Guidelines on the Use of Systemic Therapy in Patients with Advanced Thyroid Cancer.

With increasing understanding of the molecular alterations leading to thyroid cancers in recent years we have seen a rapid increase in the number of effective targeted systemic therapies available for patients with advanced thyroid cancer; firstly with the advent of the multi-kinase inhibitors and more recently with more specific RET, BRAF, MEK, ALK and NTRK inhibitors. Although these developments are very welcome, they have resulted in a paradigm shift in the management of advanced thyroid cancer to which thyroid oncologists have had to rapidly adapt, learning how to supervise treatment safely with novel agents, the management of novel toxicities, when and how to arrange molecular genetic testing of cancers and, perhaps most importantly, determining when the optimum time is to start these treatments in what can often be a relatively indolent, if progressive, disease. We hope that these guidelines will support clinicians in making these decisions with their patients, as well as signposting and providing useful supporting information both for patients and clinicians.

Functional consequences of the first reported mutations of the proto-oncogene PTTG1IP/PBF.

Pituitary tumor-transforming gene 1-binding factor (PTTG1IP; PBF) is a multifunctional glycoprotein, which is overexpressed in a wide range of tumours, and significantly associated with poorer oncological outcomes, such as early tumour recurrence, distant metastasis, extramural vascular invasion and decreased disease-specific survival. PBF transforms NIH 3T3 fibroblasts and induces tumours in nude mice, while mice harbouring transgenic thyroidal PBF expression show hyperplasia and macrofollicular lesions. Our assumption that PBF becomes an oncogene purely through increased expression has been challenged by the recent report of mutations in PBF within the Catalogue of Somatic Mutations in Cancer (COSMIC) database. We therefore sought to determine whether the first 10 PBF missense substitutions in human cancer might be oncogenic. Anisomycin half-life studies revealed that most mutations were associated with reduced protein stability compared to wild-type (WT) PBF. Proliferation assays narrowed our interest to two mutational events which significantly altered cell turnover: C51R and R140W. C51R was mainly confined to the endoplasmic reticulum while R140W was apparent in the Golgi apparatus. Both C51R and R140W lost the capacity to induce cellular migration and significantly reduced cell invasion. Colony formation and soft agar assays demonstrated that, in contrast to WT PBF, both mutants were unable to elicit significant colony formation or anchorage-independent growth. However, C51R and R140W retained the ability to repress radioiodide uptake, a functional hallmark of PBF. Our data reveal new insight into PBF function and confirm that, rather than being oncogenic, mutations in PBF are likely to be passenger effects, with overexpression of PBF the more important aetiological event in human cancer.

Elevated PTTG and PBF predicts poor patient outcome and modulates DNA damage response genes in thyroid cancer.

The proto-oncogene PTTG and its binding partner PBF have been widely studied in multiple cancer types, particularly thyroid and colorectal, but their combined role in tumourigenesis is uncharacterised. Here, we show for the first time that together PTTG and PBF significantly modulate DNA damage response (DDR) genes, including p53 target genes, required to maintain genomic integrity in thyroid cells. Critically, DDR genes were extensively repressed in primary thyrocytes from a bitransgenic murine model (Bi-Tg) of thyroid-specific PBF and PTTG overexpression. Irradiation exposure to amplify p53 levels further induced significant repression of DDR genes in Bi-Tg thyrocytes (P=2.4 × 10-4) compared with either PBF- (P=1.5 × 10-3) or PTTG-expressing thyrocytes (P=NS). Consistent with this, genetic instability was greatest in Bi-Tg thyrocytes with a mean genetic instability (GI) index of 35.8±2.6%, as well as significant induction of gross chromosomal aberrations in thyroidal TPC-1 cells following overexpression of PBF and PTTG. We extended our findings to human thyroid cancer using TCGA data sets (n=322) and found striking correlations with PBF and PTTG expression in well-characterised DDR gene panel RNA-seq data. In addition, genetic associations and transient transfection identified PBF as a downstream target of the receptor tyrosine kinase-BRAF signalling pathway, emphasising a role for PBF as a novel component in a pathway well described to drive neoplastic growth. We also showed that overall survival (P=1.91 × 10-5) and disease-free survival (P=4.9 × 10-5) was poorer for TCGA patients with elevated tumoural PBF/PTTG expression and mutationally activated BRAF. Together our findings indicate that PBF and PTTG have a critical role in promoting thyroid cancer that is predictive of poorer patient outcome.

Manipulation of PBF/PTTG1IP phosphorylation status; a potential new therapeutic strategy for improving radioiodine uptake in thyroid and other tumors.

CONTEXT: The clinical effectiveness of ablative radioiodine treatment of thyroid tumors is limited by the availability of the sodium iodide symporter (NIS) at the plasma membrane (PM) for uptake of ¹³¹I. A significant proportion of well-differentiated thyroid tumors are unable to concentrate sufficient radioiodine for effective therapy, and in other tumor models such as breast tumors, where radioiodine uptake would be an attractive therapeutic option, uptake is insufficient. OBJECTIVE: Pituitary tumor-transforming gene-binding factor (PBF; PTTG1IP) is overexpressed in multiple cancers and significantly decreases NIS expression at the PM. The goal of this study was to identify a method by which PBF repression of NIS may be overcome in human tumors. RESULTS: Here, we identify PBF as a tyrosine phosphoprotein that specifically binds the proto-oncogene tyrosine protein kinase Src in mass spectrometry, glutathione S-transferase pulldown and coimmunoprecipitation assays. Src induction leads to phosphorylation at PBF residue Y174. Abrogation of this residue results in PM retention and a markedly reduced ability to bind NIS. The Src inhibitor PP1 inhibits PBF phosphorylation in multiple cell lines in vitro, including human primary thyroid cells. Of direct clinical importance to the treatment of thyroid cancer, PP1 stimulates iodide uptake by transfected NIS in TPC1 thyroid carcinoma cells and entirely overcomes PBF repression of iodide uptake in human primary thyroid cells. CONCLUSIONS: We propose that targeting PBF phosphorylation at residue Y174 via tyrosine kinase inhibitors may be a novel therapeutic strategy to enhance the efficacy of ablative radioiodine treatment in thyroid and other endocrine and endocrine-related tumors.

The pituitary tumor transforming gene in thyroid cancer.

The pituitary tumor transforming gene (PTTG) is a multifunctional proto-oncogene that is over-expressed in various tumors including thyroid carcinomas, where it is a prognostic indicator of tumor recurrence. PTTG has potent transforming capabilities in vitro and in vivo, and many studies have investigated the potential mechanisms by which PTTG contributes to tumorigenesis. As the human securin, PTTG is involved in critical mechanisms of cell cycle regulation, whereby aberrant expression induces aneuploidy. PTTG may further contribute to tumorigenesis through its role in DNA damage response pathways and via complex interactions with hormones and growth factors. Furthermore, PTTG over-expression negatively impacts upon the efficacy of radioiodine therapy in thyroid cancer, through repression of expression and function of the sodium iodide symporter. Given its various roles at all disease stages, PTTG appears to be an important oncogene in thyroid cancer. This review discusses the current knowledge of PTTG with particular focus on its role in thyroid cancer.

PTTG-binding factor (PBF) is a novel regulator of the thyroid hormone transporter MCT8.

Within the basolateral membrane of thyroid follicular epithelial cells, two transporter proteins are central to thyroid hormone (TH) biosynthesis and secretion. The sodium iodide symporter (NIS) delivers iodide from the bloodstream into the thyroid, and after TH biosynthesis, monocarboxylate transporter 8 (MCT8) mediates TH secretion from the thyroid gland. Pituitary tumor-transforming gene-binding factor (PBF; PTTG1IP) is a protooncogene that is up-regulated in thyroid cancer and that binds NIS and modulates its subcellular localization and function. We now show that PBF binds MCT8 in vitro, eliciting a marked shift in MCT8 subcellular localization and resulting in a significant reduction in the amount of MCT8 at the plasma membrane as determined by cell surface biotinylation assays. Colocalization and interaction between PBF and Mct8 was also observed in vivo in a mouse model of thyroid-specific PBF overexpression driven by a bovine thyroglobulin (Tg) promoter (PBF-Tg). Thyroidal Mct8 mRNA and protein expression levels were similar to wild-type mice. Critically, however, PBF-Tg mice demonstrated significantly enhanced thyroidal TH accumulation and reduced TH secretion upon TSH stimulation. Importantly, Mct8-knockout mice share this phenotype. These data show that PBF binds and alters the subcellular localization of MCT8 in vitro, with PBF overexpression leading to an accumulation of TH within the thyroid in vivo. Overall, these studies identify PBF as the first protein to interact with the critical TH transporter MCT8 and modulate its function in vivo. Furthermore, alongside NIS repression, PBF may thus represent a new regulator of TH biosynthesis and secretion.

Older subjects with hyperthyroidism present with a paucity of symptoms and signs: a large cross-sectional study.

CONTEXT: The absence of classical symptoms and signs of hyperthyroidism often results in delayed diagnosis and treatment. OBJECTIVES: The objective of the study was to determine the prevalence of symptoms and signs of hyperthyroidism according to patients' age and gender as well as severity and type of hyperthyroidism. DESIGN, PARTICIPANTS AND SETTING: This was a cross-sectional study of 3049 consecutive patients with hyperthyroidism presenting to a single secondary/tertiary care clinic. MAIN OUTCOME MEASURES: Calculation of adjusted odds ratios for presence/absence of symptoms/signs of hyperthyroidism simultaneously analyzing the influence of patients' age/gender, disease etiology/severity, symptom duration, and smoking. RESULTS: The majority of patients older than 61 yr had two or more symptoms. The lowest proportion of subjects reporting five or more symptoms was found in those older than 61 yr. Increasing age was associated with reduced adjusted odds ratio for the presence of most classical symptoms except for weight loss and shortness of breath, independent of disease severity. Those with more severe hyperthyroidism and smokers had increased odds ratios for most symptoms. Older age, higher serum free T(4) concentrations at diagnosis, male gender, and toxic nodular hyperthyroidism were independently associated with risk of atrial fibrillation. Signs of ophthalmopathy were associated with increasing age, smoking, longer symptom duration, and female gender. CONCLUSIONS: Classical symptoms and signs of hyperthyroidism are significantly less prevalent in older patients and more prevalent in smokers and subjects with higher free T(4) concentrations. We propose a lower threshold for performing thyroid function tests in patients older than 60 yr, especially in those presenting with atrial fibrillation, weight loss, or shortness of breath.

Prediction of cure and risk of hypothyroidism in patients receiving 131I for hyperthyroidism.

CONTEXT: There is little consensus regarding the most appropriate dose of radioiodine ((131)I) to be administered to patients with hyperthyroidism. OBJECTIVE: To compare the efficacy of fixed dose regimens of (131)I in curing hyperthyroidism and to define simple clinical and biochemical factors that predict outcome in individual patients. DESIGN: Consecutive series of hyperthyroid subjects treated with (131)I. SETTING: Single Secondary/Tertiary Care Hospital Clinic. PARTICIPANTS: A total of 1278 patients (1013 females and 262 males, mean age 49.7 years) presenting with hyperthyroidism between 1984 and 2006. INTERVENTION: Treatment with (131)I using a fixed dose regimen. MAIN OUTCOME MEASURES: Probability of cure and risk of development of hypothyroidism following a single dose of (131)I. RESULTS: Patients given a single dose of (131)I of 600 MBq (n = 485) had a higher cure rate (84.1%) compared with those receiving either 370 MBq (74.9%, P < 0.001) or those given 185 Bq (63%, P < 0.001). An increased incidence of hypothyroidism by 1 year was evident with higher doses (600 MBq: 60.4%; 370 MBq: 49.2%, P = 0.001; 185 Bq: 38.1%, P < 0.001). Binary logistic regression analysis identified a 600 Bq dose of (131)I [adjusted odds ratio, AOR 3.33 (2.28-4.85), P < 0.001], female gender [AOR 1.75 (1.23-2.47), P = 0.002], lower presenting serum free T4 concentration [AOR 1.01 (1.01-1.02), P < 0.001] and absence of a palpable goitre [AOR 3.33 (2.00-5.56), P < 0.001] to be independent predictors of cure. Similarly, a 600 MBq dose [AOR 3.79 (2.66-5.38), P < 0.001], female gender [AOR 1.46 (1.05-2.02), P = 0.02], younger age [AOR 1.03 (1.02-1.04), P < 0.001], absence of a palpable goitre [AOR 3.85 (2.38-5.88), P < 0.001] and presence of ophthalmopathy [AOR 1.57 (1.06-2.31), P = 0.02] were identified as independent factors predicting the probability of development of hypothyroidism at one year. Based on these findings, formulae to indicate probability of cure and risk of hypothyroidism for application to individual patients were derived. CONCLUSIONS: Simple clinical/biochemical criteria can be used to predict outcome after (131)I treatment. These factors determine that males, those with severe biochemical hyperthyroidism, and those with a palpable goitre require larger doses (600 MBq) in order to achieve cure.

Separase, securin and Rad21 in neural cell growth.

The key mitotic regulator securin is expressed at low levels in fetal brain compared with adult, and modulates the proliferation of human embryonic neuronal N-Tera2 (NT2) cells. We now examine the function and expression of securin's interacting partner separase, along with Rad21, the functional component of cohesin, which is cleaved by separase following interaction with securin. In contrast to securin, the cleaved forms of separase and Rad21 were highly expressed in human fetal cerebral cortex compared with adult. In a murine model of absent securin expression - the PTTG knock-out mouse - separase and Rad21 were over-expressed in multiple brain regions. In addition, cDNA array analysis of other key mitotic regulators additionally identified cyclin C and sestrin 2 to be induced in the brains of securin-null mice compared with wild type. Further, Rad21 mRNA expression was highly correlated with that of securin, separase, cyclin C and sestrin 2 in fetal brains. In embryonic neuronal NT2 cells, siRNA repression of separase failed to significantly alter cell turnover, whereas repression of securin expression resulted in increased levels of the activated forms of Rad21 and separase, and promoted cell proliferation. Our data suggest that the co-ordinated expression of separase, securin and Rad21 is fundamental for the developing brain.

PTTG and PBF repress the human sodium iodide symporter.

The ability of the thyroid to accumulate iodide provides the basis for radioiodine ablation of differentiated thyroid cancers and their metastases. Most thyroid tumours exhibit reduced iodide uptake, although the mechanisms accounting for this remain poorly understood. Pituitary tumour transforming gene (PTTG) is a proto-oncogene implicated in the pathogenesis of thyroid tumours. We now show that PTTG and its binding factor PBF repress expression of sodium iodide symporter (NIS) messenger RNA (mRNA), and inhibit iodide uptake. This process is mediated at least in part through fibroblast growth factor-2. In detailed studies of the NIS promoter in rat FRTL-5 cells, PTTG and PBF demonstrated specific inhibition of promoter activity via the human upstream enhancer element (hNUE). Within this approximately 1 kb element, a complex PAX8-upstream stimulating factor 1 (USF1) response element proved critical both to basal promoter activity and to PTTG and PBF repression of NIS. In particular, repression by PTTG was contingent upon the USF1, but not the PAX8, site. Finally, in human primary thyroid cells, PTTG and PBF similarly repressed the NIS promoter via hNUE. Taken together, our data suggest that the reported overexpression of PTTG and PBF in differentiated thyroid cancer has profound implications for activity of the NIS gene, and hence significantly impacts upon the efficacy of radioiodine treatment.

Influences of age, gender, smoking, and family history on autoimmune thyroid disease phenotype.

CONTEXT: Both genetic and environmental factors contribute to susceptibility to Graves' disease (GD) and Hashimoto's thyroiditis (HT), as well as disease manifestations. OBJECTIVE: The objective of the study was to define how endogenous/environmental factors contribute to variation in phenotype. DESIGN/SETTING: This was a multicenter cohort study. PATIENTS/OUTCOME MEASURES: We prospectively collected clinical/biochemical data as part of the protocol for a United Kingdom DNA collection for GD and HT. We investigated, in 2805 Caucasian subjects, whether age at diagnosis, gender, family history (FH), smoking history, and presence of goiter influenced disease manifestations. RESULTS: For 2405 subjects with GD, the presence of goiter was independently associated with disease severity (serum free T4 at diagnosis) (P < 0.001). Free T4 (P < 0.05) and current smoking (P < 0.001) were both independent predictors of the presence of ophthalmopathy. Approximately half of those with GD (47.4% of females, 40.0% of males) and HT (n = 400) (56.4% of females, 51.7% of males) reported a FH of thyroid dysfunction. In GD, a FH of hyperthyroidism in any relative was more frequent than hypothyroidism (30.1 vs. 24.4% in affected females, P < 0.001). In HT, a FH of hypothyroidism was more common than hyperthyroidism (42.1 vs. 22.8% in affected females, P < 0.001). For GD (P < 0.001) and HT (P < 0.05), a FH was more common in maternal than paternal relatives. The reporting of a parent with thyroid dysfunction (hyper or hypo) was associated with lower median age at diagnosis of both GD (mother with hyperthyroidism, P < 0.001) and HT (father with hypothyroidism, P < 0.05). In GD and HT, there was an inverse relationship between the number of relatives with thyroid dysfunction and age at diagnosis (P < 0.01). CONCLUSIONS: Marked associations among age at diagnosis, disease severity, goiter, ophthalmopathy, smoking, and FH provide evidence for interactions between genetic and environmental/endogenous factors; understanding these may allow preventive measures or better tailoring of therapies.

Pituitary tumor transforming gene (PTTG) stimulates thyroid cell proliferation via a vascular endothelial growth factor/kinase insert domain receptor/inhibitor of DNA binding-3 autocrine pathway.

CONTEXT: Vascular endothelial growth factor (VEGF) exerts its biological effects by binding to the tyrosine kinase receptors VEGF receptor type 1 (VEGFR1/Flt-1) and VEGFR2 (Flk-1/KDR). Kinase insert domain receptor (KDR) is the critical receptor controlling proliferation and migration of endothelial cells and has been shown to be expressed in some nonendothelial cells. We recently reported that the proangiogenic pituitary tumor transforming gene (PTTG) stimulates VEGF and up-regulates inhibitor of DNA binding-3 (ID3), an important gene in VEGF-dependent angiogenesis. OBJECTIVE: Our objective was to test whether VEGF, ID3, and KDR confer a PTTG-mediated effect on thyroid cell growth. DESIGN: Gene expression, MAPK stimulation, and cell proliferation were assessed in follicular thyroid cancer FTC133 cells. Gene expression and clinical associations were determined in 21 normal and 38 tumorous thyroid specimens (nine follicular and 29 papillary). RESULTS: ID3 correlated with VEGF mRNA expression in our series of thyroid cancers, which also showed up-regulated KDR mRNA. Stimulation of FTC133 cells with exogenous VEGF enhanced ID3 expression, which could be abrogated by the KDR-specific inhibitor ZM323881, suggesting that VEGF regulation of ID3 is KDR dependent. PTTG significantly correlated with KDR mRNA expression in our thyroid cancer cohort and up-regulated KDR and VEGF expression in FTC133 cells. Finally, cells transfected with PTTG demonstrated increased cell proliferation and phosphorylation of MAPK, which was abrogated by ZM323881. CONCLUSIONS: We report the presence of a VEGF/KDR/ID3-dependent autocrine pathway in FTC133 thyroid cells. By up-regulating both VEGF and KDR expression, we propose a novel PTTG-mediated proliferative pathway that may be critical to thyroid cancer growth and progression.

Serum thyrotropin concentration as a novel predictor of malignancy in thyroid nodules investigated by fine-needle aspiration.

CONTEXT: Thyroid nodules and goiter are common, and fine-needle aspiration biopsy (FNAB) is the first investigation of choice in distinguishing benign from malignant disease. OBJECTIVE: The objective of the study was to assess whether simple clinical and biochemical parameters can predict the likelihood of thyroid malignancy in subjects undergoing FNAB. DESIGN: The design was a prospective cohort. SETTING: The study was conducted at a single secondary/tertiary care clinic. PARTICIPANTS: One thousand five hundred consecutive patients without overt thyroid dysfunction (1304 females and 196 males, mean age 47.8 yr) presenting with palpable thyroid enlargement between 1984 and 2002 were evaluated by FNAB of the thyroid. INTERVENTION(S): There were no interventions. MAIN OUTCOME MEASURES: Goiter type was assessed clinically and classified as diffuse in 183, multinodular in 456, or solitary nodule in 861 cases. Serum TSH concentration at presentation was measured in a sensitive assay in patients presenting after 1988 (n = 1183). The final cytological or histological diagnosis was determined after surgery (n = 553) or a minimum 2-yr clinical follow-up period (mean 9.5 yr, range 2-18 yr). RESULTS: The overall sensitivity and specificity of FNAB in predicting malignancy were 88 and 84%, respectively. The risk of diagnosis of malignancy rose in parallel with the serum TSH at presentation, with significant increases evident in patients with serum TSH greater than 0.9 mU/liter, compared with those with lower TSH. Binary logistic regression analysis revealed significantly increased adjusted odds ratios (AORs) for the diagnosis of malignancy in subjects with serum TSH 1.0-1.7 mU/liter, compared with TSH less than 0.4 mU/liter [AOR 2.72, 95% confidence interval (CI) 1.02-7.27, P = 0.046], with further increases evident in those with TSH 1.8-5.5 mU/liter (AOR 3.88, 95% CI 1.48-10.19, P = 0.006, compared with TSH < 0.4 mU/liter) and greater than 5.5 mU/liter (AOR 11.18, 95% CI 3.23-8.63, P < 0.001, compared with TSH < 0.4 mU/liter). Males (AOR 1.8, 95% CI 1.04-3.1, P = 0.04), younger patients (AOR 1.1, 95% CI 1.01-1.15, P = 0.025), and those with clinically solitary nodules (AOR 2.53, 95% CI 1.5-4.28, P = 0.001) were also at increased risk. Based on these findings, a formula to predict the risk of the diagnosis of thyroid malignancy in individual patients, taking into account their gender, age, goiter type determined clinically, and serum TSH, was calculated. CONCLUSIONS: The risk of malignancy in a thyroid nodule increases with serum TSH concentrations within the normal range. In addition to patient's gender, age, and goiter type, the serum TSH concentration at presentation is an independent predictor of the presence of thyroid malignancy. We propose that these simple clinical and biochemical factors can serve as an adjunct to FNAB in predicting risk of malignancy.

Pituitary tumor-transforming gene regulates multiple downstream angiogenic genes in thyroid cancer.

CONTEXT: Pituitary tumor-transforming gene (PTTG) is a multifunctional protein involved in several tumorigenic mechanisms, including angiogenesis. PTTG has been shown to promote angiogenesis, a key rate-limiting step in tumor progression, by up-regulation of fibroblast growth factor-2 and vascular endothelial growth factor. OBJECTIVE: To investigate whether PTTG regulates other angiogenic genes in thyroid cells, we performed angiogenesis-specific cDNA arrays after PTTG transfection. Two of the genes [inhibitor of DNA binding-3 (ID3) and thrombospondin-1 (TSP-1)] which showed differential expression in primary thyroid cells were validated in vitro and in vivo. RESULTS: TSP-1 showed a 2.5-fold reduction and ID3 showed a 3.5-fold induction in expression in response to PTTG overexpression in vitro. Conversely, suppression of PTTG with small interfering RNA was associated with a 2-fold induction of TSP-1 and a 2.2-fold reduction in ID3 expression. When we examined TSP-1 and ID3 expression in 34 differentiated thyroid cancers, ID3 was significantly increased in tumors compared with normal thyroid tissue. Furthermore, ID3 expression was significantly higher in follicular thyroid tumors than in papillary tumors. Although mean TSP-1 expression was not altered in cancers compared with normal thyroids, we observed a significant independent association between TSP-1 expression and early tumor recurrence, with recurrent tumors demonstrating 4.2-fold lower TSP-1 expression than normal thyroid tissues. CONCLUSION: We have identified ID3 and TSP-1 as two new downstream targets of PTTG in thyroid cancer. We propose that PTTG may promote angiogenesis by regulating the expression of multiple genes with both pro- and antiangiogenic properties and may thus be a key gene in triggering the angiogenic switch in thyroid tumorigenesis.

Lack of association between serum TSH or free T4 and body mass index in euthyroid subjects.

BACKGROUND: There is ongoing debate regarding the influence of minor changes in thyroid status within the normal range and body mass index (BMI). Overt thyroid dysfunction is well recognized to affect weight, but the influence of minor perturbations of thyroid function remains unclear. AIM OF THE STUDY: To examine in euthyroid subjects the association of serum concentrations of TSH and free T4 within the normal range and BMI. To compare serum TSH and free T4 concentrations in nonobese and obese subjects. SUBJECTS AND METHODS: A cohort of 401 euthyroid subjects with normal serum TSH (361 females, 40 males, mean age 48.2 years) who had been referred to a Thyroid Clinic due to the presence of a thyroid nodule or goitre. Measurements of serum TSH and free T4 were recorded, together with BMI (calculated from weight and height). Associations between measures of TSH, free T4 and BMI were investigated. RESULTS: There was no association between either serum TSH or free T4 concentration when considered as a continuous variable and BMI, and no difference in BMI when subjects were categorized according to serum TSH or free T4. There was also no difference in serum TSH or free T4 between lean and obese euthyroid subjects. Evidence of thyroid autoimmunity indicated by the presence of antibodies to thyroid peroxidase was likewise not associated with a difference in BMI. CONCLUSION: This study provides no evidence for an association between thyroid status within the normal range and BMI.

ESHRE PGD Consortium data collection V: cycles from January to December 2002 with pregnancy follow-up to October 2003.

The fifth report of the ESHRE PGD Consortium is presented (data collection V). For the first time, the cycle data were collected for one calendar year (2002) in the following October, so that data collection was complete for pregnancies and babies. The data were collected using a Filemaker Pro database and divided into referrals, cycles, pregnancies and babies. There are currently 66 active centres registered with the consortium; however, the data presented here were obtained from 43 centres and included 1603 referrals, 2219 cycles, 485 pregnancies and 382 babies born. The cycle data were divided into preimplantation genetic diagnosis (PGD) for inherited disorders (including chromosome abnormalities, sexing for X-linked disease and monogenic disorders), aneuploidy screening (PGS) and the use of PGD for social sexing. Data collection V is compared with the previous cumulative data collection (I-IV), which comprised 4058 PGD/PGS cycles that reached oocyte retrieval.

Thyroid hormone in health and disease.

Thyroid disease is common, affecting around 2% of women and 0.2% of men in the UK. Our understanding of the effects of thyroid hormones under physiological circumstances, as well as in pathological conditions, has increased dramatically during the last two centuries and it has become clear that overt thyroid dysfunction is associated with significant morbidity and mortality. Both hypo-and hyperthyroidism and their treatments have been linked with increased risk from cardiovascular disease and the adverse effects of thyrotoxicosis in terms of osteoporosis risk are well established. Although the evidence suggests that successful treatment of overt thyroid dysfunction significantly improves overall survival, the issue of treating mild or subclinical hyper- and hypothyroidism remains controversial. Furthermore, the now well-established effects of thyroid hormones on neurodevelopment have sparked a whole new debate regarding the need to screen pregnant women for thyroid function abnormalities. This review describes the current evidence of the effects of thyroid hormone on the cardiovascular, skeletal and neurological systems, as well as the influence of thyroid diseases and their treatments on the development of malignancy. Furthermore we will describe some recent developments in our understanding of the relationship between thyroid status and health.

PTTG's C-terminal PXXP motifs modulate critical cellular processes in vitro.

Human pituitary tumor-transforming gene (PTTG), known also as securin, is a multifunctional protein implicated in the control of mitosis and the pathogenesis of thyroid, colon, oesophageal and other tumour types. Critical to PTTG function is a C-terminal double PXXP motif, forming a putative SH3-interacting domain and housing the gene's sole reported phosphorylation site. The exact role of phosphorylation and PXXP structure in the modulation of PTTG action in vitro remains poorly understood. We therefore examined the mitotic, transformation, proliferation and transactivation function of the C-terminal PXXP motifs of human PTTG. Live-cell imaging studies using an EGFP-PTTG construct indicated that PTTG's regulation of mitosis is retained regardless of phosphorylation status. Colony-formation assays demonstrated that phosphorylation of PTTG may act as a potent inhibitor of cell transformation. In proliferation assays, NIH-3T3 cells stable transfected and overexpressing mutations preventing PTTG phosphorylation (Phos-) showed significantly increased [3H]thymidine incorporation compared with WT, whereas mutants mimicking constitutive phosphorylation of PTTG (Phos+) exhibited reduced cell proliferation. We demonstrated that PTTG transactivation of FGF-2 in primary thyroid and PTTG-null cell lines was not affected by PTTG phosphorylation but was prevented by a mutant disrupting the PXXP motifs (SH3-). Taken together, our data suggest that PXXP structure and phosphorylation are likely to exert independent and critical influences upon PTTG's diverse actions in vitro.

A potential role for PTTG/securin in the developing human fetal brain.

Human securin, known also as PTTG, has established oncogenic and cell cycle regulatory functions. PTTG/securin transforms cells in vitro, inhibits sister chromatid separation, and regulates secretion of fibroblast growth factor-2. FGF-2 is a key regulator of CNS development and PTTG/securin expression has been reported in murine fetal brain. We examined the expression and function of securin and FGF-2 in the developing human fetal brain and in a fetal neuronal cell line (NT 2). Securin expression was significantly reduced in first and second trimester fetal cerebral cortex compared with adult cerebral cortex, where immunocytochemistry revealed intense securin staining in neuronal cell bodies. FGF-2 protein was concordantly lower in fetal cortex, whereas pretranslational expression of PTTG binding factor (PBF) was not significantly altered in fetal brain compared with adult. PCNA expression demonstrated that high securin levels in adult cortex were associated with absent cell proliferation. In NT-2 cells, securin stimulated FGF-2 expression, which could be abrogated by a carboxyl-terminal mutation. Low transient expression of securin resulted in a significant proliferative effect, whereas high levels of securin expression inhibited cell turnover. We propose a potential role for human PTTG/securin in modulating cell proliferation and FGF-2 expression during human neurogenesis.