Association of TERT promoter mutation 1,295,228 C>T with BRAF V600E mutation, older patient age, and distant metastasis in anaplastic thyroid cancer

An Overview on Prevalence and Detection Approaches of BRAF V600E Mutation in Anaplastic Thyroid Carcinoma: A Systematic Review and Meta-Analysis

Background

BRAF V600E mutation is proved critical in the progression and invasion of thyroid cancer, and as a prognostic biomarker. As anaplastic thyroid cancer (ATC) is a rare and aggressive form of thyroid cancer, this study was conducted to provide a view on prevalence of BRAF V600E as well as the best molecular diagnostic method in ATC patients.

Methods

A comprehensive literature search was performed from their inception to Oct 2022 in PubMed, Scopus, Google Scholar, and Web of Science (WoS). The data of the prevalence of ATC were extracted. Moreover, the diagnostic feature of the available diagnostic tools was extracted to measure the sensitivity and specificity. To pool the prevalence data, we used meta-proportion analysis and diagnostic meta-analysis was conducted to determine the specificity and sensitivity of the immunohistochemistry method in detecting BRAF V600E mutation among patients with ATC.

Results

Overall, 34 studies were included in this meta-analysis. The incidence of BRAF V600E was shown 33% in the 978 patients. The sensitivity and specificity of IHC in detecting BRAF V600E were detected 78.9% (95%CI: 60.1-97.2), and 69.7% (95%CI: 41.2-98.1), respectively.

Conclusion

IHC had an acceptable prognostic profile for detecting BRAF V600E in ATC patients. The diagnosis of BRAF mutation is critical in clinical trials and may be helpful for choosing proper-targeted therapy strategies in ATC patients.

Knowledge mapping of anaplastic thyroid cancer treatments: a bibliometric analysis (2000-2023)

Context

Anaplastic thyroid cancer (ATC) is a relatively rare and extensively malignant kind of thyroid carcinoma. The poor prognosis and high mortality rate of ATC can be attributed to its invasive features and undifferentiated phenotype. At present, there is a lack of efficacious therapeutic options. In light of the elevated fatality rate, it is vital to possess a comprehensive comprehension of the scientific terrain pertaining to ATC. To gather the perspectives of different researchers about the topic of ATC treatment, we did a bibliometric network analysis, which offers a comprehensive view of the scholarly literature.

Methodology

A systematic search was conducted on the WoSCC database to identify publications pertaining to ATC treatment between the years 2000 and 2023. In this bibliometric investigation, the tools VOSviewers, CiteSpace, and the R package "bibliometrix" were employed to investigate the general attributes, developmental framework, and academic frontiers of the subject matter.

Results

1223 publications in total, written by 6937 scholars from 53 areas and 1402 institutions and published in 358 scholarly journals, were analyzed. There has been a gradual increase in the quantity of publications pertaining to ATC treatment. The United States and China emerged as the most prominent nations. The University of Texas MD Anderson Cancer Center and Memorial Sloan Kettering Cancer Counseling Center are prominent research institutions in highly productive countries. The journal Thyroid holds a prominent position within its discipline, being widely recognized as both the most popular and highly co-cited publication. According to the available data, Maria Cabanillas has authored the highest number of published articles, while RC Smallridge has received the highest number of co-citations. It turned out that the prevailing keywords encompassed expression, therapy, apoptosis, survival, activation, proliferation, metastasis, and other related terms. Immunotherapy, targeted therapy, and prognostic factors are the emerging research hotspots and trends.

Conclusions

This paper presents a complete overview of research trends and advancements in the treatment of ATC using bibliometric analysis. The acquisition of information will offer vital insights for funding and potential creative strategies in researching the treatment of ATC, which indicates the research frontiers as well as prevalent directions in recent years.

Reactivation of telomerase reverse transcriptase expression in cancer: the role of TERT promoter mutations

Telomerase activity and telomere elongation are essential conditions for the unlimited proliferation of neoplastic cells. Point mutations in the core promoter region of the telomerase reverse transcriptase (TERT) gene have been found to occur at high frequencies in several tumour types and considered a primary cause of telomerase reactivation in cancer cells. These mutations promote TERT gene expression by multiple mechanisms, including the generation of novel binding sites for nuclear transcription factors, displacement of negative regulators from DNA G-quadruplexes, recruitment of epigenetic activators and disruption of long-range interactions between TERT locus and telomeres. Furthermore, TERT promoter mutations cooperate with TPP1 promoter nucleotide changes to lengthen telomeres and with mutated BRAF and FGFR3 oncoproteins to enhance oncogenic signalling in cancer cells. TERT promoter mutations have been recognized as an early marker of tumour development or a major indicator of poor outcome and reduced patients survival in several cancer types. In this review, we summarize recent findings on the role of TERT promoter mutations, telomerase expression and telomeres elongation in cancer development, their clinical significance and therapeutic opportunities.

Telomerase Upregulation Induces Progression of Mouse BrafV600E-Driven Thyroid Cancers and Triggers Nontelomeric Effects

Mutations in the promoter of the telomerase reverse transcriptase (TERT) gene are the paradigm of a cross-cancer alteration in a noncoding region. TERT promoter mutations (TPM) are biomarkers of poor prognosis in cancer, including thyroid tumors. TPMs enhance TERT transcription, which is otherwise silenced in adult tissues, thus reactivating a bona fide oncoprotein. To study TERT deregulation and its downstream consequences, we generated a Tert mutant promoter mouse model via CRISPR/Cas9 engineering of the murine equivalent locus (Tert-123C>T) and crossed it with thyroid-specific BrafV600E-mutant mice. We also employed an alternative model of Tert overexpression (K5-Tert). Whereas all BrafV600E animals developed well-differentiated papillary thyroid tumors, 29% and 36% of BrafV600E+Tert-123C>T and BrafV600E+K5-Tert mice progressed to poorly differentiated cancers at week 20, respectively. Tert-upregulated tumors showed increased mitosis and necrosis in areas of solid growth, and older animals displayed anaplastic-like features, that is, spindle cells and macrophage infiltration. Murine TPM increased Tert transcription in vitro and in vivo, but temporal and intratumoral heterogeneity was observed. RNA-sequencing of thyroid tumor cells showed that processes other than the canonical Tert-mediated telomere maintenance role operate in these specimens. Pathway analysis showed that MAPK and PI3K/AKT signaling, as well as processes not previously associated with this tumor etiology, involving cytokine, and chemokine signaling, were overactivated. These models constitute useful preclinical tools to understand the cell-autonomous and microenvironment-related consequences of Tert-mediated progression in advanced thyroid cancers and other aggressive tumors carrying TPMs.

IMPLICATIONS

Telomerase-driven cancer progression activates pathways that can be dissected and perhaps therapeutically exploited.

Efficacy and safety of anlotinib-based chemotherapy for locally advanced or metastatic anaplastic thyroid carcinoma

PURPOSE

Anaplastic thyroid carcinoma (ATC) is one of the most lethal malignancies with no effective treatment. In this study, we investigated the efficacy and safety of anlotinib-based chemotherapy as first-line therapy for ATC.

METHODS

Locally advanced or metastatic (LA/M) ATC patients who never received antitumor treatment of any sort were eligible for this study. The patients received 2-6 cycles anlotinib12mg on days 1-14 per 21 days. Chemotherapy regimens consisted of paclitaxel, capecitabine, or paclitaxel plus carboplatin/capecitabine. The end points including Objective Response Rate (ORR), Disease Control Rate (DCR), Progression-Free Survival (PFS), and Disease Specification Survival (DCS) were analyzed.

RESULTS

A total of 25 patients were enrolled. 1 patient achieved a Complete Response (CR) and 14 patients achieved Partial Response (PR). The best ORR was 60.0%, and the DCR was 88.0%. The median PFS was 25.1 weeks, and the median DCS was 96.0 weeks. Approximately 56% (14 patients) had at least one Adverse Event (AE) of any grade. Most AEs were well tolerated. The most common AEs was palmar-plantar erythrodysesthesia syndrome (28.0%).

CONCLUSIONS

Anlotinib-based chemotherapy as first-line therapy is a safe and effective intervention for the treatment of LA/M ATC patients.

InTERTwined: how TERT promoter mutations impact BRAFV600E-driven thyroid cancers

Thyroid cancers are often initiated by the acquisition of a BRAFV600E mutation. BRAFV600E-driven thyroid tumors display a wide range of behaviors, from the slow-growing papillary carcinomas to the highly aggressive anaplastic. Mutations in the promoter of TERT (telomerase reverse transcriptase) gene were discovered a decade ago and identified as prevalent events in thyroid cancers. Multiple studies showed that TERT promoter mutations, particularly when co-occurring with BRAFV600E, are markers of poor prognosis across thyroid cancer subtypes, and can be implemented for routine clinical stratification. Mechanistically, TERT promoter mutations reactivate telomerase expression via the differential recruitment of transcriptional complexes. Re-expression of TERT impacts tumor biology, plausibly via both the well-known function of telomerase maintaining telomeres and by affecting other cancer-relevant processes.

Telomerase reactivation induces progression of mouse Braf V600E -driven thyroid cancers without telomere lengthening

Mutations in the promoter of the telomerase reverse transcriptase ( TERT ) gene are the paradigm of a cross-cancer alteration in a non-coding region. TERT promoter mutations (TPMs) are biomarkers of poor prognosis in several tumors, including thyroid cancers. TPMs enhance TERT transcription, which is otherwise silenced in adult tissues, thus reactivating a bona fide oncoprotein. To study TERT deregulation and its downstream consequences, we generated a Tert mutant promoter mouse model via CRISPR/Cas9 engineering of the murine equivalent locus (Tert -123C>T ) and crossed it with thyroid-specific Braf V600E -mutant mice. We also employed an alternative model of Tert overexpression (K5-Tert). Whereas all Braf V600E animals developed well-differentiated papillary thyroid tumors, 29% and 36% of Braf V600E +Tert -123C>T and Braf V600E +K5-Tert mice progressed to poorly differentiated thyroid cancers at week 20, respectively. Braf+Tert tumors showed increased mitosis and necrosis in areas of solid growth, and older animals from these cohorts displayed anaplastic-like features, i.e., spindle cells and macrophage infiltration. Murine Tert promoter mutation increased Tert transcription in vitro and in vivo , but temporal and intra-tumoral heterogeneity was observed. RNA-sequencing of thyroid tumor cells showed that processes other than the canonical Tert-mediated telomere maintenance role operate in these specimens. Pathway analysis showed that MAPK and PI3K/AKT signaling, as well as processes not previously associated with this tumor etiology, involving cytokine and chemokine signaling, were overactivated. Braf+Tert animals remained responsive to MAPK pathway inhibitors. These models constitute useful pre-clinical tools to understand the cell-autonomous and microenvironment-related consequences of Tert-mediated progression in advanced thyroid cancers and other aggressive tumors carrying TPMs.

Advancement of secretory breast carcinoma: a narrative review

BACKGROUND AND OBJECTIVE

Secretory breast carcinoma (SBC) is a rare breast malignancy. Most available studies on SBC are case reports or small case series, and the few large-sample studies available lack critical information due to database limitations. To improve the understanding of SBC and provide a reference for clinical practice, we systematically reviewed the demographic, clinical, pathologic, and genetic characteristics of SBC, as well as its treatment and prognosis.

METHODS

We conducted a PubMed search with the keywords "secretory breast carcinoma" or "juvenile breast carcinoma". Relevant English-language publications published from January 1966 to February 2022 were screened manually at 3 levels-title, abstract, and full text-to identify the articles that presented the demographic, clinical, pathologic, and genetic characteristics of SBC, as well as its treatment and prognosis.

KEY CONTENT AND FINDINGS

SBC lacks specific clinical manifestations and has typical pathological and molecular characteristics, including intracellular and extracellular eosinophilic secretions, immune spectrum similar to hormone receptor-positive tumors, and the ETV6-NTRK3 fusion gene. Surgery remains the primary treatment for SBC. Postoperative radiotherapy is recommended by most researchers for adult SBC but not for pediatric patients. The evidence of chemotherapy and endocrine therapy is insufficient, and targeted therapy of the ETV6-NTRK3 fusion gene shows a good response. Most patients with SBC have a good prognosis except for a few patients who experience distant metastases. Future studies will be focused on the molecular characteristics of those patients with SBC who have a poor prognosis.

CONCLUSIONS

The development of histopathology and molecular genetics has promoted the progress of the clinical diagnosis of SBC. The purpose of this review is to serve as a guide for the better clinical treatment of SBC, particularly in the areas of disease identification and prognosis classification for patients.

Tumor mutation burden-assisted risk stratification for papillary thyroid cancer

PURPOSE

Although papillary thyroid cancer (PTC) has a low mortality rate, the rate of recurrence remains relatively high. This study aims to develop a molecular signature to predict the recurrence of PTC.

METHODS

A total of 333 PTC patients' data from The Cancer Genome Atlas (TCGA) were included. We calculated tumor mutation burden (TMB) and analyzed the mutation status of BRAF and TERT promoter.

RESULTS

Tumor recurrence occurred in 17 of 263 cases in TMB-L patients versus 14 of 70 cases in TMB-H patients (hazard ratio [HR], 3.55; 95% confidence interval [CI], 1.75-7.21; P < 0.001). The HR for recurrence in TMB-H patients remained significant after adjustment for classical clinicopathologic factors (patient age, gender, extrathyroidal extension and lymph node metastasis). These clinical factors had no effect on recurrence rate in TMB-L patients, but had a strong adverse effect on the prognosis of TMB-H patients. Compared with TMB-L patients lacking mutation, the HR (95% CI) of recurrence for TMB-H patients with coexisting BRAF V600E and/or TERT C228/250 T mutations was 6.68 (2.41-18.57), which remained significant after adjustment for clinicopathological factors. The mutation status of BRAF V600E and TERT C228/250 T had little effect on PTC recurrence in TMB-L patients. Either of the mutation was associated with high recurrence rate in TMB-H patients.

CONCLUSIONS

The presence of BRAF V600E and/or TERT promoter mutations denotes a high risk of recurrence in TMB-H patients. This represents a powerful molecular prognostic genotype that can help predict patients with the highest risk of recurrence.

Telomere length and Wnt/β-catenin pathway in adamantinomatous craniopharyngiomas

OBJECTIVES

To evaluate how telomere length behaves in adamantinomtous craniopharyngioma (aCP) and if it contributes to the pathogenesis of aCPs with and without CTNNB1 mutations.

DESIGN

Retrospective cross-sectional study enrolling 42 aCP patients from 2 tertiary institutions.

METHODS

Clinicopathological features were retrieved from the patient's charts. Fresh frozen tumors were used for RNA and DNA analyses. Telomere length was evaluated by qPCR (T/S ratio). Somatic mutations in TERT promoter (TERTp) and CTNNB1 were detected by Sanger and/or whole-exome sequencing. We performed RNA-Seq to identify differentially expressed genes in aCPs presenting with shorter or longer telomere lengths.

RESULTS

Mutations in CTNNB1 were detected in 29 (69%) tumors. There was higher frequency of CTNNB1 mutations in aCPs from patients diagnosed under the age of 15 years (85% vs 15%; P = 0.04) and a trend to recurrent disease (76% vs 24%; P = 0.1). No mutation was detected in the TERTp region. The telomeres were shorter in CTNNB1-mutated aCPs (0.441, IQR: 0.297-0.597vs 0.607, IQR: 0.445-0.778; P = 0.04), but it was neither associated with clinicopathological features nor with recurrence. RNAseq identified a total of 387 differentially expressed genes, generating two clusters, being one enriched for short telomeres and CTNNB1-mutated aCPs.

CONCLUSIONS: CTNNB1

mutations are more frequent in children and adolescents and appear to associate with progressive disease. CTNNB1-mutated aCPs have shorter telomeres, demonstrating a relationship between the Wnt/β-catenin pathway and telomere biology in the pathogenesis of aCPs.

Emerging mechanisms of telomerase reactivation in cancer

Mutations in the promoter of human telomerase reverse transcriptase (hTERT) result in hyperactivation of hTERT. Notably, all mutations are G>A transitions, frequently found in a wide range of cancer types, and causally associated with cancer progression. Initially, the mutations were understood to reactivate hTERT by generating novel E26 transformation-specific (ETS) binding sites. Recent work reveals the role of DNA secondary structure G-quadruplexes, telomere binding factor(s), and chromatin looping in hTERT regulation. Here, we discuss these emerging findings in relation to the clinically significant promoter mutations to provide a broader understanding of the context-dependent outcomes that result in hTERT activation in normal and pathogenic conditions.

TERT Promoter Mutations Increase Sense and Antisense Transcription from the TERT Promoter

Background: Chief among mechanisms of telomerase reverse transcriptase (TERT) reactivation is the appearance of mutations in the TERT promoter. The two main TERT promoter mutations are C>T transitions located −146C>T and −124C>T upstream from the translational start site. They generate a novel Ets/TCF binding site. Both mutations are mutually exclusive and −124C>T is strikingly overrepresented in most cancers. We investigated whether this mutational bias and mutual exclusion could be due to transcriptional constraints. Methods: We compared sense and antisense transcription of a panel of TERT promoter-luciferase vectors harboring the −124C>T and -146C>T mutations alone or together. lncRNA TAPAS levels were measured by RT-PCR. Results: Both mutations generally increased TERT transcription by 2–4-fold regardless of upstream and downstream regulatory elements. The double mutant increased transcription in an additive fashion, arguing against a direct transcriptional constraint. The −146C>T mutation, alone or in combination with −124C>T, also unleashed antisense transcription. In line with this finding, lncRNA TAPAS was higher in cells with mutated TERT promoter (T98G and U87) than in cells with wild-type promoter, suggesting that lncRNA TAPAS may balance the effect of TERT promoter mutations. Conclusions: −146C>T and −124C>T TERT promoter mutations increase TERT sense and antisense transcription, and the double mutant features higher transcription levels. Increased antisense transcription may contain TERT expression within sustainable levels.

Papillary Thyroid Cancer Prognosis: An Evolving Field

Simple Summary

Over the last couple of decades, the prognostic stratification systems of differentiated thyroid cancer (DTC) patients have been revised several times in an attempt to achieve a tailored clinical management reflecting the single patients’ needs. Such revisions are likely to continue in the near future, since the prognostic value of a number of promising clinicopathological features and new molecular biomarkers are being evaluated. Here, we will review the current staging systems of thyroid cancer patients and discuss the most relevant clinicopathological parameters and new molecular markers that are potentially capable of refining the prognosis.

Abstract

Over the last few years, a great advance has been made in the comprehension of the molecular pathogenesis underlying thyroid cancer progression, particularly for the papillary thyroid cancer (PTC), which represents the most common thyroid malignancy. Putative cancer driver mutations have been identified in more than 98% of PTC, and a new PTC classification into molecular subtypes has been proposed in order to resolve clinical uncertainties still present in the clinical management of patients. Additionally, the prognostic stratification systems have been profoundly modified over the last decade, with a view to refine patients’ staging and being able to choose a clinical approach tailored on single patient’s needs. Here, we will briefly discuss the recent changes in the clinical management of thyroid nodules, and review the current staging systems of thyroid cancer patients by analyzing promising clinicopathological features (i.e., gender, thyroid auto-immunity, multifocality, PTC histological variants, and vascular invasion) as well as new molecular markers (i.e., BRAF/TERT promoter mutations, miRNAs, and components of the plasminogen activating system) potentially capable of ameliorating the prognosis of PTC patients.

Preoperative detection of the TERT promoter mutations in papillary thyroid carcinomas

OBJECTIVE

Telomerase reverse transcriptase promoter (TERT-p) mutations are strongly associated with tumour aggressiveness and worse prognosis in papillary thyroid carcinomas (PTCs). Since the TERT-p mutations have been reported to be subclonal, it is unclear how accurately they can be detected by preoperative fine-needle aspiration (FNA). The objective of this study was to analyse the concordance rate of the TERT-p mutations between preoperative FNA and corresponding postoperative surgical specimens.

DESIGN AND PATIENTS

Ninety-six cases of PTC aged 55 years or older were studied. The mutational status of TERT-p was detected by droplet digital polymerase chain reaction assay.

RESULTS

The mutational status of the TERT-p in FNA samples was highly concordant with that in postoperative formalin-fixed and paraffin-embedded (FFPE) specimens. The TERT-p mutation was significantly associated with age, tumour size, extrathyroidal extension and the Ki-67 labelling index in multivariate analysis in both FNA and FFPE samples.

CONCLUSIONS

The detection of the TERT-p mutations using FNA samples has a good ability to predict disease aggressiveness and, therefore, could be clinically useful in the determination of PTC management.

The ETS Inhibitor YK-4-279 Suppresses Thyroid Cancer Progression Independent of TERT Promoter Mutations

Hotspot mutations in the core promoter region of the telomerase reverse transcriptase (TERT) gene have been well established to associate with aggressive clinical characteristics, radioiodine refractory, tumor recurrence, and mortality in thyroid cancer. Several E-twenty-six (ETS) transcription factors were reported to selectively bound to the mutant TERT promoter and activated TERT expression. In this study we aimed to investigate whether TERT promoter mutations confer sensitivity to ETS inhibitor YK-4-279 in thyroid cancer cells and whether this inhibitor could be served as a potential therapeutic agent for thyroid cancer. In vitro assays showed that YK-4-279 treatment sharply suppressed cell viability, colony formation, migration, and invasion, as well as induced cell cycle arrest and apoptosis in a panel of thyroid cancer cells. The cell viability after YK-4-279 treatment was similar between cell lines harboring mutant and wild-type TERT promoters. Furthermore, YK-4-279 treatment reduced both luciferase activity and mRNA expression of TERT independent of TERT promoter mutation status. Data from RNA-seq further revealed that YK-4-279 significantly affected biological processes including DNA replication and cell cycle. Reduced DNA helicase activity and decreased expression of several helicase genes were observed after YK-4-279 treatment. Moreover, YK-4-279 significantly inhibited tumor growth and induced apoptosis in a xenograft mice model. Thus, ETS inhibitor YK-4-279 suppressed TERT expression and conferred anti-tumor activity in a TERT promoter mutation-independent manner, and it could be a potential agent for the treatment of advanced thyroid cancers.

Anaplastic Thyroid Carcinoma: Current Issues in Genomics and Therapeutics

PURPOSE OF REVIEW

Anaplastic thyroid carcinoma is a type of thyroid carcinoma with the most aggressive biological behaviour amongst thyroid cancer. Here, we review the current genomic and the impacts of advances in therapies to improve the management of patients with the cancer.

RECENT FINDINGS

Common mutations being identified in anaplastic thyroid carcinoma are p53 and TERT promoter mutations. Other common mutated genes included BRAF, RAS, EIF1AX, PIK3CA, PTEN and AKT1, SWI/SNF, ALK and CDKN2A. Changes in expression of different microRNAs are also involved in the pathogenesis of anaplastic thyroid carcinoma. Curative resection combined with radiotherapy and combination chemotherapies (such as anthracyclines, platins and taxanes) has been shown to have effects in the treatment of some patients with anaplastic thyroid carcinoma. Newer molecular targeted therapies in clinical trials target mostly the cell membrane kinase and downstream proteins. These include targeting the EGFR, FGFR, VEGFR, c-kit, PDGFR and RET on the cell membrane as well as VEGF itself and the downstream targets such as BRAF, MEK and mTOR. Immunotherapy is also being tested in the cancer. Updated knowledge of genomic as well as clinical trials on novel therapies is needed to improve the management of the patients with this aggressive cancer.

Metastatic-prone telomerase reverse transcriptase (TERT) promoter and v-Raf murine sarcoma viral oncogene homolog B (BRAF) mutated tall cell variant of papillary thyroid carcinoma arising in ectopic thyroid tissue: A case report

RATIONALE

Mutations of the v-Raf murine sarcoma viral oncogene homolog B (BRAF) oncogene and telomerase reverse transcriptase (TERT) promoter region are indicators of poor prognosis in papillary thyroid carcinoma (PTC) and might predict future occurrences of distant metastases. However, the clinical significance of these genetic aberrancies in PTCs arising in ectopic locations is not well established.

PATIENT CONCERNS

We describe a patient with a previous history of radioiodine (RAI)-treated hyperthyroidism and a surgically resected right-sided follicular thyroid adenoma. In 2013, a 6 mm follicular variant papillary thyroid carcinoma was diagnosed following a left-sided thyroid lobectomy. The central compartment displayed 9 tumor-free lymph nodes, and no adjuvant treatment was planned.

DIAGNOSES

Three years later, a 26 mm pre-tracheal relapse was noted, however, the excised lesion was consistent with a tall cell variant of papillary thyroid carcinoma (TCV-PTC) arising in ectopic thyroid tissue. RAI treatment was commenced. Four years later, a 5 mm subcutaneous lesion in the anterior neck was surgically removed and diagnosed as metastatic TCV-PTC with a codon 600 BRAF mutation and a C228T TERT promoter mutation.

INTERVENTIONS

RAI treatment was re-initiated. Molecular re-examination of the primary follicular variant papillary thyroid carcinoma demonstrated a codon 600 BRAF mutation and a TERT promoter wildtype sequence, while the primary TCV-PTC was positive for mutations in both codon 600 of BRAF as well as the TERT promoter.

OUTCOMES

The patient is alive and well without signs of relapse 7 months after the latest round of RAI.

LESSONS

We conclude that the occurrence of combined BRAF and TERT promoter mutations in the primary lesion from 2016 was associated to the manifestation of distant metastases 4 years later, strengthening the benefit of mutational screening of these genes in clinical routine for thyroid carcinomas arising in aberrant locations.

SWI/SNF Complex Mutations Promote Thyroid Tumor Progression and Insensitivity to Redifferentiation Therapies

Mutations of subunits of the SWI/SNF chromatin remodeling complexes occur commonly in cancers of different lineages, including advanced thyroid cancers. Here we show that thyroid-specific loss of Arid1a, Arid2, or Smarcb1 in mouse BRAF^V600E-mutant tumors promotes disease progression and decreased survival, associated with lesion-specific effects on chromatin accessibility and differentiation. As compared with normal thyrocytes, BRAF^V600E-mutant mouse papillary thyroid cancers have decreased lineage transcription factor expression and accessibility to their target DNA binding sites, leading to impairment of thyroid-differentiated gene expression and radioiodine incorporation, which is rescued by MAPK inhibition. Loss of individual SWI/SNF subunits in BRAF tumors leads to a repressive chromatin state that cannot be reversed by MAPK pathway blockade, rendering them insensitive to its redifferentiation effects. Our results show that SWI/SNF complexes are central to the maintenance of differentiated function in thyroid cancers, and their loss confers radioiodine refractoriness and resistance to MAPK inhibitor-based redifferentiation therapies. SIGNIFICANCE: Reprogramming cancer differentiation confers therapeutic benefit in various disease contexts. Oncogenic BRAF silences genes required for radioiodine responsiveness in thyroid cancer. Mutations in SWI/SNF genes result in loss of chromatin accessibility at thyroid lineage specification genes in BRAF-mutant thyroid tumors, rendering them insensitive to the redifferentiation effects of MAPK blockade.This article is highlighted in the In This Issue feature, p. 995.

Histopathologic Features and Clinical Outcome of Anaplastic Thyroid Carcinoma with a Minor Anaplastic Component

Although prior studies have reported that patients with anaplastic thyroid carcinoma (ATC) with a focal anaplastic component may have a prolonged survival compared to other ATC patients, the outcome data are limited. We evaluated a cohort of ATC resected between 2003 and 2018. Tumor slides were reviewed to confirm the diagnosis and to identify cases with a minor ATC component (defined as comprising < 10% of the tumor). We evaluated the clinical outcome of these patients compared to that of all other cohort patients (characterized as having conventional ATC). Our cohort was composed of 24 cases of ATC that underwent resection, including 8 (33%) with a minor ATC component. Tumors with a minor ATC component were predominantly associated with papillary thyroid carcinoma. For patients with tumors with a minor ATC component, the 1-year and 2-year survival rates and median survival for patients who died of disease were 88%, 43%, and 17 months (range 6-73 months), respectively. In comparison, for patients with conventional ATC, the 1-year and 2-year survival rates and median survival for patients who died of disease were 56%, 44%, and 7 months (range 2-26 months), respectively. There was no difference in 1- and 2-year survival or overall survival by Kaplan-Meier analysis for patients with tumors with a minor ATC component and those with conventional ATC. In conclusion, the difference in overall survival between ATC groups in our cohort was not significant; however, this could be due to the small cohort size or due to characteristics of our group with a minor ATC component; that is, no tumors in this group were limited to the thyroid (stage IVA), resectability with negative margins was infrequent, and 38% of this group had distant metastases at diagnosis (stage IVC).

Histological features of BRAF V600E-mutant anaplastic thyroid carcinoma

AIMS

Treatment with a BRAF inhibitor, alone or in combination with a MEK inhibitor, may be considered for BRAF-mutant anaplastic thyroid carcinoma (ATC). The purpose of this study was to characterise the histology of BRAF V600E-mutant ATC.

METHODS AND RESULTS

We identified 28 ATC that were consecutively resected between 2003 and 2019. All tumour slides for each case were evaluated for the presence of a precursor tumour and for ATC morphology (sarcomatoid, pleomorphic giant cell, epithelioid or squamous). BRAF V600E mutation status was determined by BRAF V600E IHC or molecular analysis (OncoPanel NGS). Eighteen (64%) ATC had an associated well-differentiated precursor, including 10 (36%) with associated papillary thyroid carcinoma (PTC) and eight (29%) with associated follicular thyroid carcinoma (FTC) or Hürthle cell carcinoma (HCC). Most ATC (19 cases, 68%) demonstrated a mixed anaplastic morphology. Squamous morphology was present in four cases. Ten (36%) ATC had a BRAF V600E mutation. All ATC that had a PTC precursor had a BRAF V600E mutation (and all ATC with a BRAF V600E mutation had a PTC precursor), whereas no ATC with an FTC or HCC precursor had a BRAF V600E mutation. All four cases of ATC with a squamous morphology had a PTC precursor and a BRAF V600E mutation.

CONCLUSION

In our cohort, the presence of a PTC precursor predicted the presence of the BRAF V600E mutation, whereas ATC with an FTC or HCC precursor lacked a BRAF V600E mutation. A squamous morphology was associated with the presence of a PTC precursor and a BRAF V600E mutation.

Anaplastic thyroid carcinoma

Anaplastic thyroid carcinoma (ATC) is a rare but significant malignancy due to its high mortality rate. Rendering an accurate diagnosis is crucial given the prognostic implications and treatment ramifications. Based on the prognostic significance of the extent of invasion of the primary tumor, T staging for ATC changed in the most recent edition of the American Joint Committee on Cancer (AJCC) staging manual. In the past 5 years there has been a rapid increase in our understanding of the molecular basis of ATC which has provided the basis for targeted therapy for some ATC patients. In this review, ATC prognostic factors, histologic and immunotypic features, staging updates, and molecular alterations, with an emphasis on those that may impact treatment, will be discussed.

Metastatic propagation of thyroid cancer; organ tropism and major modulators

Thyroid cancer, as the most prevalent endocrine malignancy, comprises nearly 1% of all cancers in the world. The metastatic propagation of thyroid cancer is under the control of a number of modulating processes and factors such as signaling pathways and their components, cell division regulators, metabolic reprogramming factors, extracellular matrix remodelers, epithelial to mesenchymal transition modulators, epigenetic mechanisms, hypoxia and cytokines. Identifying the exact molecular mechanisms of these dysregulated processes could help to discover the key targets for therapeutic purposes and utilizing them as diagnostic, prognostic and predictors of the clinical course of patients. In this review article, we describe different aspects of thyroid cancer metastasis by focusing on defective genes and pathways involved in its metastatic spread.

Genomic characterization of high-recurrence risk papillary thyroid carcinoma in a southern Chinese population

BACKGROUND

The objective of this study was to investigate genetic variations and the relationships between these genetic variations and clinicopathological features of high-recurrence risk papillary thyroid carcinoma in a southern Chinese population.

METHODS

One hundred sixty-eight patients of high-recurrence risk papillary thyroid carcinoma were recruited for this study from 2017 to 2018. Formalin-fixed paraffin-embedded tissue and the data of clinicopathological characteristics were all collected and analyzed from these patients. We used next-generation sequencing technology to investigate the targeted gene mutations and gene fusions of the pathology specimens.

RESULTS

The frequency of candidate tumor driver gene mutation was 85.1% in 143 patients, including BRAF V600E mutation in 119 patients(70.8%), RET fusion in 13 patients(7.7%), TERT promoter mutations in 11 patients(6.5%), RAS (HRAS, NRAS, KRAS) gene mutations in 10 patients(6.0%), and other mutations involving TP53, PIK3CA, AKT1, PTEN and NTRK1. Concomitant presence of more than two genetic aberrations was seen in 27 patients (16.1%). Our study showed that BRAF V600E mutation is highly correlated with conventional PTC (p < 0.001), BRAF V600E and TERT promoter mutation duet was associated with older patient age (> 45, p = 0.003) and higher disease stage of III or IV (p = 0.002). RAS gene and BRAF V600E co-mutations were only seen in multifocal PTC (p = 0.015).

CONCLUSION

In our high-recurrence risk PTC cohort, most patients had more than one driver gene aberration. Coexistence of BRAF V600E with TERT promoter mutations or with RAS mutations were significantly correlated with worse clinicopathological characteristics.

The Solo Play of TERT Promoter Mutations

The reactivation of telomerase reverse transcriptase (TERT) protein is the principal mechanism of telomere maintenance in cancer cells. Mutations in the TERT promoter (TERTp) are a common mechanism of TERT reactivation in many solid cancers, particularly those originating from slow-replicating tissues. They are associated with increased TERT levels, telomere stabilization, and cell immortalization and proliferation. Much effort has been invested in recent years in characterizing their prevalence in different cancers and their potential as biomarkers for tumor stratification, as well as assessing their molecular mechanism of action, but much remains to be understood. Notably, they appear late in cell transformation and are mutually exclusive with each other as well as with other telomere maintenance mechanisms, indicative of overlapping selective advantages and of a strict regulation of TERT expression levels. In this review, we summarized the latest literature on the role and prevalence of TERTp mutations across different cancer types, highlighting their biased distribution. We then discussed the need to maintain TERT levels at sufficient levels to immortalize cells and promote proliferation while remaining within cell sustainability levels. A better understanding of TERT regulation is crucial when considering its use as a possible target in antitumor strategies.

The Long Non-Coding RNA Prader Willi/Angelman Region RNA5 (PAR5) Is Downregulated in Anaplastic Thyroid Carcinomas Where It Acts as a Tumor Suppressor by Reducing EZH2 Activity

Anaplastic thyroid carcinoma (ATC) represents one the most aggressive neoplasias in humans, and, nowadays, limited advances have been made to extend the survival and reduce the mortality of ATC. Thus, the identification of molecular mechanism underlying its progression is needed. Here, we evaluated the long non-coding RNA (lncRNA) expression profile of nine ATC in comparison with five normal thyroid tissues by a lncRNA microarray. By this analysis, we identified 19 upregulated and 28 downregulated lncRNAs with a fold change >1.1 or <−1.1 and p-value < 0.05, in ATC samples. Some of them were subsequently validated by qRT-PCR. Then, we investigated the role of the lncRNA Prader Willi/Angelman region RNA5 (PAR5), drastically and specifically downregulated in ATC. The restoration of PAR5 reduces proliferation and migration rates of ATC-derived cell lines indicating that its downregulation contributes to thyroid cancer progression. Our results suggest that PAR5 exerts its anti-oncogenic role by impairing Enhancer of Zeste Homolog 2 (EZH2) oncogenic activity since we demonstrated that PAR5 interacts with it in thyroid cancer cell lines, reducing EZH2 protein levels and its binding on the E-cadherin promoter, relieving E-cadherin from the negative regulation by EZH2. Consistently, EZH2 is overexpressed in ATC, but not in differentiated thyroid carcinomas. The results reported here define a tumor suppressor role for PAR5 in undifferentiated thyroid neoplasias, further highlighting the pivotal role of lncRNAs in thyroid carcinogenesis.

Genetic alterations in anaplastic thyroid carcinoma and targeted therapies

Thyroid cancer is the most common type of endocrine malignancy, and its incidence is increasing. Anaplastic thyroid cancer (ATC), referring to undifferentiated subtypes, is considered to be aggressive and associated with poor prognosis. Conventional therapies, including surgery, chemotherapy and radioiodine therapy, have been used for ATC, but these do not provide any significant reduction of the overall mortality rate. The tumorigenesis, development, dedifferentiation and metastasis of ATC are closely associated with the activation of various tyrosine cascades and inactivation of tumor suppressor genes, including B-Raf proto-oncogene, serine/threonine kinase^V600E, phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit α,tumor protein 53 mutations and telomerase reverse transcriptase mutation. These pathways exert their functions individually or through a complex network. Identification of these mutations may provide a deeper understanding of ATC. A variety of tyrosine kinase inhibitors have been successfully employed for controlling ATC growth in vitro and in xenografts. Certain novel compounds are still in clinical trials. Multi-kinase inhibitors provide a novel approach with great potential. This systematic review determined the prevalence of the major genetic alterations and their inhibitors in ATC.

Secretory carcinoma of the breast: clinicopathologic profile of 14 cases emphasising distant metastatic potential

AIMS

Secretory carcinoma of the breast (SCB) is a rare histological type of breast carcinoma with a generally indolent clinical behaviour. We aim to elucidate the clinical, pathological and molecular findings of SCB cases and identify characteristics associated with aggressive clinical courses.

METHODS AND RESULTS

Fourteen patients with SCB were identified, including 12 women and two men, with a median age of 56 years (range = 8-81 years). Clinical data, histological diagnosis, molecular findings and follow-up were reviewed. Eight patients presented with palpable masses and four patients with radiographic abnormalities. All cases were unilateral. Surgical procedures included excisional biopsies and ipsilateral mastectomies. In 10 cases, oestrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) results were obtained, with six cases positive for ER and three positive for PR. All cases lacked HER2 overexpression. Sentinel lymph node biopsy was performed in 10 cases, and two patients had axillary lymph node metastasis. Follow-up ranged from 21 to 212 months (median = 70 months). Two patients developed distant metastasis of SCB. Molecular analysis of these aggressive tumours revealed amplification of the 16p13.3 locus, a TERT promotor mutation and loss of 9p21.3 locus. Review of the literature for SCB cases with distant metastasis was performed.

CONCLUSIONS

Although SCBs are generally associated with a favourable prognosis, our study and review demonstrate that a subset of SCBs may develop distant metastases. Further studies are warranted to identify markers predictive of more aggressive clinical behaviour in this rare breast cancer subtype.

Telomerase and Telomeres Biology in Thyroid Cancer

Telomere and telomerase regulation contributes to the onset and evolution of several tumors, including highly aggressive thyroid cancers (TCs). TCs are the most common endocrine malignancies and are generally characterized by a high rate of curability. However, a small but significant percentage develops distant metastasis or progresses into undifferentiated forms associated with bad prognosis and for which poor therapeutic options are available. Mutations in telomerase reverse transcriptase (TERT) promoter are among the most credited prognostic marker of aggressiveness in TCs. Indeed, their frequency progressively increases passing from indolent lesions to aggressive and anaplastic forms. TERT promoter mutations create binding sites for transcription factors, increasing TERT expression and telomerase activity. Furthermore, aggressiveness of TCs is associated with TERT locus amplification. These data encourage investigating telomerase regulating pathways as relevant drivers of TC development and progression to foster the identification of new therapeutics targets. Here, we summarize the current knowledge about telomere regulation and TCs, exploring both canonical and less conventional pathways. We discuss the possible role of telomere homeostasis in mediating response to cancer therapies and the possibility of using epigenetic drugs to re-evaluate the use of telomerase inhibitors. Combined treatments could be of support to currently used therapies still presenting weaknesses.

A Clinical Overview of Telomerase-Associated Aberrancies in Follicular Thyroid Tumors as Diagnostic and Prognostic Markers: Tert Alert!

Background and Aims:

Endocrine surgeons and pathologists alike are well aware of the diagnostic predicament that follicular thyroid tumors impose in the clinical setting, best exemplified by the current inability to preoperatively assess the malignant potential of each individual lesion. As the proper recognition of a follicular thyroid carcinoma lies in the histopathological identification of invasive behavior, preoperative cytology alone is not yet sufficient to identify malignant tumors eligible for a total thyroidectomy upfront. Numerous auxiliary markers have been proposed as discriminating markers between follicular thyroid carcinomas and follicular thyroid adenomas, although many have proven suboptimal in terms of sensitivity, specificity, or overall clinical practicality. Of late, recurrent promoter mutations in the telomerase reverse transcriptase gene have been intimately coupled to subsets of well-differentiated thyroid cancer specimen with aggressive clinical characteristics as well as less differentiated forms of thyroid cancer with exceedingly poor prognosis. The mutations are thought to enhance the telomerase reverse transcriptase gene expressional output and cause immortalization through telomerase-associated mechanisms.

Materials and Methods:

In this review, the current value of telomerase reverse transcriptase promoter mutations is detailed from a clinical angle—as well as the possible future application of additional telomerase reverse transcriptase gene aberrations as adjunct markers for the proper recognition of malignant potential.

Results:

Telomerase reverse transcriptase promoter mutations are found in subsets of follicular thyroid carcinomas and follicular tumors of uncertain malignant potential while exceedingly rare in recurrence-free follicular thyroid adenomas. Collectively, these aberrancies are suggested as possible diagnostic and prognostic discriminators of follicular thyroid tumors.

Conclusions:

Telomerase reverse transcriptase gene analyses greatly facilitate the clinical assessment of follicular thyroid tumors, and pinpoints cases at risk of future recurrences. High-volume, tertiary thyroid centers are therefore recommended to implement the mutational screening in clinical routine.

Genetic-guided Risk Assessment and Management of Thyroid Cancer

Controversies exist on how to optimally manage thyroid cancer because the prognosis is often uncertain based on clinical backgrounds. This can now be helped with prognostic genetic markers in thyroid cancer, exemplified by BRAF V600E and TERT promoter mutations, which have been well characterized and widely appreciated. The genetic duet of BRAF V600E/RAS and TERT promoter mutations is a most robust prognostic genetic pattern for poor prognosis of differentiated thyroid cancer. The high negative predictive values of the prognostic genetic markers are equally valuable. The best prognostic value of genetic markers in thyroid cancer is achieved through a clinical risk level-based and genotype-individualized manner.

Diagnosis and Management of Anaplastic Thyroid Cancer

Anaplastic thyroid cancer (ATC) is a devastating and usually incurable diagnosis. Clinical and pathologic diagnosis is best assessed at a tertiary center with concentrated ATC expertise. Expeditious multidisciplinary management is recommended for optimal patient outcomes. Based on multiinstitutional and population-based studies, multimodal therapy that includes chemoradiotherapy with surgery (when feasible) is the preferred initial treatment because it is associated with incrementally improved overall survival. In ATC that carries a BRAF V600E somatic mutation, combination therapy with BRAF and MEK inhibitors has shown promise but needs further study. Immunotherapeutic agents in neoadjuvant and metastatic settings are being investigated.

Coding Molecular Determinants of Thyroid Cancer Development and Progression

Thyroid cancer is the most common endocrine malignancy. Its incidence and mortality rates have increased for patients with advanced-stage papillary thyroid cancer. The characterization of the molecular pathways essential in thyroid cancer initiation and progression has made huge progress, underlining the role of intracellular signaling to promote clonal evolution, dedifferentiation, metastasis, and drug resistance. The discovery of genetic alterations that include mutations (BRAF, hTERT), translocations, deletions (eg, 9p), and copy-number gain (eg, 1q) has provided new biological insights with clinical applications. Understanding how molecular pathways interplay is one of the key strategies to develop new therapeutic treatments and improve prognosis.

Molecular aberrations and signaling cascades implicated in the pathogenesis of anaplastic thyroid cancer

Anaplastic Thyroid Cancer (ATC) accounts for >40% thyroid cancer-related deaths and has a dismal prognosis. In the past decade, significant efforts have been made towards understanding the pathogenesis of this disease and developing novel therapeutics. Unfortunately, effective treatment is still lacking and a more thorough understanding of ATC pathogenesis may provide new opportunities to improve ATC therapeutics. This review provides insights into ATC clinical presentation and pathology, and the putative role of genetic aberrations and alterations in molecular signaling pathways in ATC pathogenesis. We reviewed prevalent mutations, chromosomal abnormalities and fusions, epigenetic alterations and dysregulations in ATC, and highlighted several signaling cascades which appeared to be integral to ATC pathogenesis. Moreover, these features offer insights into de-differentiated, aggressive and drug-resistant phenotype of ATC, and thus may help in exploring potential new molecular targets for developing novel therapeutics.

TERTp mutation is associated with a shorter progression free survival in patients with aggressive histology subtypes of follicular-cell derived thyroid carcinoma

PURPOSE

Evaluate the impact of TERTp mutation on the outcomes after initial treatment of 45 patients with thyroid carcinomas derived from follicular cells (TCDFC) with aggressive histology, in which the role of this mutation is not yet well defined.

METHODS

Analysis of the presence of TERTp (-124C > T and -146C > T), BRAF (V600E), and NRAS (Q 61R) mutations by Sanger sequencing and analysis of their correlation with the patient's outcomes.

RESULTS

Forty-five patients with aggressive histopathologic variants were included in the study. Of these, 68.9% had aggressive variants of papillary thyroid cancer (PTC), 22.2% had poorly differentiated thyroid carcinoma (PDTC)/insular carcinoma, and 8.9% had invasive follicular thyroid cancer (FTC) with Hurthle cell features (Hurthle cell carcinoma). Lymph node metastases were present in 46.7% and distant metastases in 54.6%. The response to the initial therapy was excellent in 45.5% and structurally incomplete in 50%. During the follow-up period (median of 56 months; 5-360 months), 47.7% presented with disease progression and 17.8% experienced disease-related death. In 53.3% of the cases at least one molecular alteration (TERTp in 33.4%, BRAF in 24.5%, RAS in 8.9%) was detected. In the multivariate analysis, TERTp mutation was the factor associated with the highest risk (6 times) of having structural disease after initial therapy (p = 0.01), followed by vascular invasion (p = 0.02), gross extrathyroidal extension (ETE) (p = 0.02) and distant metastasis (p = 0.04). Regarding mutational status, only TERTp mutation was associated with disease progression, and diminished disease progression-free survival (PFS). The presence of distant metastasis, vascular invasion and gross ETE were significantly associated with the risk of disease progression.

CONCLUSIONS

TERTp mutation appears be an indicator of both persistence and progression of structural disease after initial therapy in aggressive variants of TCDFC, and associates with a shorter progression free survival regardless of the therapy employed.

The role of TERT promoter mutations in postoperative and preoperative diagnosis and prognosis in thyroid cancer

BACKGROUND

Telomerase reverse transcriptase (TERT) promoter mutations have been described in different pathological types of thyroid cancers (TC). After many types of research focusing on the mutations rate in malignant tumors, the main role of TERT promoter mutations has been changed to the preoperative diagnosis and prognosis of TC, according to their high prevalence in aggressive TC.

METHODS

We searched Pubmed, Web of Science, Scopus, and VHL and reviewed the most common 2 mutations C288T and C250T in different types of TC, the association between them and some specific clinicopathological features, and their significance in preoperative diagnosis and prognosis of TC. we chose 38 studies into our qualitative research. We also chose 22 studies to do a meta-analysis on this subject.

RESULTS

The overall rate of these mutations in different types of TC was 10.0%, with 86.1% C228T mutation, 12% C250T mutation, and 2.1% other type mutations. The rate increases significantly as the TC become more aggressive, and reaches 56.8% in anaplastic thyroid cancer (ATC). Statistically meaningful association is found between TERT promoter mutations and older age, larger tumor size, extrathyroidal extension, lymph node metastasis, distance metastasis, advanced TNM stage, recurrence, and BRAF V600E mutation. Some studies concentrating on DNA sequencing based on fine needle aspiration biopsy (FNAB) also proved their significance in preoperative stage, with 7% to 16.5% sensitivity.

CONCLUSIONS

TERT promoter mutations were likely to occur in BRAF V600E positive TC. Patients with these 2 combined mutations were more likely to have a poor prognosis and outcome. TERT promoter mutations is an essential part of the ThySeq gene panel. The mechanism of how they influence the appearance and development of TC has not been expounded. The next study direction may be the mechanism exploration and the further study to prove their significance in preoperative diagnosis.

[Genetics of thyroid nodules and thyroid carcinoma]

Thyroid nodules are heterogeneous tumors with variable genetic signatures. Thyroid cancers are monoclonal lesions with a defined histomorphology that largely depends on the underlying somatic mutation. While the mutation rate is generally low in differentiated thyroid cancers, poorly differentiated and anaplastic thyroid cancers show a high mutation load. The identification of somatic mutations in fine needle aspirates can be helpful for the differential diagnostics of thyroid nodules; however, a prognostic contribution is less certain. The molecular pathology of thyroid tumors is helpful for the development of targeted therapies and may infer novel immuno-oncological concepts for advanced aggressive thyroid cancers.

Diagnostic value and lymph node metastasis prediction of a custom‑made panel (thyroline) in thyroid cancer

Differentiation of benign and malignant thyroid nodules is crucial for clinical management. Here, we explored the efficacy of next-generation sequencing (NGS) in predicting the classification of benign and malignant thyroid nodules and lymph node metastasis status, and simultaneously compared the results with ultrasound (US). Thyroline was designed to detect 15 target gene mutations and 2 fusions in 98 formalin-fixed, paraffin-embedded (FFPE) tissues, including those from 82 thyroid cancer (TC) patients and 16 patients with benign nodules. BRAF mutations were found in 57.69% of the papillary thyroid cancer (PTC) cases, while RET mutations were detected among all the medullary thyroid cancer (MTC) cases. Multiple mutations were positive but none showed dominance in anaplastic thyroid cancer (ATC) and follicular thyroid cancer (FTC). The sensitivity and specificity of NGS prediction in differentiation of benign and malignant thyroid nodules were 79.27 and 93.75%, respectively, and the positive predictive value (PPV) and negative predictive value (NPV) were 98.48 and 46.88%, respectively. The sensitivity and specificity of US were 76.83 and 6.25%, respectively, and the PPV and NPV were 80.77 and 5.00%, respectively. The area under curve (AUC) of NGS and US were 0.865 and 0.415, respectively. A total of 27 patients had ≥1 metastases to lymph nodes, 19 of which carried mutations, including BRAF, RET, NRAS, PIK3CA, TP53, CTNNB1 and PTEN. However, there was no correlation between the variant allele frequency of specific gene mutations and the number of metastatic lymph nodes. In conclusion, the prediction value of NGS was higher than the US-based Thyroid Imaging Reporting and Data System (TI-RADS). NGS is valuable for the accurate differentiation of benign and malignant thyroid nodules, and pathological subtypes in FFPE samples. The findings of the present study may pave the way for the application of NGS in analyzing fine-needle aspiration (FNA) biopsy samples.

Telomere Maintenance Mechanisms in Cancer

Tumour cells can adopt telomere maintenance mechanisms (TMMs) to avoid telomere shortening, an inevitable process due to successive cell divisions. In most tumour cells, telomere length (TL) is maintained by reactivation of telomerase, while a small part acquires immortality through the telomerase-independent alternative lengthening of telomeres (ALT) mechanism. In the last years, a great amount of data was generated, and different TMMs were reported and explained in detail, benefiting from genome-scale studies of major importance. In this review, we address seven different TMMs in tumour cells: mutations of the TERT promoter (TERTp), amplification of the genes TERT and TERC, polymorphic variants of the TERT gene and of its promoter, rearrangements of the TERT gene, epigenetic changes, ALT, and non-defined TMM (NDTMM). We gathered information from over fifty thousand patients reported in 288 papers in the last years. This wide data collection enabled us to portray, by organ/system and histotypes, the prevalence of TERTp mutations, TERT and TERC amplifications, and ALT in human tumours. Based on this information, we discuss the putative future clinical impact of the aforementioned mechanisms on the malignant transformation process in different setups, and provide insights for screening, prognosis, and patient management stratification.

NGS based identification of mutational hotspots for targeted therapy in anaplastic thyroid carcinoma

CONTEXT

Anaplastic thyroid carcinoma (ATC) represents one of the most aggressive carcinomas with no consistent survival benefit when treated with conventional radiochemotherapy. Approaches targeting "oncogene addiction" of ATC are increasingly explored and first promising results have been reported in single case studies.

OBJECTIVE

To determine the prevalence of mutations in known thyroid oncogenes and signalling pathways amendable to targeted therapy in a large cohort of ATC.

RESULTS

In 118 ATC (57 male/ 61 female) a total of 165 mutations were found. Genes involved in the MAPK/ERK and PI3K pathway (BRAF 11.0%, HRAS 4.2%, KRAS 7.6%, NRAS 7.6%, PI3KCA 11.8%) were altered in 33%. Targetable receptor tyrosine kinases were mutated in 11%. The most frequently altered genes were TERT in 86/118 (73%) and p53 in 65/118 (55%) cases. No mutations were found analysing ALK, KIT, MET and mTOR.

MATERIALS AND METHODS

Next generation sequencing (NGS) was performed in FFPE samples from 118 ATC using MiSeq (Illumina) and CLC Cancer Research Workbench (CLCbio; Qiagen) for mutation analysis in: ALK, BRAF, CDKN2A, EGFR, ERBB2, HRAS, KIT, KRAS, MET, mTOR, NRAS, PDGFRA, PI3KCA, p53, RB1, RET and TSC2. Sanger sequencing was used to detect TERT promotor mutations.

CONCLUSIONS

To our knowledge this is the largest study analysing mutations for targeted therapy of ATC. We found that 33% of ATC harbour mutations in pathways amendable to targeted therapy. Molecular screening in ATC is suggested for targeted therapies since current conventional treatment for ATC proved mainly futile.

Clinical, pathological and genetic features of anaplastic and poorly differentiated thyroid cancer: A single institute experience

Anaplastic (ATC) and poorly differentiated thyroid cancer (PDTC) are very aggressive cancers whose histological diagnosis is not always straightforward. Clinical, pathological and genetic features may be useful to improve the identification of these rare histotypes. In the present study the clinical, pathological and genetic features of two groups of ATC (n=21) and PDTC (n=21) patients were analyzed. Clinical data were retrieved from a computerized database. The oncogenic profiles were studied using the Sanger sequencing method of a selected series of oncogenes and/or tumor suppressor genes known to be altered in these tumors. The presence of macrophages in both series of tissues was evaluated by immunohistochemistry. Patients with ATC were older and affected by a more advanced disease at diagnosis than those with PDTC. The median survival was significantly shorter in ATC compared with PDTC patients (P=0.0014). ATC showed a higher prevalence of TP53 and TERT mutations (10/21, 47.6% and 9/21, 42.8%, respectively) while TERT and BRAF mutations were the most prevalent in the PDTC group (7/21, 33.3% and 4/23, 19% respectively). Genetic heterogeneity (i.e., >2 mutations) was more frequent in ATC (10/21, 28.6%) compared with in PDTC (3/21, 4.7%) (P=0.03). Macrophages were more frequently present in ATC, particularly in those cases with TP53 mutations. In conclusion, these data indicate that ATC and PDTC may be characterized by different clinical, pathological and genetic profiles. In particular ATC, but not PDTC, were positive for TP53 and PTEN alterations. Complex mutations were also found in ATC but not in PDTC. Moreover, genetic heterogeneity was more frequent in ATC than PDTC. Finally, TP53 mutation and the accumulation of several mutations correlated with a shorter survival time.

TERT promoter mutations and their correlation with BRAF and RAS mutations in a consecutive cohort of 145 thyroid cancer cases

Papillary thyroid carcinoma (PTC) is the most common type of endocrine malignancy and accounts for ~80% of thyroid carcinomas in adults and 90% in children. Risk stratification is important for identifying patients at higher risk and, for this reason, recent advances in molecular genetics of thyroid cancer can be applied to provide novel biomarkers useful in understanding tumor behavior. B-Raf proto-oncogene, serine/threonine kinase (BRAF) and rat sarcoma (RAS) mutations have been widely studied and appear to have an important role in thyroid tumorigenesis. Somatic telomerase reverse transcriptase (TERT) promoter mutations have been recently identified in several types of malignant tumors, including thyroid neoplasia; however, the actual role of TERT mutations in thyroid tumorigenesis is still under debate. In the present study, the mutational status of BRAF, RAS and TERT was analyzed in order to elucidate the roles of these genes in thyroid tumorigenesis. The TERT mutational analysis was also correlated with an immunohistochemical study of TERT protein expression. According to the literature, our data provide evidence of the BRAF and RAS roles in thyroid tumorigenesis, supporting an association between BRAF (V600E) mutations and the more aggressive clinical and pathological features of thyroid tumors. By contrast, TERT mutations were not significantly associated with any clinical parameters; therefore, its role in initial tumorigenesis should be further investigated.

Ultrasound and clinicopathological features of papillary thyroid carcinomas with BRAF and TERT promoter mutations

This study is to investigate if any relationship exists between the telomerase reverse transcriptase (TERT) promoter or proto-oncogene BRAF mutation and ultrasound (US) and clinicopathological features of papillary thyroid carcinomas (PTCs). The study included 150 patients with surgically confirmed PTC from October 1994 to December 2004. According to the existence of TERT promoter or BRAF mutations, we categorized patients into three groups (no mutation, BRAF mutation alone, or TERT+BRAF mutations) and analyzed the relationships between TERT promoter or BRAF mutation and US and clinicopathological features. The rate of recurrence or death according to mutation analysis was estimated. There were 35 (23.3%) cases with no mutation, 104 (69.3%) with BRAF mutation alone, and 11 (7.3%) with TERT+BRAF mutations. As the number of genetic mutations increased from no mutation to BRAF mutation alone to both BRAF and TERT mutations, the proportions of hypoechogenicity, non-parallel orientation, spiculated/microlobulated margin, microcalcifications, and high suspicion category increased. PTCs with TERT+BRAF mutations recurred more frequently than other groups (odd ratio = 17.921 and 31.468). The intervals to recurrence and overall survival were significantly shorter in the TERT+BRAF mutation group than in the other groups (Ps <.0001). PTCs with no mutation, with BRAF mutation alone, and with both TERT and BRAF mutations linearly increase in the probability of displaying malignant US features. In PTCs, the coexistence of BRAF with TERT mutations is more strongly correlated with recurrence and mortality than BRAF mutation alone.

Molecular alterations of coexisting thyroid papillary carcinoma and anaplastic carcinoma: identification of TERT mutation as an independent risk factor for transformation

Thyroid papillary carcinoma is the most common endocrine neoplasm and generally carries a favorable prognosis. However, a small subset of papillary carcinomas transforms into anaplastic carcinoma, an undifferentiated cancer with a dismal prognosis. Recent studies using next-generation sequencing revealed the genomic landscape of papillary carcinoma and anaplastic carcinoma. However, risk factors for anaplastic transformation in papillary carcinoma remain obscure. In the present study, we investigated molecular alterations of papillary carcinoma and anaplastic carcinoma components in 27 tumors in which anaplastic carcinoma coexisted with antecedent papillary carcinoma. We conducted direct sequencing for BRAF, TERT promoter and PIK3CA, and immunohistochemistry for p53, TTF-1 and subunits of the SWI/SNF complex (ARID1A, ARID1B, ATRX, SMARCA2, SMARCA4, SMARCB1, and PBRM1). BRAF^V600E and TERT promoter mutated at the rate of 90% and 95%, respectively, and these mutational statuses were almost identical between the papillary carcinoma and anaplastic carcinoma components. PIK3CA mutation was positive in 33% of our samples with a heterogeneous mutation pattern of the papillary carcinoma and anaplastic carcinoma components. Aberrant expression of p53 and loss of TTF-1 were present in 63 and 59%, respectively, and these two alterations were confined to the anaplastic carcinoma components. There was a loss of the SWI/SNF complex in a subset of the tumors with a heterogeneous pattern of the papillary carcinoma and anaplastic carcinoma components: SMARCA4 in 4% and PBRM1 in 4%. In a multivariate comparison between the antecedent papillary carcinoma components and control papillary carcinomas without anaplastic transformation, TERT promoter mutation was independently associated with anaplastic transformation. Collectively, papillary carcinoma-derived anaplastic carcinomas are characterized by BRAF and TERT promoter mutations, and these mutations occur prior to anaplastic transformation. Alterations of PIK3CA and the SWI/SNF complex are relatively rare and temporally heterogeneous. Of note, a papillary carcinoma harboring TERT promoter mutation is at higher risk for anaplastic transformation.

Key signaling pathways in thyroid cancer

Whole genome sequencing approaches have provided unprecedented insights into the genetic lesions responsible for the onset, progression and dedifferentiation of various types of thyroid carcinomas. Through these efforts, the MAPK and PI3K signaling cascades have emerged as the main activation pathways implicated in thyroid tumorigenesis. The nature of these essential pathways is highly complex, with hundreds of components, multiple points of crosstalk, different subcellular localizations and with the ability to potentially regulate many cellular processes. Small-molecule inhibitors targeting key kinases of these pathways hold great promise as novel therapeutics and several have reached clinical trials. However, while some remarkable responses have been reported, the development of resistance remains a matter of concern and limits the benefit for patients. In this review, we discuss the latest findings on the major components of the MAPK and PI3K pathways, including their mechanisms of activation in physiological and pathological contexts, their genetic alterations with respect to the different types of thyroid carcinomas and the more relevant drugs designed to block their activity.

[Molecular Pathogenesis of Thyroid Nodules: Relevance for Clinical Care]

Thyroid nodules represent heterogeneous tumors with distinct molecular signatures. While benign thyroid nodules correspond to poly- or monoclonal tumors, thyroid carcinomas are monoclonal and thus "real" neoplasms. These are caused by somatic mutations that lead to the constitutive activation of specific signaling cascades and determine the corresponding histology and also partly the functional phenotype of the thyroid tumor. Dedifferentiation of thyroid carcinomas is accompanied by the occurrence of additional mutations in the tumors. The mutation load of thyroid carcinomas correlates with their biological behavior. In clinical practice, detection of somatic mutations can help in the cytological differential diagnosis. In the prognostic assessment of thyroid tumors, proof of classical oncogene mutations (BRAF, RAS) has little relevance. Other genetic alterations, especially TERT promoter mutations that occur with increasing frequency in advanced thyroid carcinomas, probably have a prognostic significance. The molecular signature, however, is of great relevance for the development and application of targeted therapies in advanced carcinomas (radioactive iodine-refractory DTC, PDTC and ATC, metastatic medullary carcinoma). For this, there is increasing evidence from clinical studies and case reports that underline the concept of "oncogene addiction" as a pathogenetically relevant mechanism of thyroid tumorigenesis and carcinogenesis.

Prognostic indicators for papillary thyroid carcinoma

Differentiated thyroid cancer (DTC) includes more than 90% of all thyroid carcinoma and its incidence is growing, mainly due to an increase in the incidence of papillary thyroid cancer (PTC) for the widespread use of neck ultrasonography. Areas covered: Several prognostic factors should be considered during the management of PTC in order to provide the most effective treatment. The most important prognostic factors in PTC include personal and pathological features such as patient's age, gender, hystotype, tumor size, extrathyroidal extension, lymph node involvement, presence of local or distant metastases and molecular analyses. We performed a search in the PubMed database for studies published in English since 1960 using the terms: 'thyroid cancer', 'prognostic factors', 'age', 'gender', 'hystotype', 'tumor size', 'extrathyroidal extension', 'lymph node', 'metastases' and 'molecular analyses'. Expert commentary: Prognostic factors can guide clinicians during the treatment and follow-up of DTC patients, but it is now evident that the risk of recurrence or death must be evaluated periodically, on the basis of individual risk, according to the response to initial therapy or the subsequent therapy required during follow-up.

A six-genotype genetic prognostic model for papillary thyroid cancer

A unique prognostic role of the genetic duet of BRAF V600E and TERT promoter mutations in papillary thyroid cancer (PTC) has been recently established, but the role of RAS mutation in this genetic interplay remains to be established. Using The Cancer Genome Atlas (TCGA) data of patients with PTC from 19 medical centers, we investigated the interactions among the three mutations in clinical outcomes of PTC. We found that BRAF and RAS mutations were mutually exclusive, but both were associated with TERT promoter mutations, with the genetic duet of BRAF/RAS and TERT mutations occurring in 34/388 (8.76%) patients. BRAF/RAS or TERT mutation had no or minimal effect alone, whereas coexisting BRAF/RAS and TERT mutations had a robust synergistic effect on poor clinicopathologic outcomes of PTC, including disease recurrence and patient mortality. For example, PTC recurrence rate was 52% with coexisting BRAF V600E/RAS and TERT promoter mutations vs 6.9% with no mutation, corresponding to a HR of 8.17 (95% CI 3.09-21.58), which remained significant at 14.71 (95% CI 2.79-77.61) after adjustment for clinicopathologic factors and institution. BRAF/RAS mutation or TERT mutation alone minimally affected Kaplan-Meier patient survival curves, whereas the genetic duet was associated with a sharp curve decline. Thus, by confirming and expanding previous findings in single-institution studies, this multicenter data analysis establishes a six-genotype genetic prognostic model for poor outcomes of PTC with a risk order of genetic duet of BRAF V600E/RAS mutation and TERT mutation >>>>BRAF V600E = TERT mutation alone >RAS mutation alone = wild-type genes.

Targeted next-generation sequencing for TP53, RAS, BRAF, ALK and NF1 mutations in anaplastic thyroid cancer

Anaplastic thyroid carcinoma (ATC) is the most aggressive thyroid cancer with a median survival of 4-6 months. Identification of mutations contributing to aberrant activation of signaling cascades in ATC may provide novel opportunities for targeted therapy. Thirty-nine ATC samples were studied by next-generation sequencing (NGS) with an established gene panel. High quality readout was obtained in 30/39 ATC. Twenty-eight ATC harbored a mutation in at least one of the studied genes: TP53 (18/30), NF1 (11/30), ALK (6/30), NRAS (4/30), ATRX (3/30), BRAF (2/30), HRAS (2/30), KRAS (1/30). In 17/30 ATC (54 %) mutations were found in two or more genes. Twenty-one of the identified variants are listed in COSMIC as somatic mutations reported in other cancer entities. In three ATC samples no mutations were detected and none of the ATCs was positive for BRAF^V600E. The most frequent mutations were found in TP53 (60 %), followed by NF1 (37 %). ALK mutations were detected in 20 % of ATC and were more frequent than RAS or BRAF mutations. ATRX mutations were identified in 10 % of the ATC samples. These sequencing data from 30 ATC samples demonstrate the accumulation of genetic alterations in ATC because in 90 % of samples mutations were already found in the investigated nine genes alone. Mutations were found with high prevalence in established tumor suppressor and oncogenes in ATC, such as TP53 and H/K/NRAS, but also, although less frequent, in genes that may harbor the potential for targeted treatment in a subset of ATC patients, such as ALK and NF1.