Conventional Papillary Thyroid Carcinoma Research Articles

Development and characterization of six new human papillary thyroid carcinoma cell lines.

Cell lines are a widely used tool in cancer research. However, despite the relatively high incidence of papillary thyroid carcinoma (PTC), there are only four PTC cell lines available for international research audience. The objective of this study was to establish and characterize new PTC cell lines that represent primary tumor biology. Surgical specimens were obtained to generate PTC cell lines. Short tandem repeat profiling was used to confirm the uniqueness of the cell lines against databases of known cell lines and mutations were assessed using Sequenom. The expression of thyroid-specific genes was examined using real-time PCR. Tumorigenicity was determined using an orthotopic thyroid xenograft tumor mouse model. Six PTC cell lines (five conventional PTCs and one follicular variant of PTC) were generated and found to be unique when compared by short tandem repeat profiling against databases of all existing cell lines. The five conventional PTC cell lines carry the BRAF V600E mutation and the follicular variant of PTC cell line had an NRAS mutation. Five of the six cell lines had a mutation in the promoter of the human telomerase reverse transcriptase gene. None of the cell lines have RET/PTC rearrangements. Three cell lines were tumorigenic in the orthotopic thyroid xenograft tumor mouse model. These five characterized conventional PTC cell lines and the unique follicular variant of PTC cell line should be valuable reagents for thyroid cancer research. The three tumorigenic cell lines can be used for in vivo testing of targeted therapeutic and novel agents.

Clinical Implication of Highly Sensitive Detection of the BRAFV600E Mutation in Fine-Needle Aspirations According to the Thyroid Bethesda System in Patients With Conventional Papillary Thyroid Carcinoma.

We investigated the additional diagnostic yield of the mutation test and evaluated the frequency of the BRAF mutation in conventional PTC (cPTC) according to ultrasound (US) features and the Bethesda System for Reporting Thyroid Cytopathology (BSRTC) based on the BRAFV600E mutation status. During the study period, 279 patients who underwent FNA with an additional BRAFV600E mutation test were diagnosed as cPTC after surgery. We analyzed the association between the mutation and several clinical factors. Of the 279 cPTCs, 250 (89.6%) had the BRAFV600E mutation. The BRAF mutation test was helpful in diagnosing an additional 19% (53/279) of cPTCs. The frequency of the BRAF mutation in cPTCs with suspicious US features was higher than that of cPTCs with negative US features regardless of the BSRTC. Suspicious US features may be helpful in deciding whether an additional BRAFV600E mutation test should be done in thyroid nodules with indeterminate cytology.

Clinicopathologic correlations of the BRAFV600E mutation, BRAF V600E immunohistochemistry, and BRAF RNA in situ hybridization in papillary thyroid carcinoma

BackgroundThe BRAFV600E mutation is the most common genetic alteration in papillary thyroid carcinoma (PTC). The aim of this study is to analyze the clinicopathologic correlations of the BRAFV600E mutation, BRAF V600E immunohistochemistry (IHC) and BRAF RNA in situ hybridization (ISH) in PTC. MethodsThis study included 467 patients with PTC who underwent surgical resection. We studied the BRAFV600E mutation using real-time PCR and BRAF V600E and BRAF RNA ISH using tissue microarray (TMA). ResultsThe frequencies of a positive BRAFV600E mutation by real-time PCR, positive BRAF V600E IHC, and high BRAF RNA ISH were 84%, 86%, and 70%, respectively, in PTC. Conventional PTC had higher positive rates in all three tests than other histologic types. The BRAFV600E mutation, BRAF V600E IHC, low ΔCt, and high BRAF RNA ISH were significantly associated with lymph node metastasis. The BRAFV600E mutation was significantly associated with positive immunostaining for BRAF V600E mutant protein (P<0.001) overall, with high BRAF RNA ISH only in the follicular variant (P=0.035). No significant correlation was noted between BRAF V600E IHC and BRAF RNA ISH. The sensitivity of BRAF V600E IHC for the BRAFV600E mutation was 95%, and the specificity was 61% overall, 96% and 54% in the conventional type, and 85% and 70% in the follicular variant. ConclusionsOur results showed that positive BRAF V600E IHC significantly correlated with the BRAFV600E mutation. This suggests its clinical utility as a screening tool for the BRAFV600E mutation. In addition, a high BRAF RNA ISH score could be a candidate marker of aggressive behavior in BRAFV600E mutation-positive cases of PTC.

Associations of the BRAF(V600E) mutation with sonographic features and clinicopathologic characteristics in a large population with conventional papillary thyroid carcinoma.

ObjectiveTo evaluate the association of the BRAFV600E mutation with sonographic features and clinicopathologic characteristics in a large population with conventional papillary thyroid carcinoma (PTC).MethodsWe retrospectively reviewed the sonographic features, clinicopathologic characteristics, and presence of the BRAFV600E mutation in 688 patients who underwent thyroidectomy for conventional PTC between January and July 2010 at a single institution. The incidence of the BRAFV600E mutation was calculated. The sonographic features and clinicopathologic characteristics were compared between BRAF-positive and BRAF-negative patients. BRAF-positive patients were subdivided into those with papillary thyroid microcarcinoma (the PTMC group) and those with PTC larger than 10 mm (the PTC>10 mm group), and their sonographic features were compared.ResultsThe BRAFV600E mutation was detected in 69.2% of patients (476 of 688). Sonographic features were not significantly different between BRAF-positive and BRAF-negative PTC, nor between PTMC and PTC>10 mm groups. The BRAFV600E mutation was associated with male sex (P = 0.028), large tumor size, extrathyroidal extension, central and lateral lymph node metastasis, and advanced tumor stage (P<0.0001).ConclusionThe BRAFV600E mutation was significantly associated with several poor clinicopathologic characteristics, but was not associated with sonographic features, regardless of tumor size. We recommend that patients with a thyroid nodule with any suspicious sonographic feature undergo preoperative BRAFV600E testing for risk stratification and to guide the initial surgical approach in PTC.

Abstract 528: The modulatory role of miRNA 126 in thyroid cancer angiogenesis

Abstract MicroRNAs (miRNAs) have been described as one of the novel class of molecular regulators. Due to the crucial role miRNA-126 plays in angiogenesis, as well as the necessity of angiogenesis in malignancy, miRNA-126 has been found in association with several types of cancer. Vascular endothelial growth factor (VEGF) promotes angiogenesis and is a potent mediator of vascular permeability, as well as being a key mediator of tumour-associated neoangiogenesis and progression. In this study, we have investigated the role of miRNA-126, VEGF-A and their impact on angiogenesis in thyroid cancers. 51 conventional papillary thyroid carcinomas, 37 follicular variant of papillary thyroid carcinomas, 13 undifferentiated thyroid carcinomas, 13 matched lymph nodes metastasis and 21 normal thyroid tissues obtained from non-cancer adjacent to benign lesions were recruited as controls. Firstly, extracted miRNAs from selected samples were loaded on a miRNA microarray chip developed by Agilent (Agilent Technologies, Inc., Santa Clara, CA, USA) using a pooling method to confirm the expression differences of miRNAs including miRNA-126. Then, miRNA-126 and VEGF-A was tested in individual samples using real-time PCR. In addition, 2 papillary thyroid cancer cell lines (K1 and B-CPAP) and a normal thyroid cell line (Nthy-ori 3-1) were used for the exogenous manipulation of the miRNA-126 and investigation of its effect on VEGF-A expression. The expression of VEGF-A were then measured by immunofluorescence and western blot techniques. The expression of miRNA-126 was noticeably higher in the pool of papillary thyroid carcinoma with metastasis. Using real time PCR, miRNA-126 and VEGF-A were significantly over-expressed in cancer populations compared to controls (p=0.009 and 0.011 respectively). A significant positive correlation between miRNA-126 and VEGF-A expression was also noted (p= 0.00009). Real time PCR of extracted RNA from the cell lines has shown under-expression of miRNA-126 compared to normal cells while VEGF-A RNA and protein were over-expressed. The reduction of VEGF-A protein expression after transfection of miRNA-126 mimic into K1 and B-CPAP, confirms the regulatory role of miRNA-126 on VEGF-A expression in thyroid cancer cell lines. These findings add weight to our previous understanding about the angiogenic role of miRNA-126 in cancer. These experiments provide information on the functional consequences of VEGF manipulation via miRNA on cancer. The data will provide primary information regarding the utility of over-expressing miRNA-126 in cancer management and future development of effective tumour-specific anti-angiogenic therapy. Citation Format: Ali Salajegheh, Haleh Vosgha, Md. Atiqur Rahman, Vinod Gopalan, Robert Anthony Smith, Alfred King-Yin Lam. The modulatory role of miRNA 126 in thyroid cancer angiogenesis. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 528. doi:10.1158/1538-7445.AM2014-528

Conventional papillary thyroid carcinoma: effects of cystic changes visible on ultrasonography on disease prognosis.

PurposeTo investigate the characteristics of papillary thyroid carcinoma (PTC) with cystic changes visible on ultrasonography (US).MethodsThis study included 553 PTCs in 553 patients between January 2003 and August 2004. One radiologist with 10 years of experience in thyroid imaging retrospectively reviewed the preoperative US images. Two different groups were formed according to two different reference points (group 1, 25%; group 2, 50%) of the cystic component. Patients between the groups were compared according to their clinicopathologic characteristics. Disease-free survival (DFS) was estimated. Cox’s multivariate proportional hazards regression model was used to identify the effect of variable factors on the recurrence risk.ResultsFifty-six patients (10.1%) were confirmed to have tumor recurrence within the follow-up period. Thirty-five patients had regional metastasis, one had distant metastasis, eight had multiple site metastases, and 12 had biochemical recurrence. PTC patients with a ≤ 50% or PTC patients with a ≤ 25% cystic component did not have a statistically significant longer DFS than those with a >50% (hazard ratio [HR], 1.118; 95% confidence interval [CI], 0.255 to 4.910; P=0.883) or those with a >25% cystic component (HR, 0.569; 95% CI, 0.164 to 1.976; P=0.375), respectively. Moreover, independent predictors of recurrence were pathologic size, male gender, and lymph node metastasis, not a >50% or >25% cystic component.ConclusionThe proportion of the cystic component in PTCs did not affect DFS.

Assessment of molecular testing in fine-needle aspiration biopsy samples: An experience in a Chinese population

Fine-needle aspiration biopsy remains the mainstay for preoperative examination of thyroid nodules; however, it does not provide a definite diagnosis in up to 25% of nodules. Considerable studies have been performed to identify molecular markers to resolve this diagnostic dilemma. The aim of this study was to establish the distribution and frequency of common genetic alterations in a comprehensive set of benign and malignant thyroid nodules, and to determine the feasibility and role of testing for a panel of genetic alterations in improving the accuracy of cytology diagnosis in a Chinese population. This study was conducted in 314 thyroid nodules comprising 104 papillary thyroid carcinomas, 13 suspicious nodules, 52 indeterminate nodules, and 145 benign nodules. Point mutations and RET/PTC rearrangements, were evaluated by pyrosequencing and TaqMan real-time PCR, respectively. After surgery, 115 nodules were confirmed as conventional papillary thyroid carcinoma and 102 (88.70%) of these nodules harbored either the BRAFV600E mutation (76.52%) or RET/PTC rearrangements (12.17%). RAS mutation was found in 1 (33.33%) follicular thyroid carcinoma, 1 (14.29%) follicular thyroid adenoma and 4 (10%) goiter nodules. With cytology and molecular testing, the diagnostic accuracy was further increased to 98.82% in papillary thyroid carcinoma diagnosis, and was preoperatively increased to 76.92% and 84.00%, respectively, in nodules with suspicious and indeterminate cytology. In conclusion, molecular testing of a panel of genetic alterations in fine-needle aspiration biopsy can be effectively performed in clinical practice. It enhances the accuracy of cytology and is of particular value for indeterminate nodules in the Chinese population.

Nodal metastasis and recurrence in papillary thyroid microcarcinoma.

Despite the majority of papillary thyroid microcarcinoma (PTMC) patients has benign clinical courses, some PTMCs have a clinical presentation similar to conventional papillary thyroid carcinoma (PTC). The aim of this study was to identify risk factors for lymph node metastasis at presentation and prognostic parameters influencing nodal recurrence in PTMC. From January 1998 to October 2013, 556 consecutive patients had a diagnosis of differentiated thyroid carcinoma in our surgical department. A total of 219 (39.4%) patients who had a pathological diagnosis of PTMC represented the cohort for the current study. We carried out a retrospective cohort study to compare 24 PTMC patients with lymph node metastasis at diagnosis (N1) and 195 PTMC patients without lymph node involvement (N0). The comparison between groups involved evaluation of patients and tumor characteristics. A diameter >8mm, the presence of multifocality, and extrathyroid invasion (T3) were independent risk factors for nodal involvement at presentation. The presence of T3 was the only independent prognostic parameter influencing nodal recurrence. Prognostic factors for N1 at presentation and for recurrence are pathological parameters, thus it is not possible before surgery to detect PTMC patients who are at risk. However, we believe that a full treatment protocol should be also indicated in the case of PTMC according to risk stratification and cancer stage as for the conventional counterpart of PTC.

Warthin-like variant of papillary thyroid carcinoma: single institution experience.

Correct diagnosis of the variants of papillary thyroid carcinoma (PTC) is important because these variants differ in clinical course. The Warthin-like variant (WLV) is relatively uncommon and is recognized as not different from conventional PTC. We therefore assessed the clinicopathological features of patients with WLV of PTC who were diagnosed and treated at our institution. Of the 8179 patients treated for PTC at the Thyroid Cancer Center, Gangnam Severance Hospital, Yonsei University College of Medicine, between January 2007 and December 2012, 16 patients (0.2%) were pathologically diagnosed with WLV of PTC. Their clinicopathological features and post-operative follow-up for local recurrence and distant metastasis were retrospectively investigated. Mean patient age was 44.9 years (range: 23-61 years), with seven (44%) being younger than 45 years. Only one of the 16 patients was male (6%). Mean tumour size was 8.9 mm (range: 3-22 mm). Extrathyroidal extension was observed in seven patients (44%), associated thyroiditis in 11 (69%) and lymph node metastasis in six (38%). The mean follow-up period was 37 months (range: 13-78 months), during which none of the 16 patients experienced recurrence or metastasis. Fifteen patients (94%) had MACIS score <6, with the remaining patient having a MACIS score of 6.33. WLV of PTC is rare, with favourable prognosis. Nevertheless, it is important to determine the histopathological features of these tumours.

High-density microarray expression profiling in conventional papillary thyroid carcinomas with versus without a BRAF mutation

Materials and methods Affymetrix HuGene 1.0 ST microarrays were used to generate whole transcript expression profiles in 11 BRAF and 14 BRAF PTCs. A p-value with a false discovery rate (FDR) ≤ 0.05 and a fold change > 2 were used as a threshold of significance for differential expression. Spearman’s correlation as a similarity matrix was utilized for unsupervised two dimensional hierarchical clustering. The BRAF mutational status was surveyed by direct sequencing the hotspot region of BRAF exon 15.

Frequent microdeletions in conventional papillary thyroid carcinoma detected by high-density oligonucleotide microarrays

Materials and methods We used SurePrint G3 human CGH+SNP, 2×400K, microarrays to assess gains and losses in 47 PTCs in comparison to male and female human reference DNA. Interpretation of results was accomplished by using the HG19 version of the design file and the default analysis method of the Cytogenomics 2.7 research software [1]. To compare BRAF mutant (BRAF) PTCs with BRAF wild type (BRAF) PTCs, the BRAF mutational status was established in 42 cases by direct sequencing the mutational hotspot region in exon 15 [2].

Diagnostic Value of Immunohistochemistry for the Detection of the BRAFV600E Mutation in Papillary Thyroid Carcinoma: Comparative Analysis with Three DNA-Based Assays

The aim of this study was to compare the detection of BRAF(V600E) by immunohistochemistry (IHC) using a mutation-specific antibody with molecular biology methods for evaluation of papillary thyroid carcinoma (PTC) patients. This study concerned 198 consecutive conventional PTC patients, of which the majority were women (133/198; 67%), with a mean age of 56 years (range 19-79 years). BRAF mutation analysis was performed using DNA-based (direct sequencing, pyrosequencing, and SNaPshot) and IHC (VE1 antibody) methods. The sensitivity and specificity of IHC for BRAF(V600E) was compared with the molecular biology data. A BRAF mutational result was obtained in 194 cases. A BRAF(V600E) mutation was detected in 153/194 (79%) cases of PTC when using at least one molecular method, and in 151/194 (78%) cases with IHC. No false positive results were noted using IHC to detect the BRAF(V600E) mutation. Besides this mutation, other rare BRAF mutations (BRAF(V600K) and BRAF(K601E)), used as negative controls, were consistently negative with IHC. The sensitivity and specificity of IHC for the detection of this mutation were 98.7% and 100% respectively. The IHC test demonstrated excellent performance at a level equivalent to two DNA-based counterparts (pyrosequencing and SNaPshot). Failure to achieve a result was more frequent with the direct sequencing method than with the three other methods. IHC using the VE1 antibody is a specific and sensitive method for the detection of the BRAF(V600E) mutation in PTC. IHC may be an alternative to molecular biology approaches for the routine detection of this mutation in PTC patients.

Prevalence, Tumorigenic Role, and Biochemical Implications of Rare BRAF Alterations

Papillary thyroid carcinoma (PTC) is the most common malignant tumor of the thyroid gland, accounting for 74-80% of all thyroid cancers. The 1799T>A transversion is an activating mutation of the BRAF oncogene that is common in and specific to conventional PTC. We studied the prevalence, tumorigenic role, and biochemical implications of rare BRAF variants in a large cohort of patients. A total of 2131 fine-needle aspiration biopsy samples were collected and subjected to BRAF mutation analysis. BRAF genetic variants were analyzed by Western blot, immunofluorescence, and in silico analysis. BRAF mutations were found in 50% (347/700) of thyroid cancers (644 PTCs, 22 anaplastic thyroid carcinomas, 34 follicular thyroid carcinomas). They were the classic (c.1799T>A, p.V600E) mutation in 96.8% (336/347) and rare genetic variants in 3.2% (11/347). In all, five infrequent BRAF alterations were detected: (i) c.1795_1797dupACA (p.T599dup); (ii) c.1801A>G (p.K601E); (iii) c.1799_1801delTGA (p.V600_K601>E); (iv) c.1799_1814>A (p.V600_S605>D); and (v) c.1798_1810delinsA (p.V600_W604>R). The last BRAF variant has never been described in the literature. Western blot analysis and immunofluorescence both revealed a variegated reactivity pattern, again emphasizing the peculiar role of every specific BRAF genetic alteration. In silico analysis of the samples studied revealed a stabilization of the "active" geometrical conformation of the B-raf enzyme associated with the activated and productive state of the kinase domain. Rare BRAF variants were found in 1.6% of all thyroid malignancies, all clustered around the codon V600, in the binding pocket named A-loop, confirming its crucial role in the enzymatic activation of the B-Raf protein. These mutations were associated mainly with the activation of key effectors in the mitogen-activated protein kinase pathway, but a simultaneous stimulation of the PI3k/Akt cascade was demonstrated in some cases. The rare BRAF variants were not generally associated with an aggressive behavior of the PTC. To our knowledge, this is the largest series of thyroid cancers analyzed to identify and functionally characterize rare BRAF variants.

Diffuse Sclerosing Variant of Papillary Thyroid Carcinoma with Concomitant Thyrotoxicosis: A Case Report and Literature Review

Diffuse sclerosing variant of papillary thyroid carcinoma (DSVPC) is a rare variant of conventional papillary thyroid carcinoma which was first reported in 1985. It appears to be more aggressive than conventional type of papillary thyroid carcinoma. We present a case in a 14-year-old girl who initially presented with thyrotoxicosis and was later diagnosed with DSVPC on subsequent ultrasound and fine need leaspiration when cervicallymph node was evident on clinical examination. Concomitant thyrotoxicosis in thyroid carcinoma is uncommon. The prevalence, clinical presentation, characteristic radiological and histological features, management and prognosis of DSVPC are discussed with literature review. We also hope to illustrate through this case that ultrasound as a non-invasive imaging modality is an invaluable tool for workup in functional thyroid problems and concomitant malignancy may not be that uncommon, so that we could provide prompt treatment to our patients.

BRAF mutation assessment in papillary thyroid cancer: are we ready to use it in clinical practice?

In 2002, large-scale genomic screens allowed uncovering the occurrence of BRAF mutations in melanomas (67 %), colon carcinomas (12 %), and ovarian tumors (14 %) [1]. In the subsequent years, constitutively activating mutations in the BRAF oncogene, encoding a serine/threonine protein kinase activating the MAP kinase/ERK-signaling pathway, have been reported in papillary thyroid carcinomas (PTC) (44 %) [2] and in hairy cell leukemias (100 %) [3]. Accordingly, the impact of BRAF mutation on clinical outcome has been extensively exploited in a variety of cancers, often resulting in controversial or unsettled findings. A T-to-A transversion at nucleotide 1799, which results in a valine to glutamate substitution at residue 600 (BRAF), is by far the most common mutation in differentiated thyroid cancer (DTC) [2]; however, it has been found as well in a fraction of poorly differentiated (PDTC) (10–15 %) and anaplastic thyroid carcinomas (ATC) (10–44 %) [4, 5]. The BRAF mutation’s high prevalence and detection easiness have facilitated the understanding of its pathogenetic, diagnostic, prognostic, and therapeutic roles in thyroid tumors. Experimental studies with transgenic mice characterized by thyroid-targeted expression of the oncogene consistently indicated that BRAF is a clonal-initiating event in thyroid follicular cell carcinogenesis [6]. Mutual exclusivity in PTCs of the most common genetic mutations, including BRAF and RAS mutations and RET/PTC rearrangements, indicate that each event is self-sufficient to constitutively activate the tumor-initiating MAPK pathway [6]. Conversely, more recently, a study that used pyrosequencing to determine the percentage of mutant BRAF alleles in conventional PTCs concluded that BRAF is a rare clonal event and more often a nonclonal mutation, occurring late during PTC progression [7]. If confirmed, this finding would have important ramifications because it would undermine the rationale for using therapies targeted against this oncoprotein. An intense scientific debate is ongoing on this topic [8] and, hopefully, it will help in clarifying this controversy soon. Another important question is if BRAF mutation might have a diagnostic role as malignant marker in a thyroid nodule aspirate, especially in the case of indeterminate fine-needle aspiration cytology (FNAC). The latter cytological picture occurs quite frequently (10–26 % of nodules) and harbors an intermediate risk of malignancy (14–48 %). Improvements of thyroid cytopathology by the introduction of thin core needle biopsy, with the assessment of the nodule capsule and the perinodular tissue, have appeared to ameliorate recognition of malignancy in cytologically indeterminate nodules [9]. Similarly, combination of nodule ultrasound features with measures of nodule stiffness, obtained by real-time elastography, has appeared to increase sensitivity for malignancy and to strengthen the selection of patients who do not need further diagnostic testing [10]. However, the analysis of diagnostic molecular markers on indeterminate FNAC specimens has caught the greatest interest. Search of DNA-based point mutations of BRAF has a sound biological rationale in view of its high frequency and driving role in PTCs and peculiar assay robustness due to DNA stability [6]. However, more than 50–60 % of DTCs do not harbor this molecular E. Puxeddu Department of Medicine, University of Perugia, Via Gambuli, 1, 06132 Perugia, Italy

Association Between Expression of X-Linked Inhibitor of Apoptosis Protein and the Clinical Outcome in a BRAFV600E-Prevalent Papillary Thyroid Cancer Population

The X-linked inhibitor of apoptosis protein (XIAP) is associated with carcinogenesis, cancer progression, and metastasis through inhibition of the caspase-mediated apoptotic pathway. The BRAF(V600E) mutation is the most common genetic alteration and an established prognostic marker in papillary thyroid cancer (PTC). The prevalence of the BRAF mutation is very high and is up to 80% in Korean PTC patients. In the present study, we evaluated the potential role of XIAP expression as a novel prognostic marker to predict recurrence, in combination with the BRAF(V600E) mutational status. The study enrolled 164 patients with conventional PTC who underwent bilateral thyroidectomy followed by immediate (131)I ablation. The presence of the BRAF(V600E) mutation was evaluated by direct sequencing. The degree of XIAP expression was evaluated by immunohistochemical (IHC) staining using a monoclonal antibody. The BRAF(V600E) mutation was found in 123 of 164 patients (75%) with classical PTC. XIAP expression was positive in 128 of 164 patients (75%), and positive XIAP expression was significantly associated with the presence of lateral cervical lymph node metastases (p=0.01). XIAP expression was more frequent in BRAF(V600E) mutated PTCs than in BRAF wild type PTCs (p=0.048). The BRAF(V600E) mutation was significantly associated with cancer recurrence in study subjects (hazard ratio=2.98, p=0.039). PTCs positive for the BRAF(V600E) mutation but negative for XIAP expression had a significantly higher rate of recurrent PTC (hazard ratio=4.53, p=0.012). The evaluation of XIAP expression and BRAF mutational analysis was more useful for the prediction of cancer recurrence in patients with PTC than BRAF genotype alone.

Familial history of non‐medullary thyroid cancer is an independent prognostic factor for tumor recurrence in younger patients with conventional papillary thyroid carcinoma

It is not clear whether familial non-medullary thyroid cancer (FNMTC) is more aggressive and has a poorer prognosis, than sporadic carcinoma. Therefore, the optimal clinical approach for FNMTC is yet to be established. In this study, we investigated the biological behavior and prognosis of FNMTC compared with its sporadic counterpart. Between 1996 and 2004, 1,262 patients underwent a total thyroidectomy for conventional PTC at Asan Medical Center and 113 (9.0%) were diagnosed with FNMTC. We compared the clinico-pathologic characteristics, treatment modalities, and prognosis between familial and sporadic NMTC. FNMTC was significantly more multi-centric than sporadic. We also found that family history itself was an independent risk factor for recurrence. Moreover, disease-free survival in the familial group was significantly shorter than in the sporadic group in the subgroups in which age was <45 years, and in which the tumors were multi-centric, bilateral, and of N1b node status. FNMTC may be considered as a separate clinical entity with a higher rate of recurrence and worse DFS than its sporadic counterpart. Furthermore, familial history of NMTC is an independent risk factor for recurrence, especially in younger patients with conventional PTC.

Low expression of sodium iodide symporter expression in aggressive variants of papillary thyroid carcinoma

A decreased radioiodine uptake is associated with high recurrence rate and reduced survival in papillary thyroid carcinoma (PTC). Sodium iodide symporter (NIS) expression status in aggressive PTC variants is unknown. NIS expression in conventional PTC and aggressive PTC variants such as tall cell variant (TCV) and diffuse sclerosing variant (DSPTC) was investigated using immunohistochemical detection. Patients having TCV and DSPTC were significantly more likely to have extrathyroidal extension and lymph nodes metastases (P < 0.05). Positive NIS staining was identified in 228 of 312 (73.1 %) patients with conventional PTC, 9 of 28 (32.1 %) patients with TCV and 12 of 30 (40.0 %) patients with DSPTC. NIS expression distinguished conventional PTC from TCV and DSPTC significantly (P < 0.01). Due to their low NIS expression, TCV and DSPTC need higher cumulative doses of radioactive iodine therapy to improve their prognosis.

Clinicopathologic Implications of the BRAFV600E Mutation in Papillary Thyroid Cancer: A Subgroup Analysis of 3130 Cases in a Single Center

The BRAF mutation has been shown to be associated with aggressive clinicopathologic characteristics of papillary thyroid cancer (PTC). However, several studies that analyzed hundreds of patients have not demonstrated any correlation. The objective of this study was to investigate the relationship of the BRAF mutation with clinicopathologic factors in a large group of homogenous PTC patients. We collected data of PTC patients who received curative resection of the thyroid gland and who had undergone BRAF mutation tests of their thyroid cancer tissue. Minor variant PTCs and mixed-type thyroid cancers were excluded in this analysis. Clinicopathologic characteristics, including age, sex, BRAF mutation, tumor histology, size, extrathyroidal extension, tumor margin, lymph node metastasis, multifocality, stage, and associated thyroid disease, were collected. The relationship of the BRAF mutation with clinicopathologic factors was analyzed in each homogenous histologic PTC. There were 3130 PTC patients who met the criteria, and these patients were divided into three major histologic groups: conventional PTC (n = 2947), diffuse sclerosing variant PTC (n = 98), and follicular variant PTC (n = 85). The BRAF mutation was variably detected in 75.3%, 61%, and 40% of patients, respectively. In conventional PTC cases, the BRAF mutation was significantly associated with large tumor size, extrathyroidal extension, and lymph node metastasis. Coexistent chronic lymphocytic thyroiditis was significantly less prevalent in the BRAF mutant group. Age, sex, and tumor margin status were not significantly correlated with the BRAF status. There was no evidence that any clinicopathologic factors were linked with the BRAF mutation status in diffuse sclerosing and follicular variant PTCs. The BRAF mutation was differentially detected in each histologic subtype of PTC and was strongly correlated with pathologic factors, most strongly with no coexistent chronic lymphocytic thyroiditis, in conventional PTC. The BRAF mutation is suggested to be a poor prognostic marker in conventional PTC, and the BRAF mutational analysis may lead to better management for individual PTC patients.

Significance of p53‐binding protein 1 (53BP1) expression in thyroid papillary microcarcinoma: association with BRAFV600E mutation status

In a previous report, we proposed that analysis of 53BP1 expression by immunofluorescence could be a useful tool in estimating the level of genomic instability (GIN), as well as the malignant potential, of thyroid tumours. In an attempt to clarify the value of 53BP1 expression as a new molecular marker for the aggressiveness of thyroid papillary microcarcinoma (PMC), we assessed the association between the type of 53BP1 expression and clinicopathological features such as tumour size, extrathyroidal invasion, lymph node metastasis and BRAF(V) (600E) mutation of PMC. A total of 36 surgically resected thyroid tumours, including 13 PMC and 23 conventional papillary thyroid carcinomas (PTC), were available for this study. Analysis using immunofluorescence revealed that the incidence of an abnormal or high DNA damage response (DDR) type of 53BP1 expression was significantly higher in PTC than PMC. BRAF(V) (600E) mutation was not associated significantly with tumour aggressiveness in either PMC or PTC cases. Abnormal/high DDR type of 53BP1 expression was associated closely with both BRAF(V) (600E) mutation and papillary and/or trabecular architecture of PMC. Abnormal/high DDR type of 53BP1 expression might be associated with GIN and papillary/trabecular morphology at an early stage of PTC carcinogenesis through BRAF(V) (600E) mutation.