Genetic Analysis of 779 Advanced Differentiated and Anaplastic Thyroid Cancers

A New Way Out of the Predicament of Anaplastic Thyroid Carcinoma From Existing Data Analysis

BACKGROUND

Anaplastic thyroid carcinoma (ATC) is an endocrine tumor with a low incidence but a very poor prognosis. The vast majority of patients have a survival time of only three to six months, but a few survive for two years or more. In recent years, there have been major breakthroughs in targeted and immunotherapy in the field of oncology therapy. Although the preliminary study for ATC showed a promising prospect, more clinical trials are needed. It is the best approach to explore the measures that can improve survival time of ATC from the available clinical data, especially those with long survival.

METHODS

We report on an 82-year-old ATC patient who survived for 3 years and systematically review the clinical characteristics of 45 ATC patients with complete data from the two largest centers in northwest China. In particular, factors related to long-term survival were analyzed and summarized.

RESULTS

Three years prior, an 82-year-old woman was diagnosed with ATC by core needle biopsy following a physical examination. The thyroid tumor was resected within one month, and then the patient was treated with radiotherapy. The patient was still healthy after three years of follow-up. Analysis of prognostic factors for the 45 reviewed patients showed that those undergoing radical surgery (median overall survival (OS) = 472 days, p = 0.0261) and radiotherapy (median OS = 220 days, p = 0.0136) had better outcomes. In addition, patients younger than 65 years (median OS = 164.5 days, p = 0.0176) and with a lower tumor stage (IV A, median OS = 633.5 days, p = 0.0191) also had a better outcome.

CONCLUSION

ATC is a highly malignant tumor, but timely early diagnosis and standardized treatment with radical surgery and radiotherapy as the core can achieve good results. Some patients can achieve long-term survival.

Genomic and Transcriptomic Correlates of Thyroid Carcinoma Evolution after BRAF Inhibitor Therapy

Targeted inhibition of BRAF V600E achieves tumor control in a subset of advanced thyroid tumors. Nearly all tumors develop resistance, and some have been observed to subsequently undergo dedifferentiation. The molecular alterations associated with thyroid cancer dedifferentiation in the setting of BRAF inhibition are unknown. We analyzed targeted next-generation sequencing data from 639 advanced, recurrent and/or metastatic thyroid carcinomas, including 15 tumors that were treated with BRAF inhibitor drugs and had tissue sampled during or posttreatment, 8 of which had matched pretherapy samples. Pre- and posttherapy tissues from one additional patient were profiled with whole-exome sequencing and RNA expression profiling. Mutations in genes comprising the SWI/SNF chromatin remodeling complex and the PI3K-AKT-mTOR, MAPK, and JAK-STAT pathways all increased in prevalence across more dedifferentiated thyroid cancer histologies. Of 7 thyroid cancers that dedifferentiated after BRAF inhibition, 6 had mutations in these pathways. These mutations were mostly absent from matched pretreatment samples and were rarely detected in tumors that did not dedifferentiate. Additional analyses in one of the vemurafenib-treated tumors before and after anaplastic transformation revealed the emergence of an oncogenic PIK3CA mutation, activation of ERK signaling, dedifferentiation, and development of an immunosuppressive tumor microenvironment. These findings validate earlier preclinical data implicating these genetic pathways in resistance to BRAF inhibitors, and suggest that genetic alterations mediating acquired drug resistance may also promote thyroid tumor dedifferentiation. IMPLICATIONS: The possibility that thyroid cancer dedifferentiation may be attributed to selective pressure applied by BRAF inhibitor-targeted therapy should be investigated further.

What is the status of immunotherapy in thyroid neoplasms?

Immunotherapy has changed the treatment of patients with advanced cancer, with different phase III trials showing durable responses across different histologies. This review focuses on the preclinical and clinical evidence of potential predictive biomarkers of response and efficacy of immunotherapy in thyroid neoplasms. Programmed death-ligand 1 (PD-L1) staining by immunohistochemistry has shown higher expression in anaplastic thyroid cancer (ATC) compared to other subtypes. The tumor mutational burden in thyroid neoplasms is low but seems to be higher in ATC. Immune infiltrates in the tumor microenvironment (TME) differ between the different thyroid neoplasm subtypes. In general, differentiated thyroid cancer (DTC) has a higher number of tumor-associated lymphocytes and regulatory T cells (Tregs), while ATC and medullary thyroid cancer (MTC) display a high density of tumor-associated macrophages (TAMs). Nevertheless, results from clinical trials with immunotherapy as monotherapy or combinations have shown limited efficacy. Further investigation into new strategies aside from anti-cytotoxic T-lymphocyte antigen 4 (CTLA-4)/programmed death 1 (PD-1)/PD-L1 antibodies, validation of predictive biomarkers, and better population selection for clinical trials in thyroid neoplasms is more than needed in the near future.

Emerging Biomarkers in Thyroid Practice and Research

Simple Summary

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

Abstract

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

Epigenetic modification and BRAF gene mutation in thyroid carcinoma

Thyroid cancer remains the most prevailing endocrine malignancy, and a progressively increasing incidence rate has been observed in recent years, with 95% of thyroid cancer represented by differentiated thyroid carcinomas. The genetics and epigenetics of thyroid cancer are gradually increasing, and gene mutations and methylation changes play an important roles in its occurrence and development. Although the role of RAS and BRAF mutations in thyroid cancer have been partially clarified,but the pathogenesis and molecular mechanisms of thyroid cancer remain to be elucidated. Epigenetic modification refer to genetic modification that does not change the DNA sequence of a gene but causes heritable phenotypic changes in its expression. Epigenetic modification mainly includes four aspects: DNA methylation, chromatin remodelling, noncoding RNA regulation, and histone modification. This article reviews the importance of thyroid cancer epigenetic modification and BRAF gene mutation in the treatment of thyroid cancer.

Pan-Genomic Sequencing Reveals Actionable CDKN2A/2B Deletions and Kataegis in Anaplastic Thyroid Carcinoma

Anaplastic thyroid carcinoma (ATC) is a lethal malignancy characterized by poor response to conventional therapies. Whole-genome sequencing (WGS) analyses of this tumor type are limited, and we therefore interrogated eight ATCs using WGS and RNA sequencing. Five out of eight cases (63%) displayed cyclin-dependent kinase inhibitor 2A (CDKN2A) abnormalities, either copy number loss (n = 4) or truncating mutations (n = 1). All four cases with loss of the CDKN2A locus (encoding p16 and p14arf) also exhibited loss of the neighboring CDKN2B gene (encoding p15ink4b), and displayed reduced CDKN2A/2B mRNA levels. Mutations in established ATC-related genes were observed, including TP53, BRAF, ARID1A, and RB1, and overrepresentation of mutations were also noted in 13 additional cancer genes. One of the more predominant mutational signatures was intimately coupled to the activity of Apolipoprotein B mRNA-editing enzyme, the catalytic polypeptide-like (APOBEC) family of cytidine deaminases implied in kataegis, a focal hypermutation phenotype, which was observed in 4/8 (50%) cases. We corroborate the roles of CDKN2A/2B in ATC development and identify kataegis as a recurrent phenomenon. Our findings pinpoint clinically relevant alterations, which may indicate response to CDK inhibitors, and focal hypermutational phenotypes that may be coupled to improved responses using immune checkpoint inhibitors.

Bibliometric Insights in Advances of Anaplastic Thyroid Cancer: Research Landscapes, Turning Points, and Global Trends

Background

Thyroid cancers are the most common endocrine malignancies with a dramatic increase in incidences. Anaplastic thyroid cancer is a rare but deadly form among thyroid cancers. To better understand of this field, we assessed the global scientific outputs and tried to depict its overview via bibliometric methods.

Methods

Approximately 1,492 science publications published between 1997 and 2020 were included by systematic retrieval in the WoS database. The general information of them was characterized, and the developmental skeleton and research frontiers were explored.

Results

The article number in this field has been increasing in the past 24 years. North America, East Asia, and Western Europe have reached remarkable achievements. Mutations of BARF and TERT and their downstream pathways have attracted researchers’ attention, where genetic diagnosis provides new clinical insight and several targeted therapeutic approaches have been on the clinical trial.

Conclusions

Numerous efforts have been made to figure out gene expression reprogramming of anaplastic thyroid cancer and key mechanism in driving its dedifferentiation, invasion and migration process. Targeted therapy, immunotherapy, and systematic combination therapy are the recent current research hotspots. These results provide insightful clues for the funding direction and the potential breakthrough direction of the anaplastic thyroid cancer study.

Primary Versus Secondary Anaplastic Thyroid Carcinoma: Perspectives from Multi-institutional and Population-Level Data

Primary (or de novo) anaplastic thyroid carcinoma (ATC) is ATC without pre-existing history of differentiated thyroid carcinoma (DTC) and no co-existing DTC foci at the time of diagnosis. Secondary ATC is diagnosed if the patient had a history of DTC or co-existing DTC components at time of diagnosis. This study aimed to investigate the incidence, clinical presentations, outcomes, and genetic backgrounds of primary versus secondary ATCs. We searched for ATCs in our institutional databases and the Surveillance, Epidemiology, and End Result (SEER) database. We also performed a systematic review and meta-analysis to analyze the genetic alterations of primary and secondary ATCs. From our multi-institutional database, 22 primary and 23 secondary ATCs were retrieved. We also identified 620 and 24 primary and secondary ATCs in the SEER database, respectively. Compared to primary ATCs, secondary ATCs were not statistically different in terms of demographic, clinical manifestations, and patient survival. The only clinical discrepancy between the two groups was a significantly larger tumor diameter of the primary ATCs. The prevalence of TERT promoter, PIK3CA, and TP53 mutations was comparable between the two subtypes. In comparison to primary ATCs, however, BRAF mutations were more prevalent (OR = 4.70; 95% CI = 2.84-7.78) whereas RAS mutations were less frequent (OR = 0.43; 95% CI = 0.21-0.85) in secondary tumors. In summary, our results indicated that de novo and secondary ATCs might share many potential developmental steps, but there are other factors that suggest distinct developmental pathways.

Poorly differentiated thyroid carcinoma arising from a lithium-induced goiter in a patient with schizophrenia: a case report

BACKGROUND

Lithium use causes goiter by increasing serum thyroid-stimulating hormone levels through the inhibition of thyroid hormone release. However, there are no reports of poorly differentiated thyroid carcinoma resulting from lithium-induced goiter. Herein, we report the case of a patient with schizophrenia who developed poorly differentiated thyroid carcinoma arising from a lithium-induced goiter.

CASE PRESENTATION

A 61-year-old woman who was taking lithium for schizophrenia, visited the thyroid-endocrine center with a 10 × 12 cm anterior neck mass. She had a slowly growing goiter approximately 30 years ago; however, when she came to the hospital for diabetes diagnosis 2 years ago, she had no accompanying symptoms and refused evaluation. Three months before her visit, her dysphagia and dyspnea worsened as the size of her goiter increased rapidly. A neck ultrasound and enhanced thyroid computed tomography (CT) examination revealed a 10.9 × 9.2 × 12.8 cm size multi-lobulated mass on the right thyroid gland, leading to a leftward deviation of the trachea. Diagnostic total thyroidectomy was performed, and microscopic findings and immunohistochemical staining results indicated poorly differentiated thyroid carcinoma (PDTC) in the right thyroid mass. Mutation analyses for BRAF and the telomerase reverse transcriptase (TERT) promoter was performed. No BRAF gene mutations were detected; however, TERT promoter C228T point mutation was present in the PDTC. The patient underwent radioactive iodine therapy two months after the surgery. At a recent follow-up 4 months postoperatively, she was taking thyroid hormone replacement and remained in a relatively good health with a serum thyroglobulin level of 0.55 ng/ml.

CONCLUSIONS

Thyroid examination of psychiatric patients who develop goiter due to long-term lithium treatment should be monitored regularly, and appropriate investigations and surgery should be performed in a timely manner if the goiter is growing rapidly.

Genome-wide identification of m6A-associated functional SNPs as potential functional variants for thyroid cancer

m6A methylation has been demonstrated to be one of the most important epigenetic regulation mechanisms in cell differentiation and cancer development especially m6A derived diagnostic and prognostic biomarkers have been identified in the past several years. However, systemic investigation to the interaction between germline single-nucleotide polymorphisms (SNPs) and m6A has not been conducted yet. In this study, we collected previous identified significant thyroid cancer associated SNPs from UKB cohort (358 cases and 407,399 controls) and ICR cohort (3,001 patients and 287,550 controls) and thyroid eQTL (sample size = 574 from GTEx project) and m6A-SNP (N = 1,678,126) were applied to prioritize the candidate SNPs. Finally, five candidate genes (PLEKHA8, SMUG1, CDC123, RMI2, ACSM5) were identified to be thyroid cancer associated m6A-related genetic susceptibility. Loss and gain function studies of m6A writer proteins confirm that ACSM5 is regulated by m6A methylation of mRNA. Moreover, ACSM5 is downregulated in thyroid cancer and inversely correlated with PTC malignancy and patient survival. Together, our study highlight mRNA-seq and m6A-seq double analysis provided a novel approach to identify cancer biomarkers and understanding the heterogeneity of human cancers.

Targeting transcriptional regulators for treatment of anaplastic thyroid cancer

Dysregulation of genes perpetuates cancer progression. During carcinogenesis, cancer cells acquire dependency of aberrant transcriptional programs (known as “transcription addiction”) to meet the high demands for uncontrolled proliferation. The needs for particular transcription programs for cancer growth could be cancer-type-selective. The dependencies of certain transcription regulators could be exploited for therapeutic benefits. Anaplastic thyroid cancer (ATC) is an extremely aggressive human cancer for which new treatment modalities are urgently needed. Its resistance to conventional treatments and the lack of therapeutic options for improving survival might have been attributed to extensive genetic heterogeneity due to subsequent evolving genetic alterations and clonal selections during carcinogenesis. Despite this genetic complexity, mounting evidence has revealed a characteristic transcriptional addiction of ATC cells resulting in evolving diverse oncogenic signaling for cancer cell survival. The transcriptional addiction has presented a huge challenge for effective targeting as shown by the failure of previous targeted therapies. However, an emerging notion is that many different oncogenic signaling pathways activated by multiple upstream driver mutations might ultimately converge on the transcriptional responses, which would provide an opportunity to target transcriptional regulators for treatment of ATC. Here, we review the current understanding of how genetic alterations in cancer distorted the transcription program, leading to acquisition of transcriptional addiction. We also highlight recent findings from studies aiming to exploit the opportunity for targeting transcription regulators as potential therapeutics for ATC.

Analysis of Prognostic Alternative Splicing Reveals the Landscape of Immune Microenvironment in Thyroid Cancer

Background

The incidence of thyroid cancer (THCA) continues to increase in recent decades. Accumulating evidence showed that the unbalanced alternative splicing (AS) promotes the occurrence of cancers and leads to poor prognosis of patients. However, the research on alternative splicing events in THCA is lacking, and its underlying mechanism is not fully understood. This study identifies a novel prognostic signature based on AS events to reveal the relationship of AS with tumor immune microenvironment.

Methods

Based on the AS data, transcriptional data, and clinical information, the differentially expressed alternative splicings (DEASs) were screened out. Least absolute shrinkage and selection operator (LASSO) regression and multi-Cox regression analyses were employed to identify prognostic results related to AS events and establish a prognostic signature. The predictive ability of the signature was assessed by Kaplan-Meier (K-M) survival curve, risk plots, and receiver operating characteristic (ROC) curves. Furthermore, correlations between tumor-infiltrating immune cells, immune checkpoints, immune score and prognostic signature were analyzed.

Results

According to the LASSO regression analysis, a total of five AS events were selected to construct the signature. K-M survival curve showed that the higher the risk score, the worse the OS of the patients. Risk plots further confirmed this result. ROC curves indicated the high predictive efficiency of the prognostic signature. As for tumor immune microenvironment, patients in the high-risk group had a higher proportion of immune cells, including plasma cell, CD8+ T cell, macrophages (M0 and M2), and activated dendritic cell. Immune checkpoint proteins, such as PDCD1LG2, HAVCR2, CD274, etc., were significantly higher in the high-risk group. We also found that the ESTIMATE score, stromal score, and immune score were lower in the high-risk group, while the result of tumor purity was the opposite.

Conclusions

Collectively, a prognostic signature consisting of five AS events in THCA was established. Furthermore, there was an inextricable correlation between immune cell infiltration, immune checkpoint proteins, and AS events. This study will provide a basis for THCA immunotherapy in the future.

Novel Inhibitor-Based Therapies for Thyroid Cancer-An Update

Thyroid cancers (TCs) are the most common tumors of the endocrine system and a constant rise in the number of TC cases has been observed for the past few decades. TCs are one of the most frequent tumors in younger adults, especially in women, therefore early diagnosis and effective therapy are especially important. Ultrasonography examination followed by fine needle biopsy have become the gold standard for diagnosis of TCs, as these strategies allow for early-stage detection and aid accurate qualification for further procedures, including surgical treatment. Despite all the advancements in detection and treatment of TCs, constant mortality levels are still observed. Therefore, a novel generation line of targeted treatment strategies is being developed, including personalized therapies with kinase inhibitors. Recent molecular studies on TCs demonstrate that kinase inhibitor-based therapies might be considered as the most promising. In the past decade, new kinase inhibitors with different mechanisms of action have been reported and approved for clinical trials. This review presents an up-to-date picture of new approaches and challenges of inhibitor-based therapies in treatment of TCs, focusing on the latest findings reported over the past two years.

Synergistic effect of metformin and vemurufenib (PLX4032) as a molecular targeted therapy in anaplastic thyroid cancer: an in vitro study

BACKGROUND

Survival rate of patients affected with anaplastic thyroid carcinoma (ATC) is less than 5% with current treatment. In ATC, BRAF^V600E mutation is the major mutation that results in the transformation of normal cells in to an undifferentiated cancer cells via aberrant molecular signaling mechanisms. Although vemurufenib is a selective oral drug for the BRAF^V600E mutant kinase with a response rate of nearly 50% in metastatic melanoma, our study has showed resistance to this drug in ATC. Hence the rationale of the study is to explore combinational therapeutic effect to improve the efficacy of vemurafenib along with metformin. Metformin, a diabetic drug is an AMPK activator and has recently proved to be involved in preventing or treating several types of cancer.

METHODS AND RESULTS

Using iGEMDock software, a protein-ligand interaction was successful between Metformin and TSHR (receptor present in the thyroid follicular cells). Our study demonstrates that combination of vemurufenib with metformin has synergistic anti-cancer effects which was evaluated through MTT assay (cytotoxicity), colony formation assay (antiproliferation evaluation) and suppressed the progression of ATC cells growth by inducing significant apoptosis, proven by Annexin V-FITC assay (Early Apoptosis Detection). Downregulation of ERK signaling, upregulation of AMPK pathway and precision in epithelial-mesenchymal transition (EMT) pathway which were assessed by RT-PCR and Western blot provide the evidence that the combination of drugs involved in the precision of altered molecular signaling Further our results suggest that Metformin act as a demethylating agent in anaplastic thyroid cancer cells by inducing the expression of NIS and TSHR. Our study for the first time explored cAMP signaling in ATC wherein cAMP signaling is downregulated due to decrease in intracellular cAMP level upon metformin treatment.

CONCLUSION

To conclude, our findings demonstrate novel therapeutic targets and treatment strategies for undifferentiated ATC.

Molecular Signature Expands the Landscape of Driver Negative Thyroid Cancers

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

The prevalence of DNA microsatellite instability in anaplastic thyroid carcinoma - systematic review and discussion of current therapeutic options

INTRODUCTION

Anaplastic thyroid carcinoma is a rare, rapidly progressing, highly aggressive thyroid malignancy. Responses to immune checkpoint inhibitors in mismatch repair-deficient/microsatellite instability-high tumours of other locations have shown promising results, and with the extended approval of the PD-1 receptor inhibitor pembrolizumab by the Food and Drug Administration, also anaplastic thyroid cancer (ATC) requires analysis for microsatellite instability (MSI) status.

MATERIAL AND METHODS

Systematic research for relevant literature was conducted in different databases. Prevalence, detection methods, and the potential prognostic/predictive value of MSI in view of the available targeted therapies were of special focus.

RESULTS

Selected citations revealed the prevalence of MSI in 7.4%, with mutations in the MSH2 gene (33%) being the most frequent, followed by MSH6 (25%) and MLH1 (16.7%) occurring in the following combinations: MLH1-MSH2 (8.3%), MSH2-MSH6 (8.3%), and MLH3-MSH5 (8.3%). No mutations in the PMS2 gene were reported. Sixty-six co-mutations in 9 cases were found, with TP53 (88.9%), NF1 (44.4 %), ATM (33.3%), and RB1 (33.3%) being the most frequent. No RAS mutations were noted. Survival ranged between 2.8 and 48 months, and patient age varied between 49 and 84 years. There are insufficient and heterogenous data concerning the predictive or prognostic value of mismatch repair-deficient/microsatellite instability status.

CONCLUSIONS

Tumour molecular profiling is fundamental in ATC for predictive, prognostic, as well as therapeutic reasons, and analysis of MSI status is strongly suggested because a small subgroup show the MSI signature and might profit from recently approved targeted therapies.

[Molecular genotyping in refractory thyroid cancers in 2021: When, how and why? A review from the TUTHYREF network]

Refractory thyroid cancers include radio-iodine-refractory cancers, metastatic or locally advanced unresectable medullary and anaplastic thyroid cancers. Their management has been based for several years on the use of multi-target kinase inhibitors, with anti-angiogenic action, with the exception of anaplastic cancers usually treated with chemo- and radiotherapy. The situation has recently evolved due to the availability of molecular genotyping techniques allowing the discovery of rare but targetable molecular abnormalities. New treatment options have become available, more effective and less toxic than the previously available multi-target kinase inhibitors. The management of refractory thyroid cancers is therefore becoming more complex both at a diagnosis level with the need to know when, how and why to look for these molecular abnormalities but also at a therapeutic level, innovative treatments being hardly accessible. The cost of molecular analyzes and the access to treatments need also to be homogenized because disparities could lead to inequality of care at a national or international level. Finally, the strategy of identifying molecular alterations and treating these rare tumors reinforces the importance of a discussion in a multidisciplinary consultation meeting.

CSPG4 Is a Potential Therapeutic Target in Anaplastic Thyroid Cancer

Background: Anaplastic thyroid cancer (ATC) is a rare cancer with poor prognosis and few treatment options. The objective of this study was to investigate new immune-associated therapeutic targets by identifying ATC-derived, human leukocyte antigen (HLA) class II-presenting peptides. One protein that generated multiple peptides in ATC was chondroitin sulfate-proteoglycan-4 (CSPG4), a transmembrane proteoglycan with increased expression in multiple aggressive cancers, but not yet investigated in ATC. Methods: We applied autologous peripheral blood T cells to ATC patient-derived xenografted mice to examine whether ATC induces a tumor-specific T cell response. We then identified peptide antigens eluted from the HLA-DQ complex in ATC patient-derived cells using mass spectrometry, detecting abundant CSPG4-derived peptides specific to the ATC sample. Next, we analyzed the surface expression level of CSPG4 in thyroid cancer cell lines and primary cell culture using flow cytometry. In addition, we used immunohistochemistry to compare the expression level and localization of the CSPG4 protein in ATC, papillary thyroid cancer, and normal thyroid tissue. We then investigated the correlation between CSPG4 expression and clinicopathological features of patients with thyroid cancer. Results: We found that ATC tissue had a high level of HLA-DQ expression and that the patient's CD4⁺ T cells showed activation when exposed to ATC. By eluting the HLA-DQ complex of ATC tissue, we found that CSPG4 generated one of the most abundant and specific peptides. CSPG4 expression at the cell surface of thyroid cancer was also significantly high when determined by flow cytometry, with the majority of ATC cell lines exhibiting ∼10-fold higher mean fluorescence intensity. Furthermore, most ATC patient cases expressed CSPG4 in the cytoplasm or membrane of the tumor cells. CSPG4 expression was correlated with tumor size, extrathyroidal extension, and intercellular adhesion molecule-1 (ICAM-1) circumferential expression. CSPG4 mRNA overexpression was associated with worse overall survival in patients with ATC and poorly differentiated thyroid cancer. Conclusions: CSPG4 expression is significantly elevated in aggressive thyroid cancers, with a strong correlation with a poor prognosis. The vast number of HLA-DQ eluted CSPG4 peptides was identified in ATC, demonstrating the potential of CSPG4 as a novel immunotherapeutic target for ATC.

Progress in Treating Advanced Thyroid Cancers in the Era of Targeted Therapy

Background: Thyroid cancer is a common malignancy whose detection has increased significantly in past decades. Most of the increased incidence is due to detection of early well-differentiated thyroid cancer, but the incidence of more advanced thyroid cancers has increased as well. Recent methodological advancements have allowed for a deep understanding of the molecular underpinnings of the various types of thyroid cancer. Summary: Thyroid cancers harbor a high frequency of potential druggable molecular alterations, including the highest frequency of oncogenic driver kinase fusions seen across all solid tumors. Analyses of poorly differentiated and anaplastic thyroid carcinoma confirmed that these tumors develop from more well-differentiated follicular-derived thyroid cancers through acquired additional mutations. The recognition of driver genomic alterations in thyroid cancers not only predicts tumor phenotype but also now can inform treatment approaches. Conclusions: Major progress in understanding the oncogenic molecular underpinnings across the array of thyroid cancers has led to considerable gains in gene-specific systemic therapies for many cancers. This article focuses on the molecular characteristics of aggressive follicular-derived thyroid cancers and medullary thyroid cancer and highlights advancements in treating thyroid cancer in the era of targeted therapy.

Advances in Functional Imaging of Differentiated Thyroid Cancer

Simple Summary

Since the 1940s, radioactive iodine has been used for functional imaging and for treating patients with differentiated thyroid cancer (DTC). During this long-lasting experience, the use of iodine isotopes evolved, especially during the last years due to improved knowledge of thyroid cancer biology and improved performances of imaging tools. The present review summarizes recent advances in the field of functional imaging and theragnostic approach of DTC.

Abstract

The present review provides a description of recent advances in the field of functional imaging that takes advantage of the functional characteristics of thyroid neoplastic cells (such as radioiodine uptake and FDG uptake) and theragnostic approach of differentiated thyroid cancer (DTC). Physical and biological characteristics of available radiopharmaceuticals and their use with state-of-the-art technologies for diagnosis, treatment, and follow-up of DTC patients are depicted. Radioactive iodine is used mostly with a therapeutic intent, while PET/CT with ¹⁸F-FDG emerges as a useful tool in the diagnostic management and complements the use of radioactive iodine. Beyond ¹⁸F-FDG PET/CT, other tracers including ¹²⁴I, ¹⁸F-TFB and ⁶⁸Ga-PSMA, and new methods such as PET/MR, might offer new opportunities in selecting patients with DTC for specific imaging modalities or treatments.

Emerging systemic antitarget treatment for differentiated thyroid carcinoma

PURPOSE OF REVIEW

We review the new systemic treatment strategies for differentiated thyroid carcinoma, as well as the acquaintance of its molecular biology.

RECENT FINDINGS

Multiple kinase inhibitor drugs have become the standard therapy for thyroid cancer, albeit several adverse effects. In the last few years, new molecules have raised with an overall safety profile. Most of them, are considered targeted therapies directed toward driven-molecules alterations, such as neurotrophic tyrosine kinase receptor (NTRK) inhibitors for NTRK-fusion thyroid cancer and rearranged during transfection (RET) inhibitors for RET-fusion thyroid cancer. Recently, promising outcomes and safety data have been presented. Furthermore, other novel strategies for advanced thyroid carcinoma are currently investigated in clinical trials.The ability to provide precision medicine to patients in routine clinical settings depends on the availability of molecular profiling test at their cancer centers. The impossibility to perform molecular characterization could turn out to be a diagnostic and treatment limitation for some patients.

SUMMARY

The treatment of advanced differentiated thyroid carcinoma has undergone rapid evolution in the last decade. An emerging treatment era is coming. From now to then, we will need to face the different types of diagnostic tools for molecular characterization, their interpretation and, finally the access to targeted therapies.

The mutation profile of differentiated thyroid cancer coexisting with undifferentiated anaplastic cancer resembles that of anaplastic thyroid cancer but not that of archetypal differentiated thyroid cancer

Differentiated thyroid cancer (DTC) has one of the lowest cancer mutational burdens, while anaplastic thyroid cancer (ATC) has a much higher mutation frequency. A fraction of ATC has an associated differentiated component, which suggests the coevolution of both cancers. Here, we aimed to compare mutation frequency in coexisting ATC and DTC diagnosed concurrently in the same thyroid gland (3 cases) as well as in archetypal DTC and ATC alone (5 cases each). Single-nucleotide variations (SNV) and copy number variations (CNV) were analyzed in each case based on the next-generation sequencing data. We found a similar extent of mutational events, both SNV and CNV, in undifferentiated and differentiated components of thyroid cancers coexisting in one patient. The magnitude of these mutations was comparable to the level of mutations observed in ATC alone; yet, it was much higher than in archetypal DTC. This suggested that, despite histopathological features of differentiated tumors, molecular characteristics of such cancers coexisting with ATC and archetypal DTC could be significantly different. Pairwise comparison of mutational profiles of coexisting cancers enabled assumption on the possible evolution of both components, which appeared distinct in 3 analyzed cases. This included independent development of ATC and DTC diagnosed concurrently in two lobes of the same thyroid, as well as the development of anaplastic and differentiated cancer from the common ancestor that putatively gained a key driver mutation (BRAF^V600E or KRAS^Q61R), which was followed either by early or late molecular separation of both cancers.

Targeted genomic analysis of 364 adrenocortical carcinomas

Despite recent advances in elucidating molecular pathways underlying adrenocortical carcinoma (ACC), this orphan malignancy is associated with poor survival. Identification of targetable genomic alterations is critical to improve outcomes. The objective of this study was to characterize the genomic profile of a large cohort of patient ACC samples to identify actionable genomic alterations. Three hundred sixty-four individual patient ACC tumors were analyzed. The median age of the cohort was 52 years and 60.9% (n = 222) were female. ACC samples had common alterations in epigenetic pathways with 38% of tumors carrying alterations in genes involved in histone modification, 21% in telomere lengthening, and 21% in SWI/SNF complex. Tumor suppressor genes and WNT signaling pathway were each mutated in 51% of tumors. Fifty (13.7%) ACC tumors had a genomic alteration in genes involved in the DNA mismatch repair (MMR) pathway with many tumors also displaying an unusually high number of mutations and a corresponding MMR mutation signature. In addition, genomic alterations in several genes not previously associated with ACC were observed, including IL7R, LRP1B, FRS2 mutated in 6, 8 and 4% of tumors, respectively. In total, 58.5% of ACC (n = 213) had at least one potentially actionable genomic alteration in 46 different genes. As more than half of ACC have one or more potentially actionable genomic alterations, this highlights the value of targeted sequencing for this orphan cancer with a poor prognosis. In addition, significant incidence of MMR gene alterations suggests that immunotherapy is a promising therapeutic for a considerable subset of ACC patients.

Clinical Utility of Circulating Cell-Free DNA Mutations in Anaplastic Thyroid Carcinoma

Background: Anaplastic thyroid carcinoma (ATC) is an aggressive thyroid cancer that requires a rapid diagnosis and treatment to achieve disease control. Gene mutation profiling of circulating cell-free DNA (cfDNA) in peripheral blood may help to facilitate early diagnosis and treatment selection. The relatively rapid turnaround time compared with conventional tumor mutation testing is a major advantage. The objectives of this study were to examine the concordance of ATC-related mutations detected in cfDNA with those detected in the corresponding tumor tissue, and to determine the prognostic significance of cfDNA mutations in ATC patients. Methods: The ATC patients who were diagnosed and treated at The University of Texas MD Anderson Cancer Center between January 2015 and February 2018 and who had cfDNA testing were included in this study. cfDNA was collected by blood draw and was analyzed by next-generation sequencing (NGS) using the Guardant360-73 gene platform. Results: A total of 87 patients were included in the study. The most frequently mutated genes detected in cfDNA were TP53, BRAF, and PIK3CA. In 28 treatment naive ATC patients, the concordance rate of detected mutations in TP53, BRAFV600E, and PIK3CA between cfDNA and matched tissue NGS was 82.1%, 92.9%, and 92.9%, respectively. Patients with a PIK3CA mutation detected on cfDNA had worse overall survival (OS) (p = 0.03). This association was observed across various treatment modalities, including surgery, cytotoxic chemotherapy, radiation, and BRAF inhibitor (BRAFi) therapy. With regard to treatment, BRAFi therapy significantly improved ATC OS (p = 0.003). Conclusions: cfDNA is a valuable tool to evaluate a tumor's molecular profile in ATC patients. We identified high concordance rates between the gene mutations identified via cfDNA analysis and those identified from the NGS of the corresponding tumor tissue sequencing. Identified mutations in cfDNA can potentially provide timely information to guide treatment selection and evaluate the prognosis in patients with ATC.

Management of Anaplastic and Recurrent Differentiated Thyroid Cancer: Indications for Surgical Resection, Molecular Testing, and Systemic Therapy

Differentiated and anaplastic thyroid cancer are tumors derived from follicular thyroid cancers and are clinically and genetically distinct. Treatment of these tumors has evolved over the past decade, with 6 drugs/drug combinations that are US Food and Drug Administration approved.

Afirma Genomic Sequencing Classifier and Xpression Atlas Molecular Findings in Consecutive Bethesda III-VI Thyroid Nodules

CONTEXT

Broad genomic analyses among thyroid histologies have been described from relatively small cohorts.

OBJECTIVE

Investigate the molecular findings across a large, real-world cohort of thyroid fine-needle aspiration (FNA) samples.

DESIGN

Retrospective analysis of RNA sequencing data files.

SETTING

Clinical Laboratory Improvement Amendments laboratory performing Afirma Genomic Sequencing Classifier (GSC) and Xpression Atlas (XA) testing.

PARTICIPANTS

A total of 50 644 consecutive Bethesda III-VI nodules.

INTERVENTION

None.

MAIN OUTCOME MEASURES

Molecular test results.

RESULTS

Of 48 952 Bethesda III/IV FNAs studied, 66% were benign by Afirma GSC. The prevalence of BRAF V600E was 2% among all Bethesda III/IV FNAs and 76% among Bethesda VI FNAs. Fusions involving NTRK, RET, BRAF, and ALK were most prevalent in Bethesda V (10%), and 130 different gene partners were identified. Among small consecutive Bethesda III/IV sample cohorts with one of these fusions and available surgical pathology excision data, the positive predictive value of an NTRK or RET fusion for carcinoma or noninvasive follicular thyroid neoplasm with papillary-like nuclear features was >95%, whereas for BRAF and ALK fusions it was 81% and 67%, respectively. At least 1 genomic alteration was identified by the expanded Afirma XA panel in 70% of medullary thyroid carcinoma classifier-positive FNAs, 44% of Bethesda III or IV Afirma GSC suspicious FNAs, 64% of Bethesda V FNAs, and 87% of Bethesda VI FNAs.

CONCLUSIONS

This large study demonstrates that almost one-half of Bethesda III/IV Afirma GSC suspicious and most Bethesda V/VI nodules had at least 1 genomic variant or fusion identified, which may optimize personalized treatment decisions.

Translational Utility of Liquid Biopsies in Thyroid Cancer Management

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

NTRK- and RET-fusion-directed therapy in pediatric thyroid cancer yields a tumor response and radioiodine uptake

BACKGROUND

Molecular characterization in pediatric papillary thyroid cancer (PTC), distinct from adult PTC, is important for developing molecular targeted therapies for progressive 131I-refractory PTC.

METHODS

PTC samples from 106 pediatric patients (age: 4.3-19.8 years; 21 boys) who attended Seoul National University Hospital (January 1983-March 2020) were available for genomic profiling. Previous transcriptome data from 125 adult PTCs were used for comparison.

RESULTS

Genetic drivers were found in 80 tumors; 31 with fusion oncogenes (RET in 21, ALK in 6, and NTRK1/3 in 4), 47 with point mutations (BRAFV600E in 41, TERTC228T in 2, and DICER1 variants in 5), and 2 with amplifications. Fusion-oncogene PTCs, predominantly detected in younger patients, presented with a more advanced stage and showed more recurrent or persistent disease than BRAFV600E PTCs, which were detected mostly in adolescents. Pediatric fusion PTCs (in those aged < 10 years) showed lower expression of thyroid differentiation genes, including SLC5A5, than adult fusion PTCs. Two girls with progressive 131I-refractory lung metastases harboring a TPR-NTRK1 or CCDC6-RET fusion received fusion-targeted therapy; larotrectinib and selpercatinib decreased the tumor extent and restored radioiodine uptake. The girl with the CCDC6-RET fusion received 131I therapy combined with selpercatinib, leading to a tumor response. In vitro 125I uptake and 131I clonogenic assays showed that larotrectinib inhibited growth and restored radioiodine avidity.

CONCLUSIONS

In pediatric fusion-oncogene PTC cases with 131I-refractory advanced disease, selective fusion-directed therapy may restore radioiodine avidity and lead to a dramatic tumor response, underscoring the importance of molecular testing in pediatric PTC patients.

FUNDING

The Ministry of Science, ICT & Future Planning (grant number NRF-2016R1A2B4012417 91 and 2019R1A2C2084332), the Ministry of Health & Welfare, Republic of Korea (grant number 92 H14C1277), the Ministry of Education (grant number 2020R1A6A1A03047972), and the Seoul 93 National University Hospital Research Fund (grant number 04-2015-0830).

Poorly Differentiated and Anaplastic Thyroid Cancer: Insights into Genomics, Microenvironment and New Drugs

Simple Summary

In the last decades, many researchers produced promising data concerning genetics and tumor microenvironment of poorly differentiated thyroid cancer (PDTC) and anaplastic thyroid cancer (ATC). They are trying to tear the veil covering these orphan cancers, suggesting new therapeutic weapons as single or combined therapies.

Abstract

PDTC and ATC present median overall survival of 6 years and 6 months, respectively. In spite of their rarity, patients with PDTC and ATC represent a significant clinical problem, because of their poor survival and the substantial inefficacy of classical therapies. We reviewed the newest findings about genetic features of PDTC and ATC, from mutations occurring in DNA to alterations in RNA. Therefore, we describe their tumor microenvironments (both immune and not-immune) and the interactions between tumor and neighboring cells. Finally, we recapitulate how this upcoming evidence are changing the treatment of PDTC and ATC.

Neutrophil-to-Lymphocyte Ratio as a Prognostic Marker for Anaplastic Thyroid Cancer Treated With Lenvatinib

BACKGROUND/AIM

Lenvatinib is one of the few options for patients with anaplastic thyroid cancer (ATC). However, tumor markers for ATC treated with lenvatinib is lacking. The aim of this study was to explore whether the neutrophil-to-lymphocyte ratio (NLR) can be a tumor marker for ATC treated with lenvatinib.

PATIENTS AND METHODS

We retrospectively analyzed the prognostic significance of the NLR in 13 ATC patients treated with lenvatinib.

RESULTS

The disease control rate was better in patients with lower NLR (<8; 89%) than higher NLR (≥8; 25%) (p=0.05). Median progression-free survival and overall survival were longer in patients with lower NLR than higher NLR (4.0 vs. 1.6 months, p<0.05; and 10.2 vs. 3.8 months, p<0.05, respectively). Patients whose NLR on day 14 decreased compared to baseline had a slightly higher overall response rate than patients without NLR decrease (42.9% vs. 0%, p=0.19).

CONCLUSION

The baseline NLR is a potential prognostic marker, and the change of NLR can be an early indicator of response for ATC patients treated with lenvatinib.

Precision Medicine in Oncology: A Review of Multi-Tumor Actionable Molecular Targets with an Emphasis on Non-Small Cell Lung Cancer

Precision medicine is essential for the modern care of a patient with cancer. Comprehensive molecular profiling of the tumor itself is necessary to determine the presence or absence of certain targetable abnormalities or biomarkers. In particular, lung cancer is a disease for which targetable genomic alterations will soon guide therapy in the majority of cases. In this comprehensive review of solid tumor-based biomarkers, we describe the genomic alterations for which targeted agents have been approved by the United States Food and Drug Administration (FDA). While focusing on alterations leading to approvals in a tumor-agnostic fashion (MSI-h, TMB-h, NTRK) and on those alterations with approvals in multiple malignancies (BRAF, ERBB2, RET, BRCA, PD-L1), we also describe several biomarkers or indications that are likely to lead to an approved drug in the near future (e.g., KRAS G12C, PD-L1 amplification, HER2 overexpression in colon cancer, HER2 mutations in lung cancer). Finally, we detail the current landscape of additional actionable alterations (EGFR, ALK, ROS1, MET) in lung cancer, a biomarker-rich malignancy that has greatly benefitted from the precision oncology revolution.

E-Cadherin expression in human tumors: a tissue microarray study on 10,851 tumors

BACKGROUND

The E-Cadherin gene (CDH1, Cadherin 1), located at 16q22.1 encodes for a calcium-dependent membranous glycoprotein with an important role in cellular adhesion and polarity maintenance.

METHODS

To systematically determine E-Cadherin protein expression in normal and cancerous tissues, 14,637 tumor samples from 112 different tumor types and subtypes as well as 608 samples of 76 different normal tissue types were analyzed by immunohistochemistry in a tissue microarray format.

RESULTS

E-Cadherin was strongly expressed in normal epithelial cells of most organs. From 77 tumor entities derived from cell types normally positive for E-Cadherin, 35 (45.5%) retained at least a weak E-Cadherin immunostaining in ≥99% of cases and 61 (79.2%) in ≥90% of cases. Tumors with the highest rates of E-Cadherin loss included Merkel cell carcinoma, anaplastic thyroid carcinoma, lobular carcinoma of the breast, and sarcomatoid and small cell neuroendocrine carcinomas of the urinary bladder. Reduced E-Cadherin expression was linked to higher grade (p = 0.0009), triple negative receptor status (p = 0.0336), and poor prognosis (p = 0.0466) in invasive breast carcinoma of no special type, triple negative receptor status in lobular carcinoma of the breast (p = 0.0454), advanced pT stage (p = 0.0047) and lymph node metastasis in colorectal cancer (p < 0.0001), and was more common in recurrent than in primary prostate cancer (p < 0.0001). Of 29 tumor entities derived from E-Cadherin negative normal tissues, a weak to strong E-Cadherin staining could be detected in at least 10% of cases in 15 different tumor entities (51.7%). Tumors with the highest frequency of E-Cadherin upregulation included various subtypes of testicular germ cell tumors and renal cell carcinomas (RCC). E-Cadherin upregulation was more commonly seen in malignant than in benign soft tissue tumors (p = 0.0104) and was associated with advanced tumor stage (p = 0.0276) and higher grade (p = 0.0035) in clear cell RCC, and linked to advanced tumor stage (p = 0.0424) and poor prognosis in papillary RCC (p ≤ 0.05).

CONCLUSION

E-Cadherin is consistently expressed in various epithelial cancers. Down-regulation or loss of E-Cadherin expression in cancers arising from E-Cadherin positive tissues as well as E-Cadherin neo-expression in cancers arising from E-Cadherin negative tissues is linked to cancer progression and may reflect tumor dedifferentiation.

Oncogenic Mutations in PI3K/AKT/mTOR Pathway Effectors Associate with Worse Prognosis in BRAFV600E -Driven Papillary Thyroid Cancer Patients

PURPOSE

The extent to which routine genomic sequencing can identify relevant secondary genomic alterations among BRAF^V600E -mutant papillary thyroid carcinoma (PTC) is unknown. Such markers would prove highly valuable for prognostic purposes.

EXPERIMENTAL DESIGN

We reviewed clinicopathologic data of 225 patients with BRAF^V600E -mutant PTC and integrated them with genomic data derived from targeted next-generation sequencing (NGS) on tumor specimens. We defined patient subgroups based on bona fide secondary oncogenic events (separate from BRAF^V600E ) and compared their clinical features and outcomes with those without additional oncogenic alterations.

RESULTS

Additional oncogenic alterations were identified in 16% of tumors. Patients in the "BRAF+additional mutations" group were more likely to be at high American Thyroid Association (ATA) risk of recurrence (48.6% vs. 17.6%; P = 0.0009), had larger baseline tumor (2.7 vs. 1.9 cm; P = 0.0005) and more advanced stage at presentation (14.3% vs. 1.1% stage 4; P < 0.0001). Importantly, over a 65-month follow-up, disease-specific mortality (DSM) was increased when additional mutations were identified (13.8% vs. 1.4% in the BRAF-only group; P = 0.005). Separately, we identified a subcluster of patients harboring oncogenic mutations in key effectors of the PI3K/AKT/mTOR pathway, which were independently associated with DSM (OR = 47.9; 95% confidence interval, 3.5-1,246.5; P = 0.0043).

CONCLUSIONS

Identification of additional PIK3/AKT/mTOR alterations in patients with BRAF^V600E -mutant PTC provides important and actionable prognostic risk stratification. These data support genomic profiling of PTC tumors to inform prognosis and clinical strategy.

BRAF Inhibitors Induce Feedback Activation of RAS Pathway in Thyroid Cancer Cells

BRAF^V600E is the most frequent oncogenic mutation identified in papillary thyroid cancer (PTC). In PTC patients who do not respond to standard treatment, BRAF inhibitors are currently tested as alternative strategies. However, as observed for other targeted therapies, patients eventually develop drug resistance. The mechanisms of BRAF inhibitors response are still poorly understood in a thyroid cancer (TC) context. In this study, we investigated in BRAF^V600E mutated TC cell lines the effects of Vemurafenib and Dabrafenib, two BRAF inhibitors currently used in a clinical setting. We assessed cell proliferation, and the expression and activity of the thyroid function related transporter NIS following the treatment with BRAF inhibitors. In addition, we investigated the global gene expression by microarray, the relevant modulated biological processes by gene set enrichment analysis (GSEA), and TC specific gene signatures related to MAPK pathway activation, thyroid differentiation, and transcriptional profile associated with BRAF^V600E or RAS mutation. We found that both inhibitors induce antiproliferative and redifferentiative effects on TC cells, as well as a rewiring of the MAPK pathway related to RAS signaling. Our results suggest a possible mechanism of drug response to the BRAF inhibitors Vemurafenib or Dabrafenib, supporting very recent findings in TC patients treated with targeted therapies.

Pembrolizumab in a Patient with Treatment-Naïve Unresectable BRAF-Mutation Negative Anaplastic Thyroid Cancer

Immune check point inhibitor (ICI) therapy can be a potentially effective salvage treatment for anaplastic thyroid cancer (ATC) with progression despite standard of care therapies. We report a case of unresectable treatment-naïve ATC showing a dramatic and durable response to first-line pembrolizumab therapy. A 69-year-old male presented with a large, right-sided neck mass associated with compressive symptoms. A neck ultrasound showed a large, right-sided, and highly suspicious thyroid nodule. A fine needle aspiration (FNA) biopsy revealed tumor cells consistent with ATC that were positive for PD-L1, with an expression score of >95% and negative for the BRAF V600E mutation. Imaging studies were negative for distant metastases. The disease was declared surgically inoperable, and the patient declined chemotherapy/radiation therapy (XRT), but agreed to ICI therapy with intravenous pembrolizumab 200 mg every three weeks. The patient has received 25 doses of pembrolizumab to date, with rapid resolution of symptoms and a significant reduction in tumor size. He remains alive without disease progression 18 months since initial diagnosis.

Kinase-inhibitors for iodine-refractory differentiated thyroid cancer: still far from a structured therapeutic algorithm

The kinase-inhibitors (KIs) sorafenib and lenvatinib demonstrated efficacy in iodine-refractory DTC upon phase III studies. However, evidence allowing a punctual balance of benefits and risks is poor. Furthermore, the lack of a direct comparison hampers to establish the proper sequence of administration. However, some insights may provided: a) indirect comparison between phase III trials showed milder toxicity for sorafenib, which should be preferred in case of cardiovascular comorbidities; b) prospective evidence of efficacy in KIs pre-treated patients is available only for lenvatinib, which should be used as second-line. Promising activity was found for the majority of other tested KIs, but no placebo-controlled trials are available. Emerging, but still early, frontiers include the restoration of iodine-sensitivity and the selective activity on pathogenic mutations. In conclusion, the use of KIs in iodine-refractory DTC is far from a structured therapeutic algorithm.

Targeting EML4-ALK gene fusion variant 3 in thyroid cancer

Finding targetable gene fusions can expand the limited treatment options in radioactive iodine-refractory (RAI-r) thyroid cancer. To that end, we established a novel cell line 'JVE404' derived from an advanced RAI-r papillary thyroid cancer (PTC) patient, harboring an EML4-ALK gene fusion variant 3 (v3). Different EML4-ALK gene fusions can have different clinical repercussions. JVE404 cells were evaluated for cell viability and cell signaling in response to ALK inhibitors crizotinib, ceritinib and lorlatinib, in parallel to the patient's treatment. He received, after first-line lenvatinib, crizotinib (Drug Rediscovery Protocol (DRUP) trial), and lorlatinib (compassionate use). In vitro treatment with crizotinib or ceritinib decreased viability in JVE404, but most potently and significantly only with lorlatinib. Western blot analysis showed a near total decrease of 99% and 89%, respectively, in pALK and pERK expression levels in JVE404 cells with lorlatinib, in contrast to remaining signal intensities of a half and a third of control, respectively, with crizotinib. The patient had a 6-month lasting stable disease on crizotinib, but progressive disease occurred, including the finding of cerebral metastases, at 8 months. With lorlatinib, partial response, including clinical cerebral activity, was already achieved at 11 weeks' use and ongoing partial response at 7 months. To our best knowledge, this is the first reported case describing a patient-specific targeted treatment with lorlatinib based on an EML4-ALK gene fusion v3 in a thyroid cancer patient, and own cancer cell line. Tumor-agnostic targeted therapy may provide valuable treatment options in personalized medicine.

The Genomic Landscape of Thyroid Cancer Tumourigenesis and Implications for Immunotherapy

Thyroid cancer is the most prevalent endocrine malignancy that comprises mostly indolent differentiated cancers (DTCs) and less frequently aggressive poorly differentiated (PDTC) or anaplastic cancers (ATCs) with high mortality. Utilisation of next-generation sequencing (NGS) and advanced sequencing data analysis can aid in understanding the multi-step progression model in the development of thyroid cancers and their metastatic potential at a molecular level, promoting a targeted approach to further research and development of targeted treatment options including immunotherapy, especially for the aggressive variants. Tumour initiation and progression in thyroid cancer occurs through constitutional activation of the mitogen-activated protein kinase (MAPK) pathway through mutations in BRAF, RAS, mutations in the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) pathway and/or receptor tyrosine kinase fusions/translocations, and other genetic aberrations acquired in a stepwise manner. This review provides a summary of the recent genetic aberrations implicated in the development and progression of thyroid cancer and implications for immunotherapy.

Genetics of Familial Non-Medullary Thyroid Carcinoma (FNMTC)

Non-medullary thyroid carcinoma (NMTC) is the most frequent endocrine tumor and originates from the follicular epithelial cells of the thyroid. Familial NMTC (FNMTC) has been defined in pedigrees where two or more first-degree relatives of the patient present the disease in absence of other predisposing environmental factors. Compared to sporadic cases, FNMTCs are often multifocal, recurring more frequently and showing an early age at onset with a worse outcome. FNMTC cases show a high degree of genetic heterogeneity, thus impairing the identification of the underlying molecular causes. Over the last two decades, many efforts in identifying the susceptibility genes in large pedigrees were carried out using linkage-based approaches and genome-wide association studies, leading to the identification of susceptibility loci and variants associated with NMTC risk. The introduction of next-generation sequencing technologies has greatly contributed to the elucidation of FNMTC predisposition, leading to the identification of novel candidate variants, shortening the time and cost of gene tests. In this review we report the most significant genes identified for the FNMTC predisposition. Integrating these new molecular findings in the clinical data of patients is fundamental for an early detection and the development of tailored therapies, in order to optimize patient management.

Identification of Key Functional Gene Signatures Indicative of Dedifferentiation in Papillary Thyroid Cancer

Background: Differentiated thyroid cancer (DTC) is the most common type of thyroid cancer. Many of them can relapse to dedifferentiated thyroid cancer (DDTC) and exhibit different gene expression profiles. The underlying mechanism of dedifferentiation and the involved genes or pathways remained to be investigated.

Methods: A discovery cohort obtained from patients who received surgical resection in the Fudan University Shanghai Cancer Center (FUSCC) and two validation cohorts derived from Gene Expression Omnibus (GEO) database were used to screen out differentially expressed genes in the dedifferentiation process. Weighted gene co-expression network analysis (WGCNA) was constructed to identify modules highly related to differentiation. Gene Set Enrichment Analysis (GSEA) was used to identify pathways related to differentiation, and all differentially expressed genes were grouped by function based on the GSEA and literature reviewing data. Least absolute shrinkage and selection operator (LASSO) regression analysis was used to control the number of variables in each group. Next, we used logistic regression to build a gene signature in each group to indicate differentiation status, and we computed receiver operating characteristic (ROC) curve to evaluate the indicative performance of each signature.

Results: A total of 307 upregulated and 313 downregulated genes in poorly differentiated thyroid cancer (PDTC) compared with papillary thyroid cancer (PTC) and normal thyroid (NT) were screened out in FUSCC cohort and validated in two GEO cohorts. WGCNA of 620 differential genes yielded the seven core genes with the highest correlation with thyroid differentiation score (TDS). Furthermore, 395 genes significantly correlated with TDS in univariate logistic regression analysis were divided into 11 groups. The areas under the ROC curve (AUCs) of the gene signature of group transcription and epigenetic modification, signal and substance transport, extracellular matrix (ECM), and metabolism in the training set [The Cancer Genome Atlas (TCGA) cohort] and validation set (combined GEO cohort) were both >0.75. The gene signature based on group transcription and epigenetic modification, cilia formation and movement, and proliferation can reflect the patient's disease recurrence state.

Conclusion: The dedifferentiation of DTC is affected by a variety of mechanisms including many genes. The gene signature of group transcription and epigenetic modification, signal and substance transport, ECM, and metabolism can be used as biomarkers for DDTC.

Interstitial Deletions Generating Fusion Genes

A fusion gene is the physical juxtaposition of two different genes resulting in a structure consisting of the head of one gene and the tail of the other. Gene fusion is often a primary neoplasia-inducing event in leukemias, lymphomas, solid malignancies as well as benign tumors. Knowledge about fusion genes is crucial not only for our understanding of tumorigenesis, but also for the diagnosis, prognostication, and treatment of cancer. Balanced chromosomal rearrangements, in particular translocations and inversions, are the most frequent genetic events leading to the generation of fusion genes. In the present review, we summarize the existing knowledge on chromosome deletions as a mechanism for fusion gene formation. Such deletions are mostly submicroscopic and, hence, not detected by cytogenetic analyses but by array comparative genome hybridization (aCGH) and/or high throughput sequencing (HTS). They are found across the genome in a variety of neoplasias. As tumors are increasingly analyzed using aCGH and HTS, it is likely that more interstitial deletions giving rise to fusion genes will be found, significantly impacting our understanding and treatment of cancer.

Mechanistic Differences of Activation of Rac1P29S and Rac1A159V

Rac1 is a small GTPase that plays key roles in actin reorganization, cell motility, and cell survival/growth as well as in various cancer types and neurodegenerative diseases. Similar to other Ras superfamily GTPases, Rac1 switches between active GTP-bound and inactive GDP-bound states. Switch I and II regions open and close during GDP/GTP exchange. P29S and A159V (paralogous to K-RasA146) mutations are the two most common somatic mutations of Rac1. Rac1P29S is a known hotspot for melanoma, whereas Rac1A159V most commonly occurs in head and neck cancer. To investigate how these substitutions induce the Rac1 dynamics, we used atomistic molecular dynamics simulations on the wild-type Rac1 and two mutant systems (P29S and A159V) in the GTP bound state, and on the wild-type Rac1 and P29S mutated system in the GDP bound state. Here, we show that P29S and A159V mutations activate Rac1 with different mechanisms. In Rac1P29S-GTP, the substitution increases the flexibility of Switch I based on RMSF and dihedral angle calculations and leads to an open conformation. We propose that the open Switch I conformation is one of the underlying reasons for rapid GDP/GTP exchange of Rac1P29S. On the other hand, in Rac1A159V-GTP, some of the contacts of the guanosine ring of GTP with Rac1 are temporarily lost, enabling the guanosine ring to move toward Switch I and subsequently close the switch. Rac1A159V-GTP adopts a Ras state 2 like conformation, where both switch regions are in closed conformation and Thr35 forms a hydrogen bond with the nucleotide.

Histology-based molecular profiling improves mutation detection for advanced thyroid cancer

Advanced cancers frequently show histologic and molecular intratumoral heterogeneity. Therefore, we comprehensively characterized advanced, metastatic, radioiodine-resistant (RAIR) thyroid carcinomas at the molecular level in the context of histologic heterogeneity with the aim to identify potentially actionable mutations that may guide the use of specific tyrosine kinase inhibitor (TKI) treatment. Whole exome sequencing (WES) was applied to 29 macrodissected tissue samples of histologically heterogeneous and homogeneous areas, lymph node and lung metastases from six clinically and histologically well-characterized metastatic RAIR thyroid cancer patients with structural incomplete response to treatment. WES data were analyzed to identify potential driver mutations in oncogenic pathways, copy number alterations, microsatellite instability, mutant-allele tumor heterogeneity, and the relevance of histologic heterogeneity to molecular profiling. In addition to known driver mutations in BRAF, NRAS, EIF1AX, NCOA4-RET, and TERT, further potentially actionable drivers were identified in AKT1, ATM, E2F1, HTR2A, and MLH3. The analysis of the evolutionary history of the mutations and the reconstruction of the molecular phylogeny of the cancers show a remarkable association between histologic and molecular heterogeneity. A comprehensive molecular analysis of the primary tumor guided by histologic analysis may help to better stratify patients for precision medicine approaches. Given the association between the molecular and the histologic heterogeneity, the selection of tumor samples for molecular analysis should be based on meticulous histologic evaluation of the entire tumor.

Genomic profile of columnar cell variant of papillary thyroid carcinoma

BACKGROUND AND AIMS

Columnar cell variant (CCV) is a rare papillary thyroid carcinoma subtype. The majority of CCV occur in older patients and are large, invasive tumours that pursue an aggressive clinical course. Rare well-circumscribed CCV occur in younger female patients and are comparatively indolent.

METHODS AND RESULTS

We retrospectively identified CCV with material available to perform targeted next-generation sequencing and correlated molecular results with clinicopathological features and outcome. Our cohort was comprised of nine CCV. Nearly all were aggressive tumours; however, one was predominantly well-circumscribed and arose in a thyroglossal duct cyst of a 26-year-old woman who had no evidence of disease at last follow-up. Seven (78%) cases demonstrated activating oncogenic driver alterations in BRAF, including BRAF V600E, an activating N486_P490del deletion, and BRAF-AGK fusions. Activating RAS mutations were seen in two (22%) cases. Additionally, three (33%) cases had TERT promoter mutations, four (44%) had loss of the tumour suppressor CDKN2A and one (11%) case had a loss of function TP53 mutation. Most cases (89%) also demonstrated copy number alterations, including recurrent gain of chromosome 1q (five cases) and losses of chromosome 9p (three cases) and 22q (four cases). The one case without secondary pathogenic mutations or copy number alterations was the tumour in the 26-year-old woman.

CONCLUSIONS

We found that CCV is primarily a BRAF-driven tumour, with most also harbouring secondary oncogenic mutations and multiple chromosomal gains and losses. Moreover, our findings suggest that molecular analysis could potentially be used to help risk stratify CCV.

Novel Recurrent Altered Genes in Chinese Patients With Anaplastic Thyroid Cancer

BACKGROUND

Anaplastic thyroid cancer (ATC) is a rare but lethal malignancy, and few systematic investigations on genomic profiles of ATC have been performed in Chinese patients.

METHODS

Fifty-four ATC patients in West China Hospital between 2010 to 2020 were retrospectively analyzed, while 29 patients with available samples were sequenced by whole-exome sequencing (WES). The associations between genomic alterations and clinical characteristics were statistically evaluated.

RESULTS

The median overall survival was 3.0 months in the entire cohort, which was impacted by multiple clinical features, including age, tumor size, and different treatment strategies. In the WES cohort, totally 797 nonsilent mutations were detected; the most frequently altered genes were TP53 (48%), BRAF (24%), PIK3CA (24%), and TERT promoter (21%). Although these mutations have been well-reported in previous studies, ethnic specificity was exhibited in terms of mutation frequency. Moreover, several novel significantly mutated genes were identified including RBM15 (17%), NOTCH2NL (14%), CTNNA3 (10%), and KATNAL2 (10%). WES-based copy number alteration analysis also revealed a high frequent gain of NOTCH2NL (41%), which induced its increased expression. Gene mutations and copy number alterations were enriched in phosphatidylinositol 3-kinase/AKT/mechanistic target of rapamycin (mTOR), NOTCH, and WNT pathways.

CONCLUSIONS

This study reveals shared and ethnicity-specific genomic profiles of ATC in Chinese patients and suggests NOTCH2NL may act as a novel candidate driver gene for ATC tumorigenesis.

Molecular Genetics of Follicular-Derived Thyroid Cancer

Simple Summary

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

Abstract

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

Molecular Pathology of Poorly Differentiated and Anaplastic Thyroid Cancer: What Do Pathologists Need to Know?

The molecular characterization of poorly and anaplastic thyroid carcinomas has been greatly improved in the last years following the advent of high throughput technologies. However, with special reference to genomic data, the prevalence of reported alterations is partly affected by classification criteria. The impact of molecular pathology in these tumors is multifaceted and bears diagnostic, prognostic, and predictive implications although its use in the clinical practice is not completely assessed. Genomic profiling data claim that genetic alterations in poorly differentiated and anaplastic thyroid carcinomas include "Early" and "Late" molecular events, which are consistent with a multi-step model of progression. "Early" driver events are mostly RAS and BRAF mutations, whereas "Late" changes include above all TP53 and TERT promoter mutations, as well as dysregulation of gene involved in the cell cycle, chromatin remodeling, histone modifications, and DNA mismatch repair. Gene fusions are rare but represent relevant therapeutic targets. Epigenetic modifications are also playing a relevant role in poorly differentiated and anaplastic thyroid carcinomas, with altered regulation of either genes by methylation/deacetylation or non-coding RNAs. The biological effects of epigenetic modifications are not fully elucidated but interfere with a wide spectrum of cellular functions. From a clinical standpoint, the combination of genomic and epigenetic data shows that several molecular alterations affect druggable cellular pathways in poorly differentiated and anaplastic thyroid carcinomas, although the clinical impact of molecular typing of these tumors in terms of predictive biomarker testing is still under exploration.

2021 American Thyroid Association Guidelines for Management of Patients with Anaplastic Thyroid Cancer

Background: Anaplastic thyroid cancer (ATC) is a rare but highly lethal form of thyroid cancer. Since the guidelines for the management of ATC by the American Thyroid Association were first published in 2012, significant clinical and scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, and researchers on published evidence relating to the diagnosis and management of ATC. Methods: The specific clinical questions and topics addressed in these guidelines were based on prior versions of the guidelines, stakeholder input, and input of the Task Force members (authors of the guideline). Relevant literature was reviewed, including serial PubMed searches supplemented with additional articles. The American College of Physicians Guideline Grading System was used for critical appraisal of evidence and grading strength of recommendations. Results: The guidelines include the diagnosis, initial evaluation, establishment of treatment goals, approaches to locoregional disease (surgery, radiotherapy, targeted/systemic therapy, supportive care during active therapy), approaches to advanced/metastatic disease, palliative care options, surveillance and long-term monitoring, and ethical issues, including end of life. The guidelines include 31 recommendations and 16 good practice statements. Conclusions: We have developed evidence-based recommendations to inform clinical decision-making in the management of ATC. While all care must be individualized, such recommendations provide, in our opinion, optimal care paradigms for patients with ATC.

Do Molecular Profiles of Primary Versus Metastatic Radioiodine Refractory Differentiated Thyroid Cancer Differ?

Management of metastatic radioiodine refractory differentiated thyroid cancer (DTC) can be a therapeutic challenge. Generally, little is known about the paired molecular profile of the primary tumor and the metastases and whether they harbor the same genetic abnormalities. The present study compared the molecular profile of paired tumor specimens (primary tumor/metastatic sites) from patients with radioiodine refractory DTC in order to gain insight into a possible basis for resistance to radioiodine. Twelve patients with radioiodine refractory metastases were studied; median age at diagnosis of 61 years (range, 25-82). Nine patients had papillary TC (PTC), one had follicular TC (FTC), and two had Hürthle cell TC (HTC). Distant metastases were present in the lungs (n = 10), bones (n = 4), and liver (n = 1). The molecular profiling of paired tumors was performed with a panel of 592 genes for Next Generation Sequencing, RNA-sequencing, and immunohistochemistry. Digital microfluidic PCR was used to investigate TERT promoter mutations. The genetic landscape of all paired sites comprised BRAF, NRAS, HRAS, TP53, ATM, MUTYH, POLE, and NTRK genes, including BRAF and NTRK fusions. BRAF V600E was the most common point mutation in the paired specimens (5/12). TERT promoter mutation C228T was detected in one case. PD-L1 expression at metastatic sites was highly positive (95%) for one patient with HTC. All specimens were stable for microsatellite instability testing, and the tumor mutation burden was low to intermediate. Therefore, the molecular profile of DTC primary and metastatic lesions can show heterogeneity, which may help explain some altered responses to therapeutic intervention.