Molecular analysis of thyroid tumors

Clinical and Histopathological Features of Thyroid Cancer with TERT Promoter Molecular Alterations in Isolation Versus with Concurrent Molecular Alterations: A Multicenter Retrospective Study

Background/Objectives: Molecular testing of thyroid nodules enables the detection of genetic alterations, which can help assess the risk of malignancy and tumor behavior. While telomerase reverse transcriptase (TERTp) mutations are known to be associated with aggressive disease, their exact prognostic significance when occurring alone or with other molecular alterations remains underreported. Methods: This study examined patients with thyroid cancer treated at two tertiary care hospitals from 2017 to 2024. We compared tumor behavior in patients with TERTp molecular alterations occurring alone and with concurrent molecular alterations. Aggressive histologic subtypes were defined as tall-cell, hobnail, and columnar variants of papillary carcinoma, as well as poorly differentiated and anaplastic carcinoma. High-risk disease was defined according to the 2015 ATA guidelines as gross extrathyroidal extension, lymph node metastasis >3 cm, postoperative elevated serum thyroglobulin, distant metastases, and/or positive resection margins. Statistical analysis was performed to assess differences between groups. Results: 30 patients with TERTp-positive thyroid malignancies were included. TERTp/BRAF V600E was the most prevalent mutation combination (n = 13, 43.3%), followed by TERTp alone (n = 8, 26.7%) and TERTp/RAS (n = 7, 23.4%). TERTp/EIF1AX/GNAS and TERTp/EIF1AX/PIK3CA were the least common combinations (n = 1, 3.3% each). Nodules with TERTp and concurrent mutations were significantly more likely to be classified as high-risk (p = 0.006) and were more frequently associated with aggressive histologic subtypes (p = 0.003) compared to those with TERTp mutations alone, which tended to exhibit more benign behavior. Conclusions: Thyroid carcinomas harboring both TERTp and concurrent molecular alterations are associated with more aggressive features and a higher likelihood of being classified as high-risk. In contrast, TERTp mutations occurring alone do not confer an elevated risk.

Combining Clinicopathologic and Ultrasonic Features for Predicting Skip Metastasis of Lateral Lymph Nodes in Papillary Thyroid Carcinoma

Background

Skip metastasis, regarded as lateral lymph node metastasis (LLNM) without involving the central lymph node metastasis (CLNM), in papillary thyroid carcinoma (PTC) patients is commonly unpredictable. The purpose of the present research was to investigate the independent risk factors of skip metastasis in patients with PTC.

Methods and Materials

In the present research, 228 consecutive PTC patients who experienced total thyroidectomy coupled with central and lateral lymph node dissection from May 2020 to September 2022 at the Affiliated hospital of Jiangsu University were included in our research. Univariate and multivariate analysis were then applied to investigate the risk factors of skip metastasis in patients with PTC. Furthermore, a predictive model of skip metastasis was then constructed based on risk factors.

Results

The skip metastasis rate was 11.8% (27/228) in the current research. After the univariate and multivariate analysis, tumor size ≤ 10 mm, unilaterality, microcalcification, and upper tumor location were determined to be predictive factors of skip metastasis. The risk score of skip metastasis was calculated: risk score = 1.229 × (if tumor nodule ≤ 10mm) + 1.518 × (if unilaterality nodule) + 1.074 × (if microcalcification in nodule) + 2.332 × (if nodule in upper location).

Conclusion

Tumor size ≤ 10 mm, unilaterality, microcalcification, and upper tumor location can increase the occurrence of skip metastasis in patients with PTC, which is expected to provide useful information to guide the suitable intraoperative window.

p18INK4C and BRCA1 inhibit follicular cell proliferation and dedifferentiation in thyroid cancer

Only 3% of thyroid cancers are medullary thyroid carcinomas (MTCs), the rest are follicular epithelial cell derived non-MTCs (NMTCs). A dysfunctional INK4-CDK4-RB pathway is detected in most of NMTCs. DNA repair defects and genome instability are associated with NMTC dedifferentiation and aggressiveness. Whether inactivation of the INK4-CDK4-RB pathway induces NMTCs and how differentiation of NMTC cells is controlled remain elusive. In this study, we generated p18Ink4c and Brca1 singly and doubly deficient mice as well as p16Ink4a and Brca1 singly and doubly deficient mice. By using these mice and human thyroid carcinoma cell lines, we discovered that loss of p18Ink4c, not p16Ink4a, in mice stimulated follicular cell proliferation and induced NMTCs. Depletion of Brca1 alone or both p16Ink4a and Brca1 did not induce thyroid tumor. Depletion of Brca1 in p18Ink4c null mice results in poorly differentiated and aggressive NMTCs with epithelial-mesenchymal transition (EMT) features and enhanced DNA damage. Knockdown of BRCA1 in thyroid carcinoma cells activated EMT and promoted tumorigenesis whereas overexpression of BRCA1 inhibited EMT. BRCA1 and EMT marker expression were inversely related in human thyroid cancers. Our finding, for the first time, demonstrates that inactivation of INK4-CDK4-RB pathway induces NMTCs and that Brca1 deficiency promotes dedifferentiation of NMTC cells. These results suggest that BRCA1 and p18INK4C collaboratively suppress thyroid tumorigenesis and progression and CDK4 inhibitors will be effective for treatment of INK4-inactivated or cyclin D-overexpressed thyroid carcinomas.

Discovery of a highly potent pan-RAF inhibitor IHMT-RAF-128 for cancer treatment

Although rat sarcoma viral oncogene homolog (RAS) mutations occur in about 30% of solid tumors, targeting RAS mutations other than KRAS-G12C is still challenging. As an alternative approach, developing inhibitors targeting RAF, the downstream effector of RAS signaling, is currently one of the main strategies for cancer therapy. Selective v-raf murine sarcoma viral oncogene homolog B1 (BRAF)-V600E inhibitors Vemurafenib, Encorafenib, and Dabrafenib have been approved by FDA and received remarkable clinical responses, but these drugs are ineffective against RAS mutant tumors due to limited inhibition on dimerized RAF. In this study, we developed a highly potent pan-RAF inhibitor, IHMT-RAF-128, which exhibited similarly high efficacies in inhibiting both partners of the RAF dimer, and showed potent anti-tumor efficacy against a variety of cancer cells harboring either RAF or RAS mutations, especially Adagrasib and Sotorasib (AMG510) resistant-KRAS-G12C secondary mutations, such as KRAS-G12C-Y96C and KRAS-G12C-H95Q. In addition, IHMT-RAF-128 showed excellent pharmacokinetic profile (PK), and the bioavailability in mice and rats were 63.9%, and 144.1%, respectively. Furthermore, IHMT-RAF-128 exhibited potent anti-tumor efficacy on xenograft mouse tumor models in a dose-dependent manner without any obvious toxicities. Together, these results support further investigation of IHMT-RAF-128 as a potential clinical drug candidate for the treatment of cancer patients with RAF or RAS mutations.

Long-term outcomes and prognostic factors of patients with lung metastases from differentiated thyroid cancer after radioiodine therapy in Japan

Long-term survival in patients with differentiated thyroid cancer (DTC) and lung metastasis remains unexplored in Japan. This study aimed to investigate the long-term survival and prognostic factors of radioiodine therapy (RIT) in a University Hospital setting. This retrospective study included 62 patients with lung metastases from DTC who received RIT between March 2005 and December 2016. According to the ¹³¹I whole-body scan and chest computed tomography results, lung metastases were classified as ¹³¹I-avid or non-¹³¹I-avid, and miliary, micronodular, or macronodular metastases. The 5- and 10-year overall survival (OS) rates from the initial RIT were calculated by the Kaplan-Meier method, and a proportional hazard fit analysis was performed to determine prognostic factors. With a median follow-up of 7.9 years, the 5- and 10-year OS rates from the initial RIT were 93% and 72%, respectively. Univariable and multivariable analyses of patient subgroups revealed that macronodular lung metastases (defined as nodules >1 cm), older age at initial RIT, and high thyroglobulin values (>400 ng/mL) at initial RIT predicted low OS. The 5- and 10-year OS rates of DTC patients with lung metastases were similar to those in previous Japanese reports, which included a smaller sample size compared with ours. Patients with ≤1 cm lung metastases, aged ≤55 years, and a thyroglobulin level of ≤400 ng/mL at the initial RIT had favorable outcomes.

An omics-to-omics joint knowledge association subtensor model for radiogenomics cross-modal modules from genomics and ultrasonic images of breast cancers

The radiogenomics analysis can provide the connections between genomics and radiomics, which can infer the genomic features of tumors from their radiogenomic associations through the low-cost and non-invasiveness screening ultrasonic images. Although there are a number of pioneer approaches exploring the connections between genomic aberrations and ultrasonic features, these studies mainly focus on the relationship between ultrasonic features and only the most popular cancer genes, confronting two difficulties: missing many-to-many relationships as omics-to-omics view, and confounding group-specific associations with whole sample associations. To overcome the difficulty of omics-to-omics view and the issue of tumor heterogeneity, we propose an omics-to-omics joint knowledge association subtensor model. Specifically, the subtensor factorization framework can successfully discover the joint cross-modal module via an omics-to-omics view, while the sparse weight sample indication strategy can mine sample subgroups from the multi-omic data with tumor heterogeneity. The experimental evaluation result shows the jointness of the discovered modules across omics, their association with tumorigenesis contribution, and their relation for cancer related functions. In summary, our proposed omics-to-omics joint knowledge association subtensor model can serve as an efficient tool for radiogenomic knowledge associations, promoting the cross-modal knowledge graph construction of in explainable artificial intelligence cancer diagnosis.

LncRNA H19 is a potential biomarker and correlated with immune infiltration in thyroid carcinoma

The bulk of evidence has revealed that dysregulated expression of long non-coding RNAs (lncRNAs) plays a crucial functional role in cancer biology. However, the mechanistic role of lncRNAs in the initiation, progression and immune landscape of thyroid carcinoma (THCA) still remains largely unknown. This study aimed to explore the significance of H19 in the diagnostic and immune related roles in THCA. The expression level of H19 was analyzed using the TNMplot, GSCA, UALCAN, GEPIA, Wanderer, UCSC Xena and GEO databases. Enrichment analyses were performed to investigate the possible underlying biological pathways by LinkedOmics. Moreover, cBioPortal web tool was used to analyze genetic alterations of H19. Finally, we used TIMER and GEPIA databases to explore the correlations between H19 and tumor-infiltrated immune cells and immune markers. LncRNA H19 was differentially expressed in various cancers and also remarkably downregulated in the THCA tissues compared to the normal ones. Genetic alteration analysis revealed that there was a significant correlation between alterations in H19 and overall survival of THCA patients. Furthermore, enrichment analysis indicated the functional relationship between co-expression network of H19 and extracellular structure organization, and immune microenvironment. In addition, H19 expression was positively correlated with infiltration level of diverse immune cells including CD4+T cells, CD8+T cells, B cells, dendritic cells, neutrophils and macrophages and was closely associated with multiple immune markers in THCA. Conclusively, this comprehensive study indicates the lncRNA H19 might have a significant role in the initiation and progression of THCA. Hence, our findings might provide ideas on the selection of novel diagnostic biomarkers and assist in the designing of the effective pharmaceutical targets for THCA.

LncRNA H19 is a potential biomarker and correlated with immune infiltration in thyroid carcinoma

The bulk of evidence has revealed that dysregulated expression of long non-coding RNAs (lncRNAs) plays a crucial functional role in cancer biology. However, the mechanistic role of lncRNAs in the initiation, progression and immune landscape of thyroid carcinoma (THCA) still remains largely unknown. This study aimed to explore the significance of H19 in the diagnostic and immune related roles in THCA. The expression level of H19 was analyzed using the TNMplot, GSCA, UALCAN, GEPIA, Wanderer, UCSC Xena and GEO databases. Enrichment analyses were performed to investigate the possible underlying biological pathways by LinkedOmics. Moreover, cBioPortal web tool was used to analyze genetic alterations of H19. Finally, we used TIMER and GEPIA databases to explore the correlations between H19 and tumor-infiltrated immune cells and immune markers. LncRNA H19 was differentially expressed in various cancers and also remarkably downregulated in the THCA tissues compared to the normal ones. Genetic alteration analysis revealed that there was a significant correlation between alterations in H19 and overall survival of THCA patients. Furthermore, enrichment analysis indicated the functional relationship between co-expression network of H19 and extracellular structure organization, and immune microenvironment. In addition, H19 expression was positively correlated with infiltration level of diverse immune cells including CD4+T cells, CD8+T cells, B cells, dendritic cells, neutrophils and macrophages and was closely associated with multiple immune markers in THCA. Conclusively, this comprehensive study indicates the lncRNA H19 might have a significant role in the initiation and progression of THCA. Hence, our findings might provide ideas on the selection of novel diagnostic biomarkers and assist in the designing of the effective pharmaceutical targets for THCA.

Risk and Prognostic Factors for BRAFV600E Mutations in Papillary Thyroid Carcinoma

BACKGROUND

Over the past ten years, the incidence rate of papillary thyroid carcinoma (PTC) worldwide has been increasing rapidly year by year, with the incidence rate increasing 6% annually. PTC has become the malignant tumor with the highest growth rate in the world that fourteen PTC-related mutant genes have been identified. Whether the BRAFV600E mutation related to more aggressive clinicopathologic features and worse outcome in PTC remains variable and controversial. We aim to investigate the risk factors that may predict the BRAFV600E mutation potential of these lesions and new prevention strategies in PTC patients.

METHODS

A total of 9,908 papillary thyroid carcinoma patients with average 74.6% BRAFV600E mutations were analyzed (RevMan 5.3 software) in this study. The PubMed, Embase, and ISI Web of Science databases were systematically searched for works published through December 15, 2021.

RESULTS

The following variables were associated with an increased risk of BRAFV600E mutation in PTC patients: age ≥ 45 years (OR = 1.39, 95%CI = 1.21-1.60, p < 0.00001), male gender (OR = 1.13, 95%CI = 0.99-1.28, p = 0.06), multifocality (OR = 1.22, 95%CI = 1.07-1.40, p = 0.004), lymph node metastasis (OR = 1.33, 95%CI = 0.79-2.23, p = 0.28), extrathyroidal extension + (OR = 1.61, 95%CI = 1.06-2.44, p = 0.03), vascular invasion + (OR = 2.04, 95%CI = 1.32-3.15, p = 0.001), and tumor node metastasis stage (OR = 1.61, 95%CI = 1.38-1.88, p < 0.00001). In addition, tumor size (>1 cm) (OR = 0.51, 95%CI = 0.32-0.81, p = 0.005) and distant metastasis (OR = 0.69, 95%CI = 0.22-2.21, p = 0.54) had no association or risk with BRAFV600E mutation in PTC patients.

CONCLUSION

Our systematic review identified the following significant risk factors of BRAFV600E mutation in PTC patients: age (≥45 years), gender (male), multifocality, lymph node metastasis, vascular invasion, extrathyroidal extension, and advanced tumor node metastasis stage (stages III and IV). Tumor size (>1 cm) and distant metastasis do not appear to be correlated with BRAFV600E mutation in PTC patients.

Integrating BRAFV600E mutation, ultrasonic and clinicopathologic characteristics for predicting the risk of cervical central lymph node metastasis in papillary thyroid carcinoma

Background

The advantages of prophylactic central lymph node dissection (CLND) for clinically node-negative patients remained a great deal of controversies. Our research was aimed to analyze the relationship between cervical central lymph node metastasis (CLNM) and BRAF^V600E mutation, ultrasonic and clinicopathologic characterizes in papillary thyroid carcinoma (PTC).

Methods and materials

In current study, a total of 112 consecutive PTC patients who experienced thyroidectomy plus cervical central neck dissection were included in our research. All PTC were pre-operatively analyzed by ultrasonic features, including tumor size, multifocality or not, tumor location, internal components, echogenicity, microcalcification, margins, orientation, taller than wide shape, and internal vascularity. The presence of clinicopathologic factors, including age, sex, T stage, Hashimoto’s thyroiditis, and BRAF^V600E mutation was then investigated. Univariate and multivariate analysis were conducted to check into the relationship between predictive factors and cervical CLNM in PTC patients, and then a predictive model was also established.

Results

Pathologically, 58.0% (65/112) of the PTC patients harbored cervical CLNM. Univariate and multivariate analysis were conducted to identify age < 55 years, tumor size > 10 mm, microcalcification, non-concomitant Hashimoto’s thyroiditis and BRAF^V600E mutation were predictive factors for cervical CLNM in PTC. The risk score for cervical CLNM in PTC patients was calculated: risk score = 1.284 × (if age < 55 years) + 1.241 × (if tumor size > 10 mm) + 1.143 × (if microcalcification) – 2.097 × (if concomitant Hashimoto’s thyroiditis) + 1.628 × (if BRAF^V600E mutation).

Conclusion

Age < 55 years old, PTC > 10 mm, microcalcification, non-concomitant Hashimoto’s thyroiditis and BRAF^V600E mutation are predictive factors for cervical CLNM. BRAF^V600E mutation by pre-operative US-FNA technology synergized with clinicopathologic and ultrasonic features is expected to guide the appropriate surgical management for PTC patients.

Age-related long-term response in rat thyroid tissue and plasma after internal low dose exposure to 131I

131I is used clinically for therapy, and may be released during nuclear accidents. After the Chernobyl accident papillary thyroid carcinoma incidence increased in children, but not adults. The aims of this study were to compare 131I irradiation-dependent differences in RNA and protein expression in the thyroid and plasma of young and adult rats, and identify potential age-dependent biomarkers for 131I exposure. Twelve young (5 weeks) and twelve adult Sprague Dawley rats (17 weeks) were i.v. injected with 50 kBq 131I (absorbed dose to thyroid = 0.1 Gy), and sixteen unexposed age-matched rats were used as controls. The rats were killed 3-9 months after administration. Microarray analysis was performed using RNA from thyroid samples, while LC-MS/MS analysis was performed on proteins extracted from thyroid tissue and plasma. Canonical pathways, biological functions and upstream regulators were analysed for the identified transcripts and proteins. Distinct age-dependent differences in gene and protein expression were observed. Novel biomarkers for thyroid 131I exposure were identified: (PTH), age-dependent dose response (CA1, FTL1, PVALB (youngsters) and HSPB6 (adults)), thyroid function (Vegfb (adults)). Further validation using clinical samples are needed to explore the role of the identified biomarkers.

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.

The Prediction of Malignancy Risk in Thyroid Nodules Classified as Bethesda System Category III (AUS/FLUS) and the Role of Ultrasound Finding for Prediction of Malignancy Risk

Objective

To predict the risk of malignancy in category III of the Bethesda System for Reporting Thyroid Cytopathology "Atypia of Undetermined Significance/Follicular Lesion of Undetermined Significance (AUS/FLUS)" at King Abdulaziz Medical City, Riyadh, Saudi Arabia. It also intends to determine other possible contributing predictors of malignancy in thyroid nodules such as age, sex, and ultrasound (US) findings.

Method

This retrospectively designed study included 187 patients (mean age, 43.9 ± 14.1 years) with thyroid nodules, which were diagnosed as AUS/FLUS and all patients included had total thyroidectomy or lobectomy between January 2013 and December 2018 at King Abdulaziz Medical City in Riyadh, Saudi Arabia. The electronic medical records, US images, and final cytopathology and histopathology reports were reviewed and analyzed.

Result

The overall incidence of AUS/FLUS was (46.5%). Multivariate analysis of US features revealed that malignancy was significantly associated with nodules with irregular margins, microcalcification, multiple numbers (P < 0.001), and hypoechogenicity (P 0.04).

Conclusion

Despite the high rate of malignancy of nodules AUS/FLUS, it is still consistent with previously reported studies. The highly suspicious ultrasound features (irregular margins, microcalcification, multiple nodules, and hypoechogenicity) could be helpful in the diagnosis of thyroid cancer.

Association of Bethesda category and molecular mutation in patients undergoing thyroidectomy

OBJECTIVES

The aim of this study was to ascertain the relationship between Bethesda category and molecular mutation of thyroid nodules in patients undergoing thyroidectomy.

DESIGN

A retrospective cohort of patients who underwent thyroidectomy following needle biopsy and molecular profile testing was performed.

SETTING

Two tertiary care academic hospitals.

PARTICIPANTS

Consecutive patients with a dominant thyroid nodule who underwent both USFNA and molecular profile testing followed by thyroidectomy were included in the study.

MAIN OUTCOME AND MEASURES

The main outcome was postoperative diagnosis of thyroid cancer and aggressivity of disease based on histopathological variants, nodal metastasis or extra-thyroidal extension. Associations between Bethesda category, molecular mutation and postoperative pathology was assessed using descriptive analysis and chi-square testing.

RESULTS

Four hundred fifty-one patients were included. 95.9% (93/97) of patients with a BRAFV600E mutation had a Bethesda category V or VI (p < .001), and all had confirmed thyroid cancer on postoperative pathology. Those with H, K or N RAS or EIF1AX mutations, gene expression profiling (GEP) or copy number alterations showed an association with Bethesda categories III and IV (p ≤ .01). Those with no identified molecular mutation had a lower incidence of aggressive thyroid cancer compared to those with an identified mutation (12.6% vs. 44.3%, p < .01).

CONCLUSION

BRAFV600E mutations were associated with thyroid cancer subtypes known to be more aggressive whereas RAS and EIF1AX mutations, copy number alterations, and GEP were related to Bethesda categories III and IV. These findings may help thyroid specialists better identify aggressive thyroid nodules associated with indeterminate Bethesda categories.

Preoperative Typing of Thyroid and Parathyroid Tumors with a Combined Molecular Classifier

In previous studies, we described a method for detecting and typing malignant tumors of the thyroid gland in fine-needle aspiration biopsy samples via analysis of a molecular marker panel (normalized HMGA2 mRNA level; normalized microRNA-146b, -221, and -375 levels; mitochondrial-to-nuclear DNA ratio; and BRAF^V600E mutation) in cytological preparations by quantitative PCR. In the present study, we aimed to estimate the specificity of the typing of different thyroid tumors by the proposed method. Fine-needle aspiration cytological preparations from 278 patients were used. The histological diagnosis was known for each sample. The positive and negative predictive values of the method assessed in this study were, respectively, 100% and 98% for papillary thyroid carcinoma (n = 63), 100% and 100% for medullary thyroid carcinoma (n = 19), 43.5% and 98% for follicular carcinoma (n = 15), and 86% and 100% for Hürthle cell carcinoma (n = 6). Thus, we demonstrate that the diagnostic panel, including the analysis of microRNA expression, mRNA expression, the BRAF^V600E mutation, and the mitochondrial-to-nuclear DNA ratio, allows the highly accurate identification of papillary thyroid carcinoma, medullary thyroid carcinoma, and Hürthle cell carcinoma but not malignant follicular tumors (positive predictive value was below 50%).

Association analysis between the interaction of RAS family genes mutations and papillary thyroid carcinoma in the Han Chinese population

Papillary thyroid carcinoma (PTC) is the major subtype of thyroid cancer, accounting for 75%-85% of all thyroid malignancies. This study aimed to identify the association between the interactions of single nucleotide polymorphisms (SNPs) in RAS family genes and PTC in the Han Chinese population, to provide clues to the pathogenesis and potential therapeutic targets for PTC. Hap Map and NCBI-db SNP databases were used to retrieve SNPs. Haploview 4.2 software was used to filter SNPs based on specific parameters, six SNPs of RAS gene (KRAS-rs12427141, KRAS-rs712, KRAS-rs7315339, HRAS-rs12628, NRAS-rs14804 and NRAS-rs2273267) were genotyped by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) in 673 PTC patients and 657 healthy controls, the interactive effect was evaluated by crossover analysis, logistic regression and GMDR software. We found that genetic mutation in rs712 have significant associations with PTC risk after Bonferroni correction (p<0.001). The interaction between KRAS-rs12427141 and HRAS-rs12628 increased the risk of PTC (U=-2.119, p<0.05), the interaction between KRAS-rs2273267 and HRAS-rs7315339 reduced the risk of PTC (U=2.195, p<0.05). GMDR analysis showed that the two-factor model (KRAS-rs712, NRAS-rs2273267) was the best (p=0.0107). Summarily, there are PTC-related interactions between RAS family genes polymorphisms in the Han Chinese population.

The role of molecular genetics in the presurgical management of thyroid nodules

INTRODUCTION

Fine-needle aspiration (FNA) is an important diagnostic tool for the evaluation of thyroid nodules. However, in almost ¼ of all nodules submitted to FNA cytology is indeterminate. Since the majority of genetic alterations in thyroid cancer have been identified, the use of molecular testing platforms has been endorsed by American Thyroid Association for management of indeterminate nodules.

EVIDENCE ACQUISITION

Several commercial tests were based on mRNA expression of FNA samples (Afirma®, Veracyte, South San Francisco, CA, USA) while others detect DNA alterations (ThyroSeq, UPMC, Pittsburgh, PA, USA). Noncommercial tests detect limited number of point mutations or re-arrangements (gene panels). Literature study included a Pubmed research for adult original studies from 2003 to 2020, focusing on terms such as "molecular tests," "nodules with indeterminate AUS/FLUS and FN/SFN cytology."

EVIDENCE SYNTHESIS

Gene expression profile tests serve as "rule out" tests due to their high negative predictive value and perform better in a setting of low cancer pretest probability. Genetic alteration platforms display high positive predictive value and serve as rather "rule in" tests but their diagnostic accuracy is hampered either because a small proportion of nodules does not harbor any of these alterations targeted (gene panels) or because commonly identified RAS mutations can also be found in benign nodules.

CONCLUSIONS

Next generation sequencing development and incorporation of other genetic markers such as miRNA can improve diagnostic accuracy of molecular tests.

Molecular alterations in Hürthle cell neoplasms of thyroid: A fine needle aspiration cytology study with cytology-histology correlation

BACKGROUND

Hürthle cell features are frequently observed on the fine-needle aspiration (FNA) cytology of thyroid nodules and often pose a diagnostic challenge because of a significant overlap between cytomorphologic features seen in benign and malignant lesions. Molecular alterations (MAs) associated with these lesions are not well described. The objective of the current study was to evaluate the molecular profile of Hürthle cell lesions classified as Hürthle cell neoplasm (HCN) on cytologic evaluation.

METHODS

The authors retrospectively reviewed their electronic database for cytologic diagnoses of HCN from January 1, 2017 to March 31, 2020.

RESULTS

In total, 279 cases from 275 patients who had a diagnosis of HCN were included in the study. Molecular testing results were available in 85 cases (51 with MAs and 34 without MAs) and, of those, 42 had histologic follow-up available. Eight of 10 malignant cases had MAs, whereas the remaining 2 cases were negative for MAs. The most frequently encountered predominant genetic alterations or classifier findings were chromosome copy number alterations (n = 15), followed by NRAS (n = 8), KRAS (n = 7), suspicious (n = 6), EIF1AX (n = 4), TSHR (n = 3), gene overexpression (n = 3), positive microRNA classifier (n = 2), and 1 each of BRAF K601E, TERT, and HRAS mutations. One hundred thirty-seven cases had histologic follow-up available; of those, 28 were classified as malignant, and 109 were classified as benign (neoplastic and nonneoplastic). The overall risk of malignancy associated with HCN was 20%, and the risk of HCN with MAs was 25%.

CONCLUSIONS

The cytologic diagnosis of HCN includes various MAs without any obvious trend, and most malignant cases (80%) have some type of MA.

Impact of molecular testing on thyroid nodule neoplastic diagnosis, stratified by 4-cm size, in a surgical series

Whether molecular testing adds diagnostic value to the evaluation of thyroid nodules 4-cm or larger is unknown. The impact of molecular testing on cytopathologic-histopathologic diagnosis of neoplasm (adenoma or malignant), stratified by nodule size Collapse

Key Words

• thyroid diseases
• thyroid cancer

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MESH Headings

• Adenoma/genetics
• Adenoma/pathology
• Biomarkers, Tumor/genetics
• Biomarkers, Tumor/standards
• Biopsy, Fine-Needle/statistics & numerical data
• Genetic Testing/standards
• Genetic Testing/statistics & numerical data
• Humans
• Mutation
• Thyroid Nodule/genetics
• Thyroid Nodule/pathology

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Grants

• UL1TR002494 U.S. Department of Health & Human Services | NIH | National Center for Advancing Translational Sciences (NCATS)
• The Scientific and Technical Research Council of turkey (TUBITAK)

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Affiliation(s)

Rupendra T Shrestha Department of Medicine, University of Minnesota, Minneapolis, USA
Muhammed Kizilgul Department of Medicine, University of Minnesota, Minneapolis, USA Department of Endocrinology and Metabolism, UHS Diskapi Training and Research Hospital, Ankara, Turkey
Maryam Shahi Department of Pathology, University of Minnesota, Minneapolis, USA
Khalid Amin Department of Pathology, University of Minnesota, Minneapolis, USA
Maria R Evasovich Department of Surgery, University of Minnesota, Minneapolis, USA
Lynn A Burmeister Department of Medicine, University of Minnesota, Minneapolis, USA.

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Combined quantitation of HMGA2 mRNA, microRNAs, and mitochondrial-DNA content enables the identification and typing of thyroid tumors in fine-needle aspiration smears

Background

Analysis of molecular markers in addition to cytological analysis of fine-needle aspiration (FNA) samples is a promising way to improve the preoperative diagnosis of thyroid nodules. Nonetheless, in clinical practice, applications of existing diagnostic solutions based on the detection of somatic mutations or analysis of gene expression are limited by their high cost and difficulties with clinical interpretation.

The aim of our work was to develop an algorithm for the differential diagnosis of thyroid nodules on the basis of a small set of molecular markers analyzed by real-time PCR.

Methods

A total of 494 preoperative FNA samples of thyroid goiters and tumors from 232 patients with known histological reports were analyzed: goiter, 105 samples (50 patients); follicular adenoma, 101 (48); follicular carcinoma, 43 (28); Hürthle cell carcinoma, 25 (11); papillary carcinoma, 121 (56); follicular variant of papillary carcinoma, 80 (32); and medullary carcinoma, 19 (12). Total nucleic acids extracted from dried FNA smears were analyzed for five somatic point mutations and two translocations typical of thyroid tumors as well as for relative concentrations of HMGA2 mRNA and 13 microRNAs and the ratio of mitochondrial to nuclear DNA by real-time PCR. A decision tree–based algorithm was built to discriminate benign and malignant tumors and to type the thyroid cancer. Leave-p-out cross-validation with five partitions was performed to estimate prediction quality. A comparison of two independent samples by quantitative traits was carried out via the Mann–Whitney U test.

Results

A minimum set of markers was selected (levels of HMGA2 mRNA and miR-375, − 221, and -146b in combination with the mitochondrial-to-nuclear DNA ratio) and yielded highly accurate discrimination (sensitivity = 0.97; positive predictive value = 0.98) between goiters with benign tumors and malignant tumors and accurate typing of papillary, medullary, and Hürthle cell carcinomas. The results support an alternative classification of follicular tumors, which differs from the histological one.

Conclusions

The study shows the feasibility of the preoperative differential diagnosis of thyroid nodules using a panel of several molecular markers by a simple PCR-based method. Combining markers of different types increases the accuracy of classification.

Constitutive Expression of NRAS with Q61R Driver Mutation Activates Processes of Epithelial-Mesenchymal Transition and Leads to Substantial Transcriptome Change of Nthy-ori 3-1 Thyroid Epithelial Cells

The Q61R mutation of the NRAS gene is one of the most frequent driver mutations of thyroid cancer. Tumors with this mutation are characterized by invasion into blood vessels and formation of distant metastases. To study the role of this mutation in the growth of thyroid cancer, we developed a model system on the basis of thyroid epithelial cell line Nthy-ori 3-1 transduced by a lentiviral vector containing the NRAS gene with the Q61R mutation. It was found that the expression of NRAS(Q61R) in thyroid epithelial cells has a profound influence on groups of genes involved in the formation of intercellular contacts, as well as in processes of epithelial-mesenchymal transition and cell invasion. The alteration in the expression of these genes affects the phenotype of the model cells, which acquire traits of mesenchymal cells and demonstrate increased ability for survival and growth without attachment to the substrate. The key regulators of these processes are transcription factors belonging to families SNAIL, ZEB, and TWIST, and in different types of tumors the contribution of each individual factor can vary greatly. In our model system, phenotype change correlates with an increase in the expression of SNAIL2 and TWIST2 factors, which indicates their possible role in regulating invasive growth of thyroid cancer with the mutation of NRAS(Q61R).

A single nuclear polymorphism in let-7g binding site affects the doubling time of thyroid nodule by regulating KRAS-induced cell proliferation

As an indicator for the malignancy of thyroid nodules (TN), the doubling time of TN was studied in this study to evaluate the effect of rs712 polymorphism on the progression of TN. In addition, we aimed to study the potential molecular mechanisms underlying the pathological effect of rs712 polymorphism upon TN. A Taqman method was used to genotype the patients according to their rs712 polymorphism. Real-time polymerase chain reaction, western blot, Terminal deoxynucleotidyl transferase dUTP nick end labeling assay and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay was conducted to study the correlation between KRAS expression and the pathological effect of rs712 polymorphism. In-silicon analysis and luciferase assay were utilized to establish the regulatory relationship between let-7g and KRAS. KRAS messenger RNA (mRNA)/protein levels in the GG group were upregulated with a decreased apoptosis index. KRAS mRNA was validated to be a virtual target of let-7g. In addition, the mRNA/protein level of KRAS as well as cell proliferation index was decreased in primary thyroid cancer cells genotyped as TT/TG and transfected with KRAS small interfering RNA (siRNA)/let-7g precursors. The cell apoptosis index was evidently elevated in the KRAS siRNA/let-7g precursors group compared with that in the scramble controls. Moreover, KRAS mRNA/protein only showed slight reduction when GG-genotyped primary thyroid cancer cells were transfected by let-7g precursors. Additionally, let-7g precursors exhibited no significant effect on cell proliferation index or cell apoptosis in GG cells. Rs712 polymorphism T>G in the 3'-untranslated region of KRAS interrupts the interactions between let-7g and KRAS mRNA, leading to a higher cell proliferation index and reduced doubling time of TN.

RAS-mediated oncogenic signaling pathways in human malignancies

Abnormally activated RAS proteins are the main oncogenic driver that governs the functioning of major signaling pathways involved in the initiation and development of human malignancies. Mutations in RAS genes and or its regulators, most frequent in human cancers, are the main force for incessant RAS activation and associated pathological conditions including cancer. In general, RAS is the main upstream regulator of the highly conserved signaling mechanisms associated with a plethora of important cellular activities vital for normal homeostasis. Mutated or the oncogenic RAS aberrantly activates a web of interconnected signaling pathways including RAF-MEK (mitogen-activated protein kinase kinase)-ERK (extracellular signal-regulated kinase), phosphoinositide-3 kinase (PI3K)/AKT (protein kinase B), protein kinase C (PKC) and ral guanine nucleotide dissociation stimulator (RALGDS), etc., leading to uncontrolled transcriptional expression and reprogramming in the functioning of a range of nuclear and cytosolic effectors critically associated with the hallmarks of carcinogenesis. This review highlights the recent literature on how oncogenic RAS negatively use its signaling web in deregulating the expression and functioning of various effector molecules in the pathogenesis of human malignancies.

Special types of thyroid carcinoma

This article reviews the small percentage of thyroid tumours that are not classified as classic papillary thyroid carcinoma, follicular thyroid carcinoma, and medullary thyroid carcinoma. It includes subtypes of papillary thyroid carcinoma, including, tall-cell, hobnail/micropapillary, columnar cell, diffuse sclerosing and solid variants. Poorly differentiated carcinoma, high-grade carcinoma and anaplastic thyroid carcinoma are reviewed. Also discussed are entities that are unusual but need to be recognized as primary thyroid neoplasms, i.e. mucoepidermoid carcinoma, sclerosing mucoepidermoid carcinoma with eosinophilia, and mammary analogue secretory carcinoma/secretory carcinoma. The pathological features and prognostic factors are described; a brief review of molecular correlates of these neoplasms is included.

Metabolic Reprogramming in Thyroid Carcinoma

Among all the adaptations of cancer cells, their ability to change metabolism from the oxidative to the glycolytic phenotype is a hallmark called the Warburg effect. Studies on tumor metabolism show that improved glycolysis and glutaminolysis are necessary to maintain rapid cell proliferation, tumor progression, and resistance to cell death. Thyroid neoplasms are common endocrine tumors that are more prevalent in women and elderly individuals. The incidence of thyroid cancer has increased in the Past decades, and recent findings describing the metabolic profiles of thyroid tumors have emerged. Currently, several drugs are in development or clinical trials that target the altered metabolic pathways of tumors are undergoing. We present a review of the metabolic reprogramming in cancerous thyroid tissues with a focus on the factors that promote enhanced glycolysis and the possible identification of promising metabolic targets in thyroid cancer.

ATF1 and RAS in exosomes are potential clinical diagnostic markers for cervical cancer

Cervical cancer is one of the most common cancers among women worldwide. It is highly lethal yet can be treated when found in early stage. Thus, early detection is of significant important for early diagnosis of cervical cancer. Exosomes have been used as biomarkers in clinical diagnosis. It is unknown that whether blood exosomes associated with cervical cancer can be detected and if these exosomes can accurately represent the developmental stage of cervical cancer. Mouse models were made out of a relapsed cervical cancer patient's tumour sample for original and recurrent cervical cancer, and gene analysis in both tumours and exosomes in these mouse models were performed. We found that activating transcription factor 1 (ATF1) and RAS genes were significantly up-regulated in tumours of both primary and recurrent cervical cancer mouse model, and they can also be detected in the blood exosomes of the mouse model. Our results indicated that ATF1 and RAS could be potential candidate biomarkers for cervical cancer in early diagnosis. ATF1 and RAS genes were found significantly elevated in tumours of primary and recurrent cervical cancer mouse model, and they were also detected in the blood exosomes. Therefore, ATF1 and RAS could be used as a diagnostic marker for cervical cancer in the future.

Primary Benign and Malignant Thyroid Neoplasms With Signet Ring Cells: Cytologic, Histologic, and Molecular Features

OBJECTIVES

Signet ring cells (SRCs) can be seen in a variety of thyroid tumors and can pose a diagnostic pitfall on cytology. This study describes the cytologic, histomorphologic, and molecular aspects of a cohort of primary thyroid tumors with SRCs.

METHODS

A search was performed of the Massachusetts General Hospital and Brigham and Women's Hospital (Boston, MA) pathology archives for the keywords thyroid, signet, and signet ring features between 2000 and 2014. Seven thyroidectomy specimens with corresponding thyroid fine-needle aspiration (FNA) were obtained. Cytology and histopathology slides were evaluated. Molecular analysis was performed using anchored multiplex polymerase chain reaction (AMP).

RESULTS

The cohort consisted of four follicular adenomas (FAs), two noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTPs), and one secretory carcinoma (SC). The FNA diagnoses were atypia of undetermined significance (n = 3), suspicious for follicular neoplasm (n = 3), and suspicious for malignancy (n = 1). Molecular analyses revealed PTEN and FGFR3 mutations in an FA and NIFTP, respectively, and an ETV6-NTRK3 fusion in a case of primary thyroid gland SC.

CONCLUSIONS

Our study demonstrates the range of thyroid tumors with SRCs. While most thyroid tumors with SRCs are benign, primary thyroid SC should also be considered in the differential diagnosis.

Clinicopathological characteristics of thyroid cancer in the federal state of Salzburg

OBJECTIVE

The aim of our investigation was to evaluate the clinicopathological characteristics and mutation patterns in newly diagnosed cases of thyroid cancer in the federal state of Salzburg, Austria, in the year 2013.

METHODS

The medical records of all patients newly diagnosed with thyroid cancer in 2013 in the federal state of Salzburg were retrospectively reviewed. The clinicopathological characteristics and mutations of thyroid cancers were analyzed.

RESULTS

63 patients (mean age: 51.0 years, range: 21-81 years; female 75%, male 25%) were identified. 53 patients had papillary (12 follicular variant), 4 patients follicular (1 oxyphilic variant), 3 patients medullary, and 3 patients anaplastic thyroid cancer. T1 tumors were found in 34 patients (pT1a, 20 patients; pT1b, 14 patients), T2 tumors in 10 patients, T3 tumors in 16 patients, and T4 tumors in 3 patients. Lymph node involvement was seen in 15 patients and metastatic disease in 1 patient. Mutations of BRAF (B-type Raf kinase) were detected in 23 and mutation of NRAS (Neuroblastoma RAS Viral Oncogene Homolog) in 2 papillary thyroid cancers. No concomitant mutations of BRAF and NRAS were found.

CONCLUSION

Females accounted for 75% of the patients with newly diagnosed thyroid cancer and the incidence peaked at a younger age than in males. Papillary thyroid cancer was the most frequent tumor type, accounting for 84% of the cases. A high frequency of T1 tumors and cancers with no lymph node involvement was found. Males had a higher proportion of large tumors and more aggressive forms of thyroid cancer than females. Mutations (mostly of BRAF) were found in 47% of the cases. Neither mutations of KRAS (Kirsten rat sarcoma viral oncogene homologue) nor concomitant mutations of BRAF and NRAS were found.

Nuclear morphometric findings in undetermined cytology: A possible clue for prediction of BRAF mutation in papillary thyroid carcinomas

PURPOSE

To investigate the possible relationship between the nuclear morphometric characteristics (nuclear perimeter, roundness, nuclear area, and nuclear shape) and BRAF mutation status in papillary thyroid carcinoma cases with a prior diagnosis of undetermined cytology.

MATERIALS AND METHODS

Total thyroidectomy specimens obtained from 48 patients with papillary thyroid carcinoma with a prior diagnosis of undetermined cytology were included. Morphometric analysis under light microscopy included measurements of the perimeter, shape factor, nuclear area, and roundness of thyrocyte nuclei from the cytological smear preparations. Mutational analysis, including immunohistochemistry and polymerase chain reaction, was performed in formalin fixed paraffin embedded tissue blocks.

RESULTS

BRAF V600E mutation was detected in 7 of 48 cases (14.5%). The nuclear perimeter and nuclear area in mutated cases were significantly higher than the wild type (p = 0.005). Shape factor (p = 0.681) and roundness (p = 0.752) values did not significantly differ between the wild-type and mutant groups. No significant relationship was evident between BRAF expression and BRAF point mutation.

CONCLUSION

In cases with positivity for BRAF mutation, the nuclear perimeter and nuclear area were significantly increased. These findings suggest that morphometric variables are predictive markers for papillary thyroid carcinoma cases with positivity for BRAF mutation. However, further trials on larger series are warranted to understand the significance and predictive value of nuclear morphometric analysis in these circumstances.

LMTK3 knockdown retards cell growth and invasion and promotes apoptosis in thyroid cancer

Lemur tyrosine kinase-3 (LMTK3) is a member of the serine/threonine tyrosine kinase family, which is thought to be involved in tumor progression and prognosis. The purpose of the present study was to determine the diagnostic significance and therapeutic targets in thyroid cancer. ELISA assay was used to detect the protein expression of serum LMTK3. Immunohistochemistry and reverse transcription-quantitative polymerase chain reaction were employed to measure the expression of LMTK3. Flow cytometry was used to determine the cell cycle. Transwell assay was used to measure the invasion and migration of SW579 cells and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay to detect cell apoptosis. The LMTK3 level was positively associated with disease stage and pathological type, whereas there was no correlation between LMTK3 level and gender, age, tumor size or lymph node metastasis. The serum LMTK3 level was significantly increased in 102 thyroid carcinoma patients compared with 52 benign thyroid tumor patients and 50 healthy volunteers (P=0.001). The protein and mRNA expression of LMTK3 was markedly higher in thyroid cancer patients compared with patients with benign thyroid tumors. Notably, LMTK3 knockdown retarded proliferation, invasion and migration in SW579 cells. In addition, downregulation of LMTK3 promoted apoptosis in SW579 cells. These findings indicated that LMTK3 knockdown retards the growth of thyroid cancer cells partly through inhibiting proliferation, invasion, migration and inducing apoptosis in SW579 cells. It may serve as a useful diagnostic biomarker and a novel therapeutic target for patients with thyroid cancer.

RAC1b overexpression stimulates proliferation and NF-kB-mediated anti-apoptotic signaling in thyroid cancer cells

Overexpression of tumor-associated RAC1b has been recently highlighted as one of the most promising targets for therapeutic intervention in colon, breast, lung and pancreatic cancer. RAC1b is a hyperactive variant of the small GTPase RAC1 and has been recently shown to be overexpressed in a subset of papillary thyroid carcinomas associated with unfavorable outcome. Using the K1 PTC derived cell line as an in vitro model, we observed that both RAC1 and RAC1b were able to induce a significant increase on NF-kB and cyclin D1 reporter activity. A clear p65 nuclear localization was found in cells transfected with RAC1b-WT, confirming NF-kB canonical pathway activation. Consistently, we observed a RAC1b-mediated decrease in IκBα (NF-kB inhibitor) protein levels. Moreover, we show that RAC1b overexpression stimulates G1/S progression and protects thyroid cells against induced apoptosis, the latter through a process involving the NF-kB pathway. Present data support previous findings suggesting an important role for RAC1b in the development of follicular cell-derived thyroid malignancies and point out NF-kB activation as one of the molecular mechanisms associated with the pro-tumorigenic advantage of RAC1b overexpression in thyroid carcinomas.

Molecular perspectives in differentiated thyroid cancer

Progress in understanding the molecular genetics of thyroid cancer in the last 20 years has accelerated recently with the advent of high-throughput sequencing technologies known as Next-Generation Sequencing. Besides classical molecular abnormalities involving the MAPK (Mitogen Activated Protein Kinase) and PI3K (PhosphoInositide 3-Kinase) pathways that play a key role in follicular-derived thyroid tumorigenesis, new molecular abnormalities have been discovered. The major advances in recent years have been the discovery of new somatic driver gene point mutations (such as RASAL1 [RAS protein activator Like 1] mutations in follicular cancer) and/or mutations that have prognostic value (such as TERT [Telomerase reverse transcriptase] promoter mutations); new chromosomal rearrangements, usually having close connection with exposure to ionizing radiation (such as ALK [Anaplastic Lymphoma Kinase] rearrangements); and deregulation of some gene or microRNA expression representing a molecular signature. Progress made in understanding the molecular mechanisms of thyroid cancer offers new perspectives for the diagnosis of the benign or malignant status of a thyroid nodule, to refine prognosis and offer new perspectives of targeted therapy for radioiodine-refractory cancers.

Correlation Between Histological Diagnosis and Mutational Panel Testing of Thyroid Nodules: A Two-Year Institutional Experience

BACKGROUND

Indeterminate thyroid fine-needle aspiration (FNA) cytology, including atypia of undetermined significance (AUS/FLUS) and suspicious for follicular neoplasm (SFN), continues to generate uncertainty about the presence of malignancy, resulting in repeated follow-up, repeat FNA, or diagnostic surgery. Mutational panel testing may improve the malignancy risk prediction in indeterminate nodules, but the general application of such testing has not been investigated extensively.

METHODS

A retrospective review was performed of all patients undergoing thyroidectomy at a tertiary care facility over a two-year period. Mutational panel test results, when present, were analyzed relative to FNA cytologic result and surgical histopathologic diagnosis. Malignancy rates, sensitivity, specificity, positive predictive values (PPV), negative predictive values (NPV) and positive and negative likelihood ratios (LR) were calculated.

RESULTS

A total of 261 operated thyroid nodules had the following initial FNA cytology results: 2% non-diagnostic, 23% benign, 28% AUS/FLUS, 11% SFN, 9% suspicious for malignancy (SUSP), and 27% malignant. The histopathologic malignancy rate was 48%, subcategorized by cytology into benign 7%, AUS/FLUS 30%, SFN 38%, and SUSP 83%. Mutations were more frequent in indeterminate nodules that were histologically malignant versus benign (p < 0.0001) or versus adenoma (p = 0.001). Mutational analysis in 44 AUS/FLUS nodules resulted in a malignancy detection sensitivity of 85%, a specificity of 65%, a PPV of 50%, a NPV of 91%, and a positive LR of 2.4. In 12 SFN nodules analyzed with ThyroSeq(®) testing, sensitivity was 100%, specificity 57%, PPV 63%, NPV 100%, and LR 2.3. Performance of the seven-gene mutational panel was not significantly different from the ThyroSeq(®) panel in the AUS/FLUS group. The malignancy yield, comparing the mutation positive AUS/FLUS group with the untested AUS/FLUS surgical cohort, did not reach statistical significance (p = 0.17).

CONCLUSIONS

In a surgical cohort, a similar NPV but a lower PPV was found with the use of mutational panel testing compared to the published literature. Following the identification of a mutation, the prevalence of malignancy in the AUS/FLUS or SFN category was increased by nearly 15% to 45% and 53%, respectively. Further study is needed to confirm these results and to analyze clinical outcome subcategories relative to the utility of mutational testing.

5'-AMP-Activated Protein Kinase Regulates Papillary (TPC-1 and BCPAP) Thyroid Cancer Cell Survival, Migration, Invasion, and Epithelial-to-Mesenchymal Transition

BACKGROUND

Differentiated thyroid carcinomas (DTC) are associated with a good prognosis and a high survival rate. However, tumor recurrence occurs in approximately 20-30% of DTC patients, reinforcing the importance of identifying new molecular targets for cancer management. It has been shown that the 5'-AMP-activated protein kinase (AMPK) is over-activated in papillary thyroid cancer (PTC). This study aimed to investigate the effects of 5-aminoimidazole-4-carboxamide-ribonucleoside (AICAR), an AMPK activator, on various aspects of thyroid cancer cell behavior, including cell survival, apoptosis, migration, invasion, and epithelial-to-mesenchymal transition (EMT), in the human thyroid cancer cell lines BCPAP and TPC-1.

METHODS

BCPAP and TPC-1 cells were cultivated in Dulbecco's modified Eagle's medium, and the non-tumor-derived cell line Nthy-ORI was grown in RPMI. Cells were treated or not with AICAR for different periods of time. The cell growth rate, cell cycle phase, apoptosis, cell migration, and invasion were analyzed using transwell inserts, and EMT was quantified by the expression of mesenchymal and epithelial markers.

RESULTS

AMPK is activated in thyroid cancer cell lines, and AICAR treatment further increased AMPK phosphorylation. After 48 hours of AICAR treatment, the percentage of cells in the G2/M phase decreased, and a G0/G1-phase arrest was induced in both cell lines. AMPK activation effectively induced apoptosis in the BCPAP and TPC-1 cancer cell lines, while no apoptosis induction was observed in Nthy-ORI cells. AICAR also reduced the migration of Nthy-ORI and BCPAP cells by 30% and approximately 60% in TPC-1 cells. AICAR had no effect on cell invasion in Nthy-ORI and TPC-1 cells, but a significant reduction of cell invasion was observed in BCPAP cells. AICAR induced a significant reduction of N-cadherin and no changes in the expression of vimentin or TCF/Zeb1 protein in BCPAP cells. No differences in the expression of EMT markers were found in the AICAR-treated Nthy-ORI cells. A remarkable reduction of vimentin, TCF/Zeb1, and N-cadherin protein expression was detected in the TPC-1 cells.

CONCLUSIONS

Increased activation of AMPK in PTC cell lines leads to a strong antitumor response, as measured by the inhibition of cell proliferation, cell migration, and induction of cell death. AMPK activation also reverses EMT in TPC-1 cells.

Treatment of advanced thyroid cancer with targeted therapies: ten years of experience

Thyroid cancer is rare, but it is the most frequent endocrine malignancy. Its prognosis is generally favorable, especially in cases of well-differentiated thyroid cancers (DTCs), such as papillary and follicular cancers, which have survival rates of approximately 95% at 40 years. However, 15-20% of cases became radioiodine refractory (RAI-R), and until now, no other treatments have been effective. The same problems are found in cases of poorly differentiated (PDTC) and anaplastic (ATC) thyroid cancers and in at least 30% of medullary thyroid cancer (MTC) cases, which are very aggressive and not sensitive to radioiodine. Tyrosine kinase inhibitors (TKIs) represent a new approach to the treatment of advanced cases of RAI-R DTC, MTC, PDTC, and, possibly, ATC. In the past 10 years, several TKIs have been tested for the treatment of advanced, progressive, and RAI-R thyroid tumors, and some of them have been recently approved for use in clinical practice: sorafenib and lenvatinib for DTC and PDTC and vandetanib and cabozantinib for MTC. The objective of this review is to present the current status of the treatment of advanced thyroid cancer with the use of innovative targeted therapies by describing both the benefits and the limits of their use based on the experiences reported so far. A comprehensive analysis and description of the molecular basis of these therapies, as well as new therapeutic perspectives, are reported. Some practical suggestions are given for both the choice of patients to be treated and their management, with particular regard to the potential side effects.

Family of microRNA-146 Regulates RARβ in Papillary Thyroid Carcinoma

Retinoic acid is a promising tool in adjuvant cancer therapies, including refractory thyroid cancer, and its biological role is mediated by the retinoic acid receptor beta (RARβ). However, expression of RARβ is lowered in papillary thyroid carcinoma (PTC), contributing to promotion of tumor growth and inefficiency of retinoic acid and radioactive iodine treatment. The causes of aberrant RARB expression are largely unknown. We hypothesized that the culpable mechanisms include the action of microRNAs from the miR-146 family, previously identified as significantly upregulated in PTC tumors. To test this hypothesis, we assessed the expression of RARB as well as miR-146a-5p and miR-146b-5p in 48 PTC tumor/normal tissue pairs by Taqman assay to reveal that the expression of RARB was 3.28-fold decreased, and miR-146b-5p was 28.9-fold increased in PTC tumors. Direct interaction between miRs and RARB was determined in the luciferase assay and further confirmed in cell lines, where overexpression of miR-146a-5p and miR-146b-5p caused a 31% and 33% decrease in endogenous RARB mRNA levels. Inhibition of miR-146a and miR-146b resulted in 62.5% and 45.4% increase of RARB, respectively, and a concomitant decrease in proliferation rates of thyroid cancer cell lines, analyzed in xCELLigence system.We showed that two microRNAs of the miR-146 family directly regulate RARB. Inhibition of miRs resulted in restoration of RARB expression and decreased rates of proliferation of thyroid cancer cells. By restoring RARB levels, microRNA inhibitors may become part of an adjuvant therapy in thyroid cancer patients.

Herpes and polyoma family viruses in thyroid cancer

Thyroid cancer is considered the most common malignancy that affects the endocrine system. Generally, thyroid cancer derives from follicular epithelial cells, and thyroid cancer is divided into well-differentiated papillary (80% of cases) and follicular (15% of cases) carcinoma. Follicular thyroid cancer is further divided into the conventional and oncocytic (Hürthle cell) type, poorly differentiated carcinoma and anaplastic carcinoma. Both poorly differentiated and anaplastic carcinoma can arise either de novo, or secondarily from papillary and follicular thyroid cancer. The incidence of thyroid cancer has significantly increased for both males and females of all ages, particularly for females between 55–64 years of age, from 1999 through 2008. The increased rates refer to tumors of all stages, though they were mostly noted in localized disease. Recently, viruses have been implicated in the direct regulation of epithelial-mesenchymal transition (EMT) and the development of metastases. More specifically, Epstein-Barr virus (EBV) proteins may potentially lead to the development of metastasis through the regulation of the metastasis suppressor, Nm23, and the control of Twist expression. The significant enhancement of the metastatic potential, through the induction of angiogenesis and changes to the tumor microenvironment, subsequent to viral infection, has been documented, while EMT also contributes to cancer cell permissiveness to viruses. A number of viruses have been identified to be associated with carcinogenesis, and these include lymphotropic herpesviruses, namely EBV and Kaposi's sarcoma-associated herpesvirus [KSHV, also known as human herpesvirus type 8 (HHV8)]; two hepatitis viruses, hepatitis B virus (HBV) and hepatitis C virus (HCV); human papillomaviruses (HPVs); human T cell lymphoma virus (HTLV); and a new polyomavirus, Merkel cell polyomavirus identified in 2008. In this review, we examined the association between thyroid cancer and two oncogenic virus families, the herpes and polyoma family viruses, and we discuss their potential role as causative agents in thyroid carcinogenesis.

Extending the Impact of RAC1b Overexpression to Follicular Thyroid Carcinomas

RAC1b is a hyperactive variant of the small GTPase RAC1 known to be a relevant molecular player in different cancers. Previous studies from our group lead to the evidence that its overexpression in papillary thyroid carcinoma (PTC) is associated with an unfavorable prognosis. In the present study, we intended to extend the analysis of RAC1b expression to thyroid follicular neoplasms and to seek for clinical correlations. RAC1b expression levels were determined by RT-qPCR in thyroid follicular tumor samples comprising 23 follicular thyroid carcinomas (FTCs) and 33 follicular thyroid adenomas (FTAs). RAC1b was found to be overexpressed in 33% of carcinomas while no RAC1b overexpression was documented among follicular adenomas. Patients with a diagnosis of FTC were divided into two groups based on longitudinal evolution and final outcome. RAC1b overexpression was significantly associated with both the presence of distant metastases (P = 0.01) and poorer clinical outcome (P = 0.01) suggesting that, similarly to that previously found in PTCs, RAC1b overexpression in FTCs is also associated with worse outcomes. Furthermore, the absence of RAC1b overexpression in follicular adenomas hints its potential as a molecular marker likely to contribute, in conjunction with other putative markers, to the preoperative differential diagnosis of thyroid follicular lesions.

Encapsulated Thyroid Carcinoma of Follicular Cell Origin

Encapsulated carcinomas of follicular cell origin are subject to considerable controversies. This group includes an encapsulated/well-circumscribed (E/WC) follicular variant of papillary carcinoma (FVPTC) and encapsulated follicular and Hurthle cell carcinoma (EFC, EHC respectively). FVPTC usually presents as an E/WC tumor and less commonly as an infiltrative neoplasm. E/WC FVPTC rarely metastasizes to lymph nodes, whereas infiltrative tumors often present with cervical nodal metastases. Many studies revealed FVPTC in general to be genetically close to the follicular adenomas (FA)/EFC group of tumors. This is particularly true for the E/WC FVPTC which has a high rate of RAS and lack BRAFV600E mutations. Infiltrative FVPTC has an opposite molecular profile closer to classical papillary carcinoma than to FA/EFC (BRAFV600E > RAS mutations). Noninvasive E/WC FVPTCs are extremely indolent even if treated with lobectomy alone. While EFC and EHC with capsular invasion only have an excellent outcome, those with extensive (≥4 foci) lymphovascular invasion (LVI) have a significant rate of distant recurrence. The prognosis of those with focal LVI seems good, but more studies are needed to confirm their behavior. In EHC, those with extensive/significant LVI have a different RNA expression profile than those with less LVI. EHC appear to recur earlier, are less RAI avid, and have a different mutation profile than EFC. Noninvasive E/WC FVPTC should be treated conservatively. There is therefore a need to reclassify the E/WC FVPTC in order to prevent overtreatment. In view of their molecular and behavioral differences, EHC should not be considered a subset of EFC.

Investigation of BK virus, Epstein-Barr virus and human papillomavirus sequences in postoperative thyroid gland specimens

BACKGROUND

Although recent evidence has implicated viruses in the regulation of epithelial-to-mesenchymal transition and tumor progression, little is known regarding viral infections in thyroid malignancies. Thus the aim of this study was to detect sequences of 3 potentially oncogenic viruses - BK virus (BKV), Epstein-Barr virus (EBV) and human papillomavirus (HPV) - in a series of postoperative thyroid gland specimens.

METHODS

Thirty patients with thyroid nodules who underwent surgery for thyroid disease within a 3-year period were enrolled. Both nodular and adjacent normal thyroid tissue was surgically excised from each patient. Viral gene sequences of BKV (VP1), EBV (LMP1, EBNA2 and EBER1) and HPV were amplified by PCR. The PCR results were confirmed by direct sequencing analysis.

RESULTS

VP1 gene sequences were detected in 60% (18/30) of thyroid cancer or multinodular hyperplasia lesions compared with in 43.3% (13/30) of adjacent normal thyroid tissue specimens. Fifteen of thirty (50%) of thyroid cancer or multinodular hyperplasia samples revealed LMP1 sequences compared with 46.7% (14/30) of corresponding normal thyroid tissues. EBNA2 gene sequences were detected in 90% (27/30) of thyroid cancer or multinodular hyperplasia samples, compared with 90% (27/30) of adjacent normal thyroid tissue specimens. All samples were negative for EBER1 sequences, while HPV DNA was not detected in either nodular or normal thyroid tissue.

CONCLUSIONS

This study suggests that BKV and EBV "infection" is an early event, occurring within normal tissue. Our findings do not show a clear role for the viruses examined, instead they suggest an "endemicity" pattern rather than a causal effect.

miR-219-5p modulates cell growth of papillary thyroid carcinoma by targeting estrogen receptor α

CONTEXT

Papillary thyroid carcinoma (PTC) is the most common endocrine malignancy. It has been demonstrated that micro-RNAs (miRNAs) are involved in the development of PTC. The miRNA-chromatin immunoprecipitation microarray assay revealed down-regulation of miR-219-5p; however, the effect of miR-219-5p on PTC cell growth remains unknown. This result implied the critical role of miR-219-5p in the development of PTC.

METHODS

We investigated the association between miR-219-5p and PTC development. Expression of miR-219-5p was monitored in 30 PTC tissue specimens and compared with that in 30 normal thyroid tissue specimens. The effect of miR-219-5p on PTC development was studied by cell proliferation, migration, and apoptosis assays. The underlying mechanism was clarified by a reporter assay and rescue experiment.

RESULTS

The current study confirmed that miR-219-5p expression was inhibited in PTC tissue samples. There were statistically significant differences in the expression of miR-219-5p with regard to sex, tumor size, and lymph node metastasis in patients with PTC. Forced expression of miR-219-5p suppressed PTC cell proliferation and migration and promoted apoptosis. Further study showed that estrogen receptor (ER) α was the direct target of miR-219-5p and mediated the effect of miR-219-5p on PTC occurrence. Expression of miR-219-5p was inversely correlated with that of ERα. Importantly, ERα overexpression in PTC cells rescued the inhibitory effect of miR-219-5p on PTC cell proliferation and migration. Thus, our results indicated that miR-219-5p played a critical role in PTC growth by inhibiting ERα.

CONCLUSION

Our investigation identified miR-219-5p as a negative regulator of PTC development through targeting of ERα.

Thyroid atypia of undetermined significance or follicular lesion of undetermined significance: an indispensable Bethesda 2010 diagnostic category or waste garbage?

OBJECTIVE

The Bethesda System for Reporting Thyroid Cytopathology (BSRTC) was introduced in thyroid cytology in 2007 and is now generally accepted. BSRTC categories include a morphologic description and risk of malignancy as well as follow-up suggestions in each group. However, the category entitled 'atypia of undetermined significance or follicular lesion of undetermined significance' (AUS/FLUS) is problematic. This category is heterogeneous and has been overused so far.

STUDY DESIGN

Twenty-six studies were included in a meta-analysis. In addition to AUS/FLUS percentage, we analysed repeated AUS/FLUS percentage, cytological and histological correlations, and risk of malignancy and neoplasm for AUS/FLUS. Furthermore, stratification, inter- and intra-observer variability, and the possibility of a switch to another category and its clinical consequences were reviewed.

RESULTS

Out of a total of 81,833 cases, AUS/FLUS accounted for 10.9%, with a 34% risk of malignancy. Persistent AUS/FLUS was found in 21.6% in repeated cytology. Cytohistological correlation was analysed from 16 studies (4,964 cases), revealing 10.4% as AUS/FLUS and a 21.5% risk of malignancy.

CONCLUSIONS

An AUS/FLUS category seems to be currently reasonable with clearly defined cytomorphological criteria which do not correspond unequivocally with those of the other categories. An AUS/FLUS category is justified and possible means of its improvement with immunohistochemistry, molecular analysis and imaging are discussed.

Recurrent thyroid papillary carcinoma in children under ten years old: report of two cases and literature review

Papillary thyroid carcinoma (PTC) in children under ten years old is very rare. To date, 18 cases of PTC in children under ten years old (including our two cases) have been reported in Korea. Here, we describe two cases of recurrent PTC with follicular variant and conventional type in an 8-year-old boy and a 7-year-old boy, respectively, and discuss clinicopathologic and molecular characteristics that differ in pediatric patients from adults.

Combined BRAF(V600E)- and SRC-inhibition induces apoptosis, evokes an immune response and reduces tumor growth in an immunocompetent orthotopic mouse model of anaplastic thyroid cancer

Anaplastic (ATC) and refractory papillary thyroid cancer (PTC) lack effective treatments. Inhibition of either oncogenic BRAF or SRC has marked anti-tumor effects in mouse models of thyroid cancer, however, neither drug induces notable apoptosis. Here we report that the SRC-inhibitor dasatinib further sensitizes BRAFV600E-positive thyroid cancer cells to the BRAFV600E-inhibitor PLX4720. Combined treatment with PLX4720 and dasatinib synergistically inhibited proliferation and reduced migration in PTC and ATC cells. Whereas PLX4720 did not induce robust apoptosis in thyroid cancer cells, combined treatment with dasatinib induced apoptosis in 4 of 6 lines. In an immunocompetent orthotopic mouse model of ATC, combined PLX4720 and dasatinib treatment significantly reduced tumor volume relative to PLX4720 treatment alone. Immune cell infiltration was increased by PLX4720 treatment and this effect was maintained in mice treated with both PLX4720 and dasatinib. Further, combined treatment significantly increased caspase 3 cleavage in vivo relative to control or either treatment alone. In conclusion, combined PLX4720 and dasatinib treatment induces apoptosis, increases immune cell infiltration and reduces tumor volume in a preclinical model of ATC, suggesting that the combination of these FDA-approved drugs may have potential for the treatment of patients with ATC or refractory PTC.