BRAF V600E and decreased NIS and TPO expression are associated with aggressiveness of a subgroup of papillary thyroid microcarcinoma

Radioiodine therapy in advanced differentiated thyroid cancer: Resistance and overcoming strategy

Thyroid cancer is the most prevalent endocrine tumor and its incidence is fast-growing worldwide in recent years. Differentiated thyroid cancer (DTC) is the most common pathological subtype which is typically curable with surgery and Radioactive iodine (RAI) therapy (approximately 85%). Radioactive iodine is the first-line treatment for patients with metastatic Papillary Thyroid Cancer (PTC). However, 60% of patients with aggressive metastasis DTC developed resistance to RAI treatment and had a poor overall prognosis. The molecular mechanisms of RAI resistance include gene mutation and fusion, failure to transport RAI into the DTC cells, and interference with the tumor microenvironment (TME). However, it is unclear whether the above are the main drivers of the inability of patients with DTC to benefit from iodine therapy. With the development of new biological technologies, strategies that bolster RAI function include TKI-targeted therapy, DTC cell redifferentiation, and improved drug delivery via extracellular vesicles (EVs) have emerged. Despite some promising data and early success, overall survival was not prolonged in the majority of patients, and the disease continued to progress. It is still necessary to understand the genetic landscape and signaling pathways leading to iodine resistance and enhance the effectiveness and safety of the RAI sensitization approach. This review will summarize the mechanisms of RAI resistance, predictive biomarkers of RAI resistance, and the current RAI sensitization strategies.

Blood Profiles in the Prediction of Radioiodine Refractory Papillary Thyroid Cancer: A Case-Control Study

Purpose

Although most patients with papillary thyroid cancer can be cured by surgery and I-131 ablation, a small proportion will progress to radioactive iodine refractory (RAIR) thyroid cancer. The prediction of RAIR in its early stages can improve patient prognosis. The aim of this article is to evaluate the blood biomarkers in patients with RAIR and to establish a prediction model.

Patients and Methods

Data collected from patients with thyroid cancer that were enrolled from Jan. 2017 to Dec. 2021 were screened. RAIR was defined based on the criteria in the 2015 American Thyroid Association guidelines. The blood biomarkers from the study participants at three admissions timepoints (surgery and first and secondary I-131 ablations) were compared using both parametric and nonparametric tests to identify predictive factors for RAIR. Binary logistic regression analysis was used to construct a prediction model using parameters associated with surgical procedure decision. The model was then assessed with receiver operating characteristic curves.

Results

Thirty-six patients were included in the data analysis. Sixteen blood variables, including the low density lipoprotein-cholesterol-total cholesterol ratio, neutrophils, thyroglobulins, thyroglobulin antibody, thyroid peroxidase antibody, anion gap, etc., were revealed to be predictors for RAIR. The prediction model, which incorporated two parameters, reached an area under the curve of 0.861 (p<0.001).

Conclusion

Conventional blood biomarkers can be used in the prediction of early-stage RAIR. In addition, a prediction model incorporating multiple biomarkers can improve the predictive accuracy.

Association of BRAFV600E Mutation with the Aggressive Behavior of Papillary Thyroid Microcarcinoma: A Meta-Analysis of 33 Studies

An association between the BRAF^V600E mutation and the clinicopathological progression of papillary thyroid microcarcinoma (PTMC) has been suggested. We aimed to summarize the relevant literature and determine the predictive value of BRAF^V600E mutation in predicting clinical outcomes and risk stratification in patients with PTMC. A systematic search using PubMed, Cochrane, and Embase up to February 2020 was performed. A total of 33 studies met the inclusion criteria, resulting in a pool of 8838 patients, of whom 5043 (57.1%) patients were positive for BRAF^V600E mutation. Tumors with positive BRAF^V600E mutation had a higher tendency for multifocality (RR = 1.09, 95%CI = 1.03-1.16), extrathyroidal extension (RR = 1.79, 95%CI = 1.37-2.32), and lymph node metastasis (RR = 1.43, 95%CI = 1.19-1.71). Patients with BRAF^V600E mutation were at increased risk of disease recurrence (RR = 1.90, 95%CI = 1.43-2.53). PTMC in patients positive for the BRAF^V600E mutation is more aggressive than wild-type BRAF PTMC. Since BRAF-mutated PTMC is generally more resistant to radioiodine treatment, patients with BRAF^V600E-mutated PTMC may require earlier management, such as a minimally invasive ablative intervention. Conservative management by active surveillance may be suitable for patients with wild-type BRAF^V600E PTMC.

Pyruvate carboxylase promotes malignant transformation of papillary thyroid carcinoma and reduces iodine uptake

Previous studies have shown that pyruvate carboxylase (PC) plays a key role in the occurrence and progression of thyroid cancer (TC); however, the relationship between PC and iodine-refractory TC is unclear. Therefore, the present study aimed to investigate the molecular mechanism of PC in the malignant progression and loss of iodine uptake in papillary TC (PTC) and to explore the potential therapeutic effect of PC inhibitors in iodine-refractory PTC. PC increased cell proliferation, invasion, and metastasis, inhibited expression of the iodine metabolism-related genes TSHR, NIS, TPO, and TG, and decreased the iodine-uptake capacity by activating the mitogen-activated protein kinase/extracellular signal-regulated kinase pathway in PTC cell lines. Furthermore, the PC inhibitor ZY-444 effectively inhibited the activation of PC, reduced the malignant invasiveness, and restored the expression of iodine metabolism-related genes and the iodine-uptake capacity in PTC cells. These findings suggest that PC activation is involved in the progression of iodine-refractory TC and that PC inhibitors may represent a potentially novel targeted therapy for iodine-refractory TC.

Basolateral Sorting of the Sodium/Iodide Symporter Is Mediated by Adaptor Protein 1 Clathrin Adaptor Complexes

Background: The sodium/iodide symporter (NIS) is a transmembrane protein located on the basolateral membrane of thyrocytes. Despite its physiological and clinical relevance, little is known about the mechanisms that mediate NIS subcellular sorting. In the present study, we examined NIS basolateral trafficking in vitro using non-thyroid and thyroid epithelial cells. Methods: Immunofluorescence and Western blotting were performed to analyze NIS subcellular location and function in cells grown in monolayers under unpolarized and/or polarized conditions. Strategic NIS residues were mutated, and binding of NIS to clathrin adaptor complexes was determined by immunoprecipitation. Results: We show that NIS reaches the plasma membrane (PM) through a thyrotropin-dependent mechanism 24 hours after treatment with the hormone. We demonstrate that NIS basolateral trafficking is a clathrin-mediated mechanism, in which the clathrin adaptor complexes AP-1 (A and B) sort NIS from the trans-Golgi network (TGN) and recycling endosomes (REs). Specifically, we show that the AP-1B μ1 subunit controls NIS basolateral sorting through common REs. In its absence, NIS is apically missorted but remains functional. Additionally, direct NIS basolateral transport from the TGN to the basolateral membrane is mediated by AP-1A through clathrin-coated vesicles that also carry the transferrin receptor. Loss of the μ1 subunit of AP-1A is functionally compensated by AP-1B. Furthermore, loss of both subunits diminishes NIS trafficking to the PM. Finally, we demonstrate that AP-1A binds to the L121 and LL562/563 residues on NIS, whereas AP-1B binds to L583. Conclusions: Our findings highlight the novel involvement of the clathrin-coated machinery in basolateral NIS trafficking. Given that AP-1A expression is reduced in tumors, and its expression correlates with that of NIS, these findings will help uncover new targets in thyroid cancer treatment.

Receptor–ligand pair typing and prognostic risk model for papillary thyroid carcinoma based on single-cell sequencing

The papillary thyroid carcinoma (PTC) microenvironment consists of various cancer and surrounding cells, and the communication between them is mainly performed through ligand–receptor (LR) interactions. Single-cell RNA sequencing (scRNA-seq) has been performed to investigate the role of intercellular communication networks in tumor progression. In addition, scRNA-seq can accurately identify the characteristics of immune cell subsets, which is of great significance for predicting the efficacy of immunotherapy. In this study, the cell–cell communication network was analyzed through LR pairs, and a new PTC molecular phenotype was developed based on LR pairs. Furthermore, a risk model was established to predict patient response to PD-1 blockade immunotherapy. The scRNA-seq dataset was obtained from GSE184362, and the bulk tumor RNA-seq dataset was obtained from The Cancer Genome Atlas. CellPhoneDB was used for cellular communication analysis. LR pair correlations were calculated and used to identify molecular subtypes, and the least absolute shrinkage and selection operator (Lasso) Cox regression was used to develop a risk model based on LR pairs. The IMvigor210 and GSE78220 cohorts were used as external validations for the LR.score to predict responses to PD-L1 blockade therapy. A total of 149 LR pairs with significant expression and prognostic correlation were included, and three PTC molecular subtypes were obtained from those with significant prognostic differences. Then, five LR pairs were selected to construct the risk scoring model, a reliable and independent prognostic factor in the training set, test set, and whole dataset. Furthermore, two external validation sets confirmed the predictive efficacy of the LR.score for response to PD-1 blockade therapy.

Cutoff Age Between Pediatric and Adult Thyroid Differentiated Cancer: Is 18 Years Old Appropriate?

Background: The characteristics of pediatric differentiated thyroid cancer (DTC) are substantially different from those of adult DTC. This study investigated whether the cutoff age of 18 years, as recommended by the American Thyroid Association (ATA) management guidelines for pediatric DTC, is appropriate based on clinical characteristics and outcomes. Methods: The medical records of 288 patients aged <21 years with DTC, who underwent initial surgery between 1979 and 2014, were retrospectively reviewed. Disease-free survival (DFS) rates and distant metastasis-free survival (DMFS) rates were calculated using the Kaplan-Meier method. As per the International Incidence of Childhood Cancer Report and the ATA management guidelines, cutoff ages of 14 and 18 years were analyzed in this study. Results: The age distributions of the subjects were as follows: 53 patients were aged <15 years (18.4%), 118 patients were aged 15-18 years (41%), and 117 patients were aged 19-20 years (40.6%). The DMFS rates were significantly different between the two cutoff ages. The DMFS was also significantly different between patients aged >15 years and patients aged 15-18 years; however, no significant difference was observed between patients aged 15-18 and 19-20 years. Multivariate analyses showed that clinically apparent lymph node metastasis (cN1) and gross extrathyroidal extension were significant factors related to DFS and DMFS. Although age as a continuous variant was not a significant factor related to either DFS or DMFS, when the cutoff age was set as 14 years rather than 18 years, differences in patient characteristics related to DMFS and DFS stood out. Conclusions: This study found that age was not significantly related to clinical outcome. However, in the younger patient group, more patients had factors that related to DFS and DMFS. Due to the indolent biological behavior of DTC, age at presentation or thyroidectomy does not always represent the age at occurrence, but patients aged <15 years had distinct clinical manifestations. Age <15 years rather than <19 years may therefore be a more suitable cutoff age in pediatric DTC.

Preliminary Study on the Relationship of BRAF Mutations with the Outcome of the First 131I Radiotherapy and Malignant Biological Characteristics in Papillary Thyroid Carcinoma

Objective

To investigate the relationship of BRAF mutation with the outcome of the first postoperative ¹³¹I treatment and malignant biological characteristics in papillary thyroid carcinoma (PTC).

Methods

Thirty-three patients with PTC who underwent their first ¹³¹I treatment after total thyroidectomy were enrolled in this study. BRAF mutation in postoperative tumor tissue and circulating tumor DNA (ctDNA) in peripheral blood at the time of ¹³¹I treatment were detected. According to the status of BRAF mutation, all patients were divided into 2 groups in each category of tumor tissues and ctDNA, respectively: 1) BRAF mutation, 2) BRAF wild-type. The Fisher’s exact test was performed to analyze the relationship of BRAF mutation in either tumor tissue or ctDNA with the outcome of the first ¹³¹I treatment and malignant characteristics of PTC.

Results

BRAF mutation was detected in tumor tissues in 25 patients (25/33,75.8%), and all the patients had single mutation site. In ctDNA, BRAF mutation was detected in 5 patients (5/33, 15.2%), and all the patients had single mutation site. In both tumor tissues and ctDNA, BRAF mutation showed no relationship with the outcome of first ¹³¹I treatment and the malignant biological characteristics (P>0.05).

Conclusion

The value of BRAF mutation alone might be limited in predicting therapeutic outcome of the first ¹³¹I treatment in PTC. No definitive relevance was found between BRAF mutation and malignant biological features in PTC.

MAPK Inhibition Requires Active RAC1 Signaling to Effectively Improve Iodide Uptake by Thyroid Follicular Cells

Simple Summary

The Sodium/Iodide Simulator (NIS) is responsible for the uptake of iodide in the thyroid follicular cells. NIS is present in most differentiated thyroid carcinomas (DTC), allowing radioactive iodine (RAI) to be used to destroy malignant cells. However, a significant proportion of DTCs stop picking up iodide and become resistant to RAI therapy. This is mainly due to the symporter no longer being produced or not being placed correctly at the cell’s membrane. This has been associated with mechanisms linked to malignant transformation, namely the overactivation of the so-called MAPK pathway. Thus, several drugs have been developed to inhibit this pathway, attempting to increase NIS levels and iodide uptake. However, MAPK inhibitors have had only partial success in restoring NIS expression. We found that the activity of another protein, the small GTPase RAC1, has an important role in this process, determining the outcome of MAPK inhibitors. Thus, our findings open new opportunities to find effective therapeutic alternatives for DTC resistant to RAI.

Abstract

The Sodium/Iodide Symporter (NIS) is responsible for the active transport of iodide into thyroid follicular cells. Differentiated thyroid carcinomas (DTCs) usually preserve the functional expression of NIS, allowing the use of radioactive iodine (RAI) as the treatment of choice for metastatic disease. However, a significant proportion of patients with advanced forms of TC become refractory to RAI therapy and no effective therapeutic alternatives are available. Impaired iodide uptake is mainly caused by the defective functional expression of NIS, and this has been associated with several pathways linked to malignant transformation. MAPK signaling has emerged as one of the main pathways implicated in thyroid tumorigenesis, and its overactivation has been associated with the downregulation of NIS expression. Thus, several strategies have been developed to target the MAPK pathway attempting to increase iodide uptake in refractory DTC. However, MAPK inhibitors have had only partial success in restoring NIS expression and, in most cases, it remained insufficient to allow effective treatment with RAI. In a previous work, we have shown that the activity of the small GTPase RAC1 has a positive impact on TSH-induced NIS expression and iodide uptake in thyroid cells. RAC1 is a downstream effector of NRAS, but not of BRAF. Therefore, we hypothesized that the positive regulation induced by RAC1 on NIS could be a relevant signaling cue in the mechanism underlying the differential response to MEK inhibitors, observed between NRAS- and BRAF-mutant tumors. In the present study, we found that the recovery of NIS expression induced through MAPK pathway inhibition can be enhanced by potentiating RAC1 activity in thyroid cell systems. The negative impact on NIS expression induced by the MAPK-activating alterations, NRAS Q61R and BRAF V600E, was partially reversed by the presence of the MEK 1/2 inhibitors AZD6244 and CH5126766. Notably, the inhibition of RAC1 signaling partially blocked the positive impact of MEK inhibition on NIS expression in NRAS Q61R cells. Conversely, the presence of active RAC1 considerably improved the rescue of NIS expression in BRAF V600E thyroid cells treated with MEK inhibitors. Overall, our data support an important role for RAC1 signaling in enhancing MAPK inhibition in the context of RAI therapy in DTC, opening new opportunities for therapeutic intervention.

Molecular Signature Expands the Landscape of Driver Negative Thyroid Cancers

Thyroid cancer is the most common endocrine malignancy. However, the cytological diagnosis of follicular thyroid carcinoma (FTC), Hürthle cell carcinoma (HCC), and follicular variant of papillary thyroid carcinoma (FVPTC) and their benign counterparts is a challenge for preoperative diagnosis. Nearly 20-30% of biopsied thyroid nodules are classified as having indeterminate risk of malignancy and incur costs to the health care system. Based on that, 120 patients were screened for the main driver mutations previously described in thyroid cancer. Subsequently, 14 mutation-negative cases that are the main source of diagnostic errors (FTC, HCC, or FVPTC) underwent RNA-Sequencing analysis. Somatic variants in candidate driver genes (ECD, NUP98,LRP1B, NCOR1, ATM, SOS1, and SPOP) and fusions were described. NCOR1 and SPOP variants underwent validation. Moreover, expression profiling of driver-negative samples was compared to 16 BRAF V600E, RAS, or PAX8-PPARg positive samples. Negative samples were separated in two clusters, following the expression pattern of the RAS/PAX8-PPARg or BRAF V600E positive samples. Both negative groups showed distinct BRS, ERK, and TDS scores, tumor mutation burden, signaling pathways and immune cell profile. Altogether, here we report novel gene variants and describe cancer-related pathways that might impact preoperative diagnosis and provide insights into thyroid tumor biology.

Machine learning algorithm improved automated droplet classification of ddPCR for detection of BRAF V600E in paraffin-embedded samples

Somatic mutations in cancer driver genes can help diagnosis, prognosis and treatment decisions. Formalin-fixed paraffin-embedded (FFPE) specimen is the main source of DNA for somatic mutation detection. To overcome constraints of DNA isolated from FFPE, we compared pyrosequencing and ddPCR analysis for absolute quantification of BRAF V600E mutation in the DNA extracted from FFPE specimens and compared the results to the qualitative detection information obtained by Sanger Sequencing. Sanger sequencing was able to detect BRAF V600E mutation only when it was present in more than 15% total alleles. Although the sensitivity of ddPCR is higher than that observed for Sanger, it was less consistent than pyrosequencing, likely due to droplet classification bias of FFPE-derived DNA. To address the droplet allocation bias in ddPCR analysis, we have compared different algorithms for automated droplet classification and next correlated these findings with those obtained from pyrosequencing. By examining the addition of non-classifiable droplets (rain) in ddPCR, it was possible to obtain better qualitative classification of droplets and better quantitative classification compared to no rain droplets, when considering pyrosequencing results. Notable, only the Machine learning k-NN algorithm was able to automatically classify the samples, surpassing manual classification based on no-template controls, which shows promise in clinical practice.

Clinical implications of TPO and AOX1 in pediatric papillary thyroid carcinoma

BACKGROUND

Thyroid carcinoma is a common pediatric head and neck cancer, of which papillary thyroid cancer (PTC) is the most common type. Previously, we found that thyroid peroxidase (TPO) and aldehyde oxidase 1 (AOX1) were differentially expressed in PTC. This study explored the clinical importance of TPO and AOX1 in the diagnosis and prognosis of PTC in children.

METHODS

Both TPO and AOX1 expression in PTC were analyzed using datasets from Gene Expression Omnibus (GEO). TPO and AOX1 protein levels in plasma from patients with PTC and non-tumor controls were detected via enzyme-linked immunosorbent assay (ELISA). The diagnostic accuracy of TPO and AOX1 was assessed using receiver operating characteristic (ROC) curve analysis. The association between gene expression levels and patient survival was explored using the Kaplan-Meier plotter online database.

RESULTS

The results revealed that TPO and AOX1 expression was significantly downregulated in four independent datasets (GSE33630, GSE27155, GSE3678, and GSE3467). TPO and AOX1 protein levels in blood plasma were significantly decreased in patients with PTC. Quantitative analysis demonstrated that TPO and AOX1 levels in plasma had satisfactory predictive performance and the ability to discriminate PTC from healthy samples. Prognostic analysis demonstrated that low levels of TPO and AOX1 were markedly associated with poor survival in patients with PTC.

CONCLUSIONS

In summary, these results implied that TPO and AOX1 could serve as novel biomarkers for the diagnosis and prognosis of pediatric PTC.

Association Between the Presence of Female-Specific Tumors and Aggressive Clinicopathological Features in Papillary Thyroid Cancer: A Retrospective Analysis of 9,822 Cases

Objective

To investigate the association between the presence of female-specific tumors and aggressive clinicopathological features in papillary thyroid cancer (PTC).

Methods

This study retrospectively analyzed 9,822 female cases between June 2008 and December 2017. Odds ratios and corresponding 95% confidence intervals were calculated. Findings were stratified by age and body mass index (BMI) in different models.

Results

1443/9822 (14.7%) patients with PTC had a female-specific tumor. Presence of a benign breast mass was an independent risk factor for a primary PTC lesion > 1 cm in diameter (adjusted OR = 1.446, 95% CI 1.136–1.840, P = 0.003), but a protective factor against extrathyroidal extension of PTC (adjusted OR = 0.650, 95%CI 0.500–0.845, P = 0.001). Presence of a benign uterine mass was an independent risk factor for multifocal PTC (adjusted OR = 1.305, 95%CI 1.113–1.531, P = 0.001). Analyses stratified by age and BMI revealed the presence of a benign breast mass was an independent risk factor for a primary PTC lesion > 1 cm in diameter in patients aged <36 years (adjusted OR = 1.711, 95% CI 1.063–2.754, P = 0.027), and a protective factor against extrathyroidal extension of PTC in patients aged ≥36 - <42 years (OR adjusted = 0.533, 95% CI 0.302–0.941, P = 0.030) or with a BMI ≥ 23.4 kg/m² (BMI ≥ 23.4 to < 25.7 kg/m², adjusted OR = 0.441, 95% CI 0.246–0.792, P = 0.006; BMI ≥25.7 kg/m², adjusted OR = 0.558, 95% CI 0.315–0.998, P₂ = 0.045). Presence of a benign uterine mass was an independent risk factor for multifocal PTC in patients aged ≥49 years (adjusted OR = 1.397, 95% CI 1.088–1.793, P = 0.009) or with a BMI <21.5 kg/m² (OR adjusted = 1.745, 95% CI 1.214–2.509, P = 0.003).

Conclusion

The presence of a benign breast mass was an independent risk factor for a primary PTC lesion > 1 cm in diameter and a protective factor against extrathyroidal extension of PTC, while the presence of a benign uterine mass was an independent risk factor for multifocal PTC. Data from this study may help surgeons propose more personalized treatment plans when encountering patients with PTC and female-specific benign tumors.

Radio-Iodide Treatment: From Molecular Aspects to the Clinical View

Simple Summary

This year marks the 80th commemoration of the first time that radio-iodide treatment (RAI) was used. RAI is one of the most effective targeted internal radiation anticancer therapies ever devised and it has been used for many decades, however, a thorough understanding of the underlying molecular mechanisms involved could greatly improve the success of this therapy. This is an in-depth innovative review focusing on the molecular mechanisms underlying radio-iodide therapy in thyroid cancer and how the alteration of these mechanisms affects the results in the clinic.

Abstract

Thyroid radio-iodide therapy (RAI) is one of the oldest known and used targeted therapies. In thyroid cancer, it has been used for more than eight decades and is still being used to improve thyroid tumor treatment to eliminate remnants after thyroid surgery, and tumor metastases. Knowledge at the molecular level of the genes/proteins involved in the process has led to improvements in therapy, both from the point of view of when, how much, and how to use the therapy according to tumor type. The effectiveness of this therapy has spread into other types of targeted therapies, and this has made sodium/iodide symporter (NIS) one of the favorite theragnostic tools. Here we focus on describing the molecular mechanisms involved in radio-iodide therapy and how the alteration of these mechanisms in thyroid tumor progression affects the diagnosis and results of therapy in the clinic. We analyze basic questions when facing treatment, such as: (1) how the incorporation of radioiodine in normal, tumor, and metastatic thyroid cells occurs and how it is regulated; (2) the pros and cons of thyroid hormonal deprivation vs. recombinant human Thyroid Stimulating Hormone (rhTSH) in radioiodine residence time, treatment efficacy, thyroglobulin levels and organification, and its influence on diagnostic imaging tests and metastasis treatment; and (3) the effect of stunning and the possible causes. We discuss the possible incorporation of massive sequencing data into clinical practice, and we conclude with a socioeconomical and clinical vision of the above aspects.

Molecular characterisation and clinical correlation of papillary thyroid microcarcinoma

PURPOSE

Papillary thyroid microcarcinoma (mPTC) is defined as a papillary thyroid cancer sized 10 mm or less. Despite their generally indolent clinical course and good prognosis, a subset of mPTCs shows potentially aggressive behaviour.

METHODS

To search for predictors of clinical outcome of mPTCs, we retrospectively evaluated the genetic tumour profile of 100 patients (23 M/77 F, mean age ± SD 53.8 ± 13.4 years) with histologically confirmed mPTCs through analysis of BRAF, NRAS and TERT promoter mutations as well as RET/PTC translocations.

RESULTS

Mean follow-up period was 8.4 ± 3.6 years. In 55 cases, mPTC were detected incidentally after surgery. Capsular invasion, bilateralism and multifocality were found in 11/100, 17/100 and 24/100 cases, respectively, while lymph-nodes metastases were present at diagnosis in 9/100 cases. After 3.5 ± 2.0 years, tumour relapse occurred in 6/100 cases and was locoregional in five (two in the thyroid bed, three in laterocervical lymph-nodes), while lung metastasis occurred in one case. Biochemical persistence of disease was seen in 1/100 case. Mutations occurred in 55/100 cases; BRAF^V600E was the most frequently detected (49/100) and was associated with higher tumour size, bilateralism and follicular variant but not with capsular invasion. RET/PTC rearrangements were found in 2/100 cases, NRAS^Q61R in 4/100, while no mutations of TERT promoter gene were detected. Despite the observed association between BRAF^V600E mutation and unfavourable histopathological features, we found no direct association with tumour recurrence, distant metastases and mortality.

CONCLUSION

In our study, the search for the most frequent genetic alterations as prognostic markers in mPTCs would not have changed the therapeutic strategy.

The molecular and gene/miRNA expression profiles of radioiodine resistant papillary thyroid cancer

Background

Papillary thyroid cancer (PTC) is the most frequent endocrine tumor. Radioiodine (RAI) treatment is highly effective in these tumors, but up to 60% of metastatic cases become RAI-refractory. Scanty data are available on either the molecular pattern of radioiodine refractory papillary thyroid cancers (PTC) or the mechanisms responsible for RAI resistance.

Methods

We analyzed the molecular profile and gene/miRNA expression in primary PTCs, synchronous and RAI-refractory lymph node metastases (LNMs) in correlation to RAI avidity or refractoriness.

We classified patients as RAI+/D+ (RAI uptake/disease persistence), RAI−/D+ (absent RAI uptake/disease persistence), and RAI+/D- (RAI uptake/disease remission), and analyzed the molecular and gene/miRNA profiles, and the expression of thyroid differentiation (TD) related genes.

Results

A different molecular profile according to the RAI class was observed: BRAF^V600E cases were more frequent in RAI−/D+ (P = 0.032), and fusion genes in RAI+/D+ cases. RAI+/D- patients were less frequently pTERT mutations positive, and more frequently wild type for the tested mutations/fusions. Expression profiles clearly distinguished PTC from normal thyroid. On the other hand, in refractory cases (RAI+/D+ and RAI−/D+) no distinctive PTC expression patterns were associated with either tissue type, or RAI uptake, but with the driving lesion and BRAF−/RAS-like subtype. Primary tumors and RAI-refractory LNMs with BRAF^V600E mutation display transcriptome similarity suggesting that RAI minimally affects the expression profiles of RAI-refractory metastases. Molecular profiles associated with the expression of TPO, SLC26A4 and TD genes, that were found more downregulated in BRAF^V600E than in gene fusions tumors.

Conclusions

The present data indicate a different molecular profile in RAI-avid and RAI-refractory metastatic PTCs. Moreover, BRAF^V600E tumors displayed reduced differentiation and intrinsic RAI refractoriness, while PTCs with fusion oncogenes are RAI-avid but persistent, suggesting different oncogene-driven mechanisms leading to RAI refractoriness.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-020-01757-x.

Genetic Landscape of Papillary Thyroid Carcinoma and Nuclear Architecture: An Overview Comparing Pediatric and Adult Populations

Thyroid cancer is a rare malignancy in the pediatric population that is highly associated with disease aggressiveness and advanced disease stages when compared to adult population. The biological and molecular features underlying pediatric and adult thyroid cancer pathogenesis could be responsible for differences in the clinical presentation and prognosis. Despite this, the clinical assessment and treatments used in pediatric thyroid cancer are the same as those implemented for adults and specific personalized target treatments are not used in clinical practice. In this review, we focus on papillary thyroid carcinoma (PTC), which represents 80-90% of all differentiated thyroid carcinomas. PTC has a high rate of gene fusions and mutations, which can influence the histologic subtypes in both children and adults. This review also highlights telomere-related genomic instability and changes in nuclear organization as novel biomarkers for thyroid cancers.

TMT-labeling Proteomics of Papillary Thyroid Carcinoma Reveal Invasive Biomarkers

Background and Aim: Invasion and metastasis are critical events in papillary thyroid carcinoma (PTC) progression. Protein markers specific to this process may avoid over-treatment and urgently needed.

Methods: TMT-labeled mass spectrometry-based proteomics were carried out on PTC and invasive phenotype (iPTC) (3 pairs per group) and cross validate differentially expressed proteins (DEPs) (FC>1.5 and <0.67 and p<0.05) with GEO and TCGA datasets and the correlation genes of DEPs were also analyzed.

Results: We identified and quantified 4607 proteins identical to PTC and iPTC groups. Among which 12 DEPs in PTC and 179 DEPs in iPTCs were found. Cross-validation with GSE60542 and TCGA database revealed 10 DEPs that all significant correlated with metastasis and staging. Upregulated SLC27A6 showed negative correlation with 6 out of 9 downregulated DEPs including HGD, CA4, COL23A1, SLC26A7, FHL1 and TPO.

Conclusion: The panel of 7 genes (SLC27A6 and 6 downregulated DEPs) could have ideal prediction value to improve our understanding of invasiveness of PTC.

The contributing factors for lateral neck lymph node metastasis in papillary thyroid microcarcinoma (PTMC)

PURPOSE

Papillary thyroid microcarcinoma (PTMC) has an excellent prognosis due to its indolent features. Only few studies have assessed the clinical factors that can predict lateral neck lymph node metastasis (LLNM) in patients with PTMC. This study aimed to examine the clinicopathological factors associated with LLNM in patients with PTMC.

METHODS

We reviewed medical records of 3578 patients with PTMC that was ≤1 cm in diameter on final pathology at Yonsei University Hospital between January 2015 and December 2017. The patients were divided into two groups (metastasis group [n = 157] and no metastasis group [n = 3421]).

RESULTS

The proportion of patients with multifocality, extrathyroidal extension (ETE), and central node metastasis was significantly higher in metastasis group (p < 0.001, p < 0.001 and p < 0.001, respectively), and the mean tumor size was relatively larger in metastasis group than in no metastasis group (0.7 ± 0.2 vs. 0.6 ± 0.2 cm, p < 0.001). However, no statistically significant differences were observed in the tumors harboring BRAF mutation between the two groups (84.8% vs. 80.6%, p = 0.199). Multivariate analysis indicated that the significant risk factors of LLNM include ETE (odds ratio [OR]: 1.904, 95% confidence interval [CI]: 1.267-2.861), multifocality (OR: 2.255, 95% CI: 1.544-3.293), and central node metastasis (OR: 7.768, 95% CI: 4.869-12.395), but not BRAF mutation (OR: 0.542, 95% CI: 0.337-0.874).

CONCLUSION

Approximately 4.4% of patients with PTMC presented with LLNM at the time of diagnosis. Moreover, the significant risk factors of LLNM include central node metastasis, ETE, and multifocal disease but not BRAF mutation.

Polymer Nanoformulation of Sorafenib and All-Trans Retinoic Acid for Synergistic Inhibition of Thyroid Cancer

Part of differentiated thyroid cancer will relapse or develop into dedifferentiated thyroid cancer after standard therapy, such as surgery or radionuclide therapy. Sorafenib (SOR) is recommended for the treatment of advanced or radioiodine-refractory thyroid cancer. The monotherapy using SOR is often hampered by its modest efficacy, serve systemic toxicity, and high occurrence of drug resistance. In order to enhance the antitumor effect of SOR and reduce its side effects, SOR and all-trans retinoic acid (ATRA), a differentiation-promoting drug, were loaded into poly(ethylene glycol)-poly(lactide-co-glycolide) (PEG-PLGA) polymer micelles in this study. The drug-loaded micelles, PM/(SOR+ATRA), exhibited relatively slow drug release and effective cell uptake. Compared with other treatment groups, the PM/(SOR+ATRA) treatment group showed the most significant antitumor effect and minimal systemic toxicity toward the FTC-133 thyroid cancer-bearing BALB/c nude mouse model. Immunofluorescence analysis confirmed that PM/(SOR+ATRA) could significantly promote apoptosis and re-differentiation of tumor cells. All the results demonstrated that polymer micelles loaded with SOR and ATRA could treat thyroid cancer more effectively and safely.

Inhibiting SLC26A4 reverses cardiac hypertrophy in H9C2 cells and in rats

Background

It has been confirmed that mutations in solute carrier family 26 member 4 (SLC26A4) contribute to pendred syndrome. However, the role of SLC26A4 in cardiac hypertrophy and the signaling pathways remain unclear.

Methods

Cardiomyocytes were treated by 200 µM phenylephrine (PE) to induce cardiac hypertrophy. Also, the expression of SLC26A4, GSK3, cardiac hypertrophy markers including atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) was detected through real-time quantitative polymerase chain reaction (RT-qPCR). Flow cytometry assay was used to test the apoptosis of PE-induced cardiomyocytes transfected by small interfere RNA (siRNA)-SLC26A4. Furthermore, we detected the expression of autophagy-related markers including light chain 3 (LC3) and P62. Finally, we established a rat model of abdominal aortic constriction (AAC)-induced cardiac hypertrophy in vivo.

Results

RT-qPCR results showed that the mRNA expression of SLC26A4 was significantly up-regulated in PE-induced cardiac hypertrophy. After inhibiting SLC26A4, the release of ANP and BNP was significantly decreased and GSK3β was elevated in vivo and in vitro. Furthermore, inhibiting SLC26A4 promoted apoptosis of cardiac hypertrophy cells. In addition, LC3 was down-regulated and P62 was enhanced after transfection of siRNA-SLC26A4.

Conclusion

Our findings revealed that SLC26A4 increases cardiac hypertrophy, and inhibiting SLC26A4 could decrease the release of ANP/BNP and promote the expression of GSK-3β in vitro and in vivo. Moreover, SLC26A4 silencing inhibits autophagy of cardiomyocytes and induces apoptosis of cardiomyocytes. Therefore, SLC26A4 possesses potential value to be a therapeutic target of cardiac hypertrophy, and our study provides new insights into the mechanisms of cardiac hypertrophy.

Clinicopathological and Prognostic Significance of WW Domain Binding Protein 5 Expression in Papillary Thyroid Carcinoma

Objectives

Many patients with papillary thyroid cancer (PTC) have a high recurrence risk and poor prognosis, and the main obstacle to the clinical diagnosis and treatment of PTC is lack of effective predictive molecular markers. The purpose of this study was to investigate the clinicopathological and prognostic implications of WW domain binding protein 5 (WBP5) expression in PTC.

Materials and Methods

Immunohistochemistry of WBP5 was performed using tissue microarrays of 131 patients with PTC who underwent surgery during January 2006 and January 2010 in the Zhejiang Cancer Hospital. Statistical analyses were conducted to evaluate the association between WBP5 expression and the clinicopathological features and to analyze the disease-free survival (DFS) and prognostic factors.

Results and Conclusion

The positive expression rate of WBP5 in PTC and the adjacent normal tissues was 42.75% (56/131) and 45.45% (10/22), respectively. WBP5 expression was significantly correlated with bilaterality, capsule invasion, and N-stage, and it was a favorable factor of DFS. Moreover, patients with a high WBP5 expression exhibited reduced risk of disease recurrence compared with that in patients with low WBP5 expression in the univariate analysis, whereas the multivariate analysis suggested that WBP5 was not an independent prognostic factor. Our results indicate that WBP5 might be a favorable prognosis indicator of PTC.

Clinical significance of the BRAFV600E mutation in PTC and its effect on radioiodine therapy

The goal of this study was to explore the relationship of the BRAFV600E mutation with clinicopathologic factors and evaluate the effect of radioactive iodine (RAI) therapy in a large group of intermediate- and high-risk papillary thyroid cancer (PTC) patients with the BRAFV600E mutation and without distant metastases. We collected data for PTC patients who underwent total or near-total thyroidectomy and RAI treatment in our hospital from January 2014-December 2017. There were 1220 PTC patients who met the criteria, and the BRAFV600E mutation was observed in 979 of them (80.2%). Multivariate analysis identified that the BRAFV600E mutation remained independently associated with age at diagnosis, and bilaterality (OR = 1.023, 95% CI = 1.012-1.039, P < 0.001; OR = 1.685, 95% CI = 1.213-2.341, P = 0.002, respectively). In addition, the patients with bilateral PTCs had a higher prevalence of extrathyroid invasion, capsular invasion and fusion of metastatic lymph nodes than the unilateral PTC patients. The response to RAI therapy was evaluated in both the entire series and the patients with a high recurrence risk; no significant difference was discerned between the BRAFV600E mutation and the wild-type groups (P = 0.237 and P = 0.498, respectively). To summarize, our results confirmed that PTC patients with the BRAFV600E mutation exhibit more aggressive characteristics. In addition, the patients with bilateral PTC have a higher incidence of extrathyroid invasion. Moreover, BRAFV600E mutation PTC patients did not show a poorer clinical response after postsurgical RAI therapy, suggesting that RAI therapy may improve the general clinical outcome of these patients.

Targeting the BRAF Signaling Pathway in CD133pos Cancer Stem Cells of Anaplastic Thyroid Carcinoma

Background:

Cancer stem cells (CSCs) with a self-renewal ability in tumor cells population, execute a pivotal function in tumorigenesis, retrogression, and metastasis of malignant cancers such as anaplastic thyroid carcinoma (ATC).

Materials and Methods:

In this study, we isolated CSCs subpopulation with CD133 surface marker from three ATC cell lines by magnetic cell sorting assay. After confirming the segregation by the flow cytometry method, BRAF and sodium-iodide symporter (NIS) genes were investigated in them before and after incubation with BRAF inhibitor. Also, we evaluated the NIS protein expression and localization.

Results:

Established upon q-RT PCR data, when compared to human normal thyrocytes, the BRAF^V600E gene was over-expressed in CD133^pos cells (>1705.99 ± 55.55 fold, Mean ± SEM, n=3, P- value<0.05), whilst the expression of NIS gene was very restricted (< 0.0008 ± 5.43 fold, Mean ± SEM, n=3, P- value<0.05) in them. Also, our results showed that BRAF inhibition affected NIS protein expression and localization.

Conclusions:

Current study showed that the differentiate genes/proteins expression can be induced in the CSCs via focus on signal transduction pathways and targeting their molecules, that are involved in expression of these genes/proteins. Therefore, attention to targeting CSCs along with routine thyroid cancer therapy, can help to ATC treatment.

FMO1 gene expression independently predicts favorable recurrence-free survival of classical papillary thyroid cancer

Aim: To examine the expression profile of FMO1 in papillary thyroid cancer (PTC) and its prognostic value in recurrence-free survival (RFS). Methods: A retrospective analysis was performed using data from the Cancer Genome Atlas and Human Protein Atlas. Results: The most frequent variants of PTC had decreased FMO1 expression compared with their respective adjacent normal tissues. However, even under the best cut-off model, high FMO1 expression was only significantly associated with better RFS in classical PTC (p < 0.001), but not in other two variants. High FMO1 expression independently predicted favorable RFS (hazard ratio: 0.202; 95% CI: 0.084-0.487; p < 0.001) in classical PTC. Conclusion: High FMO1 expression might serve as a biomarker that independently predicts favorable RFS in classical PTC patients.

A review on the mechanism of iodide metabolic dysfunction in differentiated thyroid cancer

The incidence of differentiated thyroid cancer (DTC) has been increasing rapidly worldwide, and the risk factors remain unclear. With the growing number of patients with DTC, the related issues have been gradually highlighted. ¹³¹Iodide (¹³¹I) is an important treatment for DTC and has the potential to reduce the risk of recurrence. ¹³¹I is also an effective treatment for distant metastases of thyroid carcinoma. However, iodide metabolism dysfunction in metastatic foci causes patients to lose the opportunity of ¹³¹I treatment. This article reviews the related mechanisms of iodide metabolism dysfunction in DTC cells and summarizes the clinical transformation progression.

FAM129A regulates autophagy in thyroid carcinomas in an oncogene-dependent manner

We previously proposed that high expression of FAM129A can be used as a thyroid carcinoma biomarker in preoperative diagnostic exams of thyroid nodules. Here, we identify that FAM129A expression is increased under nutrient and growth factor depletion in a normal thyroid cell line (PCCL3), overlapping with increased expression of autophagy-related protein and inhibition of AKT/mTOR/p70S6K. Supplementation of insulin, TSH and serum to the medium was able to reduce the expression of both FAM129A and autophagy-related protein and reestablish the AKT/mTOR/p70S6K axis. To determine the direct role of FAM129A on autophagy, FAM129A was transfected into PCCL3 cells. Its overexpression induced autophagic vesicles formation, evidenced by transmission electron microscopy. Co-expression of FAM129A and mCherry-EGFP-LC3B in PCCL3 showed an increased yellow puncta formation, suggesting that FAM129Ainduces autophagy. To further confirm its role on autophagy, we knockdown FAM129A in two thyroid carcinoma cell lines (TPC1 and FTC-236). Unexpectedly, FAM129A silencing increased autophagic flux, suggesting that FAM129A inhibits autophagy in these models. We next co-transfected PCCL3 cells with FAM129A and RET/PTC1 and tested autophagy in this context. Co-expression of FAM129A and RET/PTC1 oncogene in PCCL3 cells, inhibited RET/PTC1-induced autophagy. Together, our data suggest that, in normal cells FAM129A induces autophagy in order to maintain cell homeostasis and provide substrates under starvation conditions. Instead, in cancer cells, decreased autophagy may help the cells to overcome cell death. FAM129A regulates autophagy in a cell- and/or context-dependent manner. Our data reinforce the concept that autophagy can be used as a strategy for cancer treatment.

Predictive Value of BRAFV600E Mutation for Lymph Node Metastasis in Papillary Thyroid Cancer: A Meta-analysis

BRAF^V600E mutation has been thought to be a valuable molecular marker that may predict a worse prognosis for papillary thyroid cancer (PTC). But whether BRAF^V600E mutation is associated with lymph node metastasis (LNM) remains controversial. Different surgical strategies may bring a bias in demonsstrating the association between them. In order to delineate a risk stratification to guide a tailored initial approach to tumors that express BRAF^V600E mutation, we performed this meta-analysis by using the articles in which total or near-total thyroidectomy plus bilateral central lymph node dissection was routinely performed to avoid the bias from the surgical strategy. We searched the Medline, Embase and CNKI database for eligible studies from January 2003 to May 2018. Meta-analysis was performed using the STATA 12.0 software. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated under fixed-effects or randomeffects models. Fifteen clinical studies were included with a total of 4909 PTC patients. Our meta-analysis results reported that BRAFV600E mutation was associated with LNM (OR=1.34; 95% CI: 1.09-1.65; P=0.005), as well as central LNM (OR=1.59; 95% CI: 1.35-1.88; P<0.00001). Moreover, in patients with papillary thyroid microcarcinoma, we also confirmed the predictive value of BRAF^V600E mutation for LNM (OR=3.49; 95% CI: 2.02-6.02; P<0.00001). This meta-analysis demonstrates that BRAF^V600E mutation is closely related to LNM in PTC patients. The results suggest that BRAF^V600E mutation can be considered as a risk factor for LNM in PTC. Moreover, combining BRAF^V600E mutation with other risk factors to determine the initial surgical treatment may bring benefits for PTC patients.

Current controversies and future directions in the diagnosis and management of differentiated thyroid cancers

Despite the development of novel diagnostic, surgical, and chemotherapeutic approaches to differentiated thyroid cancers (DTCs), the diagnosis and management of these tumors remains controversial. The most recent American Thyroid Association (ATA) guidelines, released in 2015, reflect a recent shift towards less aggressive management for patients with DTCs. However, many clinicians have expressed concern that more conservative management will put patients at risk for disease recurrence and metastasis. In particular, the management of indeterminate nodules on fine needle aspiration (with special attention to genetic and epigenetic markers of malignancy), the extent of surgery for known differentiated cancers, the role of adjuvant radioactive iodine (RAI) therapy, and novel targeted treatments with tyrosine kinase inhibitors (TKIs) represent current areas of uncertainty and opportunities for future research. In this review, we examine the current state of the art in these areas, and address some of the questions that remain.

Predictive factors determining incomplete response to radioiodine therapy in patients with differentiated thyroid cancer

BACKGROUND

Although differentiated thyroid cancer (DTC) has relatively favorable course, factors predicting the course of the disease are intensively searched. The aim of the study was to identify the clinical factors determining incomplete response to radioiodine therapy in patients with DTC.

METHODS

We retrospectively analyzed 385 consecutive patients with DTC treated and followed-up at a single tertiary reference center. We investigated clinical factors detectable during first hospitalization 3-6 months following total thyroidectomy due to DTC, which may serve as prognostic factors determining response to DTC therapy in a long-term follow-up.

RESULTS

Stimulated thyroglobulin (sTg) was the only parameter significantly correlated with the cumulative radioiodine activity (r=0.247, P<0.001). The need for repeated radioiodine administration (≥3 doses) was best predictable on the basis of sTg concentration assessed at the moment of qualification to radioiodine therapy (P=0.003). Predictive value of the sTg for incomplete response to radioiodine has been confirmed with the ROC curve analysis and the best proposed cut-off value was 8.17 ng/mL (sensitivity 55%, specificity 77%, positive predictive value 42.1%, negative predictive value 84.7%); sTg over 8.17 ng/mL increases the risk of incomplete response to therapy 2.5-folds (P=0.002).

CONCLUSIONS

sTg, assessed at the moment of qualification to radioiodine therapy, as the most important factor determining incomplete response to radioiodine therapy in patients with DTC, should be particularly taken into consideration in predicting the future course of the disease as well as treatment and follow-up planning. Radical thyroidectomy may help to increase the effectiveness of treatment.

LIMD2 Is Overexpressed in BRAF V600E-Positive Papillary Thyroid Carcinomas and Matched Lymph Node Metastases

We previously described that LIM domain containing 2 (LIMD2) overexpression was closely correlated with metastatic process in papillary thyroid carcinoma (PTC). We here evaluated the expression of LIMD2 in a series of non-metastatic and metastatic PTC and their matched lymph node metastases via immunohistochemistry. LIMD2 was expressed in 74 (81%) of primary PTC and 35 (95%) of lymph node metastases. Sub-analysis performed in 37 matched samples demonstrated that in four cases, LIMD2 is expressed in lymph node metastases, while it is not expressed in primary tumors. Moreover, in eight cases, the staining intensity of LIMD2 was stronger in the patient-matched lymph node metastases than in the primary tumors. Next, the expression of LIMD2 was correlated with clinical pathological parameters and BRAF V600E and RET/PTC mutational status. The expression of LIMD2 in primary tumors was correlated with the presence of BRAF V600E mutation (P = 0.0338). Western blot analysis in thyroid cell lines demonstrated that LIMD2 is expressed in two PTC cell lines, while it is not expressed in normal thyroid and follicular thyroid carcinoma cell lines. Importantly, its expression was higher in a PTC cell line that harbors BRAF V600E mutation than in a PTC cell line that harbors RET/PTC1. The available genomic profiling data generated by The Cancer Genome Atlas Research Network confirmed that LIMD2 expression is higher in BRAF-like PTC samples. Our data suggest that LIMD2 may play an important role in the metastatic process of PTC, predominantly in BRAF V600E-positive tumors.

Nomogram for predicting central lymph node metastasis in papillary thyroid microcarcinoma: A retrospective cohort study of 8668 patients

INTRODUCTION

The status of central lymph node metastasis (CLNM) is crucial to determining the surgical strategies for papillary thyroid micro carcinoma (PTMC). The objective of the study was to establish a nomogram to predict the possibility of CLNM in PTMC patients.

METHODS

A total of 8668 PTMC patients who underwent total thyroidectomy or lobectomy with central lymph node dissection (CLND) from 2006 to 2016 were retrospectively retrieved. Univariate and multivariate analysis were performed to examine risk factors associated with CLNM. A nomogram for predicting CLNM was established and internally validated.

RESULTS

Six variables significantly associated with CLNM were included in our model, these are age <55 years (odd ratio [OR] = 1.779, 95% confidence interval [CI],1.569-2.017; P < 0.001), male sex (OR = 1.718, 95%CI,1.543-1.913; P < 0.001), tumor size 0.5-1.0 cm (OR = 1.985,95%CI,1.761-2.238; P < 0.001), multifocal lesions (OR = 1.263, 95%CI,1.118-1.426; P < 0.001), extra thyroidal extension (ETE) (OR = 1.348, 95%CI,1.092-1.664; P = 0.005) and lateral lymph node metastasis (LLNM) (OR = 5.135, 95%CI, 4.236-6.225; P < 0.001). The discrimination of the prediction model was 0.711 (95%CI, 0.700-0.722; P < 0.001).

CONCLUSIONS

Based on the quantified risk stratification offered by our nomogram, clinicians might have a thorough discussion with PTMC patients during the both pre- and postoperative period. Prophylactic CLND and strict postoperative evaluation may be indicated when the patients have a high nomogram score.

Thyroid Cancer: Risk-Stratified Management and Individualized Therapy

Thyroid cancer is the most common endocrine malignancy. Differentiated thyroid cancer (DTC) with the two subtypes, papillary thyroid cancer (PTC) and follicular thyroid cancer (FTC), is the most frequent subtype of thyroid cancer; more rare subtypes are medullary thyroid cancer (MTC) and anaplastic thyroid cancer (ATC). The incidence of DTC has increased rapidly in recent years due to the more frequent use of imaging methods such as ultrasound of the neck and fine-needle aspiration (FNA) of thyroid nodules. After total thyroidectomy and radioiodine treatment, DTC remains an indolent and curable disease in most patients, whereas the cure rate in MTC is lower and depends on early diagnosis. Most ATCs are incurable. In recent years, there has been great progress in identifying genetic changes in thyroid cancer, and genetic testing of FNA samples or blood samples provides useful information for clinical decision making. Tumor staging, either postoperatively or by imaging, and measuring the tumor markers thyroglobulin for DTC and calcitonin for MTC, allow for dynamic risk-adapted stratification for follow-up procedures. In advanced metastatic thyroid cancer, molecular targeted therapy using tyrosine kinase receptor inhibitors, including sorafenib, lenvantinib, vandetanib, and cabozantinib, helps control tumor progression and prolongs progression-free survival. Using a dynamic risk-stratified approach to manage thyroid cancer, the outcomes for most thyroid cancer patients are excellent compared with those for other cancers. The major challenge in the future is to identify high-risk patients and to treat and monitor them appropriately. Clin Cancer Res; 22(20); 5012-21. ©2016 AACR SEE ALL ARTICLES IN THIS CCR FOCUS SECTION, "ENDOCRINE CANCERS REVISING PARADIGMS".

ETV6-NTRK3 and STRN-ALK kinase fusions are recurrent events in papillary thyroid cancer of adult population

OBJECTIVE

PTC-specific analysis identified novel fusions involving RET, BRAF, NTRK1, NTRK3, AGK and ALK genes in adults and pediatric PTCs. Although many novel fusions are PTC-specific events and, therefore, are ideal for diagnosis purposes, validation across additional and larger patient cohorts is essential for introducing these potential diagnostic or prognostic biomarkers into the clinical practice. As most of the BRAF, NTRK3 and ALK fusions were initially found in pediatric PTC or in more aggressive thyroid carcinomas, and there is a great disparity across population, in this study, we screened a large set of adult-sporadic PTC cases for the most prevalent kinase fusion lately described in the TCGA.

DESIGN AND METHODS

The prevalence of the fusions was determined by RT-PCR in 71 classical PTC, 45 follicular variants of PTC (FVPTC), 19 follicular thyroid adenomas (FTAs) and 22 follicular thyroid carcinomas (FTCs).

RESULTS

ETV6-NTRK3 was exclusively found in FVPTC, in both encapsulated and infiltrative variants, but was not found in FTAs and FTCs. STRN-ALK was found in both classical PTC and FVPTC. No AGK-BRAF fusion was identified in this series, endorsing that AGK-BRAF is a genetic event mainly associated with pediatric PTCs.

CONCLUSIONS

The identification of kinase fusions in thyroid carcinomas helps to expand our knowledge about the landscape of oncogenic alterations in PTC. As ETV6-NTRK3 and STRN-ALK are recurrent and not identified in benign lesions, they can certainly help with diagnosis of thyroid nodules. Further analysis is needed to define if they can also be useful for prognosis and guiding therapy.

THE ASSOCIATION BETWEEN LYMPH NODE METASTASIS AND MOLECULAR MARKERS IN DIFFERENTIATED THYROID CANCER

Context

There is no consensus regarding routine usage and benefits of molecular markers for prediction of prognosis and assessment of risk groups in differentiated thyroid cancer (DTC).

Objective

We aimed to investigate NIS, Galectin-3, PTEN, P53 and Ki67 expressions in tumor tissue and metastatic lymph nodes in PTC and their association with lymph node metastasis and prognosis.

Material and Methods

Ninety two papillary thyroid cancer patients who underwent total thyroidectomy and central lymph node dissection were included in this study. NIS, Galectin-3, PTEN, P53 and Ki67 immunohistochemical stainings were performed for all surgical tumor tissues and metastatic lymph nodes of the 38 patients. Age, gender, tumor size, multifocality, capsular invasion, extrathyroidal extension and lymphocytic thyroiditis were assessed retrospectively.

Results

Seventy three females (79.3%) and nineteen males (20.7%) were included in this study. Risk of lymph node metastasis was higher in tumors with capsular invasion and extrathyroidal extension (p=0.03 and p < 0.001). NIS, PTEN and Galectin-3 protein expressions in tumor tissue were not associated with gender, tumor size, multifocality, extrathyroidal extension, capsular invasion, lymph node metastasis and tumor recurrence. Mean Ki 67 proliferation index was 2.08±0.95%. Ki 67 proliferation index was associated with tumor size (p=0.012). Intensity and expression of NIS and PTEN in tumor tissue were concordant with intensity and expression in metastatic lymph nodes (p<0.001). Ki 67 proliferation index in tumor was concordant with metastatic lymph nodes (p=0.02).

Conclusions

NIS, PTEN, Galectin-3, Ki67 and P53 expressions were not associated with the risk of lymph node metastasis in PTC patients. Routine analysis of these markers does not seem to be favorable. Further studies with new markers are necessary to determine prognostic predictors.

NIS expression in thyroid tumors, relation with prognosis clinicopathological and molecular features

Thyroid cancer therapy is based on surgery followed by radioiodine treatment. The incorporation of radioiodine by cancer cells is mediated by sodium iodide symporter (NIS) (codified by the SLC5A5 gene), that is functional only when targeted to the cell membrane. We aimed to evaluate if NIS expression in thyroid primary tumors would be helpful in predicting tumor behavior, response to therapy and prognosis. NIS expression was addressed by qPCR and immunohistochemistry. In order to validate our data, we also studied SLC5A5 expression on 378 primary papillary thyroid carcinomas from The Cancer Genome Atlas (TCGA) database. In our series, SLC5A5 expression was lower in carcinomas with vascular invasion and with extrathyroidal extension and in those harboring BRAFV600E mutation. Analysis of SLC5A5 expression from TCGA database confirmed our results. Furthermore, it showed that larger tumors, with locoregional recurrences and/or distant metastases or harboring RAS, BRAF and/or TERT promoter (TERTp) mutations presented significantly less SLC5A5 expression. Regarding immunohistochemistry, 12/211 of the cases demonstrated NIS in the membrane of tumor cells, those cases showed variable outcomes concerning therapy success, prognosis and all but one were wild type for BRAF, NRAS and TERTp mutations. SLC5A5 mRNA lower expression is associated with features of aggressiveness and with key genetic alterations involving BRAF, RAS and TERTp. Mutations in these genes seem to decrease protein expression and its targeting to the cell membrane. SLC5A5 mRNA expression is more informative than NIS immunohistochemical expression regarding tumor aggressiveness and prognostic features.

Unfavorable efficacy to 131I ablation in BRAFV600E mutant papillary thyroid carcinoma with positive TgAb

The BRAFV600E mutation has shown a close relationship of aggressiveness in papillary thyroid carcinoma (PTC), while it remains unclear about its influence on the therapeutic response. As a common clinicopathologic risk factor, thyroglobulin antibody (TgAb) may have a correlation of prognosis in PTC. The objective was to investigate the relationship between BRAFV600E mutation and TgAb, and their combined effect on efficacy to radioiodine remnant ablation (RRA). This was a retrospective study including 298 PTC patients and they were divided into four groups according to the combined status. The BRAFV600E mutation rates declined along with increasing TgAb levels in the entire cohort. The ablative efficacy in terms of success or failure rate was statistically different among four groups (89.7%, 74.1%, 67.5%, 57.8%, respectively, P=0.009), group with both positive BRAF and TgAb presented the lowest efficacy. The combined status was associated with the poor efficacy to RRA independently (P=0.029). Among patients with positive TgAb, the effect of RRA in reducing TgAb level might be weakened in BRAF mutant status. The combined status of BRAFV600E mutation and positive TgAb predicts low efficacy to RRA and might be served as an independent unfavorable prognostic factor for PTC. BRAF mutant might weaken the effect of RRA in reducing TgAb levels in PTCs.

Role of molecular markers to predict distant metastasis in papillary thyroid carcinoma: Promising value of TERT promoter mutations and insignificant role of BRAF mutations—a meta-analysis

The presence of distant metastasis is associated with an adverse outcome in papillary thyroid cancer. We performed a meta-analysis to investigate the role of molecular markers as predictors for distant metastasis in papillary thyroid cancer. Four electronic databases including PubMed, Web of Science, Scopus, and Virtual Health Library were searched, and odds ratio and its 95% confidence interval concerning the association of BRAF, RAS, and TERT promoter mutations and RET/PTC rearrangements with distant metastasis were calculated using random-effects model. In total, 42 studies with 11,109 papillary thyroid cancers were included for meta-analyses. Overall, the presence of TERT promoter (odds ratio = 5.95; 95% confidence interval = 2.95–11.99), RAS mutations (odds ratio = 2.5; 95% confidence interval = 1.00–6.22), and RET/PTC rearrangements (odds ratio = 1.92; 95% confidence interval = 1.03–3.56) were found to be associated with a significantly increased risk for distant metastasis. BRAF mutations were not associated with an elevated risk for distant metastasis (odds ratio = 0.79; 95% confidence interval = 0.54–1.16). In conclusion, our study demonstrated the promising value of few molecular biomarkers, especially TERT promoter mutations in predicting distant metastasis in papillary thyroid cancers, while BRAF mutations showed no association with distant metastasis. Our study affirms the value of selected mutations for tumor risk stratification and assessment of patients’ prognosis.

The Genetics of Papillary Microcarcinomas of the Thyroid: Diagnostic and Prognostic Implications

Papillary microcarcinoma of the thyroid (mPTC) is defined by the WHO as a papillary thy-roid cancer measuring 10mm or less in diameter and it is nowadays a topic of intense debate among the members of the medical community due to its apparent “epidemic” rise. Although these tumors follow almost always an indolent clinical course and carry an excellent prognosis, it is known that a small sub-set may display a potentially aggressive behavior. Nevertheless, we still lack an accurate way of predict-ing those which will cause significant disease. In an attempt to address this problem, a number of clini-co-pathologic features have been studied as poor prognostic markers in mPTC, and their association with known genetic alterations in thyroid cancer has been evaluated. Herein we review the present knowledge concerning mPTC’s genetic profile, namely the prevalence of BRAF (V600E), RAS and TERT promoter mutations and RET/PTC and PAX8-PPARG rearrangements and report the results of the evaluation in the putative prognostic value of these genetic alterations in mPTC.

Fusion Oncogenes Are the Main Genetic Events Found in Sporadic Papillary Thyroid Carcinomas from Children

BACKGROUND

Previous studies reported significant differences in the clinical presentation and outcomes of papillary thyroid carcinoma (PTC) in pediatric patients compared with adults. Previous studies have suggested that the clinicopathological differences observed between pediatric and adult PTCs may be due the existence of distinct genetic alterations. However, the knowledge of genetic events in pediatric PTCs is based primarily on studies in radiation-exposed PTCs or in the few studies that enrolled predominantly adolescent patients. The aim of this study was to characterize the known oncogenic alterations of the MAPK pathway found in adult and radiation-exposed PTCs in a cohort of predominantly sporadic pediatric PTC patients.

METHODS

Thirty-five pediatric PTCs were screened for the most prevalent fusions (RET/PTC1, RET/PTC2, RET/PTC3, ETV6-NTRK3, and AGK-BRAF) and point mutations (BRAFV600E and NRASQ61) described in sporadic pediatric PTCs. The mutational status was correlated with clinicopathological data.

RESULTS

Mutations were found in 20 out of 35 (57%) PTC cases. Fusion oncogenes were the main genetic alterations found. RET/PTC1-3 rearrangements were found in 13 (37%), ETV6-NTRK3 in 3 (9%), AGK-BRAF in 4 (11%), and BRAFV600E in 3 (9%). No mutation was found in NRASQ61. BRAFV600E was associated with older age and larger tumor size (p < 0.05), and RET/PTC3 was associated with a larger tumor size and multifocality (p < 0.05).

CONCLUSIONS

The genetic signature in this cohort was remarkably different than that observed in adults. Although observed at a lower prevalence, the spectrum of mutations was quite similar to that described in radiation-exposed pediatric PTCs. As mutations were unidentifiable in over 40% of the PTC cases, more comprehensive studies conducted in these patients will help to decipher the genetic landscape of sporadic pediatric PTCs.

Cell penetrating peptide of sodium-iodide symporter effect on the I-131 radiotherapy on thyroid cancer

The aim of the present study was to clarify whether the cell penetrating peptide of sodium-iodide symporter (NIS) has an effect on the I-131 radiotherapy of thyroid cancer. Firstly, we combined the HIV-1 TAT peptide (a cell penetrating peptide, dTAT) and established a nanoparticle vector (dTAT NP) to study the delivery efficiency of this cell-penetrating strategy for tumor-targeted gene delivery. dTAT NP was transfected into cultured TPC-1 cells as a model to study the effects of I-131 radiotherapy on thyroid cancer. Reverse transcription-quantitative polymerase chain reaction and western blotting results showed that the mRNA and protein expression levels of NIS in the transfected TPC-1 cells were substantially higher than in the negative control cells. MTT and flow cytometric analyses demonstrated that the cell growth and apoptosis rates of the TPC-1 cells were significantly inhibited and activated, respectively, by treatment with dTAT NP. The results of DAPI staining showed that treatment with dTAT NP visibly increased the nuclear apoptosis rate of the TPC-1 cells. The effect of dTAT NP on TPC-1 cells was associated with the promotion of caspase-3 and downregulation of the PI3K/Akt signaling pathway. In summary, the present data provide a pre-clinical proof-of-concept for a novel gene delivery system that efficiently delivers NIS to the targeted cancer cells and presents a satisfactory efficacy. This approach may offer an effective strategy for improving thyroid cancer gene therapy.

The micropapillary/hobnail variant of papillary thyroid carcinoma: A review of series described in the literature compared to a series from one southern Italy pathology institution

Papillary thyroid carcinoma (PTC) has a good prognosis with a 10-yr survival greater than 90%. Recently, a micro-papillary pattern with hobnail appearance (MPHC) in PTC has been indicated as associated with poor prognosis, but this suggestion is based only on a few cases from geographical areas different from ours. Two-hundred ninety-nine consecutive PTC cases were collected between the years of 1992 and 2014 at our institution. The corresponding histologic sections (at least 6 for each case) were stained with hematoxylin and eosin and reviewed independently by two pathologists to reach a consensus on the identification and quantification of the MPHC. As done in other cohorts, parallel serial sections were stained with antisera for thyroglobulin, epithelial membrane antigen, thyroid-transcription-factor-1 and Ki 67. BRAF gene mutation at codon 600 and RET/PTC1 gene rearrangements were searched. A comparative statistical analysis was done between the present series and previously published series. Of the 295 PTC, 124 (42.5%) were follicular, 104 (35%) classic, 34 (11.5%) sclerosing, 15 (5%) tall cells, 10 (3.4%) Warthin-like, and 8 (2.7%) MPHC. Four MHPC cases (50%) harbored the BRAF V600E variant, while one was positive for RET/PTC1 rearrangement. Our rate of MPHC-PTC (2.7%) is 2X to 8X greater than those reported previously for cohorts from North America + North Italy, Korea and Mexico. MPHC prognosis appears to be better compared to other cohorts, probably due to not only to the lower rate of the vascular invasion, but also to the smaller size of the MPHC-PTC nodule.

Papillary thyroid microcarcinoma: time to shift from surgery to active surveillance?

The incidence of differentiated thyroid cancer is increasing greatly in high-income countries. Roughly 50% of this increase is attributable to the identification of intrathyroidal papillary thyroid microcarcinomas. Since mortality associated with these tumours remains low and stable, the increasing diagnosis has led to concerns about overdiagnosis and overtreatment. Management of papillary thyroid microcarcinomas should take into account the reported absence of mortality when diagnosed in the absence of lymph node metastases and distant metastases, as shown even in recent studies promoting active surveillance; a low recurrence rate of 1-5%; and the risk of permanent complications from surgery that cannot be decreased to less than 1-3%, even in high-volume tertiary care centres with experienced surgeons. On the basis of these data, active surveillance with curative intent, in which active treatment is delayed until the cancer shows signs of significant progression to avoid side-effects of treatment, should be considered in properly selected patients.

Therapeutic Strategies and Clinical Outcome in Papillary Thyroid Microcarcinoma: A Multicenter Observational Study

PURPOSE

Papillary thyroid microcarcinoma (MPTC) has an excellent prognosis. We aimed to evaluate the evolution of therapeutic strategies over time and the clinical outcome of MPTC.

METHODS

In this retrospective multicenter observational study in a northwest Italian region, patients with intrathyroidal, unifocal tumor ≤1 cm in size, incidentally found at histology or preoperative cytology diagnosis, were included. Exclusion criteria were a previous head-and-neck irradiation and/or node metastases.

RESULTS

From 1985 to 2012, 437 patients had an MPTC diagnosis, which was incidental in 85% and preoperative in 15%. Patients with a preoperative diagnosis were younger at the time of diagnosis (47.6 ± 12.7 years, p < 0.01) and had a larger tumor (7.0 ± 2.5 mm, p < 0.0001) than patients with an incidental diagnosis (age 52 ± 13.5 years, size 4.4 ± 2.8 mm), but there were no differences in clinical outcome between both groups. We observed a significant (p < 0.001) reduction in radioiodine remnant ablation during the years. TSH levels were: <0.1 mIU/l in 27.5%, 0.1-0.5 mlU/l in 33.7%, 0.5-2.5 mlU/l in 32.6%, 2.5-4.2 mlU/l in 3.9%, and >4.2 mlU/l in 2.3% of patients. Six patients (1.37%) had nodal recurrence; 5 of them were cured after therapy. MPTC-linked mortality was null.

CONCLUSIONS

We confirmed the favorable clinical outcome of MPTC. Despite the reduction in radioiodine ablation, overtreatment of MPTC is still observed.

A Risk Model for Predicting Central Lymph Node Metastasis of Papillary Thyroid Microcarcinoma Including Conventional Ultrasound and Acoustic Radiation Force Impulse Elastography

The aim of this prospective study was to propose a new rating system using a risk model including conventional ultrasound (US) and acoustic radiation force impulse (ARFI) elastography for predicting central lymph node metastasis (LNM) in patients with papillary thyroid microcarcinoma (PTMC).A total of 252 patients with PTMCs were enrolled, who were preoperatively evaluated by US and ARFI elastography including virtual touch tissue imaging (VTI) and virtual touch tissue quantification (VTQ). Risk factors of independent variables for central LNM were analyzed by univariate and multivariate analyses. A multivariate analysis was performed to create a predicting model and rating system.Of the 252 patients, 72 (28.6%) had central LNMs. Multivariate analysis revealed that rare internal flow (odds ratio [OR]: 4.454), multiple suspicious foci on US (OR: 5.136), capsule involvement (OR: 20.632), and VTI area ratio (VAR) > 1 (OR: 5.621) were independent risk factors for central LNM. The final predicting model was obtained and the risk score (RS) was defined as 1.5 × (if rare internal flow) + 1.6 × (if multiple suspicious foci on US) + 1.7 × (if VAR > 1) + 3.0 × (if capsule involvement). The rating system was divided into 5 stages. Stage I, <1.5; Stage II, 1.5 to 3.0; Stage III, 3.1 to 4.7; Stage IV, 4.8 to 6.3; and Stage V, 6.4 to 7.8. The risk rates of central LNM were 3.4% (2/59) in Stage I, 13.3% (13/98) in Stage II, 54.2% (39/72) in Stage III, 72.2% (13/18) in Stage IV, and 100% (5/5) in Stage V (P < 0.001).The results indicated that rare internal flow, multiple suspicious foci, capsule involvement on US, and VAR > 1 on ARFI elastography are the risk factors for predicting central LNM. The risk model developed in the study clearly predicts the risk of central LNM in patients with PTMC and thus has a potential to avoid unnecessary central compartment node dissection.

Thyroid-Specific Genes Expression Uncovered Age-Related Differences in Pediatric Thyroid Carcinomas

Despite a more advanced stage of disease at presentation, a better response to radioiodine (RAI) therapy and a reduced overall mortality have been reported in pediatric differentiated thyroid cancer (DTC) in comparison to adult DTC. Few studies suggested that the better response to RAI therapy in pediatric patients might be associated with an increased expression of NIS. However, a marked heterogeneity within the pediatric group has been recognized. Children (<10 years old) usually present a more aggressive disease than adolescents (≥10-18 years old). By analyzing the expression of thyroid-specific genes in 38 sporadic pediatric tumors, we show that the expression of NIS, PDS, and TSHR was lower in children than adolescents (P < 0.05). A linear regression confirmed the association between NIS expression and age. Most significantly, NIS was expressed at similar levels in DTC from children and adults, whereas PDS and TSHR expression was even lower in DTC from children, compared to adolescents and adults. Our data suggest that biological behaviors of DTC in adolescents might differ from those in children and adults. Therefore, the premise that the expression of thyroid-specific genes is higher in tumors from pediatric patients than in adults is not entirely true and might be too oversimplified.