A study of variation in therapeutic approach to low-risk differentiated thyroid cancer in the UK.

BACKGROUND: The British Thyroid Association and American Thyroid Association guideline definitions for low-risk differentiated thyroid cancers are susceptible to differing interpretations, resulting in different clinical management in the UK. OBJECTIVE: To explore the national effect of these guidelines on the management of low-risk differentiated thyroid cancers. METHODS: Anonymised questionnaires were sent to multidisciplinary teams performing thyroidectomies in the UK. Risk factors that multidisciplinary teams considered important when managing low-risk differentiated thyroid cancers were established. RESULTS: Most surgeons (71 out of 75; 94.7 per cent) confirmed they were core multidisciplinary team members. More than 80 per cent of respondents performed at least 30 hemi- and/or total thyroidectomies per annum. A majority of multidisciplinary teams (50 out of 75; 66.7 per cent) followed British Thyroid Association guidelines. Risk factors considered important when managing low-risk differentiated thyroid cancers included: type of tumour histology findings (87.8 per cent), tumour size of greater than 4 cm (86.5 per cent), tumour stage T3b (85.1 per cent) and central neck node involvement (85.1 per cent). Extent of thyroid surgery (e.g. hemi- or total thyroidectomy) was highly variable for low-risk differentiated thyroid cancers. CONCLUSION: Management of low-risk differentiated thyroid cancers is highly variable, leading to a heterogeneous patient experience.

Systematic Review of Recurrence Rate after Hemithyroidectomy for Low-Risk Well-Differentiated Thyroid Cancer.

BACKGROUND: Surgical extent in the management of well-differentiated thyroid cancer (DTC) remains a recurrent subject of debate. This is especially relevant in low-risk DTC of 1-4 cm, which represent the majority of new thyroid cancer diagnoses. With trends towards treatment de-escalation and recent guidelines from the American Thyroid Association and British Thyroid Association endorsing hemithyroidectomy (HT) alone for low-risk DTC of 1-4 cm, we sought to systematically appraise the literature to examine recurrence rate outcomes after HT in this low-risk group. SUMMARY: Searching PubMed, Cochrane Library, and Ovid MEDLINE, we conducted a systematic review to assess the survival and recurrence rate data presented in all published studies that had a cohort of patients treated with HT for the treatment of DTC. Pooled 10-year survival and recurrence rates, odds ratios, and 95% confidence intervals were calculated for meta-analysis. We identified 31 studies (with a total of 228,746 patients (HT: 36,129, total thyroidectomy, TT: 192,617), which had published recurrence and/or survival data for patients having had HT for DTC. We discovered a pooled recurrence rate of 9.0% for HT, which is significantly higher than in previously published reports. Further, this rate is maintained when examining patients within low-risk cohorts established with recognised risk classifications. We also discovered that of those patients who develop recurrent disease, 48% recur outside the central neck. KEY MESSAGES: Our study provides a comprehensive systematic review of evidence aimed primarily at defining the recurrence rate in DTC after HT, and more specifically within the low-risk subgroup. We describe pooled recurrence and 10-year survival rates from a larger, broader, and more contemporary patient population than has been previously reported. Our findings indicate that there is a small but significantly higher recurrence rate after HT than TT, but the evidence base is heterogenous and subject to confounding factors and would ultimately benefit from prospective randomised trials to overcome these deficiencies.

Adenoid Cystic Carcinoma of Trachea.

Adenoid cystic carcinoma (ACC) is the second most common primary malignant tumor of the trachea, after squamous cell carcinoma. Patients present with upper airway obstructive symptoms and signs including dyspnoea, cough, haemoptysis, and stridor which are often insidious, delaying diagnosis and optimal management. Described here is an unusual case of primary ACC cervical trachea with concomitant micropapillary thyroid carcinoma (microPTC) in a middle-aged lady presenting with cough and breathing difficulty since 3 months.

Germline ESR2 mutation predisposes to medullary thyroid carcinoma and causes up-regulation of RET expression.

Familial medullary thyroid cancer (MTC) and its precursor, C cell hyperplasia (CCH), is associated with germline RET mutations causing multiple endocrine neoplasia type 2. However, some rare families with apparent MTC/CCH predisposition do not have a detectable RET mutation. To identify novel MTC/CCH predisposition genes we undertook exome resequencing studies in a family with apparent predisposition to MTC/CCH and no identifiable RET mutation. We identified a novel ESR2 frameshift mutation, c.948delT, which segregated with histological diagnosis following thyroid surgery in family members and demonstrated loss of ESR2-encoded ERß expression in the MTC tumour. ERα and ERß form heterodimers binding DNA at specific oestrogen-responsive elements (EREs) to regulate gene transcription. ERß represses ERα-mediated activation of the ERE and the RET promoter contains three EREs. In vitro, we showed that ESR2 c.948delT results in unopposed ERα mediated increased cellular proliferation, activation of the ERE and increased RET expression. In vivo, immunostaining of CCH and MTC using an anti-RET antibody demonstrated increased RET expression. Together these findings identify germline ESR2 mutation as a novel cause of familial MTC/CCH and provide important insights into a novel mechanism causing increased RET expression in tumourigenesis.

The presentation, natural history and outcome of T1 a/b thyroid cancer with regard to new grading systems.

INTRODUCTION: The seventh edition tumor, node metastasis (TNM) classifies tumors <10 mm as T1a and tumors between 10 mm and 20 mm as T1b. Previous editions of the TNM staging system did not differentiate these lesions. We compare new classification in terms of presentation and outcome. METHODS: Early thyroid cancers that were previously staged under the TNM sixth edition were re-staged using the TNM seventh edition to identify whether the new staging system differentiated lesions in terms of presentation and outcome. Differences in presentation, rates of recurrent disease and surgical complications were recorded and compared. RESULTS: Of 1,415 thyroid operations, 369 were for malignant disease and there were 220 papillary carcinomas. There were 35 T1a/b lesions accounting for 11% of malignancies with no increasing incidence. Reclassification showed 64% T1a and 36% T1b lesions. There were no differences in presentation. Outcomes in terms of persistent or recurrent disease were the same after median follow up was 6.8 years. CONCLUSION: Isolated T1a/b thyroid cancer made up only a small proportion of malignancies, the majority of which were discovered incidentally. We have not seen the increase in early lesions reported elsewhere. In our series, the seventh TNM edition did not differentiate early lesions and we ultimately feel that parameters other than size of primary lesion are likely to be of greater importance in determining prognosis.

Differences in the recurrence and mortality outcomes rates of incidental and nonincidental papillary thyroid microcarcinoma: a systematic review and meta-analysis of 21 329 person-years of follow-up.

CONTEXT: There is controversy as to whether papillary thyroid microcarcinoma (PTMC) represents more than one disease entity with different outcomes, requiring different treatment. OBJECTIVES: To compare characteristics, outcomes, and factors associated with prognosis of incidental and nonincidental PTMC. SETTING AND DESIGN: Two reviewers performed searches of online databases (1966-2012), reference lists, and conference abstract books. Longitudinal studies of subjects >16 years old receiving any treatments for papillary thyroid cancer ≤10 mm in size were included. Two reviewers independently screened abstracts and articles, extracted data, and assessed quality of studies using National Institute of Clinical Excellence and PRISMA criteria. RESULTS: Of 1102 abstracts identified, 262 studies were reviewed and 17 studies included, comprising 3523 subjects, with mean follow-up of 70 months and total follow-up of 21 329 person-years. This included 854 subjects with incidental PTMC (follow-up, 4800 person-years; mean tumor size, 4.6 mm [range 3.3-6.7 mm]) and 2669 nonincidental PTMC cases (follow-up, 16 529 person-years; mean tumor size, 6.9 mm [range 5.6-8.0 mm]). The recurrence rate in the incidental group (0.5%; 95% confidence interval [CI], 0-1%, P < .001) was significantly lower than that in the nonincidental group PTMC (7.9%; 95% CI, 5-11%), with an OR of recurrence of 14.7 (95% CI, 5.6-54.8, P < .001) for nonincidental PTMC, compared with incidental PTMC. Lymph nodes were involved in 80% (126/157) of recurrences. On meta-regression, age, sex, size, tumor multifocality, lymph node involvement, and treatment modality were not significantly associated with recurrence. CONCLUSIONS: Our meta-analysis strongly suggests the existence of at least two distinct entities of PTMC. Incidental PTMC has different clinical characteristics and a much lower recurrence rate than nonincidental PTMC, suggesting that management protocols should be re-considered. Additional studies with standardized data collection are required to explore potential differences between subgroups of nonincidental PTMC.

The PTTG1-binding factor (PBF/PTTG1IP) regulates p53 activity in thyroid cells.

The PTTG1-binding factor (PBF/PTTG1IP) has an emerging repertoire of roles, especially in thyroid biology, and functions as a protooncogene. High PBF expression is independently associated with poor prognosis and lower disease-specific survival in human thyroid cancer. However, the precise role of PBF in thyroid tumorigenesis is unclear. Here, we present extensive evidence demonstrating that PBF is a novel regulator of p53, a tumor suppressor protein with a key role in maintaining genetic stability, which is infrequently mutated in differentiated thyroid cancer. By coimmunoprecipitation and proximity-ligation assays, we show that PBF binds specifically to p53 in thyroid cells and significantly represses transactivation of responsive promoters. Further, we identify that PBF decreases p53 stability by enhancing ubiquitination, which appears dependent on the E3 ligase activity of Mdm2. Impaired p53 function was evident in a transgenic mouse model with thyroid-specific PBF overexpression (transgenic PBF mice), which had significantly increased genetic instability as indicated by fluorescent inter simple sequence repeat-PCR analysis. Consistent with this, approximately 40% of all DNA repair genes examined were repressed in transgenic PBF primary cultures, including genes with critical roles in maintaining genomic integrity such as Mgmt, Rad51, and Xrcc3. Our data also revealed that PBF induction resulted in up-regulation of the E2 enzyme Rad6 in murine thyrocytes and was associated with Rad6 expression in human thyroid tumors. Overall, this work provides novel insights into the role of the protooncogene PBF as a negative regulator of p53 function in thyroid tumorigenesis, in which PBF is generally overexpressed and p53 mutations are rare compared with other tumor types.

Regulation of human thyroid follicular cell function by inhibition of vascular endothelial growth factor receptor signalling.

The potential autocrine role of human thyroid vascular endothelial growth factors (VEGFs) was examined using the VEGF receptor (VEGFR) inhibitor, ZM306416HCl. ZM306416HCl reduced VEGFR2 phosphorylation and inhibited endogenous, steady-state levels of p42/44 MAPK phosphorylation. It potently inhibited the secretion of plasminogen activators (PA) and increased (125)I uptake. Cell survival was compromised but rescued with insulin and TSH. Although the EGF receptor remained responsive to challenge by EGF in p42/44 MAPK assays, stimulatory effects of EGF on PA production were prevented by ZM306416HCl and those of protein kinase C stimulator, TPA reduced. In assays of (125)I uptake, ZM306416HCl prevented the inhibitory effects of EGF but not those of TPA. We conclude that autocrine VEGF may modulate thyroid function and that VEGFR inhibition increases iodide uptake and decreases PA production through regulation of p42/44 MAPK phosphorylation. VEGFR inhibition may have effects on thyroid function which may contribute to "off target" effects in clinical trials.

Expression of receptors for VEGFs on normal human thyroid follicular cells and their role in follicle formation.

Human thyroid follicular cells in culture expressed the mRNAs for the receptors for vascular endothelial growth factors (VEGFRs). The relative expression was neuropilin1 = neuropilin2 = VEGFR2 > VEGFR1 > VEGFR3. Western blotting for VEGFR2 showed labeling of proteins ~200-230 kDa. Clonal follicular thyroid cell lines (FRTL5 and FTC133) also expressed mRNAs for the VEGFR1 and 2 obviating concerns of endothelial cell contamination. In the primary cultures, TSH, which is essential for expression of differentiated function, reduced VEGFR2 mRNA levels by 60%. Immunostaining for VEGFRs and neuropilin2 (NRP2), showed expression on the plasma membrane but with the exception of neuropilin1 (NRP1), all VEGFRs were also found in the cytoplasm and nucleus. Antibody specific for phosphotyrosine 1214 in VEGFR2 showed that the receptor was phosphorylated in the primary cultures and the cell lines. When VEGFR signaling was blocked with a specific inhibitor, follicle formation in the primary cultures was enhanced suggesting that VEGFR activation was detrimental to follicle formation. Immunostaining of sections of normal thyroids and various pathologies showed staining for VEGFR2 and pVEGFR2. We conclude that normal thyroid follicular cell express VEGFRs. For VEGFR2 its subcellular localization suggests functions additional to that of a cell surface receptor and a role in follicular integrity.

Proto-oncogene PBF/PTTG1IP regulates thyroid cell growth and represses radioiodide treatment.

Pituitary tumor transforming gene (PTTG)-binding factor (PBF or PTTG1IP) is a little characterized proto-oncogene that has been implicated in the etiology of breast and thyroid tumors. In this study, we created a murine transgenic model to target PBF expression to the thyroid gland (PBF-Tg mice) and found that these mice exhibited normal thyroid function, but a striking enlargement of the thyroid gland associated with hyperplastic and macrofollicular lesions. Expression of the sodium iodide symporter (NIS), a gene essential to the radioiodine ablation of thyroid hyperplasia, neoplasia, and metastasis, was also potently inhibited in PBF-Tg mice. Critically, iodide uptake was repressed in primary thyroid cultures from PBF-Tg mice, which could be rescued by PBF depletion. PBF-Tg thyroids exhibited upregulation of Akt and the TSH receptor (TSHR), each known regulators of thyrocyte proliferation, along with upregulation of the downstream proliferative marker cyclin D1. We extended and confirmed findings from the mouse model by examining PBF expression in human multinodular goiters (MNG), a hyperproliferative thyroid disorder, where PBF and TSHR was strongly upregulated relative to normal thyroid tissue. Furthermore, we showed that depleting PBF in human primary thyrocytes was sufficient to increase radioiodine uptake. Together, our findings indicate that overexpression of PBF causes thyroid cell proliferation, macrofollicular lesions, and hyperplasia, as well as repression of the critical therapeutic route for radioiodide uptake.

Squamous cell carcinoma of the oral cavity rarely harbours oncogenic human papillomavirus.

Although it is now well established that a significant proportion of oropharyngeal squamous cell carcinomas (SCC) harbour oncogenic human papillomavirus (HPV) sequences, the frequency with which these sequences are detected in oral SCC (excluding oropharyngeal subsites) is highly variable. In an attempt to establish the true prevalence of HPV-16 and HPV-18 subtypes in oral SCC, we screened 142 consecutive cases from a UK cohort using both conventional PCR with consensus primers and type-specific quantitative PCR (Q-PCR), while at the same time employing a rigorous protocol to avoid sample contamination. Q-PCR revealed HPV sequences in five cases; two contained HPV-16 alone, two HPV-18 alone, and one sample carried both genotypes. However, only two of these cases (both HPV-16-positive) had moderate viral loads (51 and 91 viral copies per 100 cells respectively) and were positive for HPV DNA by conventional PCR. Both cases contained HPV DNA in tumour cells as shown by Q-PCR analysis of micro-dissected tissue and by in situ hybridisation. The remaining three cases had only very low viral loads (between 3 and 7 viral copies per 100 cells), were negative by conventional PCR and lacked HPV DNA in tumour cells. Our data provide strong evidence that oncogenic HPV is uncommon in oral SCC and that routine HPV testing of these tumours cannot be advocated.

Biomarker discovery using statistically significant gene sets.

Analysis of large gene expression data sets in the presence and absence of a phenotype can lead to the selection of a group of genes serving as biomarkers jointly predicting the phenotype. Among gene selection methods, filter methods derived from ranked individual genes have been widely used in existing products for diagnosis and prognosis. Univariate filter approaches selecting genes individually, although computationally efficient, often ignore gene interactions inherent in the biological data. On the other hand, multivariate approaches selecting gene subsets are known to have a higher risk of selecting spurious gene subsets due to the overfitting of the vast number of gene subsets evaluated. Here we propose a framework of statistical significance tests for multivariate feature selection that can reduce the risk of selecting spurious gene subsets. Using three existing data sets, we show that our proposed approach is an essential step to identify such a gene set that is generated by a significant interaction of its members, even improving classification performance when compared to established approaches. This technique can be applied for the discovery of robust biomarkers for medical diagnosis.

A rare case of a concurrent large thyroglossal duct cyst with a base of tongue haemangioma.

An 85-year-old lady presented with a large midline neck mass. After 8 years of steady growth, the previously asymptomatic mass began to cause stridor and dysphagia. The patient's comorbidities included a previous partial glossectomy for haemangioma of the tongue, chronic obstructive pulmonary disease, congestive cardiac failure and obesity (body mass index >30). CT neck revealed the midline mass was cystic in nature, most likely a thyroglossal duct cyst. This mass was closely related to an angiomatous malformation involving the tongue, floor of mouth and left parotid. Fine needle aspiration cytology was consistent with a colloid goitre characterised as Thy-1. Due to her extensive comorbidities, surgical resection of the midline mass was deemed to be a high-risk procedure. A Sistrunk's procedure was performed. Dissection proved difficult due to the intimately related base of tongue haemangioma. Histopathology confirmed it to be a benign thyroglossal duct cyst. She made an uncomplicated postoperative recovery.

Conditional meta-analysis stratifying on detailed HLA genotypes identifies a novel type 1 diabetes locus around TCF19 in the MHC.

The human leukocyte antigen (HLA) class II genes HLA-DRB1, -DQA1 and -DQB1 are the strongest genetic factors for type 1 diabetes (T1D). Additional loci in the major histocompatibility complex (MHC) are difficult to identify due to the region's high gene density and complex linkage disequilibrium (LD). To facilitate the association analysis, two novel algorithms were implemented in this study: one for phasing the multi-allelic HLA genotypes in trio families, and one for partitioning the HLA strata in conditional testing. Screening and replication were performed on two large and independent datasets: the Wellcome Trust Case-Control Consortium (WTCCC) dataset of 2,000 cases and 1,504 controls, and the T1D Genetics Consortium (T1DGC) dataset of 2,300 nuclear families. After imputation, the two datasets have 1,941 common SNPs in the MHC, of which 22 were successfully tested and replicated based on the statistical testing stratifying on the detailed DRB1 and DQB1 genotypes. Further conditional tests using the combined dataset confirmed eight novel SNP associations around 31.3 Mb on chromosome 6 (rs3094663, p = 1.66 × 10(-11) and rs2523619, p = 2.77 × 10(-10) conditional on the DR/DQ genotypes). A subsequent LD analysis established TCF19, POU5F1, CCHCR1 and PSORS1C1 as potential causal genes for the observed association.

Multi-cancer computational analysis reveals invasion-associated variant of desmoplastic reaction involving INHBA, THBS2 and COL11A1.

BACKGROUND: Despite extensive research, the details of the biological mechanisms by which cancer cells acquire motility and invasiveness are largely unknown. This study identifies an invasion associated gene signature shedding light on these mechanisms. METHODS: We analyze data from multiple cancers using a novel computational method identifying sets of genes whose coordinated overexpression indicates the presence of a particular phenotype, in this case high-stage cancer. RESULTS: We conclude that there is one shared "core" metastasis-associated gene expression signature corresponding to a specific variant of stromal desmoplastic reaction, present in a large subset of samples that have exceeded a threshold of invasive transition specific to each cancer, indicating that the corresponding biological mechanism is triggered at that point. For example this threshold is reached at stage IIIc in ovarian cancer and at stage II in colorectal cancer. Therefore, its presence indicates that the corresponding stage has been reached. It has several features, such as coordinated overexpression of particular collagens, mainly COL11A1 and other genes, mainly THBS2 and INHBA. The composition of the overexpressed genes indicates invasion-facilitating altered proteolysis in the extracellular matrix. The prominent presence in the signature of INHBA in all cancers strongly suggests a biological mechanism centered on activin A induced TGF-ß signaling, because activin A is a member of the TGF-ß superfamily consisting of an INHBA homodimer. Furthermore, we establish that the signature is predictive of neoadjuvant therapy response in at least one breast cancer data set. CONCLUSIONS: Therefore, these results can be used for developing high specificity biomarkers sensing cancer invasion and predicting response to neoadjuvant therapy, as well as potential multi-cancer metastasis inhibiting therapeutics targeting the corresponding biological mechanism.

Fifteen years' experience in thyroid surgery.

INTRODUCTION: Thyroid disease is common, thyroid cancer is uncommon. Most goitres are investigated using blood tests, fine needle aspiration cytology together with ultrasound. Surgery usually entails either lobectomy or total thyroidectomy, and for malignancy, patients may need a neck dissection. Recently, significant advances have been made regarding mechanisms involved in both thyroid growth and function (goitrogenesis) and carcinogenesis at a molecular level. PATIENTS AND METHODS: In the study cohort, 1113 patients had benign disease and 387 malignancy. For benign disease, 716 patients had lobectomy or isthmusectomy, 44 had near-total thyroidectomy and 318 a total thyroidectomy. For malignancy, patients received initial lobectomy (180) or total thyroidectomy (152). One hundred and eleven had completion surgery. Thirty patients had extensive surgery. Thyroid growth and function was investigated using 500 human thyroid cell primary cultures obtained at surgery, as well as in three animal models. The role of pituitary tumour transforming gene (PTTG), PTTG binding factor (PBF) and sodium iodide symporter (NIS) in thyroid cell function was then evaluated. RESULTS: Temporary and permanent recurrent laryngeal nerve palsy rates were 2.4% and 0.4%. Other complications included temporary (21%) and permanent (3%) hypoparathyroidism, wound infection (1.2%), haematoma (1.2%) and poor scar (0.8%). Six patients have died. Regarding thyroid growth and function, TSH represents (either directly or indirectly) the main factor mediating thyroid follicular cell growth. For carcinogenesis, over-expression of the proto-oncogenes PTTG and PBF induces tumours in nude mice, and PTTG can induce proliferation of human thyroid cells and, in addition, both repress expression and function of NIS.