RESUMO
Like other secreted peptides, nascent parathyroid hormone (PTH) is synthesized with a pre- and a pro-sequence (25 and 6 amino acids, respectively). These precursor segments are sequentially removed in parathyroid cells before packaging into secretory granules. Three patients from two unrelated families who presented during infancy with symptomatic hypocalcemia were found to have a homozygous serine (S) to proline (P) change affecting the first amino acid of the mature PTH. Unexpectedly, biological activity of synthetic [P1]PTH(1-34) was indistinguishable from that of unmodified [S1]PTH(1-34). However, in contrast to conditioned medium from COS-7 cells expressing prepro[S1]PTH(1-84), medium from cells expressing prepro[P1]PTH(1-84) failed to stimulate cAMP production despite similar PTH levels when measured by an intact assay that detects PTH(1-84) and large amino-terminally truncated fragments thereof. Analysis of the secreted, but inactive PTH variant led to the identification of pro[P1]PTH(-6 to +84). Synthetic pro[P1]PTH(-6 to +34) and pro[S1]PTH(-6 to +34) had much less bioactivity than the corresponding PTH(1-34) analogs. Unlike pro[S1]PTH(-6 to +34), pro[P1]PTH(-6 to +34) was resistant to cleavage by furin suggesting that the amino acid variant impairs preproPTH processing. Consistent with this conclusion, plasma of patients with the homozygous P1 mutation had elevated proPTH levels, as determined with an in-house assay specific for pro[P1]PTH(-6 to +84). In fact, a large fraction of PTH detected by the commercial intact assay represented the secreted pro[P1]PTH. In contrast, two commercial biointact assays that use antibodies directed against the first few amino acid residues of PTH(1-84) for capture or detection failed to detect pro[P1]PTH.
Assuntos
Hipocalcemia , Humanos , Hipocalcemia/genética , Hormônio Paratireóideo/genética , Hormônio Paratireóideo/metabolismo , Mutação , Prolina/genética , Aminoácidos/genéticaRESUMO
AIMS: Recently, there have been attempts to improve prognostication and therefore better guide treatment for patients with medullary thyroid carcinoma (MTC). In 2022, the International MTC Grading System (IMTCGS) was developed and validated using a multi-institutional cohort of 327 patients. The aim of the current study was to build upon the findings of the IMTCGS to develop and validate a prognostic nomogram to predict recurrence-free survival (RFS) in MTC. METHODS AND RESULTS: Data from 300 patients with MTC from five centres across the USA, Europe, and Australia were used to develop a prognostic nomogram that included the following variables: age, sex, AJCC stage, tumour size, mitotic count, necrosis, Ki67 index, lymphovascular invasion, microscopic extrathyroidal extension, and margin status. A process of 10-fold cross-validation was used to optimize the model's performance. To assess discrimination and calibration, the area-under-the-curve (AUC) of a receiver operating characteristic (ROC) curve, concordance-index (C-index), and dissimilarity index (D-index) were calculated. Finally, the model was externally validated using a separate cohort of 87 MTC patients. The model demonstrated very strong performance, with an AUC of 0.94, a C-index of 0.876, and a D-index of 19.06. When applied to the external validation cohort, the model had an AUC of 0.9. CONCLUSIONS: Using well-established clinicopathological prognostic variables, we developed and externally validated a robust multivariate prediction model for RFS in patients with resected MTC. The model demonstrates excellent predictive capability and may help guide decisions on patient management. The nomogram is freely available online at https://nomograms.shinyapps.io/MTC_ML_DFS/.
Assuntos
Carcinoma Neuroendócrino , Nomogramas , Neoplasias da Glândula Tireoide , Humanos , Área Sob a Curva , Prognóstico , Neoplasias da Glândula Tireoide/diagnósticoRESUMO
In severe osteoporosis, the optimal approach for sequential treatment between denosumab and romosozumab is unclear. We utilised a novel overlapping strategy in three patients with very-high fracture risk despite long-term denosumab which led to greater bone density improvements than previously reported with standard approaches. Larger confirmatory prospective studies are needed. PURPOSE/INTRODUCTION: In patients with severe osteoporosis, the optimal approach for sequential treatment between denosumab and romosozumab has not been established. The ideal strategy would maximise gains in bone mineral density (BMD) with romosozumab and effectively mitigate the risk of rebound increased bone turnover when sequencing from denosumab. Limited studies exploring the sequence from denosumab to romosozumab report only modest-to-no improvement in BMD and inadequate suppression of rebound bone turnover. METHODS: We describe three patients with severe osteoporosis and multiple fragility fractures despite long-term denosumab. A novel overlapping sequential treatment approach was utilised to maximise therapeutic benefit given these patients had a very high fracture risk. Romosozumab was commenced 3 months after the last denosumab dose. Instead of waiting until completion of romosozumab, denosumab was recommenced 6 months after commencing romosozumab in response to rising bone turnover markers. RESULTS: Patients experienced a ~ 5-22% increase in lumbar spine BMD, and one patient had an 8% increase in total hip BMD after 12 months romosozumab. Serum bone turnover markers demonstrated an anabolic effect of romosozumab occurred despite overlapping treatment with denosumab. Recommencement of denosumab suppressed an increase in bone resorption in all cases. No new vertebral fractures occurred during this treatment. CONCLUSIONS: A novel overlapping sequential treatment approach between denosumab and romosozumab produced greater improvements in lumbar spine and hip BMD than previously reported with standard approaches. Larger prospective controlled studies are needed to confirm these findings and establish the optimal use of romosozumab in patients pre-treated with denosumab to maximise BMD gains and minimise fracture risk.
Assuntos
Anticorpos Monoclonais , Conservadores da Densidade Óssea , Densidade Óssea , Denosumab , Esquema de Medicação , Osteoporose , Fraturas por Osteoporose , Humanos , Denosumab/uso terapêutico , Denosumab/administração & dosagem , Conservadores da Densidade Óssea/uso terapêutico , Conservadores da Densidade Óssea/administração & dosagem , Densidade Óssea/efeitos dos fármacos , Feminino , Fraturas por Osteoporose/prevenção & controle , Fraturas por Osteoporose/fisiopatologia , Idoso , Osteoporose/tratamento farmacológico , Osteoporose/fisiopatologia , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/uso terapêutico , Quimioterapia Combinada , Masculino , Remodelação Óssea/efeitos dos fármacos , Pessoa de Meia-Idade , Vértebras Lombares/fisiopatologiaRESUMO
Accelerated sub-lesional bone loss is common in the first 2-3 years after traumatic spinal cord injury (TSCI), particularly in the distal femur and proximal tibia. Few studies have explored efficacy of antiresorptives for acute bone loss prevention post-TSCI, with limited data for knee bone mineral density (BMD) or beyond two years follow-up. An open-label non-randomized study was performed at Royal North Shore Hospital and Royal Rehab Centre, Sydney between 2018 and 2023. An 'acute interventional cohort' (n = 11) with TSCI (duration ≤ 12-weeks) received a single infusion of 4 mg zoledronic acid (ZOL) at baseline. A 'chronic non-interventional cohort' (n = 9) with TSCI (duration 1-5-years) did not receive ZOL. All participants underwent baseline and 6-monthly blood tests (including CTx and P1NP) and 12-monthly DXA BMD scans (including distal femur and proximal tibia). Participants were predominantly Caucasian and male (mean age 38.4 years). At baseline, the 'acute' cohort had higher serum CTx, P1NP and sclerostin concentrations, while the 'chronic' cohort had lower left hip and knee BMD. Majority with acute TSCI experienced an acute phase reaction after ZOL (9/11; 82%). In the acute cohort, left hip BMD fell by mean ~ 15% by 48 months. Left distal femoral and proximal tibial BMD declined by mean ~ 6-13% at 12 months and ~ 20-23% at 48 months, with a tendency towards greater BMD loss in motor-complete TSCI. A single early ZOL infusion in acute TSCI could not attenuate rapidly declining hip and knee BMD. Prospective controlled studies are required to establish the optimal strategy for preventing early bone loss after acute TSCI.
Assuntos
Conservadores da Densidade Óssea , Densidade Óssea , Osteoporose , Traumatismos da Medula Espinal , Ácido Zoledrônico , Humanos , Ácido Zoledrônico/administração & dosagem , Ácido Zoledrônico/uso terapêutico , Traumatismos da Medula Espinal/complicações , Traumatismos da Medula Espinal/tratamento farmacológico , Osteoporose/tratamento farmacológico , Osteoporose/prevenção & controle , Masculino , Feminino , Adulto , Conservadores da Densidade Óssea/uso terapêutico , Conservadores da Densidade Óssea/administração & dosagem , Densidade Óssea/efeitos dos fármacos , Pessoa de Meia-Idade , Estudos de CoortesRESUMO
OBJECTIVE: Somatostatin receptor (SST) functional imaging with positron emission tomography (PET)/computed tomography (CT) has broadened the diagnostic and staging capabilities for medullary thyroid cancer (MTC). Gallium-68 (68Ga)-DOTA-conjugated peptide (Tyr3)-octreotate (DOTATATE) is a radiotracer with a high affinity for type 2 SSTs expressed in several, but not all, MTCs. The utility of 68Ga-DOTATATE PET/CT and 18fluorine-labeled fluoro-2-deoxy-D-glucose (18F-FDG)-PET/CT imaging in predicting MTC prognosis is also unknown. METHODS: In this single-center retrospective study, 103 of patients with MTC underwent assessment of SST2 and SST5 immunohistochemistry (IHC). A subgroup of 37 patients received 68Ga-DOTATATE PET/CT imaging, and 13 received contemporaneous 18F-FDG-PET/CT imaging. The maximum standardized uptake value (SUV), mean SUV, metabolic tumor volume, and total lesion activity (TLA) were assessed. RESULTS: Forty-two patients (41%) demonstrated positive expression of SST2, and 45 (44%) had a positive SST5 IHC result. Seventeen patients (17%) expressed both SST2 and SST5. No survival advantage was identified with SST2 or SST5 IHC positivity. No correlation was noted between the maximum SUV, mean SUV, metabolic tumor volume, or TLA and SST2 and/or SST5 expression by IHC. Shorter survival was associated with a TLA of >20 (P = .04). A RET-negative status also appeared to have shorter survival, although this may be because the small numbers did not reach statistical significance (P = .12). CONCLUSION: Assessment of TLA from 68Ga-DOTATATE PET/CT may predict survival. SST2 IHC was not correlated with 68Ga-DOTATATE avidity. Metastatic disease may be optimally assessed by concurrent 18F-FDG and 68Ga-DOTATATE imaging.
Assuntos
Carcinoma Neuroendócrino , Tumores Neuroendócrinos , Compostos Organometálicos , Cintilografia , Neoplasias da Glândula Tireoide , Humanos , Radioisótopos de Gálio , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Fluordesoxiglucose F18/metabolismo , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/métodos , Tomografia por Emissão de Pósitrons/métodos , Neoplasias da Glândula Tireoide/diagnóstico por imagem , Compostos Organometálicos/metabolismoRESUMO
Diffuse sclerosing variant papillary thyroid carcinoma (DS-PTC) is characterized clinically by a predilection for children and young adults, bulky neck nodes, and pulmonary metastases. Previous studies have suggested infrequent BRAFV600E mutation but common RET gene rearrangements. Using strict criteria, we studied 43 DS-PTCs (1.9% of unselected PTCs in our unit). Seventy-nine percent harbored pathogenic gene rearrangements involving RET, NTRK3, NTRK1, ALK, or BRAF; with the remainder driven by BRAFV600E mutations. All 10 pediatric cases were all gene rearranged (P = .02). Compared with BRAFV600E-mutated tumors, gene rearrangement was characterized by psammoma bodies involving the entire lobe (P = .038), follicular predominant or mixed follicular architecture (P = .003), pulmonary metastases (24% vs none, P = .04), and absent classical, so-called "BRAF-like" atypia (P = .014). There was no correlation between the presence of gene rearrangement and recurrence-free survival. Features associated with persistent/recurrent disease included pediatric population (P = .030), gene-rearranged tumors (P = .020), microscopic extrathyroidal extension (P = .009), metastases at presentation (P = .007), and stage II disease (P = .015). We conclude that DS-PTC represents 1.9% of papillary thyroid carcinomas and that actionable gene rearrangements are extremely common in DS-PTC. DS-PTC can be divided into 2 distinct molecular subtypes and all BRAFV600E-negative tumors (1.5% of papillary thyroid carcinomas) are driven by potentially actionable oncogenic fusions.
Assuntos
Carcinoma Papilar , Neoplasias Pulmonares , Neoplasias da Glândula Tireoide , Adulto Jovem , Humanos , Criança , Câncer Papilífero da Tireoide/genética , Neoplasias da Glândula Tireoide/genética , Neoplasias da Glândula Tireoide/patologia , Proteínas Proto-Oncogênicas B-raf/genética , Carcinoma Papilar/genética , Carcinoma Papilar/patologia , Mutação , Receptores Proteína Tirosina Quinases/genéticaRESUMO
Diagnosis of pheochromocytoma or paraganglioma (PPGL) in pregnancy has been associated historically with high rates of materno-fetal morbidity and mortality. Recent evidence suggests outcomes are improved by recognition of PPGL before or during pregnancy and appropriate medical management with alpha-blockade. Whether antepartum surgery (before the third trimester) is required remains controversial and open to case-based merits. Women with PPGL in pregnancy are more commonly delivered by Caesarean section, although vaginal delivery appears to be safe in selected cases. At least some PPGLs express the luteinizing hormone/chorionic gonadotropin receptor (LHCGR) which may explain their dramatic manifestation in pregnancy. PPGLs in pregnancy are often associated with heritable syndromes, and genetic counselling and testing should be offered routinely in this setting. Since optimal outcomes are only achieved by early recognition of PPGL in (or ideally before) pregnancy, it is incumbent for clinicians to be aware of this diagnosis in a pregnant woman with hypertension occurring before 20 weeks' gestation, and acute and/or refractory hypertension particularly if paroxysmal and accompanied by sweating, palpitations and/or headaches. All women with a past history of PPGL and/or heritable PPGL syndrome should be carefully assessed for the presence of residual or recurrent disease before considering pregnancy.
Assuntos
Neoplasias das Glândulas Suprarrenais , Hipertensão , Paraganglioma , Feocromocitoma , Gravidez , Humanos , Feminino , Feocromocitoma/diagnóstico , Feocromocitoma/genética , Feocromocitoma/terapia , Cesárea , Paraganglioma/diagnóstico , Paraganglioma/genética , Paraganglioma/terapia , Neoplasias das Glândulas Suprarrenais/diagnóstico , Neoplasias das Glândulas Suprarrenais/genética , Neoplasias das Glândulas Suprarrenais/terapiaRESUMO
BACKGROUND: SDHB is one of the major genes predisposing to paraganglioma/pheochromocytoma (PPGL). Identifying pathogenic SDHB variants in patients with PPGL is essential to the management of patients and relatives due to the increased risk of recurrences, metastases and the emergence of non-PPGL tumours. In this context, the 'NGS and PPGL (NGSnPPGL) Study Group' initiated an international effort to collect, annotate and classify SDHB variants and to provide an accurate, expert-curated and freely available SDHB variant database. METHODS: A total of 223 distinct SDHB variants from 737 patients were collected worldwide. Using multiple criteria, each variant was first classified according to a 5-tier grouping based on American College of Medical Genetics and NGSnPPGL standardised recommendations and was then manually reviewed by a panel of experts in the field. RESULTS: This multistep process resulted in 23 benign/likely benign, 149 pathogenic/likely pathogenic variants and 51 variants of unknown significance (VUS). Expert curation reduced by half the number of variants initially classified as VUS. Variant classifications are publicly accessible via the Leiden Open Variation Database system (https://databases.lovd.nl/shared/genes/SDHB). CONCLUSION: This international initiative by a panel of experts allowed us to establish a consensus classification for 223 SDHB variants that should be used as a routine tool by geneticists in charge of PPGL laboratory diagnosis. This accurate classification of SDHB genetic variants will help to clarify the diagnosis of hereditary PPGL and to improve the clinical care of patients and relatives with PPGL.
Assuntos
Neoplasias das Glândulas Suprarrenais , Paraganglioma , Feocromocitoma , Neoplasias das Glândulas Suprarrenais/genética , Testes Genéticos , Mutação em Linhagem Germinativa/genética , Humanos , Paraganglioma/diagnóstico , Paraganglioma/genética , Paraganglioma/patologia , Feocromocitoma/diagnóstico , Feocromocitoma/genética , Feocromocitoma/patologia , Succinato Desidrogenase/genéticaRESUMO
BACKGROUND: Indeterminate thyroid nodules (Bethesda III) are challenging to characterize without diagnostic surgery. Auxiliary strategies including molecular analysis, machine learning models, and ultrasound grading with Thyroid Imaging, Reporting and Data System (TI-RADS) can help to triage accordingly, but further refinement is needed to prevent unnecessary surgeries and increase positive predictive values. DESIGN: Retrospective review of 88 patients with Bethesda III nodules who had diagnostic surgery with final pathological diagnosis. MEASUREMENTS: Each nodule was retrospectively scored through TI-RADS. Two deep learning models were tested, one previously developed and trained on another data set, mainly containing determinate cases and then validated on our data set while the other one trained and tested on our data set (indeterminate cases). RESULTS: The mean TI-RADS score was 3 for benign and 4 for malignant nodules (p = .0022). Radiological high risk (TI-RADS 4,5) and low risk (TI-RADS 2,3) categories were established. The PPV for the high radiological risk category in those with >10 mm nodules was 85% (CI: 70%-93%). The NPV for low radiological risk in patients >60 years (mean age was 100% (CI: 83%-100%). The area under the curve (AUC) value of our novel classifier was 0.75 (CI: 0.62-0.84) and differed significantly from the chance-level (p < .00001). CONCLUSIONS: Novel radiomic and radiologic strategies can be employed to assist with preoperative diagnosis of indeterminate thyroid nodules.
Assuntos
Neoplasias da Glândula Tireoide , Nódulo da Glândula Tireoide , Humanos , Aprendizado de Máquina , Estudos Retrospectivos , Medição de Risco , Neoplasias da Glândula Tireoide/diagnóstico por imagem , Neoplasias da Glândula Tireoide/patologia , Nódulo da Glândula Tireoide/diagnóstico por imagem , Nódulo da Glândula Tireoide/patologia , Ultrassonografia/métodosRESUMO
The incidence of papillary thyroid carcinoma (PTC) has increased over recent decades. This apparent epidemic has been attributed to the overdiagnosis of small PTC ≤10 mm in diameter (papillary thyroid microcarcinoma [PTMC]) incidentally detected on imaging for unrelated presentations. Although most PTMCs follow an indolent disease course, there is a small but significant proportion of cases that display more biologically aggressive features such as early metastasis and lymph node involvement. Management of PTMC diagnosed preoperatively should be distinguished from managing those PTMCs incidentally discovered after thyroidectomy. Here, we will focus on the challenge of managing the preoperative patient. Current guidelines recommend against routine biopsy of nodules ≤10 mm, even if they display highly suspicious features on ultrasound; however, it is not known how to identify those PTMCs at higher risk of disease progression. In view of their good prognosis even without surgical resection, active surveillance has emerged as an alternative to operative management for low-risk PTMC without lymph node involvement or distant metastasis. This review aims to summarise active surveillance data for PTMC and identify clinical features that may differentiate the indolent majority from those PTMCs that exhibit early disease progression and metastasis.
Assuntos
Carcinoma Papilar , Neoplasias da Glândula Tireoide , Carcinoma Papilar/diagnóstico , Carcinoma Papilar/cirurgia , Humanos , Estudos Retrospectivos , Neoplasias da Glândula Tireoide/diagnóstico , Neoplasias da Glândula Tireoide/cirurgia , Tireoidectomia , Conduta ExpectanteAssuntos
Anticorpos Monoclonais , Conservadores da Densidade Óssea , Denosumab , Osteoporose , Humanos , Denosumab/uso terapêutico , Denosumab/administração & dosagem , Conservadores da Densidade Óssea/uso terapêutico , Conservadores da Densidade Óssea/administração & dosagem , Osteoporose/tratamento farmacológico , Osteoporose/fisiopatologia , Anticorpos Monoclonais/uso terapêutico , Anticorpos Monoclonais/administração & dosagem , Fraturas por Osteoporose/prevenção & controle , Esquema de MedicaçãoRESUMO
Metabolomics refers to the detection and measurement of small molecules (metabolites) within biological systems, and is therefore a powerful tool for identifying dysfunctional cellular physiologies. For pheochromocytomas and paragangliomas (PPGLs), metabolomics has the potential to become a routine addition to histology and genomics for precise diagnostic evaluation. Initial metabolomic studies of ex vivo tumors confirmed, as expected, succinate accumulation in PPGLs associated with pathogenic variants in genes encoding succinate dehydrogenase subunits or their assembly factors (SDHx). Metabolomics has now shown utility in clarifying SDHx variants of uncertain significance, as well as the accurate diagnosis of PPGLs associated with fumarate hydratase (FH), isocitrate dehydrogenase (IDH), malate dehydrogenase (MDH2) and aspartate transaminase (GOT2). The emergence of metabolomics resembles the advent of genetic testing in this field, which began with single-gene discoveries in research laboratories but is now done by standardized massively parallel sequencing (targeted panel/exome/genome testing) in pathology laboratories governed by strict credentialing and governance requirements. In this setting, metabolomics is poised for rapid translation as it can utilize existing infrastructure, namely liquid chromatography-tandem mass spectrometry (LC-MS/MS), for the measurement of catecholamine metabolites. Metabolomics has also proven tractable to in vivo diagnosis of SDH-deficient PPGLs using magnetic resonance spectroscopy (MRS). The future of metabolomics - embedded as a diagnostic tool - will require adoption by pathologists to shepherd development of standardized assays and sample preparation, reference ranges, gold standards, and credentialing.
Assuntos
Neoplasias das Glândulas Suprarrenais , Metabolômica , Feocromocitoma , Neoplasias das Glândulas Suprarrenais/diagnóstico , Neoplasias das Glândulas Suprarrenais/genética , Neoplasias das Glândulas Suprarrenais/metabolismo , Cromatografia Líquida , Exoma , Genômica , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Espectroscopia de Ressonância Magnética , Feocromocitoma/diagnóstico , Feocromocitoma/genética , Feocromocitoma/metabolismo , Espectrometria de Massas em TandemRESUMO
BACKGROUND: Until recently, determining penetrance required large observational cohort studies. Data from the Exome Aggregate Consortium (ExAC) allows a Bayesian approach to calculate penetrance, in that population frequencies of pathogenic germline variants should be inversely proportional to their penetrance for disease. We tested this hypothesis using data from two cohorts for succinate dehydrogenase subunits A, B and C (SDHA-C) genetic variants associated with hereditary pheochromocytoma/paraganglioma (PC/PGL). METHODS: Two cohorts were 575 unrelated Australian subjects and 1240 unrelated UK subjects, respectively, with PC/PGL in whom genetic testing had been performed. Penetrance of pathogenic SDHA-C variants was calculated by comparing allelic frequencies in cases versus controls from ExAC (removing those variants contributed by The Cancer Genome Atlas). RESULTS: Pathogenic SDHA-C variants were identified in 106 subjects (18.4%) in cohort 1 and 317 subjects (25.6%) in cohort 2. Of 94 different pathogenic variants from both cohorts (seven in SDHA, 75 in SDHB and 12 in SDHC), 13 are reported in ExAC (two in SDHA, nine in SDHB and two in SDHC) accounting for 21% of subjects with SDHA-C variants. Combining data from both cohorts, estimated lifetime disease penetrance was 22.0% (95% CI 15.2% to 30.9%) for SDHB variants, 8.3% (95% CI 3.5% to 18.5%) for SDHC variants and 1.7% (95% CI 0.8% to 3.8%) for SDHA variants. CONCLUSION: Pathogenic variants in SDHB are more penetrant than those in SDHC and SDHA. Our findings have important implications for counselling and surveillance of subjects carrying these pathogenic variants.
Assuntos
Teorema de Bayes , Estudos de Associação Genética , Predisposição Genética para Doença , Variação Genética , Penetrância , Succinato Desidrogenase/genética , Algoritmos , Alelos , Austrália , Estudos de Associação Genética/métodos , Genótipo , Humanos , Isoenzimas , Modelos Genéticos , Fenótipo , Reino UnidoRESUMO
The multiple endocrine neoplasia (MEN) syndromes include MEN1, MEN2 (formerly MEN2A), MEN3 (formerly MEN2B) and the recently identified MEN4. Clinical presentations are varied and often relate to the overproduction of specific hormones. Understanding the genetics of each syndrome assists in determining screening timelines. Treatments for each manifestation are dependent on location, risk of recurrence or malignancy, hormone excess and surgical morbidity. Multidisciplinary management should include geneticists, genetic counsellors, endocrinologists and endocrine surgeons.
Assuntos
Neoplasia Endócrina Múltipla/diagnóstico , Neoplasia Endócrina Múltipla/genética , Neoplasia Endócrina Múltipla/terapia , Terapia Combinada , Procedimentos Cirúrgicos Endócrinos , Marcadores Genéticos , Testes Genéticos , Humanos , Neoplasia Endócrina Múltipla/classificação , RecidivaRESUMO
Prognosis from differentiated thyroid cancer is worse when the disease becomes refractory to radioiodine. Until recently, treatment options have been limited to local therapies such as surgery and radiotherapy, but the recent availability of systemic therapies now provides some potential for disease control. Multitargeted kinase inhibitors (TKIs) including lenvatinib and sorafenib have been shown to improve progression-free survival in phase III clinical trials, but are also associated with a spectrum of adverse effects. Other TKIs have been utilized as "redifferentiation" agents, increasing sodium iodide symporter expression in metastases and thus restoring radioiodine avidity. Some patients whose disease progresses on initial TKI therapy will still respond to a different TKI and clinical trials currently in progress will clarify the best options for such patients. As these drugs are not inexpensive, care needs to be taken to minimize not only biological but also financial toxicity. In this review, we examine the basic biology of radioiodine refractory disease and discuss optimal treatment approaches, with specific focus on choice and timing of TKI treatment. This clinical field remains fluid, and directions for future research include exploring biomarkers and considering adjuvant TKI use in certain patient groups.
Assuntos
Radioisótopos do Iodo/uso terapêutico , Neoplasias da Glândula Tireoide/terapia , Humanos , Inibidores de Proteínas Quinases/efeitos adversos , Falha de TratamentoRESUMO
BACKGROUND: Germline mutations in genes encoding subunits of succinate dehydrogenase (SDH) are associated with the development of pheochromocytoma (PC) and/or paraganglioma (PGL). As assembly factors have been identified as playing a role in maturation of individual SDH subunits and assembly of the functioning SDH complex, we hypothesized that SDHAF3 variants may be associated with PC/PGL and functionality of SDH. METHODS: DNA was extracted from the blood of 37 individuals (from 23 families) with germline SDH mutations and 18 PC/PGL (15 sporadic, 3 familial) and screened for mutations using a custom gene panel, containing SDHAF3 (SDH assembly factor 3) as well as eight known PC/PGL susceptibility genes. Molecular and functional consequences of an identified sequence variant of SDHAF3 were assessed in yeast and mammalian cells (HEK293). RESULTS: Using massively parallel sequencing, we identified a variant in SDHAF3, c.157 T > C (p.Phe53Leu), associated with increased prevalence in familial and sporadic PC/PGL (6.6%) when compared to normal populations (1.2% [1000 Genomes], p = 0.003; 2.1% [Exome Aggregation Consortium], p = 0.0063). In silico prediction tools suggest this variant is probably damaging to protein function, hence we assessed molecular and functional consequences of the resulting amino acid change (p.Phe53Leu) in yeast and human cells. We showed that introduction of SDHAF3 p.Phe53Leu into Sdh7 (ortholog of SDHAF3 in humans) null yeast resulted in impaired function, as observed by its failure to restore SDH activity when expressed in Sdh7 null yeast relative to WT SDHAF3. As SDHAF3 is involved in maturation of SDHB, we tested the functional impact of SDHAF3 c.157 T > C and various clinically relevant SDHB mutations on this interaction. Our in vitro studies in human cells show that SDHAF3 interacts with SDHB (residues 46 and 242), with impaired interaction observed in the presence of the SDHAF3 c.157 T > C variant. CONCLUSIONS: Our studies reveal novel insights into the biogenesis of SDH, uncovering a vital interaction between SDHAF3 and SDHB. We have shown that SDHAF3 interacts directly with SDHB (residue 242 being key to this interaction), and that a variant in SDHAF3 (c.157 T > C [p.Phe53Leu]) may be more prevalent in individuals with PC/PGL, and is hypomorphic via impaired interaction with SDHB.
Assuntos
Predisposição Genética para Doença , Mutação em Linhagem Germinativa , Paraganglioma/enzimologia , Feocromocitoma/enzimologia , Succinato Desidrogenase/metabolismo , Animais , Feminino , Células HEK293 , Humanos , Masculino , Simulação de Acoplamento Molecular , Paraganglioma/genética , Feocromocitoma/genética , Conformação Proteica , Domínios e Motivos de Interação entre Proteínas , Mapeamento de Interação de Proteínas , Saccharomyces cerevisiae , Análise de Sequência de DNA , Succinato Desidrogenase/genética , Sus scrofa/metabolismoRESUMO
OBJECTIVE: Serum thyroglobulin (Tg) is a marker of residual differentiated thyroid cancer (DTC) after total thyroidectomy; however, circulating antithyroglobulin antibodies (TgAb) may interfere with the immunoassay for Tg. Ultrasensitive assays may have a more significant role in detecting circulating Tg in the context of samples containing TgAb. The aim of this study was to evaluate the utility of ultrasensitive thyroglobulin (US-Tg) measurement compared to standard Tg measurement and to assess the influence of serum TgAb positivity on Tg detection in a large tertiary referral centre cohort in Australia. DESIGN: All patients with DTC who had undergone total thyroidectomy were included in this retrospective, observational cohort study. PATIENTS: Patients providing samples for the period of June 2006 until January 2014 were analysed. Three thousand two hundred and eight samples were measured at the same points in time, enabling serum Tg assays to be compared for the same TSH status (stimulated or suppressed). MEASUREMENTS: The standard assay, the Siemens Immulite 2000 Tg assay, was compared to the serum ultrasensitive ELISA RSR™ Tg. TgAb were simultaneously measured using Abbott Architect or Immulite 2000. RESULTS: There were 3019 samples included in the final analysis for comparison of the standard and ultrasensitive assays along with TgAb status. The majority of samples were TgAb negative (87%), with 48% of TgAb-negative samples associated with an undetectable serum Tg, suggestive of disease-free status at the time of sampling. Of note, 26% (n = 104) of the TgAb-positive samples were positive for Tg on the ultrasensitive Tg assay, but negative on the immulite Tg assay, and 62·5% (n = 65) of these samples corresponded to DTC recurrence. CONCLUSION: The US-Tg assay has greater clinical utility than the standard immulite Tg assay specifically in the scenario of antibody positivity, with a significant number of samples corresponding to clinically relevant recurrent or metastatic disease.
RESUMO
CONTEXT: TERT promoter mutations have been associated with adverse prognosis in papillary thyroid carcinomas (PTCs). OBJECTIVE: We investigated the association between TERT promoter mutations and survival from PTC. DESIGN: Retrospective observational cohort study. PATIENTS: Eighty consecutive patients with PTC who underwent surgery between 1990 and 2003. MEASUREMENTS: TERT promoter was genotyped in DNA from 80 archival PTCs by Sanger sequencing. Median follow-up was 106 months (range 1-270). Outcomes analysis was stratified according to disease and overall survival status. For each parameter, relative risk (RR) adjusted for age at first surgery and gender was estimated. Both univariate and multivariate analyses were performed using logistic regression, Kaplan-Meier survival analysis and Cox regression models. RESULTS: PTCs from 11 patients (14%) contained either C228T or C250T TERT promoter mutation. TERT mutations were significantly associated with adverse prognostic features such as older age (P = 0·002), male gender (P = 0·01) and Stage IV disease (P = 0·03). Four patients died from PTC during follow-up: 3 patients with TERT mutations (27%) and one without (1·5%). Disease-related mortality rate with or without TERT mutations was 33·7 vs 1·6 per 1000 patient-years respectively, that is 10 (95% CI = 1·0-104·1, P = 0·05) fold higher, after adjustment for age at first surgery and gender. The combination of TERT promoter mutation and BRAF(V) (600E) significantly increased disease-related death risk (P = 0·002). TERT mutations increased expression of a reporter gene in thyroid cells containing BRAF(V) (600E) . CONCLUSIONS: TERT promoter mutations are a major indicator of death due to PTCs. Conversely, absence of TERT mutations portends better survival.
Assuntos
Carcinoma Papilar/diagnóstico , Regiões Promotoras Genéticas/genética , Telomerase/genética , Neoplasias da Glândula Tireoide/diagnóstico , Adulto , Carcinoma Papilar/genética , Carcinoma Papilar/mortalidade , Carcinoma Papilar/patologia , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Prognóstico , Recidiva , Estudos Retrospectivos , Taxa de Sobrevida , Neoplasias da Glândula Tireoide/genética , Neoplasias da Glândula Tireoide/mortalidade , Neoplasias da Glândula Tireoide/patologiaRESUMO
The treatment of papillary thyroid cancer is now based on individual patient risk and response to therapies. Molecular techniques are increasingly being used to risk stratify and to guide therapeutic decisions. There have been advances in the treatment of local disease through surgery or radioiodine. Directed techniques can target metastatic disease including bisphosphonates, radiofrequency ablation or radiotherapy. Systemic therapies such as tyrosine kinase inhibitors show great promise although such treatment must be individualized. Future therapies will target treating radioiodine refractory disease.