Iodine, thyroid autoimmunity and cancer

Thyroiditis and Thyroid Cancer: Bioinformatics Analysis of Gene Expression Data

BACKGROUND/AIM

Hashimoto thyroiditis (HT) association with thyroid lymphoma is well established; however, the association with papillary thyroid cancer (PTC) is still unclear. Thyroid cancer incidence has shown an increasing trend in recent years. It is characterized by slow growth, making it generally amenable to successful treatment.

MATERIALS AND METHODS

We aimed to identify genes considered as promising biomarkers of the progression from thyroiditis to thyroid cancer in public gene expression datasets.

RESULTS

We identified 70 differentially expressed genes (DEGs) and used them to prioritize biological risk genes for thyroiditis and thyroid cancer. Statistics and a scoring system based on six functional annotations of significant biological impact identified four genes of interest: CXCR4, IL6ST, PPARG and TP53. Kaplan-Meier plots were used to assess the expression levels related to overall survival. Furthermore, a manual bibliographic search was carried out for each gene, and a protein-protein interaction (PPI) network was built to verify their known associations.

CONCLUSION

The results showed that all four genes (CXCR4, IL6ST, PPARG, TP53) were highly relevant to thyroiditis and thyroid cancer, thus making them worthy of further investigation to understand their relationship with these two diseases.

The impact of the SARS-CoV2 pandemic on the prescription of thyroid medication in Austria - A nationwide population-based registry analysis

BACKGROUND

Case reports indicate a clinical connection between SARS-CoV-2 and thyroid dysfunctions. However, evidence from large population-based registry analyses is sparse, especially in Europe, where iodine deficiency is common. This study aimed to analyze the impact of the COVID-19 pandemic on healthcare provision for thyroid diseases in Austria.

METHODS

We performed a retrospective, population-based registry analysis of the Austrian health insurance fund database, covering more than 9 million inhabitants. Data from all patients with prescriptions of thyroid-specific drugs and/or inpatient thyroid-related diagnoses from 2017 to 2019 (pre-pandemic years) were compared to 2020 and 2021 (pandemic years; characterized by high numbers of SARS-CoV2 infections and population-wide vaccination strategy). The incidence rates of thyroid medication prescriptions for hypothyroidism and hyperthyroidism were calculated for every year to evaluate the impact of the pandemic.

RESULTS

The incidence rate for total thyroid medication prescription was 539.07/100,000 individuals (534.23-543.93 95%CI) in 2018 and declined during the pandemic (2020: 387.19/100,000 (383.12-391.29 95%CI); 2021: 336.90/100,000 (333.11-340.73 95%CI)). Similarly, the incidence rate for levothyroxine prescription was higher pre-pandemic (2018: 465.46/100,000 (460.97-469.98 95%CI) and declined during the pandemic (2020: 348.14/100,000 (344.28-352.03 95%CI); 2021: 300.30/100,000 (296.7-303.91 95%CI). The incidence rates of thiamazole prescriptions (2018: 10.24/100,000 (9.58-10.93 95%CI); 2020: 8.62/100,000 (8.03-9.26 95%CI); 2021: 11.17/100,000 (10.49-11.89 95%CI) were stable.

CONCLUSIONS

These findings suggest no clinically significant impact of SARS-CoV2 and/or vaccination on thyroid function at a population level.

Hashimoto's Thyroiditis and Papillary Thyroid Carcinoma: A Follow-Up Study in Patients with Absence of Aggressive Risk Factors at the Surgery of the Primary Tumor

Hashimoto's thyroiditis (HT) is often associated with papillary thyroid carcinoma (PC); it is still a matter of controversy whether the behavior of carcinoma is more aggressive or not. During the follow-up, we retrospectively enrolled 97 patients with PC/HT after thyroidectomy without risk factors at the surgery of the primary tumor, such as multifocality/multicentricity, extrathyroid tumor extension, vascular invasion, neck and distant metastases, and aggressive histological variants. HT diagnosis was confirmed by histology and serum thyroid antibodies. Tumor size was ≤10 mm in 64 cases (microcarcinomas); 206 matched PC patients after thyroidectomy without HT and risk factors were enrolled as controls, totaling 122 microcarcinomas. During follow-up, metastases occurred in 15/97 (15.5%) PC/HT cases, eight microcarcinomas, and in 16/206 (7.8%) without HT, eight microcarcinomas (p = 0.04). Considering both PC/HT and PC patients without HT who developed metastases, univariate analysis showed an increased risk of metastases in patients with HT coexistence, OR: 2.17 (95% CI 1.03-4.60) p = 0.043. Disease-free survival (DFS) was significantly (p = 0.0253) shorter in PC/HT than in the controls. The present study seems to demonstrate that HT is not a cancer protective factor in PC patients given the less favorable outcomes and significantly shorter DFS. HT may also represent an independent recurrence predictor without other risk factors.

Preconditioning of the immune system modulates the response of papillary thyroid cancer to immune checkpoint inhibitors

BACKGROUND

The response of solid tumors such as papillary thyroid cancer (PTC) to immune checkpoint inhibitors (ICIs) is highly variable. The biological basis of this variability remains unknown.

METHODS

To test the hypothesis that preconditioning of the immune system modulates the therapeutic effect of ICIs, we used a murine model where PTC and iodine exacerbated thyroiditis (IET) can be induced in a temporally predictable fashion. A total of 122 mice were divided into 3 experimental groups. In the first one, named concomitant IET and PTC (No.=40), IET, and PTC were induced at the same time; in the second one, named pre-existing IET (No.=44), IET was induced prior to the induction of PTC; in the third one, named no IET (No.=38), only PTC was induced. Following disease induction, mice of each group were treated with anti-PD-1 antibody, anti-lymphocyte activation gene 3 antibody (anti-Lag3), anti-T-cell immunoglobulin and mucin domain 3 antibody (anti-Tim3), or IgG control. Ten weeks after the initial ICI injection, mice were sacrificed to collect the thyroid gland for histological analysis, to quantify the incidence and burden of PTC, and to perform high-throughput single-cell RNA sequencing of infiltrating CD45⁺ cells.

RESULTS

In the concomitant IET and PTC group, ICI treatment reduced PTC incidence (p=0.002 comparing treatment with any ICI vs control), while it had no effect in the pre-existing IET and no IET groups. Single-cell sequencing of thyroidal CD45⁺ cells showed that the different ICIs tested had both specific and shared effects on all the components of the thyroidal immune cell infiltrate. The shared effect of the tested ICIs was dependent on the presence of pre-existing versus concomitant IET. In the context of concomitant IET, ICI treatment resulted in the modulation of a greater number of pathways related to both innate and adaptive immunity.

CONCLUSIONS

Response to ICIs depends on the status of the immune system of the treated individual. Modulation of the immune system should be explored as a tool to improve response to ICIs in patients with PTC or other forms of cancer.

PREDICTORS OF MULTIFOCAL PAPILLARY THYROID CANCER. DO THEY EXIST?

The aim of this study is to analyze and identify the main predictors that may indicate multifocal growth of PTC.

Materials and methods

The main and control groups included patients with the category of malignant multifocal process T1-3mN0Mx (n=109) and unifocal T1-T3N0Mx (n=50) respectively, who underwent thyroidectomy with lymphadenectomy.Ultrasound characteristics of the nodes, tissue changes of the thyroid gland were taken into account.

Results

Fibrous changes can be considered as one of the risk factors of the presence of additional PTC lesion.

Discussion

There is no unambiguity in the definition of predictors of multifocal PTC growth.

Conclusions

No clear predictors of multifocal PTC have been identified. It is advisable to improve the quality of ultrasound, to focus on single-focus PTC in patients with fibrinous changes in the thyroid gland at normal levels of TSH.

Oxidative stress in Hashimoto's thyroiditis: possible adjuvant therapies to attenuate deleterious effects

A number of studies have shown that oxidative stress is related to the pathogenesis of several immunological diseases, such as Hashimoto's thyroiditis (HT), although there is no plausible mechanism to explain it. Thus, we aimed at hypothesizing and providing some possible mechanisms linking oxidative stress to autoimmunity aspects and its implications for HT, as well as adjuvant therapeutic proposals to mitigate the deleterious effects. Our hypothesis is that deficient eating habits, autoimmune regulator gene predisposing gene, dysbiosis and molecular mimicry, unfolded proteins and stress in the endoplasmic reticulum, and thymus involution appear to be the main potential factors leading to HT oxidative stress. Likewise, we show that the use of minerals selenium and zinc, vitamins D and C, as well as probiotics, can be interesting adjuvant therapies for the control of oxidative damage and poor prognosis of HT. Further clinical trials are needed to understand the real beneficial and side effects of these supplements.

The Immune Landscape of Papillary Thyroid Cancer in the Context of Autoimmune Thyroiditis

Simple Summary

The association between papillary thyroid cancer and Hashimoto’s thyroiditis went through a long-standing human debate recently elucidated by the establishment of a novel mouse model. Papillary thyroid carcinoma is an excellent model for studying the tumor immune microenvironment because it is naturally accompanied by immune cells, making it a good candidate for the treatment with immune checkpoint inhibitors.

Abstract

Papillary thyroid cancer (PTC) often co-occurs with Hashimoto’s thyroiditis, an association that has long been reported in clinical studies, remaining controversial. Experimental evidence has recently shown that pre-existing thyroiditis has a beneficial effect on PTC growth and progression by a distinctive expansion of effector memory CD8 T cells. Although the link between inflammation and PTC might involve different components of the immune system, a deep characterization of them which includes T cells, B cells and tertiary lymphoid structures, Mye-loid cells, Neutrophils, NK cells and dendritic cells will be desirable. The present review article considers the role of the adaptive and innate immune response surrounding PTC in the context of Hashimoto’s thyroiditis. This review will focus on the current knowledge by in vivo and in vitro studies specifically performed on animals’ models; thyroid cancer cells and human samples including (i) the dual role of tumor-infiltrating lymphocytes; (ii) the emerging role of B cells and tertiary lymphoid structures; (iii) the role of myeloid cells, dendritic cells, and natural killer cells; (iv) the current knowledge of the molecular biomarkers implicated in the complex link between thyroiditis and PTC and the potential implication of cancer immunotherapy in PTC patients in the context of thyroiditis.

A glance at post-translational modifications of human thyroglobulin: potential impact on function and pathogenesis

Thyroid hormones are essential for the metabolism of vertebrates and their synthesis, storage and release in the thyroid gland are orchestrated by their large protein precursor thyroglobulin (Tg). Alterations of Tg structure and localisation often correlate with major thyroid disorders. Namely, Tg is the main antigen in autoimmune thyroid diseases, and mutations in its gene are one of the causes of congenital hypothyroidism. Post-translational modifications (PTMs) are crucial for Tg surface properties and may be affected by the disease microenvironment; yet, their role in thyroid homeostasis and pathogenesis remains elusive. The advance of electron cryo-microscopy (cryo-EM) has recently enabled the structure of Tg to be revealed in the un-iodinated and iodinated states. Moreover, ad hoc proteomic analyses have lately identified new PTMs in Tg. Here, we provide an overview of the Tg cryo-EM models obtained so far, and we build a three-dimensional map of known PTMs in Tg. Based on their location, we suggest the potential implication of each PTM in hormonogenesis, interactions with cellular partners, colloid cross-linking and hormone release. In addition, several PTMs overlap with immunogenic regions and pathogenic gene mutations. Hence, our analysis reveals a possible cross-talk between PTMs and alteration of Tg function in these disorders. In perspective, multi-omics analyses from patients, interpreted with structural and functional data, may generate more robust models to correlate phenotypes with classes of Tg functional alterations. This integrative approach will likely provide more targeted strategies to restore specific Tg functions in different thyroid pathologies.

Hashimoto's Thyroiditis and Papillary Cancer Thyroid Coexistence Exerts a Protective Effect: a Single Centre Experience

Papillary thyroid carcinoma (PTC) is the most common malignant tumour of the thyroid and it is often found in association with Hashimoto's thyroiditis (HT). This concomitance is still under debate. The aim of this study is to investigate the influence of Hashimoto's thyroiditis in patients with papillary thyroid carcinoma. Two thousand two hundred eighteen patients underwent thyroidectomy in our department between January 2015 and January 2020. Of these, 435 patients had surgery for papillary thyroid carcinoma and form the basis of our studies. The association between PTC and HT was found in 180 patients (41.4%), mostly represented in the female group (78.9%), with a lower median age than patients with PTC without HT. In comparison to patients with PTC alone, the PTC-HT group had less invasive and smaller tumours, as well as less lymph node involvement. Moreover, tumours of patients with PTC-HT were diagnosed earlier. Our data showed that Hashimoto's thyroiditis may be considered a protective factor when PTC develops. Furthermore, we concluded that patients with PTC and HT had a better prognosis and a lower risk of recurrence than those that did not have HT.

Prognostic Value of Serum Thyroglobulin and Anti-Thyroglobulin Antibody in Thyroid Carcinoma Patients following Thyroidectomy

Well-differentiated thyroid cancer (WDTC) is a malignant head and neck tumor with a very high incidence. Thyroidectomized WDTC patients have been referred to nuclear medicine for radioactive iodine (RAI) ablation therapy and/or annual follow-up with diagnostic whole-body imaging. Serum thyroglobulin (TG) and thyroglobulin antibodies (TGAb) are biochemical tumor markers used to monitor WDTC. A global rise in the prevalence of WDTC is increasing the number of thyroidectomized patients requiring lifelong monitoring for persistent or recurrent diseases. The present study aimed to identify the most successful prognostic factors in well-defined thyroid carcinoma patients following total thyroidectomy and RAI therapy, followed by an estimation of the cutoff value of TG and TGAb. In this context, a total of 100 subjects were recruited and classified as follows: 60 thyroid carcinoma patients underwent total thyroidectomy and successful RAI therapy, while 40 normal healthy individuals matched for age, sex, and socioeconomic status constituted the control group. Interestingly, the levels of TG did not differ significantly between the relapsed and non-relapsed cases, but the levels of TGAb differed significantly between the relapsed and non-relapsed cases. Collectively, TG and TGAb are considered the most successful prognostic factors in well-defined thyroid carcinoma patients after total thyroidectomy and RAI therapy. The present study also concluded that the TGAb determination was better than that of the TG level, with a cutoff value of 10 ng/mL. These findings provide baseline information for follow-up and lifelong monitoring of thyroidectomized WDTC patients. Further research is warranted to explore more about serum TG and TGAb in thyroid carcinoma patients on a larger scale.

Predicting factors of central lymph node metastasis and BRAFV600E mutation in Chinese population with papillary thyroid carcinoma

Objective

The aim of this study was to evaluate the predictive factors of central lymph node metastasis (CLNM) and BRAF^V600E mutation in Chinese patients with papillary thyroid carcinoma (PTC).

Methods

A total of 943 PTC patients who underwent thyroidectomy from 2014 to 2016 at our hospital were enrolled. Those patients were divided into PTC > 10 mm and papillary thyroid microcarcinoma (PTMC) groups by tumor size. The BRAF^V600E mutation was examined by quantitative real-time PCR. Univariate and multivariate analyses were used to examine risk factors associated with CLNM and the BRAF^V600E mutation.

Results

The frequency of CLNM was 53% (505/943). Both univariate and multivariate analyses suggested that the risk factors for CLNM in PTC patients were male, younger age, and larger tumor size (P < 0.05). Coexistent Hashimoto thyroiditis (HT) was an independent protective factor against CLNM when the tumor was > 10 mm (P = 0.006). Stratified analysis revealed that male, age ≤ 30 years, and tumor size > 5 mm were independent risk factors for CLNM. The BRAF^V600E mutation rate was 85%. Multivariate logistic regression analysis revealed that age (P < 0.001) and coexistent HT (P = 0.005) were independent predictive factors of BRAF^V600E mutation in PTC patients. Only age was a risk factor for the BRAF^V600E mutation when the tumor was > 10 mm (P = 0.004). In the PTMC group, the BRAF^V600E mutation was significantly correlated with tumor size (P < 0.001) and coexistent HT (P = 0.03). Stratified analysis revealed that age > 30 years and tumor size > 5 mm were independent predictive factors of BRAF^V600E mutation. Furthermore, the incidence of CLNM was significantly higher in BRAF^V600E mutation-positive patients (P = 0.009) when the tumor was ≤ 5 mm.

Conclusion

The factors male, younger age (≤ 30 years), large tumor size (> 5 mm), and coexistent HT are independent predicative factors for CLNM. The BRAF^V600E mutation is associated with both large size and without HT in PTMC patients, age > 30 years in the PTC > 10 mm group. The BRAF^V600E mutation was an independent risk factor for CLNM when the tumor was ≤ 5 mm. For optimal management, these features should be comprehensively evaluated to determine the initial surgical approach for PTC patients.

Cryo-EM: A new dawn in thyroid biology

The thyroid gland accumulates the rare dietary element iodine and incorporates it into iodinated thyroid hormones, utilising several tightly regulated reactions and molecular mechanisms. Thyroid hormones are essential in vertebrates and play a central role in many biological processes, such as development, thermogenesis and growth. The control of these functions is exerted through the binding of hormones to nuclear thyroid hormone receptors that rule the transcription of numerous metabolic genes. Over the last 50 years, thyroid biology has been studied extensively at the cellular and organismal levels, revealing its multiple clinical implications, yet, a complete molecular understanding is still lacking. This includes the atomic structures of crucial pathway components that would be needed to elucidate molecular mechanisms. Here we review the currently known protein structures involved in thyroid hormone synthesis, regulation, transport, and actions. We also highlight targets for future investigations that will significantly benefit from recent advances in macromolecular structure determination by electron cryo-microscopy (cryo-EM). As an example, we demonstrate how cryo-EM was crucial to obtain the structure of the large thyroid hormone precursor protein, thyroglobulin. We discuss modern cryo-EM compared to other structure determination methods and how an integrated structural and cell biological approach will help filling the molecular knowledge gap in our understanding of thyroid hormone metabolism. Together with clinical, cellular and high-throughput 'omics' studies, atomic structures of thyroid components will provide an important framework to map disease mutations and to interpret and predict thyroid phenotypes.

Prevalence and predictor for malignancy of contralateral thyroid nodules in patients with unilateral PTMC: a systematic review and meta-analysis

BACKGROUND

The presence of clinically negative nodules on the contralateral lobe is common in patients with unilateral papillary thyroid microcarcinoma (PTMC). The appropriate operational strategies of contralateral thyroid nodules remain controversial. In this study, we analyzed clinical features that could be predictors for malignancy of contralateral thyroid nodules coexisting with diagnosed unilateral PTMC.

METHODS

The literatures published from January 2000 to December 2019 were searched in PubMed, Cochrane Library, Embase, Web of Science, CNKI, and Wan Fang database. Odds ratio (OR) with 95% CI was used to describe categorical variables. Heterogeneity among studies was examined by the Q test and I2 test; potential publication bias was detected by Harbord test and 'trim and fill' method.

RESULTS

In this meta-analysis, 2541 studies were searched and 8 studies were finally included. The results showed that the rate of carcinoma in contralateral nodules was 23% (OR = 0.23, 95% CI = 0.18-0.29). The pooled data indicated that contralateral malignancy was not associated with age, gender, primary lesion size, ipsilateral central lymph node metastasis and multifocality of contralateral lesion. The following variables have correlations with an increased risk of contralateral malignancy: multifocality of primary carcinomas (OR = 3.93, 95% CI = 2.70-5.73, P < 0.0001), capsular invasion (OR = 1.61, 95% CI = 1.10-2.36, P = 0.01), and Hashimoto's thyroiditis (OR = 1.57, 95% CI = 1.13-2.20, P = 0.008).

CONCLUSIONS

Based on our meta-analysis, the rate at which contralateral malignancies are preoperatively misdiagnosed as benign is 23%. The risk factors for contralateral malignancy in unilateral PTMC patients with contralateral clinical negative nodules include multifocality of primary carcinomas, capsular invasion, and Hashimoto's thyroiditis.

Emerging Roles for Noncoding RNAs in Autoimmune Thyroid Disease

Autoimmune thyroid disease (AITD) is one of the most frequent autoimmune disorders. However, the pathogenesis of AITD has not been fully elucidated. Recently, accumulating evidence has demonstrated that abnormal expression of noncoding RNAs (ncRNAs) is closely related to the etiopathogenesis of AITD. microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs) are 3 major groups of ncRNAs that are attracting increasing attention. Herein, we summarized our present knowledge on the role of miRNAs, lncRNAs, and circRNAs in AITD. This review focused on the importance of ncRNAs in development of the most prevalent AITD, such as Hashimoto disease and Graves' diseases. Altogether, the main purpose of this review is to provide new insights in the pathogenesis of AITD and the possibility of developing novel potential therapeutic targets.

Clinical Analysis of BRAFV600E Mutation and Its Correlation With Sonographic Image Characteristics in Papillary Thyroid Carcinoma in Chinese Coastal Areas

This study analyzed the characteristics of BRAF^V600E mutation in papillary thyroid carcinoma (PTC) in Chinese coastal areas. We intended to identify noninvasive methods to determine BRAF^V600E status in thyroid nodules prior to surgery. BRAF^V600E mutation and the sonographic characteristics of thyroid nodules were investigated in 670 PTC patients in our hospital. We aimed to determine the relationship between BRAF^V600E mutation and the clinicopathological and sonographic imaging characteristics of PTC. The mutation rate of the BRAF^V600E was 78.2%. BRAF^V600E mutation was significantly associated with central node (univariate analyses, P = .005; multivariate analyses, P < .001, odds ratio [OR] = 10.255) and lateral node metastases (univariate analyses, P = .001; multivariate analyses, P < .001, OR = 22). It was less frequent in PTC coexisting with Hashimoto's thyroiditis (univariate analyses, P = .016; multivariate analyses, P < .001, OR = .034). Nodules without blood flow had a significantly higher mutation rate of BRAF^V600E in PTC patients (univariate analyses, P = .026). BRAF^V600E mutation was significantly associated with high suspicion in the Thyroid Imaging Reporting and Data System 5 (univariate analyses, P = .004; multivariate analyses, P = .014, OR = 6.456). Our results strongly suggest that BRAF^V600E mutation plays a potential role in lymph node metastasis (central node metastasis, OR = 10.225; lateral node metastasis, OR = 22). Some sonographic imaging features might be helpful in estimating the status of BRAF^V600E preoperatively.

The structure of human thyroglobulin

Thyroglobulin (TG) is the protein precursor of thyroid hormones, which are essential for growth, development and the control of metabolism in vertebrates1,2. Hormone synthesis from TG occurs in the thyroid gland via the iodination and coupling of pairs of tyrosines, and is completed by TG proteolysis3. Tyrosine proximity within TG is thought to enable the coupling reaction but hormonogenic tyrosines have not been clearly identified, and the lack of a three-dimensional structure of TG has prevented mechanistic understanding4. Here we present the structure of full-length human thyroglobulin at a resolution of approximately 3.5 Å, determined by cryo-electron microscopy. We identified all of the hormonogenic tyrosine pairs in the structure, and verified them using site-directed mutagenesis and in vitro hormone-production assays using human TG expressed in HEK293T cells. Our analysis revealed that the proximity, flexibility and solvent exposure of the tyrosines are the key characteristics of hormonogenic sites. We transferred the reaction sites from TG to an engineered tyrosine donor-acceptor pair in the unrelated bacterial maltose-binding protein (MBP), which yielded hormone production with an efficiency comparable to that of TG. Our study provides a framework to further understand the production and regulation of thyroid hormones.

Iodine promotes thyroid cancer development via SPANXA1 through the PI3K/AKT signalling pathway

The aim of this study was to examine the impact of iodine on the development of thyroid cancer cells and to detect the underlying mechanisms. It was observed that proliferation was promoted and apoptosis was inhibited in cells treated with iodine at a specific concentration. This treatment group was then selected for further analysis, to investigate how iodine affects the development of thyroid cancer cells. It was reported that sperm protein associated with the nucleus, X-linked, family member A1 (SPANXA1) expression in iodine-treated cells was significantly upregulated. Furthermore, downregulation of SPANXA1 inhibited cell proliferation, migration and invasion, and promoted cell apoptosis. These results suggested that SPANXA1 played an important role in iodine-treated thyroid cancer cells. Novel associations between SPANXA1 and thyroid cancer were described in the current study. In addition, SPANXA1 gene silencing resulted in the downregulation of PI3K and phosphorylated (p)AKT expression in iodine-treated thyroid cancer cells, whereas iodine treatment alone resulted in upregulated PI3K and p-AKT expression. Inhibiting PI3K further suppressed cell proliferation and contributed to apoptosis, even in the presence of SPANXA1 at high levels. As a consequence, PI3K/AKT may be one of the key signalling pathways by which iodine promotes thyroid cancer development in association with SPANXA1. In addition, our results further suggested that patients with thyroid cancer may need to avoid high-iodine intake.

Iodine Status in the Colombian Population and the Impact of Universal Salt Iodization: A Double-Edged Sword?

Iodine deficiency and iodine excess have severe consequences on human health and have been associated with the presence of goiter, hypothyroidism, hyperthyroidism, thyroid cancer, thyroid nodules and thyroid autoimmunity, poor mental health, and impaired intellectual development. Universal salt iodization programs have been considered one of the most cost-effective interventions for the prevention of iodine deficiency-associated disorders, as evidenced over time since the implementation of such programs. However, these efforts have also led to an excessive consumption of iodine in certain geographical regions, due to salt overuse. Consequently, the amount of iodine derived from salt intake exceeds the established limits required for achieving the right balance between salt consumption and health benefits and leads to undesirable health effects. In Colombia, the recommendations and standards for the production and commercialization of iodized salt are fully complied with. Nevertheless, there is a remarkable rate of iodine excess among the country's population, which, at least hypothetically, represents a higher risk for developing functional and structural disorders of the thyroid gland. This review analyzes universal salt iodization programs worldwide, particularly their impact on the thyroid gland and the results of the studies conducted in Colombia following the implementation of such strategy.

Lung Metastases From Papillary Thyroid Cancer With Persistently Negative Thyroglobulin and Elevated Thyroglobulin Antibody Levels During Radioactive Iodine Treatment and Follow-Up: Long-Term Outcomes and Prognostic Indicators

Background: The lung is the most frequent site of distant metastasis from differentiated thyroid cancer (DTC). However, lung metastasis from papillary thyroid cancer (PTC) with persistently negative thyroglobulin (Tg) and elevated Tg antibody (TgAb) levels is an extremely rare entity, and the prognosis is therefore elusive. We investigated the clinical characteristics, long-term outcomes, and prognostic factors of lung metastases in PTC patients with persistently negative thyroglobulin (Tg) and elevated Tg antibody (TgAb) levels during radioactive iodine (¹³¹I) treatment and follow-up. Methods: We retrospectively reviewed 10,482 patients with DTC who underwent postoperative ¹³¹I treatment from 2007 to 2017 at Shanghai Sixth's People's Hospital. The relationships between progression-free survival (PFS) and several variables were assessed by univariate and multivariate analyses using the Kaplan-Meier method and a Cox proportional hazards model, respectively. Results: Forty-seven patients with PTC were enrolled in this study (4.48‰ of all patients with DTC). The median age at the initial diagnosis of lung metastasis was 39.6 ± 15.4 years, and the patients comprised 14 male and 33 female patients (male: female ratio = 1.00:2.36). Twenty-five patients had ¹³¹I avidity and 22 had non-¹³¹I avidity. At the end of the 5-years follow-up, 12 patients exhibited progressive disease (PD), and 2 patients had died. At the end of the 10-years follow-up, 21 patients showed PD and five patients had died. The 5- and 10-year PFS rates were 74.47 and 53.32%, respectively; the 5- and 10-years overall survival (OS) rates were 95.74 and 89.36%, respectively. The timing of diagnosis of lung metastases, maximal size of lung metastases, and ¹³¹I avidity were significantly associated with the 5-years PFS rate (P = 0.035, P = 0.030, and P<0.001, respectively). Only ¹³¹I avidity was associated with the 10-years PFS rate (P < 0.001). The multivariate analyses also showed that non-¹³¹I avidity were the independent poor prognostic factors for 10-years PFS at the end of follow-up (P < 0.001). Conclusions: Lung metastases from PTC in patients with persistently negative Tg and elevated TgAb levels had an excellent prognosis and survival rate during ¹³¹I treatment and follow-up. The loss of ¹³¹I avidity remained the strongest independent predictor of a poor prognosis and survival in these patients.

Selenoproteins in human body: focus on thyroid pathophysiology

Selenium (Se) has a multilevel, complex and dynamic effect on the human body as a major component of selenocysteine, incorporated into selenoproteins, which include the selenocysteine-containing enzymes iodothyronine deiodinases. At the thyroid level, these proteins play an essential role in antioxidant protection and hormone metabolism. This is a narrative review based on PubMed/Medline database research regarding thyroid physiology and conditions with Se and Se-protein interferences. In humans, Se-dependent enzyme functions are best expressed through optimal Se intake, although there is gap in our knowledge concerning the precise mechanisms underlying the interrelation. There is a good level of evidence linking low serum Se to autoimmune thyroid diseases and, to a lesser extent, differentiated thyroid cancer. However, when it comes to routine supplementation, the results are heterogeneous, except in the case of mild Graves' orbitopathy. Autoimmune hypothyroidism is associated with a state of higher oxidative stress, but not all studies found an improvement of thyroid function after Se was introduced as antioxidant support. Meanwhile, no routine supplementation is recommended. Low Se intake is correlated with an increased risk of developing antithyroid antibodies, its supplementation decreasing their titres; there is also a potential reduction in levothyroxine replacement dose required for hypothyroidism and/or the possibility that it prevents progression of subclinical hypothyroidism, although not all studies agree. In thyroid-associated orbitopathy, euthyroidism is more rapidly achieved if the micronutrient is added to traditional drugs, while controls appear to benefit from the microelement only if they are deficient; thus, a basal assay of Se appears advisable to better select patients who need substitution. Clearly, further Se status biomarkers are required. Future introduction of individual supplementation algorithms based on baseline micronutrient levels, underlying or at-risk clinical conditions, and perhaps selenoprotein gene polymorphisms is envisaged.

Risk factors stratifying malignancy of nodules in contralateral thyroid lobe in patients with pre-operative ultrasound indicated unilateral papillary thyroid carcinoma: A retrospective analysis from single centre

OBJECTIVE

Papillary thyroid carcinoma (PTC) is the most common thyroid carcinoma with a favourable clinical outcome. For unilateral PTC patients with thyroid nodules in the contralateral lobes, the necessity of total thyroidectomy (TT) is still in doubt. In this study, we aimed to define clinical factors that could be indicators for malignancy in nodules in the contralateral thyroid lobe, which could aid the clinician in selecting the appropriate operation approach.

DESIGN, PATIENTS AND MEASUREMENTS

This is a retrospective study from January 2014 to December 2016 conducted in Shanghai Ruijin Hospital. A total of 1442 cases with unilateral PTC and ultrasonographically benign nodules in the contralateral lobe who underwent TT at a single institution were enrolled. All patients underwent pre-operative ultrasonography (US), and all the cases were confirmed by board-certified pathologists. Clinicopathological features such as age, gender, tumour location, tumour size, TgAb and TPOAb levels, capsular invasion, multifocality, central lymph node metastases and BRAF mutation were examined to evaluate the rate of malignancy in the contralateral thyroid nodules.

RESULTS

In total, 47% of patients (677 cases)were confirmed to have malignancy in the contralateral lobe. Univariant analysis indicated that capsular invasion, Hashimoto's thyroiditis, multifocal loci, central lymph node metastases as well as BRAF mutation predicted a high incidence of occult contralateral carcinoma. Multivariant analysis showed capsular invasion, multifocal ipsilateral thyroid lobe, central lymph node metastases as well as BRAF mutation can serve as independent predictors for malignancy in the contralateral thyroid lobe.

CONCLUSIONS

Malignancy in the contralateral lobe was found in 47% of patients. This finding was associated with multifocal primary carcinomas involvement, capsular invasion, Hashimoto's thyroiditis history, central lymph node metastases and BRAF mutation, which should therefore be taken into consideration when planning therapeutic strategy for the patients.

Coexistence of diffuse large B-cell lymphoma and papillary thyroid carcinoma in a patient affected by Hashimoto's thyroiditis

Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer. On the contrary, primary thyroid lymphoma (PTL) is a rare disease, accounting for 2% to 5% of all thyroid malignancies. Despite several cases in which both PTC and PTL arise in the setting of Hashimoto's thyroiditis (HT), the coexistence of both tumors in HT patients is very rare. Herein we report the case of a 66-year-old woman with long-standing nodular HT under replacement therapy, who presented with a fast, painless enlargement in the right anterior side of the neck. Thyroid ultrasonography demonstrated increased growth of a hypoechoic nodule in the right lobe measuring 32 × 20 mm. A total thyroidectomy was performed, and histology revealed a diffuse large B-cell lymphoma (DLBCL) on a background of florid HT. Moreover, a unifocal papillary microcarcinoma, classical variant (7 mm, pT1aNxMx), was discovered. The patient was then treated with chemotherapy for the PTL, but she did not undergo radioactive iodine ablation treatment for the microPTC as per guidelines. Two years after surgery, the patient had no evidence of recurrence of either malignancy. This rare case highlights the importance of monitoring HT patients with nodular lesions, especially if they have long-standing disease. In addition, PTL should be considered for differential diagnosis in elder HT patients who present with sudden thyroid enlargement.

Prognostic value of preoperative anti-thyroglobulin antibody in differentiated thyroid cancer

CONTEXT

The coexistence of differentiated thyroid cancer (DTC) and thyroid autoimmune disease could represent a better or worse prognosis. This study investigated the prognostic importance of preoperative anti-thyroglobulin antibody (TgAb) in DTC patients.

DESIGN AND PATIENTS

This retrospective hospital-cohort study enrolled 1171 consecutive DTC patients with preoperative TgAb data, who underwent total thyroidectomy between January 2006 and December 2011. Clinical parameters studied included demographics, primary tumour characteristics, radioiodine therapy, thyroid function tests, preoperative thyroglobulin (Tg) and TgAb levels, and cancer persistence/recurrence.

RESULTS

A total of 254 (21.7%) patients were preoperatively TgAb positive. The percentage positive for thyroid peroxidase (TPO) antibody and lymphocytic thyroiditis was significantly higher in the TgAb-positive group. The TgAb-positive group had a significantly higher rate of lymphatic invasion and lymph node metastasis both overall and in patients without TPOAb and lymphocytic thyroiditis (non-HT group). The mean number of total and central lymph nodes dissected and rate of lateral lymph node dissection were significantly higher in the TgAb-positive group, both overall and in non-HT patients. In regression analysis, preoperative TgAb was an independent risk factor for lateral lymph node metastasis. Over 50.2±14.5 months of follow-up, disease persistence/recurrence was not significantly different between patients with and without TgAb, both overall and in non-HT patients. Preoperative TgAb showed no significant correlation with final disease status.

CONCLUSION

Positive preoperative serum TgAb is associated with worse primary tumour characteristics but rarely showed poor prognosis, probably due to more aggressive treatment of these subjects.

Vitiligo and overt thyroid diseases: A nationwide population-based study in Korea

BACKGROUND

Associations between vitiligo and thyroid diseases have been reported repeatedly.

OBJECTIVE

We investigated the associations between vitiligo and overt autoimmune thyroid diseases and thyroid cancer using the Korean National Health Insurance claims database.

METHODS

We defined patients with vitiligo as those whose records showed ≥4 physician contacts between 2009 and 2013 in which vitiligo was the principal diagnosis. We also established an age- and sex-matched control group without vitiligo (2 per 1 vitiligo patient). The outcomes of interest were concurrent Graves disease and Hashimoto thyroiditis (the patients were taking relevant thyroid medications) and thyroid cancer.

RESULTS

The study enrolled 73,336 vitiligo patients and 146,672 controls. Patients with vitiligo were at increased risks of Graves disease (odds ratio [OR] 2.610 [95% confidence interval {CI} 2.319-02.938]), Hashimoto thyroiditis (OR 1.609 [95% CI 1.437-1.802]), and thyroid cancer (OR 1.127 [95% CI 1.022-1.242]), compared with the controls. The associations were consistently stronger in males and younger patients.

LIMITATIONS

Individual clinical information was not available, and the homogeneous population may limit the generalizability of the results.

CONCLUSION

Vitiligo was significantly associated with overt autoimmune thyroid diseases and overt thyroid cancer.

One-third of an Archivial Series of Papillary Thyroid Cancer (Years 2007-2015) Has Coexistent Chronic Lymphocytic Thyroiditis, Which Is Associated with a More Favorable Tumor-Node-Metastasis Staging

The significance and impact of the coexistence of chronic lymphocytic thyroiditis (CLT) with thyroid cancer is still debated. To verify the influence of CLT on papillary thyroid cancer (PTC), we retrospectively collected 505 PTC cases and analyzed age at diagnosis, sex, size, lymph node status, and staging. We found that CLT was present in 168 PTC (33.3%). Compared with the 337 patients without CLT (non-CLT), CLT patients were younger (44.42 ± 13.72 vs. 47.21 ± 13.76 years, P = 0.03), had smaller tumors (9.39 ± 6.10 vs. 12 ± 9.71 mm, P = 0.002), and lower rate of lymph node metastases (12.5 vs. 21.96%, P = 0.01, OR = 0.508). Tumor-node-metastasis (TNM) staging (T1a through T4) was more favorable for the CLT group compared to the non-CLT group (for instance, T1a = 65.5 vs. 49.8%, T3 = 4.8 vs. 23.4%). This study shows that one in three patients with PTC harbors CLT, which is associated with a more favorable TNM staging, consistently with a favorable outlook of PTC.

Clinical Update in Aspects of the Management of Autoimmune Thyroid Diseases

Aspects of autoimmune thyroid disease updated in this review include: immunoglobulin G4 (IgG4)-related thyroid disease (Riedel's thyroiditis, fibrosing variant of Hashimoto's thyroiditis, IgG4-related Hashimoto's thyroiditis, and Graves' disease with elevated IgG4 levels); recent epidemiological studies from China and Denmark indicating that excess iodine increases the incidence of Hashimoto's thyroiditis and hypothyroidism; immunomodulatory agents (ipilimumab, pembrolizumab, nivolumab) activate immune response by inhibiting T-cell surface receptors which down-regulate immune response, i.e., cytotoxic T-lymphocyte antigen 4 and programmed cell death protein 1 pathways; alemtuzumab is a humanised monoclonal antibody to CD52 which causes immune depletion and thyroid autoimmune disease especially Graves' hyperthyroidism; small molecule ligand (SML) agonists which activate receptors, SML neutral antagonists, which inhibit receptor activation by agonists, and SML inverse agonists which inhibit receptor activation by agonists and inhibit constitutive agonist independent signaling have been identified. SML antagonism of thyroid-stimulating hormone-receptor stimulatory antibody could treat Graves' hyperthyroidism and Graves' ophthalmopathy; and thyroxine treatment of subclinical hypothyroidism can produce iatrogenic subclinical hyperthyroidism with the risk of atrial fibrillation and osteoporosis. The increased risk of harm from subclinical hyperthyroidism may be stronger than the potential benefit from treatment of subclinical hypothyroidism.

[Thyroid cancers: from epidemiology to molecular biology]

Experts increasingly recognize the hypothesis of "over-diagnosis" as the main factor of the raising incidence of thyroid cancers (TC). The detection of multiple microtumors, mainly of a papillary type, at a sub-clinical stage, with the use of sensitive detection methods supports this hypothesis. However, the intensive management and monitoring of these cancers failed to reduce mortality. Environmental and other risk factors cannot provide a sufficient explanation, as previously thought. In this context, the use of improved tools is needed, and the most promising perspective lies in molecular biology applied to thyroid cancer for diagnosis, evaluation of prognosis and treatment. The next generation sequencing (NGS) has demonstrated its diagnostic performances in recent clinical trials. Its interest in cases with indeterminate cytology is demonstrated and should help better targeting surgical indications. Its promising prognostic and therapeutic applications must be confirmed by additional studies. The integration of NGS in current practice should have a real medical, economic and scientific impact. Indeed, the exponential increase in our knowledge of molecular mechanisms of thyroid tumorigenesis strengthens the will to "reclassify" these cancers into molecular rather than histological subtypes, in order to offer patients more specific and targeted treatment.