin-fixed, paraffin-embedded tumor tissue available and were included on the TMA. Mean age at diagnosis was 44 years (range 6-82 years); proportion of patients with female sex was (72%); 2015 American Thyroid Association (ATA) risk stratification was low (26%), intermediate (32%), and high (42%). BRAF V600E mutation was found in 74% of specimens, and IHC was scored as positive for RET (61%), MAPK (dpERK) (14%), PPARγ (27%), and pAKT (39%). Positive RET staining was associated with a lower risk of recurrence (HR = 0.46, 95% CI 0.22-0.96). No other molecular biomarkers were independent predictors of recurrence on univariable analysis. On RPA, patients with RET-negative and either MAPK(dpERK)-positive or pAKT-positive tumors were identified to have a high risk of recurrence (HR = 5.4, 95%CI 2.5-11.7). This profile remained associated with recurrence in a multivariable model including ATA risk stratification (HR = 2.8, 95% CI 1.3-6.0).

CONCLUSION

Characterization of molecular pathways involved in cPTC tumorigenesis may add further risk stratification for recurrence beyond the 2015 ATA risk categories alone.