Search

Abstract Background The transcription factor Pax8 is essential for the differentiation of thyroid cells. However, there are few data on genes transcriptionally regulated by Pax8 other than thyroid-related genes. To better understand the role of Pax8 in the biology of thyroid cells, we obtained transcriptional profiles of Pax8-silenced PCCl3 thyroid cells using whole genome expression arrays and integrated these signals with global cis-regulatory sequencing studies performed by ChIP-Seq analysis Results Exhaustive analysis of Pax8 immunoprecipitated peaks demonstrated preferential binding to intragenic regions and CpG-enriched islands, which suggests a role of Pax8 in transcriptional regulation of orphan CpG regions. In addition, ChIP-Seq allowed us to identify Pax8 partners, including proteins involved in tertiary DNA structure (CTCF) and chromatin remodeling (Sp1), and these direct transcriptional interactions were confirmed in vivo. Moreover, both factors modulate Pax8-dependent transcriptional activation of the sodium iodide symporter (Nis) gene promoter. We ultimately combined putative and novel Pax8 binding sites with actual target gene expression regulation to define Pax8-dependent genes. Functional classification suggests that Pax8-regulated genes may be directly involved in important processes of thyroid cell function such as cell proliferation and differentiation, apoptosis, cell polarity, motion and adhesion, and a plethora of DNA/protein-related processes. Conclusion Our study provides novel insights into the role of Pax8 in thyroid biology, exerted through transcriptional regulation of important genes involved in critical thyrocyte processes. In addition, we found new transcriptional partners of Pax8, which functionally cooperate with Pax8 in the regulation of thyroid gene transcription. Besides, our data demonstrate preferential location of Pax8 in non-promoter CpG regions. These data point to an orphan CpG island-mediated mechanism that represents a novel role of Pax8 in the transcriptional output of the thyrocyte.

Background: The 2022 World Health Organization classification introduced the term high-grade follicular cell-derived nonanaplastic thyroid carcinoma (HGFCTC) to define invasive/infiltrative nonanaplastic thyroid carcinoma with high-grade features, including poorly differentiated thyroid carcinoma and high-grade differentiated thyroid carcinoma. Our objectives were to compare clinicopathological characteristics, oncologic outcomes, and mutation profiles among HGFCTC subgroups to better inform prognostication and treatment. Methods: In this single-center, retrospective cohort study of 252 patients who had surgery for HGFCTC from 1986 to 2020, we categorized HGFCTC and its related entity, "encapsulated noninvasive neoplasms of follicular cells with high-grade features," into five subgroups: (A) encapsulated noninvasive, (B) encapsulated with capsular invasion only (minimally invasive), (C) encapsulated angioinvasive with focal vascular invasion (VI), (D) encapsulated angioinvasive with extensive VI, and (E) infiltrative tumors. Next-generation sequencing with Memorial Sloan Kettering Cancer Center-Integrated Mutation Profiling of Actionable Cancer Targets was available for 117/252 patients to investigate differences in mutation profiles. Results: The cohort comprised 50% infiltrative, 33% encapsulated angioinvasive, and 18% encapsulated noninvasive/minimally invasive tumors. No patients with encapsulated noninvasive or minimally invasive disease had regional or distant metastases at presentation. Patients with infiltrative tumors were significantly more likely to present with T3/T4 disease (71%), regional metastases (55%), and distant metastases (25%) ( p ≤ 0.003 ). Five-year disease-specific survival was poorer in patients with infiltrative disease (67.7%), compared to encapsulated angioinvasive focal VI (90.4%), encapsulated angioinvasive extensive VI (88.1%), and encapsulated noninvasive/minimally invasive (100%) ( p = 0.0002) subgroups. Common mutations were TERT (42%), BRAF V600E (29%), NRAS (27%), EIF1AX (11%), and TP53 (9%). Pathways altered included RTK/RAS/RAF/MAPK (69%), PI3K/AKT/MTOR (14%), histone methyltransferases (9%), and SWI/SNF chromatin remodeling complex (8%). Subgroup analysis showed the infiltrative subgroup was mainly BRAF V600E -driven, and the encapsulated angioinvasive and minimally invasive subgroups were NRAS- driven. Encapsulated noninvasive tumors had a different mutation profile, with DICER1 as the main driver mutation. Conclusions: HGFCTC comprises different subgroups with different clinical behaviors determined by the extent of vascular invasion and degree of infiltration. Excellent recurrence and survival outcomes occur in encapsulated noninvasive and minimally invasive tumors compared to infiltrative tumors. Infiltrative tumors are largely " BRAF -like," whereas encapsulated angioinvasive tumors are " RAS -like." Encapsulated noninvasive tumors have a particularly unique molecular profile consisting of DICER1 mutations and a lack of BRAF V600E mutations.

Thyroid nodules are a common endocrine condition with an increasing incidence over the decades. Data-independent acquisition has been widely utilized in discovery proteomics to identify disease biomarkers and therapeutic targets. To analyze the thyroid disease-related proteome in a high-throughput, reproducible and reliable manner, we introduce thyroid-specific peptide spectral libraries. Here, we generated four deep-coverage libraries through four mass spectrometers comprising Q Exactive HF, Orbitrap Exploris 480, ZenoTOF 7600, and timsTOF Pro. These libraries encompass over 215,000 precursors, 172,000 peptides, and 12,000 proteins, derived from 245 tissue samples across nine histological types and 50 cell lines across six histological types. Moreover, the spectral libraries are applied to nine types of thyroid samples to facilitate the exploration of disease-specific proteins. Our spectral libraries serve as a valuable resource for analyzing thyroid protein content, facilitating deeper insights into thyroid disorders., Competing Interests: Competing interests: T.G. and Y.Z. are shareholders of Westlake Omics Inc. The other authors declare no competing interests in this paper., (© 2024. The Author(s).)

RBM10 modulates transcriptome-wide cassette exon splicing. Loss-of-function RBM10 mutations are enriched in thyroid cancers with distant metastases. Analysis of transcriptomes and genes mis-spliced by RBM10 loss showed pro-migratory and RHO/RAC signaling signatures. RBM10 loss increases cell velocity. Cytoskeletal and ECM transcripts subject to exon inclusion events included vinculin (VCL), tenascin C (TNC), and CD44. Knockdown of the VCL exon inclusion transcript in RBM10-null cells reduced cell velocity, whereas knockdown of TNC and CD44 exon inclusion isoforms reduced invasiveness. RAC1-GTP levels were increased in RBM10-null cells. Mouse HrasG12V/Rbm1OKO thyrocytes develop metastases that are reversed by RBM10 expression or by combined knockdown of VCL, CD44, and TNC inclusion isoforms. Thus, RBM10 loss generates exon inclusion in transcripts regulating ECM-cytoskeletal interactions, leading to RAC1 activation and metastatic competency. Moreover, a CRISPR-Cas9 screen for synthetic lethality with RBM10 loss identified NFκB effectors as central to viability, providing a therapeutic target for these lethal thyroid cancers., (© 2025 Krishnamoorthy et al.)

Anaplastic thyroid cancer (ATC) is a clinically aggressive malignancy with a dismal prognosis. Combined BRAF/MEK inhibition offers significant therapeutic benefit in patients with BRAF V600E -mutant ATCs. However, relapses are common and overall survival remains poor. Compared with differentiated thyroid cancer, a hallmark of ATCs is significant infiltration with myeloid cells, particularly macrophages. ATCs are most common in the aging population, which also has an increased incidence of TET2 -mutant clonal hematopoiesis (CH). CH-mutant macrophages have been shown to accelerate CH-associated pathophysiology including atherosclerosis. However, the clinical and mechanistic contribution of CH-mutant clones to solid tumour biology, prognosis and therapeutic response has not been elucidated. Here we show that TET2 -mutant CH is enriched in the tumour microenvironment of patients with solid tumours and associated with adverse prognosis in ATC patients. We find that Tet2 -mutant macrophages selectively infiltrate mouse Braf V600E -mutant ATC and that their overexpression of Tgfβ-family ligands mediates resistance to BRAF/MEK inhibition. Importantly, inhibition of Tgfβ signaling restores sensitivity to MAPK pathway inhibition, opening a path for synergistic strategies to improve outcomes of patients with ATCs and concurrent CH.

Background: Fluorine 18-labelled tetrafluoroborate ([ 18 F]TFB) is a substrate for the sodium/iodide symporter. In thyroid cancer, [ 18 F]TFB-PET/CT may be an alternative to iodine imaging to evaluate the extent of disease, eligibility for radioiodine treatment, and success of redifferentiation therapies. We report the results of a pilot study to determine tumor uptake of [ 18 F]TFB and compare its properties to [ 124 I]IodinePET/CT in patients with metastatic thyroid cancer., Methods: Five patients were included in a prospective study. All patients received PET/CT 1 h after injection of 356 ± 12 MBq [ 18 F]TFB and were given 230 ± 9 MBq [ 124 I]Iodine orally on the same day, followed by PET/CT after 48 h. Before redifferentiation therapy, patients underwent an additional baseline [ 124 I]Iodine PET/CT. Cases were analyzed by two board-certified specialists. Detection rates and Spearman correlation for [ 18 F]TFB and [ 124 I]Iodine were calculated., Results: Three patients had poorly differentiated thyroid cancer and received trametinib in a redifferentiation trial. Two patients had papillary thyroid cancer and did not receive redifferentiation therapy. Of the 33 lesions seen before/without redifferentiation therapy, 19 (58%) were visible on [ 18 F]TFB and 30 (91%) on [ 124 I]Iodine imaging. In the patients who underwent redifferentiation therapy, 48 lesions were newly seen on [ 124 I]Iodine PET/CT with a median SUV max of 3.3 (range, 0.4-285.0). All of these lesions were [ 18 F]TFB-negative., Conclusion: [ 18 F]TFB failed to predict radioactive iodine uptake in patients with poorly differentiated thyroid cancer who underwent redifferentiation therapy with trametinib. It is unclear whether such discrepancies may also occur in other redifferentiation therapies or may even be encountered in redifferentiation-naïve thyroid cancer., Trial Registration Number: NCT03196518, registered on June 22, 2017., (© 2024. The Author(s).)

Background: Diffuse sclerosing papillary thyroid carcinoma (DSPTC) is an aggressive histopathologic subtype of papillary thyroid carcinoma. Correlation between genotype and phenotype has not been comprehensively described. This study aimed to describe the genomic landscape of DSPTC comprehensively using next-generation sequencing (NGS), analyze the prognostic implications of different mutations, and identify potential molecular treatment targets., Methods: Tumor tissue was available for 41 DSPTC patients treated at Memorial Sloan Kettering Cancer Center between 2004 and 2021. After DNA extraction, NGS was performed using the Memorial Sloan Kettering Integrated Mutation Profiling of Actionable Cancer Targets platform, which sequences 505 critical cancer genes. Clinicopathologic characteristics were compared using the chi-square test. The Kaplan-Meier method and log-rank statistics were used to compare outcomes., Results: The most common mutation was RET fusion, occurring in 32% (13/41) of the patients. Other oncologic drivers occurred in 68% (28/41) of the patients, including 8 BRAF V600E mutations (20%) and 4 USP8 mutations (10%), which have not been described in thyroid malignancy previously. Patients experienced RET fusion-positive tumors at a younger age than other drivers, with more aggressive histopathologic features and more advanced T stage (p = 0.019). Patients who were RET fusion-positive had a significantly poorer 5-year recurrence-free survival probability than those with other drivers (46% vs 84%; p = 0.003; median follow-up period, 45 months). In multivariable analysis, RET fusion was the only independent risk factor for recurrence (hazard ratio [HR], 7.69; p = 0.017)., Conclusion: Gene-sequencing should be strongly considered for recurrent DSPTC due to significant prognostic and treatment implications of RET fusion identification. The novel finding of USP8 mutation in DSPTC requires further investigation into its potential as a driver mutation., (© 2024. Society of Surgical Oncology.)

In the clinical development of farnesyltransferase inhibitors (FTIs) for HRAS-mutant tumors, responses varied by cancer type. Co-occurring mutations may affect responses. We aimed to uncover cooperative genetic events specific to HRAS-mutant tumors and to study their effect on sensitivity to FTIs. Using targeted sequencing data from the MSK-IMPACT and Dana-Farber Cancer Institute Genomic Evidence Neoplasia Information Exchange databases, we identified comutations that were observed predominantly in HRAS-mutant versus KRAS-mutant or NRAS-mutant cancers. HRAS-mutant cancers had a higher frequency of coaltered mutations (48.8%) in the MAPK, PI3K, or RTK pathway genes, compared with KRAS-mutant (41.4%) and NRAS-mutant (38.4%) cancers (p < 0.05). Class 3 BRAF, NF1, PTEN, and PIK3CA mutations were more prevalent in HRAS-mutant lineages. To study the effects of comutations on sensitivity to FTIs, Hras G13R was transfected into "RASless" (Kras lox/lox /Hras -/- /Nras -/- /RERT ert/ert ) mouse embryonic fibroblasts (MEFs), which sensitized nontransfected MEFs to tipifarnib. Comutation in the form of Pten or Nf1 deletion and Pik3ca H1047R transduction led to resistance to tipifarnib in Hras G13R -transfected MEFs in the presence or absence of Kras WT , whereas Braf G466E transduction led to resistance to tipifarnib only in the presence of Kras WT . Combined treatment with tipifarnib and MEK inhibition sensitized cells to tipifarnib in all settings, including in MEFs with PI3K pathway comutations. HRAS-mutant tumors demonstrate lineage-dependent MAPK or PI3K pathway alterations, which confer resistance to tipifarnib. The combined use of FTIs and MEK inhibition is a promising strategy for HRAS-mutant tumors., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

RBM10 modulates transcriptome-wide cassette exon splicing. Loss-of-function RBM10 mutations are enriched in thyroid cancers with distant metastases. Analysis of transcriptomes and genes mis-spliced by RBM10 loss showed pro-migratory and RHO/RAC signaling signatures. RBM10 loss increases cell velocity. Cytoskeletal and ECM transcripts subject to exon-inclusion events included vinculin (VCL), tenascin C (TNC) and CD44. Knockdown of the VCL exon inclusion transcript in RBM10 -null cells reduced cell velocity, whereas knockdown of TNC and CD44 exon-inclusion isoforms reduced invasiveness. RAC1-GTP levels were increased in RBM10 -null cells. Mouse Hras G12V /Rbm1O KO thyrocytes develop metastases that are reversed by RBM10 or by combined knockdown of VCL, CD44 and TNC inclusion isoforms. Thus, RBM10 loss generates exon inclusions in transcripts regulating ECM-cytoskeletal interactions, leading to RAC1 activation and metastatic competency. Moreover, a CRISPR-Cas9 screen for synthetic lethality with RBM10 loss identified NFkB effectors as central to viability, providing a therapeutic target for these lethal thyroid cancers., Competing Interests: J.A.F. is a co-inventor of intellectual property focused on HRAS as a biomarker for treating cancer using tipifarnib which has been licensed by MSK to Kura Oncology. J.A.F. received prior research funding from Eisai and was a former consultant for LOXO Oncology, both unrelated to the current manuscript. B.R.U. and J.A.K are co-inventors of intellectual property (HRAS as a biomarker of tipifarnib efficacy) that has been licensed by MSK to Kura Oncology. O.A.-W. has served as a consultant for H3B Biomedicine, Foundation Medicine Inc., Merck, Prelude Therapeutics, and Janssen, and is on the Scientific Advisory Board of Envisagenics Inc., AIChemy, Harmonic Discovery Inc., and Pfizer Boulder. O.A.-W. has received prior research funding from H3B Biomedicine, Nurix Therapeutics, Minovia Therapeutics, and LOXO Oncology unrelated to the current manuscript. R.K.B. is an inventor on patent applications filed by Fred Hutchinson Cancer Center related to modulating splicing for cancer therapy. R.K.B. and O.A.-W. are founders and scientific advisors of Codify Therapeutics, hold equity in this company and receive research support from this company unrelated to the current manuscript. R.K.B. is a founder and scientific advisor of Synthesize Bio and holds equity in this company. A.R.G is currently an Associate Professor of Surgery at the University of Sydney, Australia. M.S. is currently employed by Loxo Oncology.The remaining authors declare no competing interests.

Aims: Papillary thyroid carcinoma, tall cell subtype (PTC-TC) is a potentially aggressive histotype. The latest World Health Organisation (WHO) classification introduced a novel class of tumours; namely, high-grade differentiated thyroid carcinoma (HGDTC), characterised by elevated mitotic count and/or necrosis, which can exhibit a tall cell phenotype (HGDTC-TC)., Methods and Results: We analysed the clinical outcomes in a large retrospective cohort of 1456 consecutive thyroid carcinomas with a tall cell phenotype, including PTC-TC and HGDTC-TC. HGDTC-TC is uncommon, accounting for 5.3% (77 of 1379) of carcinomas with tall cell morphology. HGDTC-TC was associated with significantly older age, larger tumour size, angioinvasion, gross extrathyroidal extension, higher AJCC pT stage, positive resection margin and nodal metastasis (P < 0.05). Compared with PTC-TC, HGDTC was associated with a significantly decreased DSS, LRDFS and distant metastasis-free survival (DMFS; P < 0.001). The 10-year DSS was 72 and 99%, the 10-year LRDFS was 61 and 92% and the 10-year DMFS was 53 and 97%, respectively, for HGDTC-TC and PTC-TC. On multivariate analysis, the classification (HGDTC-TC versus PTC-TC) was an independent adverse prognostic factor for DSS, LRDF, and DMFS when adjusted for sex, age, angioinvasion, margin status, AJCC pT and pN stage., Conclusions: Compared with PTC-TC, HGDTC-TC is associated with adverse clinicopathological features, a higher frequency of TERT promoter mutations (59% in HGDTC-TC versus 34% in PTC-TC) and incurs a significantly worse prognosis. HGDTC-TC is an independent prognostic factor for carcinoma with tall cell morphology. This validates the concept of HGDTC and the importance of tumour necrosis and high mitotic count for accurate diagnosis and prognosis of differentiated thyroid carcinomas., (© 2024 John Wiley & Sons Ltd.)

Background: Genomic profiling is now available for risk stratification of cytologically indeterminate thyroid nodules (ITNs). Mutations in RAS genes ( HRAS , NRAS , KRAS ) are found in both benign and malignant thyroid nodules, although isolated RAS mutations are rarely associated with aggressive tumors. Because the long-term behavior of RAS -mutant ITNs is not well understood, most undergo immediate surgery. In this multicenter retrospective cohort study, we characterize tumor growth kinetics of RAS -mutant ITNs followed with active surveillance (AS) using serial ultrasound (US) scans and examine the histopathologic diagnoses of those surgically resected. Methods: US and histopathologic data were analyzed retrospectively from two cohorts: (1) RAS -mutant ITNs managed with AS at three institutions (2010-2023) and (2) RAS -mutant ITNs managed with immediate surgery at two institutions (2016-2020). AS cohort subjects had ≥3 months of follow-up and two or more US scans. Cumulative incidence of nodule growth was determined by the Kaplan-Meier method and growth by ≥72% change in tumor volume. Pathological diagnoses for the immediate surgery cohort were analyzed separately. Results: Sixty-two patients with 63 RAS -mutated ITNs under AS had a median diameter of 1.7 cm (interquartile range [IQR] 1.2-2.6) at time of diagnosis. During a median AS period of 23 months (IQR 9.5-53.5 months), growth was observed in 12 of 63 nodules (19.0%), with a cumulative incidence of 1.9% (1 year), 23.0% (3 years), and 28.0% (5 years). Most nodules (81.0%) demonstrated stability. Surgery was ultimately performed in 6 nodules, of which 1 (16.7%) was malignant. In the cohort of 209 RAS -mutant ITNs triaged to immediate surgery, 33% were malignant (23.9% American Thyroid Association [ATA] low-risk cancers, 7.2% ATA intermediate-risk, and 1.9% ATA high-risk. During a median follow-up of 6.9 (IQR 4.4-7.1) years, there were no disease-specific deaths in these patients. Conclusions: We describe the behavior of RAS -mutant ITNs under AS and find that most demonstrate stability over time. Of the resected RAS -mutant nodules, most were benign; of the cancers, most were ATA low-risk. Immediate surgical resection of all RAS -mutant ITNs appears to be a low-value practice. Further research is needed to help define cases most appropriate for AS or immediate surgery.

Purpose: The prognostic importance of RET and RAS mutations and their relationship to clinicopathologic parameters and outcomes in medullary thyroid carcinoma (MTC) need to be clarified. Experimental Design: A multicenter retrospective cohort study was performed utilizing data from 290 patients with MTC. The molecular profile was determined and associations were examined with clinicopathologic data and outcomes. Results: RET germ line mutations were detected in 40 patients (16.3%). Somatic RET and RAS mutations occurred in 135 (46.9%) and 57 (19.8%) patients, respectively. RET M918T was the most common somatic RET mutation ( n  = 75). RET somatic mutations were associated with male sex, larger tumor size, advanced American Joint Committee Cancer (AJCC) stage, vascular invasion, and high International Medullary Thyroid Carcinoma Grading System (IMTCGS) grade. When compared with other RET somatic mutations, RET M918T was associated with younger age, AJCC (eighth edition) IV, vascular invasion, extrathyroidal extension, and positive margins. RET somatic or germ line mutations were significantly associated with reduced distant metastasis-free survival on univariate analysis, but there were no significant independent associations on multivariable analysis, after adjusting for tumor grade and stage. There were no significant differences in outcomes between RET somatic and RET germ line mutations, or between RET M918T and other RET mutations. Other recurrent molecular alterations included TP53 (4.2%), ARID2 (2.9%), SETD2 (2.9%), KMT2A (2.9%), and KMT2C (2.9%). Among them, TP53 mutations were associated with decreased overall survival (OS) and disease-specific survival (DSS), independently of tumor grade and AJCC stage. Conclusions: RET somatic mutations were associated with high-grade, aggressive primary tumor characteristics, and decreased distant metastatic-free survival but this relationship was not significant after accounting for tumor grade and disease stage. RET M918T was associated with aggressive primary tumors but was not independently associated with clinical outcomes. TP53 mutation may represent an adverse molecular event associated with decreased OS and DSS in MTC, but its prognostic value needs to be confirmed in future studies.

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., (©2023 American Association for Cancer Research.)

Background: Very little was known about the molecular pathogenesis of thyroid cancer until the late 1980s. As part of the Centennial celebration of the American Thyroid Association, we review the historical discoveries that contributed to our current understanding of the genetic underpinnings of thyroid cancer. Summary: The pace of discovery was heavily dependent on scientific breakthroughs in nucleic acid sequencing technology, cancer biology, thyroid development, thyroid cell signaling, and growth regulation. Accordingly, we attempt to link the primary observations on thyroid cancer molecular genetics with the methodological and scientific advances that made them possible. Conclusions: The major genetic drivers of the common forms of thyroid cancer are now quite well established and contribute to a significant extent to how we diagnose and treat the disease. However, many challenges remain. Future work will need to unravel the complexity of thyroid cancer ecosystems, which is likely to be a major determinant of their biological behavior and on how they respond to therapy.

The genomic simplicity of differentiated cancers derived from thyroid follicular cells offers unique insights into how oncogenic drivers impact tumour phenotype. Essentially, the main oncoproteins in thyroid cancer activate nodes in the receptor tyrosine kinase-RAS-BRAF pathway, which constitutively induces MAPK signalling to varying degrees consistent with their specific biochemical mechanisms of action. The magnitude of the flux through the MAPK signalling pathway determines key elements of thyroid cancer biology, including differentiation state, invasive properties and the cellular composition of the tumour microenvironment. Progression of disease results from genomic lesions that drive immortalization, disrupt chromatin accessibility and cause cell cycle checkpoint dysfunction, in conjunction with a tumour microenvironment characterized by progressive immunosuppression. This Review charts the genomic trajectories of these common endocrine tumours, while connecting them to the biological states that they confer., (© 2023. Springer Nature Limited.)

Objective: Exposure to therapeutic radioactive iodine (RAI) is associated with an increased relative risk of myeloid malignancies. Clonal hematopoiesis (CH) is a precursor state that can be detected in blood of healthy individuals decades before overt development of leukemia. We prospective studied the effects of RAI on CH., Design: Prospective cohort study., Patients and Measurements: We examined the effect of RAI on CH in 20 patients exposed to RAI for thyroid carcinoma and 20 age-matched unexposed controls. CH status was determined at baseline, 6, 12, 18 and 24 months. We also examined the effect of CH on structural progression of disease., Results: No CH mutations were observed in the patient population that were not present at baseline. Using a variant allelic fraction (VAF) of 2% to define CH, 6/20 older patients (55-80 years old) had CH compared to 2/20 younger patients (20-40 years old) (p = 0.11). Six patients exposed to RAI had CH compared to two patients not exposed to RAI (30% vs. 10%, p = 0.11). There was no significant difference in CH VAF increase in patients treated with RAI compared to untreated age-matched controls (3.8% vs. 1.2%, p = 0.2). CH was significantly associated with somatic BRAFV600E mutations and with worse progression-free survival in the overall cohort as well as among BRAFV600E-mutant tumors., Conclusions: There was no increase in CH in patients treated with RAI over a 2-year follow-up period. Larger studies with longer follow-up periods are needed to investigate the association between RAI and clonal dynamics. The presence of CH is associated with worse structural progression in both BRAFV600E-mutant and wild-type thyroid cancers., (© 2023 John Wiley & Sons Ltd.)

Purpose: The determinants of response or resistance to radioiodine (RAI) are unknown. We aimed to identify genomic and transcriptomic factors associated with structural responses to RAI treatment of metastatic thyroid cancer, which occur infrequently, and to test whether high MAPK pathway output was associated with RAI refractoriness., Experimental Design: Exceptional response to RAI was defined as reduction of tumor volume based on RECIST v1.1. We performed a retrospective case-control study of genomic and transcriptomic characteristics of exceptional responders (ER; n = 8) versus nonresponders (NR; n = 16) matched by histologic type and stage at presentation on a 1:2 ratio., Results: ER are enriched for mutations that activate MAPK through RAF dimerization (RAS, class 2 BRAF, RTK fusions), whereas NR are associated with BRAFV600E, which signals as a monomer and is unresponsive to negative feedback. ER have a lower MAPK transcriptional output and a higher thyroid differentiation score (TDS) than NR (P < 0.05). NR are enriched for 1q-gain (P < 0.05) and mutations of genes regulating mRNA splicing and the PI3K pathway. BRAFV600E tumors with 1q-gain have a lower TDS than BRAFV600E/1q-quiet tumors and transcriptomic signatures associated with metastatic propensity., Conclusions: ER tumors have a lower MAPK output and higher TDS than NR, whereas NR have a high frequency of BRAFV600E and 1q-gain. Molecular profiling of thyroid cancers and further functional validation of the key findings discriminating ER from NR may help predict response to RAI therapy., (©2023 American Association for Cancer Research.)

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.

Therapy resistance is a major challenge in the treatment of cancer. Here, we performed CRISPR-Cas9 screens across a broad range of therapies used in acute myeloid leukemia to identify genomic determinants of drug response. Our screens uncover a selective dependency on RNA splicing factors whose loss preferentially enhances response to the BCL2 inhibitor venetoclax. Loss of the splicing factor RBM10 augments response to venetoclax in leukemia yet is completely dispensable for normal hematopoiesis. Combined RBM10 and BCL2 inhibition leads to mis-splicing and inactivation of the inhibitor of apoptosis XIAP and downregulation of BCL2A1, an anti-apoptotic protein implicated in venetoclax resistance. Inhibition of splicing kinase families CLKs (CDC-like kinases) and DYRKs (dual-specificity tyrosine-regulated kinases) leads to aberrant splicing of key splicing and apoptotic factors that synergize with venetoclax, and overcomes resistance to BCL2 inhibition. Our findings underscore the importance of splicing in modulating response to therapies and provide a strategy to improve venetoclax-based treatments., Competing Interests: Declaration of interests E.M., E.C., M.J., C.B., C.-C.M., and D.M.B. are employees of Biosplice Therapeutics. O.A.-W. has served as a consultant for H3B Biomedicine, Foundation Medicine Inc., Merck, Prelude Therapeutics, and Janssen and is on the Scientific Advisory Board of Envisagenics Inc., AIChemy, Harmonic Discovery Inc., and Pfizer Boulder. O.A.-W. has received prior research funding from H3B Biomedicine, Nurix Therapeutics, and LOXO Oncology unrelated to the current manuscript. The remaining authors declare no competing interests., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Inactivation of the Hippo pathway promotes Yap nuclear translocation, enabling execution of a transcriptional program that induces tissue growth. Genetic lesions of Hippo intermediates only identify a minority of cancers with illegitimate YAP activation. Yap has been implicated in resistance to targeted therapies, but the mechanisms by which YAP may impact adaptive resistance to MAPK inhibitors are unknown., Methods: We screened 52 thyroid cancer cell lines for illegitimate nuclear YAP localization by immunofluorescence and fractionation of cell lysates. We engineered a doxycycline (dox)-inducible thyroid-specific mouse model expressing constitutively nuclear YAP S127A , alone or in combination with endogenous expression of either Hras G12V or Braf V600E . We also generated cell lines expressing dox-inducible sh-miR-E-YAP and/or YAP S127A . We used cell viability, invasion assays, immunofluorescence, Western blotting, qRT-PCRs, flow cytometry and cell sorting, high-throughput bulk RNA sequencing and in vivo tumorigenesis to investigate YAP dependency and response of BRAF-mutant cells to vemurafenib., Results: We found that 27/52 thyroid cancer cell lines had constitutively aberrant YAP nuclear localization when cultured at high density (NU-YAP), which rendered them dependent on YAP for viability, invasiveness and sensitivity to the YAP-TEAD complex inhibitor verteporfin, whereas cells with confluency-driven nuclear exclusion of YAP (CYT-YAP) were not. Treatment of BRAF-mutant thyroid cancer cells with RAF kinase inhibitors resulted in YAP nuclear translocation and activation of its transcriptional output. Resistance to vemurafenib in BRAF-mutant thyroid cells was driven by YAP-dependent NRG1, HER2 and HER3 activation across all isogenic human and mouse thyroid cell lines tested, which was abrogated by silencing YAP and relieved by pan-HER kinase inhibitors. YAP activation induced analogous changes in BRAF melanoma, but not colorectal cells., Conclusions: YAP activation in thyroid cancer generates a dependency on this transcription factor. YAP governs adaptive resistance to RAF kinase inhibitors and induces a gene expression program in BRAF V600E -mutant cells encompassing effectors in the NRG1 signaling pathway, which play a central role in the insensitivity to MAPK inhibitors in a lineage-dependent manner. HIPPO pathway inactivation serves as a lineage-dependent rheostat controlling the magnitude of the adaptive relief of feedback responses to MAPK inhibitors in BRAF- V600E cancers., (© 2022. The Author(s).)

Accurate ancestry inference is critical for identifying genetic contributors of cancer disparities among populations. Although methods to infer genetic ancestry have historically relied upon genome-wide markers, the adaptation to targeted clinical sequencing panels presents an opportunity to incorporate ancestry inference into routine diagnostic workflows. We show that global ancestral contributions and admixture of continental populations can be quantitatively inferred using markers captured by the MSK-IMPACT clinical panel. In a pan-cancer cohort of 45,157 patients, we observed differences by ancestry in the frequency of somatic alterations, recapitulating known associations and revealing novel associations. Despite the comparable overall prevalence of driver alterations by ancestry group, the proportion of patients with clinically actionable alterations was lower for African (30%) compared with European (33%) ancestry. Although this result is largely explained by population-specific cancer subtype differences, it reveals an inequity in the degree to which different populations are served by existing precision oncology interventions., Significance: We performed a comprehensive analysis of ancestral associations with somatic mutations in a real-world pan-cancer cohort, including >5,000 non-European individuals. Using an FDA-authorized tumor sequencing panel and an FDA-recognized oncology knowledge base, we detected differences in the prevalence of clinically actionable alterations, potentially contributing to health care disparities affecting underrepresented populations. This article is highlighted in the In This Issue feature, p. 2483., (©2022 American Association for Cancer Research.)

Papillary thyroid carcinoma (PTC) is the most frequent histological subtype of thyroid cancers (TC), and BRAF V600E genetic alteration is found in 60% of this endocrine cancer. This oncogene is associated with poor prognosis, resistance to radioiodine therapy, and tumor progression. Histological follow-up by anatomo-pathologists revealed that two-thirds of surgically-removed thyroids do not present malignant lesions. Thus, continued fundamental research into the molecular mechanisms of TC downstream of BRAF V600E remains central to better understanding the clinical behavior of these tumors. To study PTC, we used a mouse model in which expression of BRAF V600E was specifically switched on in thyrocytes by doxycycline administration. Upon daily intraperitoneal doxycycline injection, thyroid tissue rapidly acquired histological features mimicking human PTC. Transcriptomic analysis revealed major changes in immune signaling pathways upon BRAF V600E induction. Multiplex immunofluorescence confirmed the abundant recruitment of macrophages, among which a population of LYVE-1+/CD206+/STABILIN-1+ was dramatically increased. By genetically inactivating the gene coding for the scavenger receptor STABILIN-1, we showed an increase of CD8+ T cells in this in situ BRAF V600E -dependent TC. Lastly, we demonstrated the presence of CD206+/STABILIN-1+ macrophages in human thyroid pathologies. Altogether, we revealed the recruitment of immunosuppressive STABILIN-1 macrophages in a PTC mouse model and the interest to further study this macrophage subpopulation in human thyroid tissues.

Hürthle cell carcinomas (HCCs) display two exceptional genotypes: near-homoplasmic mutation of mitochondrial DNA (mtDNA) and genome-wide loss of heterozygosity (gLOH). To understand the phenotypic consequences of these genetic alterations, we analyzed genomic, metabolomic, and immunophenotypic data of HCC and other thyroid cancers. Both mtDNA mutations and profound depletion of citrate pools are common in HCC and other thyroid malignancies, suggesting that thyroid cancers are broadly equipped to survive tricarboxylic acid cycle impairment, whereas metabolites in the reduced form of NADH-dependent lysine degradation pathway were elevated exclusively in HCC. The presence of gLOH was not associated with metabolic phenotypes but rather with reduced immune infiltration, indicating that gLOH confers a selective advantage partially through immunosuppression. Unsupervised multimodal clustering revealed four clusters of HCC with distinct clinical, metabolomic, and microenvironmental phenotypes but overlapping genotypes. These findings chart the metabolic and microenvironmental landscape of HCC and shed light on the interaction between genotype, metabolism, and the microenvironment in cancer.

Purpose: Selumetinib can increase radioactive iodine (RAI) avidity in RAI-refractory tumors. We investigated whether selumetinib plus adjuvant RAI improves complete remission (CR) rates in patients with differentiated thyroid cancer (DTC) at high risk of primary treatment failure versus RAI alone., Methods: ASTRA (ClinicalTrials.gov identifier: NCT01843062) is an international, phase III, randomized, placebo-controlled, double-blind trial. Patients with DTC at high risk of primary treatment failure (primary tumor > 4 cm; gross extrathyroidal extension outside the thyroid gland [T4 disease]; or N1a/N1b disease with ≥ 1 metastatic lymph node(s) ≥ 1 cm or ≥ 5 lymph nodes [any size]) were randomly assigned 2:1 to selumetinib 75 mg orally twice daily or placebo for approximately 5 weeks (no stratification). On treatment days 29-31, recombinant human thyroid-stimulating hormone (0.9 mg)-stimulated RAI ( 131 I; 100 mCi/3.7 GBq) was administered, followed by 5 days of selumetinib/placebo. The primary end point (CR rate 18 months after RAI) was assessed in the intention-to-treat population., Results: Four hundred patients were enrolled (August 27, 2013-March 23, 2016) and 233 randomly assigned (selumetinib, n = 155 [67%]; placebo, n = 78 [33%]). No statistically significant difference in CR rate 18 months after RAI was observed (selumetinib n = 62 [40%]; placebo n = 30 [38%]; odds ratio 1.07 [95% CI, 0.61 to 1.87]; P = .8205). Treatment-related grade ≥ 3 adverse events were reported in 25/154 patients (16%) with selumetinib and none with placebo. The most common adverse event with selumetinib was dermatitis acneiform (n = 11 [7%]). No treatment-related deaths were reported., Conclusion: Postoperative pathologic risk stratification identified patients with DTC at high risk of primary treatment failure, although the addition of selumetinib to adjuvant RAI failed to improve the CR rate for these patients. Future strategies should focus on tumor genotype-tailored drug selection and maintaining drug dosing to optimize RAI efficacy., Competing Interests: Alan L. HoConsulting or Advisory Role: Bristol Myers Squibb, Eisai, Genzyme, Merck, Novartis, Sun Pharma, Eisai, Regeneron, TRM Oncology, Ayala Pharmaceuticals, AstraZeneca, Sanofi, CureVac, Prelude Therapeutics, Kura Oncology, McGivney Global Advisors, Rgenta, AffyImmune Therapeutics, Exelixis, Cellestia, InxmedSpeakers’ Bureau: Medscape, Omniprex America, NovartisResearch Funding: Lilly, Genentech/Roche (Inst), AstraZeneca, Allos Therapeutics, Astellas Pharma, Ayala Pharmaceuticals, Bayer, Bristol Myers Squibb, Daiichi Sankyo, Eisai, Elevar Therapeutics, Kolltan Pharmaceuticals, Kura Oncology, Merck, Novartis, PfizerTravel, Accommodations, Expenses: Janssen Oncology, Merck, Kura Oncology, Ignyta, Ayala Pharmaceuticals, Klusa Pharma Marek DedecjusHonoraria: Sanofi/Aventis, Bayer, Berlin-ChemieResearch Funding: AstraAzeneca/Merck, Exelixis Lori J. WirthConsulting or Advisory Role: Merck, Loxo, Blueprint Medicines, Eisai, Lilly, Bayer, ExelixisResearching Funding: Checkmate Pharmaceuticals (Inst), Lilly (Inst), Ayala Pharmaceuticals (Inst), Eisai (Inst)Expert Testimony: EisaiOther Relationship: PDS Biotechnology R. Michael TuttleResearch Funding: Elesta (Inst) Fernanda VaismanConsulting or Advisory Role: AstraZeneca/Merck, Ipsen, Lilly, Bayer HealthSpeaker’s Bureau: Bayer, AstraZeneca/Merck, Sanofi, United Medical Lars BastholtResearch Funding: Bristol Myers Squibb (Inst) Andrew G. GianoukakisConsulting or Advisory Role: Eisai, Exelixs Patrice RodienConsulting or Advisory Role: Eisai EuropeResearch Funding: Pfizer (Inst) Ralf PaschkeConsulting or Advisory Role: Bayer, EisaiResearching Funding: Bayer (Inst)Patents, Royalties, Other Intellectual Property: Licensing fee for a diagnostic testRossella EliseiConsulting or Advisory Role: EISAI, Genezyme, Loxo, Ipsen, Bayer, Lilly Karen SoEmployment: AstraZenecaStock and Other Ownership Interests: AstraZeneca Danielle CarrollEmployment: AstraZeneca/MedImmune, Azeria therapeutics (I)Leadership: Azeria therapeutics (I)Stock and Other Ownership Interests: AstraZeneca/MedImmune, Azeria Therapeutics (I)Honoraria: AstraZeneca (I)Consulting or Advisory Role: Azeria therapeutics (I)Research Funding: AstraZeneca (I)Patents, Royalties, Other Intellectual Property: Royalties from Active Motif (I), Compositions featuring an attenuated Newcastle disease virus and methods of use for treating neoplasia, Anti-cxc chemokine-2 binding molecules and uses thereof Tina HoveyEmployment: PhastarConsulting or Advisory Role: AstraZenecaResearch Funding: AstraZeneca James A. FaginHonoraria: Eisai EuropeConsulting or Advisory Role: Loxo OncologyPatents, Royalties, Other Intellectual Property: 3. MSK Ref. SK 2014-024-03 Title: Treatment of H-RAS-Driven Tumors. Application Number: 15/305,788. 3. Anti-TSHR Multispecific Antibodies and Uses Thereof, provisional patent.No other potential conflicts of interest were reported.

Purpose: The development of the selective RET inhibitors selpercatinib and pralsetinib has revolutionized the treatment of metastatic progressive RET-mutant medullary thyroid carcinoma (MTC) and other RET-driven cancers, given their more favorable side-effect profile. The aim of this study is to investigate the mechanisms of selpercatinib-induced thyroid dysfunction in athyreotic patients with RET-mutant MTC and in patients with RET-mutant non-small-cell lung cancer (NSCLC) who had a functional thyroid., Materials and Methods: Thyroid hormone levels were evaluated in an observational cohort of five athyreotic patients with MTC and 30 patients with NSCLC before and after initiation of selpercatinib. In vitro experiments to identify the mechanism of selpercatinib-induced thyroid dysfunction were conducted in cells expressing endogenous D1, D2, and D3 iodothyronine deiodinases., Results: Upon initiating treatment with selpercatinib, athyreotic patients developed clinical hypothyroidism with approximately 60% lower T3 levels despite adequate levothyroxine supplementation, whereas in patients with NSCLC, who retain a normal thyroid, selpercatinib resulted in a more attenuated reduction in serum T3, which was dose-dependent. We conducted studies in cells endogenously expressing either D1, D2, or D3, the three iodothyronine deiodinases. Selpercatinib inhibited D2-mediated T3 production in MSTO-211 cells by 50%. A modest repression of D2 mRNA was present in human thyroid cancer TT cells that express RET, but not in the MSTO-211 cells that do not. No effect of the drug was observed on D1 (activating deiodinase) or D3 (inactivating deiodinase). Thus, a nontranscriptional effect of selpercatinib on D2 activity is the most plausible explanation for the low T3 levels., Conclusion: An off-target effect of selpercatinib on D2-mediated T3 production leads to clinical hypothyroidism, primarily in levothyroxine-treated athyreotic patients. Liothyronine supplementation was needed to achieve normal T3 levels and restore clinical euthyroidism., Competing Interests: Eric ShermanConsulting or Advisory Role: Eisai, UpToDate, Lilly, Blueprint Medicines, ExelixisResearch Funding: Plexxikon (Inst), Regeneron (Inst), Lilly (Inst), HUTCHMED (Inst), Novartis (Inst) Charles M. RudinConsulting or Advisory Role: Harpoon Therapeutics, Genentech/Roche, AstraZeneca, Ipsen, Bridge Medicines, Syros Pharmaceuticals, Amgen, Jazz Pharmaceuticals, Epizyme, Syros Pharmaceuticals, Earli, AbbVie, Daiichi Sankyo/UCB Japan, Kowa, MerckResearch Funding: Merck (Inst), Roche/Genentech (Inst)Open Payments Link: https://openpaymentsdata.cms.gov/physician/111056 Alexander DrilonStock and Other Ownership Interests: Treeline BiosciencesHonoraria: Pfizer, Loxo/Bayer/Lilly, IASLC, Helsinn Therapeutics, BeiGene, Remedica, TP Therapeutics, Verastem, Ignyta/Genetech/Roche, AstraZeneca, Liberum, Lungevity, NIH, PER, OncLive/MJH Life Sciences, Clinical Care Options/NCCN, Lung Cancer Research Foundation, Associazione Italiana Oncologia Toracica (AIOT), Chugai Pharma, Sirio Libanes Hospital, Answers in CME, Research to Practice, RV MoreConsulting or Advisory Role: Ignyta, Loxo, AstraZeneca, Pfizer, Blueprint Medicines, Genentech/Roche, BeiGene, Hengrui Therapeutics, Exelixis, Bayer, Tyra Biosciences, Takeda/Millennium, BerGenBio, MORE Health, Lilly, AbbVie, 14ner Oncology/Elevation Oncology, Monopteros Therapeutics, Novartis, EMD Serono/Merck, Repare Therapeutics, Melendi, Archer, Nuvalent, Inc, Janssen, Amgen, Merus, Axis Pharma, Medscape, Liberum, Med Learning, PeerView, EPG Health, Journal of the National Comprehensive Cancer Network, Ology Medical Education, Clinical Care Options, touchIME, Entos, Prelude Therapeutics, Applied Pharmaceutical Science, Treeline BioResearch Funding: Foundation MedicinePatents, Royalties, Other Intellectual Property: Wolters Kluwer (Royalties for Pocket Oncology)Other Relationship: Merck, GlaxoSmithKline, Teva, Taiho Pharmaceutical, Pfizer, PharmaMar, Puma Biotechnology, Merus, Boehringer Ingelheim Antonio C. BiancoConsulting or Advisory Role: AbbVie, Allergan, Syntonics, Sention, Thyron James A. FaginHonoraria: Eisai EuropeConsulting or Advisory Role: LoxoPatents, Royalties, Other Intellectual Property: 3. MSK Ref. SK 2014-024-03 Title: Treatment of H-RAS-Driven Tumors. Application Number: 15/305,788, Anti-TSHR Multispecific Antibodies and Uses Thereof. Provisional patent (Inst)No other potential conflicts of interest were reported.

Purpose: Anaplastic thyroid carcinoma (ATC) is the most lethal form of thyroid cancer with most patients dying of their disease within a few months. Only a very small percentage of long-term survivors (LTS) are alive for 2 years or longer. In this retrospective case-control study, we provided a comprehensive comparison between 46 ATC LTSs and 75 ATC control patients who suffered disease-specific mortality within 2 years, aiming to identify factors that may be associated with prolonged survival in ATC., Methods: A comprehensive clinicopathologic and molecular comparison was performed between 46 ATC LTSs and 75 ATC control patients. Peripheral neutrophil count and neutrophil-to-lymphocyte ratio (NLR) were recorded. The composition of the tumor microenvironment was compared using immunohistochemistry., Results: Compared with ATC control patients, ATC LTSs were characterized by 1) higher frequency of (primary) resection as well as clinicopathologic parameters attributed to resectability; 2) lower rate of concurrent RAS/BRAF and TERT promoter mutations; 3) lower peripheral neutrophil count and NLR; and 4) lower number of tumor-infiltrating neutrophils/myeloid-derived suppressor cells (MDSC). The survival benefits of low peripheral neutrophil counts and low NLR persisted even when controlling for distant metastasis status at presentation., Conclusions: In addition to traditional beneficial prognostic factors, e.g., surgical resection, factors attributed to resectability, and absence of co-existing RAS/BRAF and TERT promoter mutations, we herein show that tumor-infiltrating and circulating neutrophils/MDSC are adverse prognostic factors in ATC., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: The development of systemic treatment options leveraging the molecular landscape of advanced thyroid cancer is a burgeoning field. This is a multidisciplinary evidence-based statement on the definition of advanced thyroid cancer and its targeted systemic treatment., Methods: An expert panel was assembled, a literature review was conducted, and best practice statements were developed. The modified Delphi method was applied to assess the degree of consensus for the statements developed by the author panel., Results: A review of the current understanding of thyroid oncogenesis at a molecular level is presented and characteristics of advanced thyroid cancer are defined. Twenty statements in topics including the multidisciplinary management, molecular evaluation, and targeted systemic treatment of advanced thyroid cancer are provided., Conclusions: With the growth in targeted treatment options for thyroid cancer, a consensus definition of advanced disease and statements regarding the utility of molecular testing and available targeted systemic therapy is warranted., (© 2022 Wiley Periodicals LLC.)

Competing Interests: James A. FaginHonoraria: Eisai EuropeConsulting or Advisory Role: Loxo OncologyPatents, Royalties, Other Intellectual Property: MSK Ref. SK 2014-024-03 Title: Treatment of H-RAS–Driven Tumors. Application Number: 15/305,788, Anti-TSHR Multispecific Antibodies and Uses Thereof. Provisional patent (Inst)No other potential conflicts of interest were reported.

Context: The BRAFV600E mutation has been associated with more advanced clinical stage in papillary thyroid cancer (PTC) and decreased responsiveness to radioiodine (RAI). However, some BRAF mutant PTCs respond to RAI and have an indolent clinical behavior suggesting the presence of different subtypes of BRAF mutant tumors with distinct prognosis., Objective: To characterize the molecular and clinical features of 2 subtypes of BRAF-mutant PTCs defined by their degree of expression of iodine metabolism genes., Design: 227 BRAF-mutant PTCs from the Cancer Genome Atlas Thyroid Cancer study were divided into 2 subgroups based on their thyroid differentiation score (TDS): BRAF-TDShi and BRAF-TDSlo. Demographic, clinico-pathological, and molecular characteristics of the 2 subgroups were compared., Results: Compared to BRAF-TDShi tumors (17%), BRAF-TDSlo tumors (83%) were more frequent in blacks and Hispanics (6% vs 0%, P = 0.035 and 12% vs 0%, P = 0.05, respectively), they were larger (2.95 ± 1.7 vs 2.03 ± 1.5, P = 0.002), with more tumor-involved lymph nodes (3.9 ± 5.8 vs 2.0 ± 4.2, P = 0.042), and a higher frequency of distant metastases (3% vs 0%, P = 0.043). Gene set enrichment analysis showed positive enrichment for RAS signatures in the BRAF-TDShi cohort, with corresponding reciprocal changes in the BRAF-TDSlo group. Several microRNAs (miRs) targeting nodes in the transforming growth factor β (TGFβ)-SMAD pathway, miR-204, miR-205, and miR-144, were overexpressed in the BRAF-TDShi group. In the subset with follow-up data, BRAF-TDShi tumors had higher complete responses to therapy (94% vs 57%, P < 0.01) than BRAF-TDSlo tumors., Conclusion: Enrichment for RAS signatures, key genes involved in cell polarity and specific miRs targeting the TGFβ-SMAD pathway define 2 subtypes of BRAF-mutant PTCs with distinct clinical characteristics and prognosis., (© The Author(s) 2021. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Papillary thyroid cancer (PTC) is the most common endocrine malignancy for which diagnosis and recurrences still challenge clinicians. New perspectives to overcome these issues could come from the study of extracellular vesicle (EV) populations and content. Here, we aimed to elucidate the heterogeneity of EVs circulating in the tumor and the changes in their microRNA content during cancer progression. Using a mouse model expressing BRAF V600E , we isolated and characterized EVs from thyroid tissue by ultracentrifugations and elucidated their microRNA content by small RNA sequencing. The cellular origin of EVs was investigated by ExoView and that of deregulated EV-microRNA by qPCR on FACS-sorted cell populations. We found that PTC released more EVs bearing epithelial and immune markers, as compared to the healthy thyroid, so that changes in EV-microRNAs abundance were mainly due to their deregulated expression in thyrocytes. Altogether, our work provides a full description of in vivo-derived EVs produced by, and within, normal and cancerous thyroid. We elucidated the global EV-microRNAs signature, the dynamic loading of microRNAs in EVs upon BRAF V600E induction, and their cellular origin. Finally, we propose that thyroid tumor-derived EV-microRNAs could support the establishment of a permissive immune microenvironment.

Background: Oncogenic activation of mitogen-activated protein kinase (MAPK) signaling is associated with radioiodine refractory (RAIR) thyroid cancer. Preclinical models suggest that activation of the receptor tyrosine kinase erbB-3 (HER3) mitigates the MAPK pathway inhibition achieved by BRAF inhibitors in BRAF V600E mutant thyroid cancers. We hypothesized that combined inhibition of BRAF and HER3 using vemurafenib and the human monoclonal antibody CDX-3379, respectively, would potently inhibit MAPK activation and restore radioactive iodine (RAI) avidity in patients with BRAF- mutant RAIR thyroid cancer. Methods: Patients with BRAF V600E RAIR thyroid cancer were evaluated by thyrogen-stimulated iodine-124 ( 124 I) positron emission tomography-computed tomography (PET/CT) at baseline and after 5 weeks of treatment with oral vemurafenib 960 mg twice daily alone for 1 week, followed by vemurafenib in combination with 1000 mg of intravenous CDX-3379 every 2 weeks. Patients with adequate 124 I uptake on the second PET/CT then received therapeutic radioactive iodine ( 131 I) with vemurafenb+CDX-3379. All therapy was discontinued two days later. Treatment response was monitored by serum thyroglobulin measurements and imaging. The primary endpoints were safety and tolerability of vemurafenib+CDX-3379, as well as the proportion of patients after vemurafenb+CDX-3379 therapy with enhanced RAI incorporation warranting therapeutic 131 I. Results: Seven patients were enrolled; six were evaluable for the primary endpoints. No grade 3 or 4 toxicities related to CDX-3379 were observed. Five patients had increased RAI uptake after treatment; in 4 patients this increased uptake warranted therapeutic 131 I. At 6 months, 2 patients achieved partial response after 131 I and 2 progression of disease. Next-generation sequencing of 5 patients showed that all had co-occurring telomerase reverse transcriptase promoter alterations. A deleterious mutation in the SWItch/Sucrose Non-Fermentable (SWI/SNF) gene ARID2 was discovered in the patient without enhanced RAI avidity after therapy and an RAI-resistant tumor from another patient that was sampled off-study. Conclusions: The endpoints for success were met, providing preliminary evidence of vemurafenib+CDX-3379 safety and efficacy for enhancing RAI uptake. Preclinical data and genomic profiling in this small cohort suggest SWI/SNF gene mutations should be investigated as potential markers of resistance to redifferentiation strategies. Further evaluation of vemurafenib+CDX-3379 as a redifferentiation therapy in a larger trial is warranted (ClinicalTrials.gov: NCT02456701).

Hurthle cell carcinomas (HCCs) are refractory to radioactive iodine and unresponsive to chemotherapeutic agents, with a fatality rate that is the highest among all types of thyroid cancer after anaplastic thyroid cancer. Our previous study on the genomic landscape of HCCs identified a high incidence of disruptions of mTOR pathway effectors. Here, we report a detailed analysis of mTOR signaling in cell line and patient-derived xenograft mouse models of HCCs. We show that mTOR signaling is upregulated and that targeting mTOR signaling using mTOR inhibitors suppresses tumor growth in primary tumors and distant metastasis. Mechanistically, ablation of mTOR signaling impaired the expression of p-S6 and cyclin A2, resulting in the decrease of the S phase and blocking of cancer cell proliferation. Strikingly, mTOR inhibitor treatment significantly reduced lung metastatic lesions, with the decreased expression of Snail in xenograft tumors. Our data demonstrate that mTOR pathway blockade represents a novel treatment strategy for HCC., (©2021 American Association for Cancer Research.)