Pathology and genetics of thyroid carcinoma

Associations between rs965513/rs944289 and papillary thyroid carcinoma risk: a meta-analysis

Single-nucleotide polymorphisms of rs965513 (9q22.33) and rs944289 (14q13.3) may be involved in the pathogenesis of papillary thyroid carcinoma (PTC). But, relevant genetic studies reported different results. The aim of this meta-analysis was to derive a more precise assessment of the association of rs965513/rs944289 polymorphism with PTC risk. Relevant studies were identified using PubMed, ISI Web of knowledge, Medline, Embase, Google Scholar Search database, SinoMed (Chinese), CNKI (Chinese), GeNii (Japanese) and ICHUSHI (Japanese) (update to December, 2013). A total of eight case-control studies with 52,363 subjects for rs965513 and 51,120 subjects for rs944289 were included. The results showed significant associations of rs965513/rs944289 with PTC risk existed in overall population (for rs965513, A vs. G: OR 1.71 (1.56-1.86); for rs944289, T vs. C: OR 1.29 (1.23-1.37)). Subgroup analysis by ethnicity showed that there were significant associations in Asians (for rs965513, A vs. G: OR 1.48 (1.27-1.73); for rs944289, T vs. C: OR 1.35 (1.18-1.55)), in Europeans (for rs965513, A vs. G: OR 1.74 (1.61-1.88); for rs944289, T vs. C: OR 1.24 (1.14-1.34)), and in Americans (for rs965513, A vs. G: OR 2.00 (1.76-2.27); for rs944289, T vs. C: OR 1.29 (1.14-1.47)). In conclusion, Rs965513 [A] and rs944289 [T] are risk factors of PTC. Effect estimate for rs965513 polymorphism is higher in Americans than in Asians.

p53 antibody: is it an indicator of dedifferentiated thyroid cancer?

AIM

Radioiodine is the most effective treatment modality in differentiated thyroid carcinoma, either in metastatic or residual thyroid tissue. However, sometimes dedifferentiation can develop and the effectiveness of radioactive I-131 decreases. The p53 is a tumor suppressor gene which plays an important role in controlling normal cell proliferation regulation. In the serum of healthy individuals, the presence of p53 autoantibodies is extremely rare. Mutations in this gene cause an accumulation of non-functional proteins and may lead to development of anti-p53 antibodies. The aim of the present study was to devise a simple blood test that could lead to early identification of patients with dedifferentiation. In this respect, we investigate whether the serum level of anti-p53 antibody is of diagnostic value in the follow-up of patients with high levels of thyroglobulin (Tg) and negative I-131 scan.

MATERIALS AND METHODS

Patients who were diagnosed with thyroid cancer, treated with total or near total thyroidectomy and referred for I-131 therapy or low dose I-131 whole body scan were included in our study. Blood samples were taken before the administration of I-131 orally in the group of patients. Besides, 28 healthy subjects were included. We quantified the presence of p53 autoantibodies from serums.

RESULTS

In the present study were enrolled 171 patients with a mean age of 47.7±13.5 years (range 16–80 years) and 28 healthy subjects with an age range of 18–52 years (mean 36.0±9.8 years). One hundred and forty-eight patients had papillary (86.5%), 7 (4.1%) follicular, 10 (5.8%) thyroid tumors of uncertain malignant potential, 2 (1.2%) Hürthle cell carcinoma, 3 (1.8%) poor differentiated, and 1 (0.6%) undifferentiated thyroid carcinoma. The p53 antibodies were positive in 16 (9.4%) patients and negative in 155 (90.6%). The p53 antibodies were positive in 3 (10.7%) healthy subjects, and negative in 25 (89.3%) healthy subjects. In five patients with high Tg level and negative radioiodine scan, who were accepted as dedifferentiated, p53 antibodies were also negative.

CONCLUSION

The results of the present study suggested that the level of serum p53 antibody seems to be of limited value in the demonstration of dedifferentiation in thyroid cancer patients.

Suppressed Krüppel‑like factor 17 expression induces tumor proliferation, metastasis and a poor prognosis in papillary thyroid carcinoma

Although the role of krüppel‑like factor 17 (KLF17) in the regulation of proliferation and epithelial‑mesenchymal transition has been examined in breast and liver cancer, their effect on papillary thyroid carcinoma (PTC) remains to be elucidated. The present study aimed to investigate the expression pattern of KLF17 in PTC and the correlation between KLF17 expression and the malignant potential of PTC. KLF17 expression in PTC and adjacent liver tissues was studied by polymerase chain reaction and western blot analysis, and the association between KLF17 expression and the clinicopathological features of PTC was studied in 50 patients. By using RNA interference against KLF17, the correlation between KLF17 expression and malignant potential was examined by downregulating KLF17 expression in TPC‑1 cells, and the effects of KLF17 downregulation on cell proliferation and motility were analyzed. Furthermore, the association between KLF17 expression and the surgical outcomes of PTC patients were analyzed. Downregulated expression of KLF17 was associated with a shorter overall survival time in clinical patients (P<0.05). Low KLF17 expression was significantly associated with tumor stage, tumor size, nodal stage and metastasis stage in PTC (P<0.05). The reduced expression of KLF17 promoted the motility and proliferation ability of TPC‑1 cells by altering the expression of tight junction protein 1 and Snai1, and activating the AKT pathway by upregulating inhibitor of DNA binding 1. In conclusion, the present study demonstrated that KLF17 is important in tumor proliferation and may be a useful prognostic indicator in directing therapy. Therefore, further investigation regarding the role of KLF17 in PTC is required.

Utility of immunohistochemical markers in diagnosis of follicular cell derived thyroid lesions

Differentiating the follicular derived lesions can be challenging. Although immunohistochemistry is generally accepted as a useful ancillary technique in the diagnosis, controversy exists regarding the best marker or combination of markers to distinguish each lesion from its mimics. In this study, we aimed at evaluating multiple markers to compare their sensitivity and usefulness, and to find out if a combination of the evaluated markers can be of additional value in discriminating thyroid lesions. The study included two groups of follicular derived thyroid lesions; benign group (Grave's disease, nodular goiter, Hashimoto's and adenoma) and malignant group (papillary, follicular carcinoma, well differentiated tumors of unknown malignant potential and follicular tumour of unknown malignant potential). Immunohistochemical evaluation of CD56, HBME-1, Gaectin-3 and CK19 were done. The sensitivity, specificity for each marker and their combination were calculated. Each marker was sensitive and specific for certain lesion but the sensitivity and specificity was increased when use combination of markers. Although no single marker is completely sensitive and specific for follicular thyroid lesions, the combination of CD56, HBME-1, Gaectin-3 and CK19 attains high sensitivity and specificity in diagnosis.

Association Study of FOS-Like Antigen-2 Promoter Polymorphisms With Papillary Thyroid Cancer in Korean Population

Objectives

FOS-like antigen-2 (FOSL-2), a member of the FOS gene family, encode leucine zipper proteins that can heterodimerize with proteins of Jun family. Thus, activating protein (AP)-1 transcription factor is formed, has a crucial role in proliferation, differentiation and apoptosis of normal tissue as well as oncogenic transformation and progression. We performed an association study of single nucleotide polymorphisms (SNPs) in the FOSL-2 with papillary thyroid cancer (PTC). We also estimated the relationships between the SNPs and the clinicopathologic characteristics of PTC.

Methods

One promoter SNPs (rs925255) of FOSL-2 gene were genotyped with direct sequencing method in 94 PTC and 213 controls. PTC patients were dichotomized and compared with respect to clinical parameters of PTC. Genetic data were analyzed using Helixtree, SNPAnalyzer, SNPStats. Multivariate logistic regression analysis was fulfilled to evaluate the genetic effect with adjustment for age and sex.

Results

SNP (rs925255) in FOSL-2 showed a significant association (codominant 1 model [G/G vs. A/G]: odds ratio [OR], 0.531, 95% confidence interval [CI], 0.293 to 0.96, P=0.036; dominant model: OR, 0.50, 95% CI, 0.28 to 0.89, P=0.015) with PTC. The frequency of allele G in rs925255 was also significantly associated with PTC (OR, 0.59; 95% CI, 0.34 to 0.91; P=0.02). But we fail to prove significant association between this polymorphism (rs925255) and clinico-pathological parameters.

Conclusion

Our findings suggest that the rs925255 SNP and its allele G show significant association with the PTC in Korean population.

Are the SNPs of NKX2-1 associated with papillary thyroid carcinoma in the Han population of Northern China?

Papillary thyroid carcinoma (PTC) is one of the most common tumors of the thyroid gland. The common risk factors of PTC include ionizing radiation, positive family history, and thyroid nodular disease. PTC was identified in Europeans by conducting a genome-wide association study, and a strong association signal with PTC was observed in rs944289 and NKX2-1 (located at the 14q13.3 locus), which was probably the genetic risk factor of PTC. This study aimed to examine the association of this gene with PTC in Chinese. A total of 354 patients with PTC and 360 healthy control subjects from the Han population of Northern China were recruited in the study. These individuals were genotyped to determine rs12589672, rs12894724, rs2076751, and rs944289. The association of rs944289 with PTC was obtained (C vs. T, P = 0.027, OR = 1.264, 95% CI = 1.026 - 1.557; and C/C - C/T vs. T/T, P = 0.034, OR = 1.474, 95% CI = 1.028 - 2.112). Conducting a subgroup analysis, we found a marginal difference in the allele frequency distribution of rs944289 (adjusted P = 0.062) between the patients with PTC and multi-nodular goiter and the control subjects. We also observed an interaction (P = 0.029; OR = 2.578, 95% CI = 1.104 - 6.023) between rs944289 and diabetes in patients with PTC. In conclusion, rs944289 was associated with an increased risk of PTC in the Han population of Northern China, but no clear association was observed in either of the tag single nucleotide polymorphisms of NKX2-1.

Surgical management of thyroid cancer

Thyroid cancer is the most common endocrine neoplasm; however, it only accounts for less than 1% of all human malignances. Thyroid cancers are divided into well differentiated and non-well differentiated cancers, according to their histology and behavior. The surgical management options of well-differentiated thyroid cancer include total or near-total thyroidectomy, subtotal thyroidectomy and lobectomy plus isthmusectomy. The extent of surgery for thyroid cancer continues to be an area of controversy. Complications associated with thyroid surgery are directly proportional to the extent of thyroidectomy and inversely proportional to the experience of the operating surgeon. They occur less frequently with good surgical technique and better understanding of surgical anatomy, and include wound healing and infections (seroma, hematoma and wound infection), nerve injury, hypoparathyroidism, hypothyroidism, postoperative hemorrhage and respiratory obstruction.

Differential expression of immune-modulatory molecule HLA-E in non-neoplastic and neoplastic lesions of the thyroid

Human leukocyte antigen (HLA)–E is a non-classical molecule of the histocompatibility complex that functions as one of the main ligands of the Natural Killer (NK) cell inhibitory receptor CD94/NKG2A and inhibits its potent cytotoxic activity. Due to the important role of NK cells in combating neoplasm, we hypothesized that the differential expression of HLA-E could favor the progression of heterogeneous thyroid tumors.Using an immunohistochemistry technique in 143 biopsies of thyroid tumors, including benign and malignant neoplasms and goiters, we evaluated the expression of HLA-E among various tumor types and its association with the clinicopathological factors of diseases. We verified high HLA-E expression in all types of neoplastic tumors, although no significant differences between the groups were found. Low expression was observed in 95 percent of the goiter samples, showing significant differences between neoplastic and non-neoplastic lesions. Furthermore, a significant result was found with regard to the tumor size, with high HLA-E expression being related to smaller tumors. Therefore, our data suggest that an increase in HLA-E may be associated with the establishment of thyroid neoplasms, with either benign or malignant features.

Patterns of FOXE1 expression in papillary thyroid carcinoma by immunohistochemistry

BACKGROUND

FOXE1, a thyroid-specific transcription factor also known as TTF-2, was recently identified as a major genetic risk factor for papillary thyroid carcinoma (PTC). Its role in thyroid carcinogenesis, however, remains unknown. The purpose of the present study was to assess the relationship between the FOXE1 immunohistochemical features and the clinical and genetic characteristics of PTC.

METHODS

Immunohistochemical staining of FOXE1 was performed in 48 PTC cases. Two single nucleotide polymorphisms immediately inside (rs1867277) or in the vicinity (rs965513) of the FOXE1 gene were genotyped by direct sequencing. Histopathological, clinical, and genetic data were included in statistical analyses.

RESULTS

FOXE1 exhibited cytoplasmic overexpression in tumor tissue compared to the normal counterpart (p<0.001). Both cancer and normal thyroid cells demonstrated the highest FOXE1 scores in the areas closest to the tumor border (<300 μm) compared with more distant areas (p<0.001). No differences in FOXE1 staining distributions were found between microcarcinomas and PTC of larger size, between different histopathological variants of PTC, and encapsulated and nonencapsulated tumors. Multivariate regression analysis revealed that nuclear FOXE1 expression in neoplastic cells in the vicinity of the tumor border independently associated with the genotype at rs1867277 (the dominant model of inheritance, p=0.037) and tumor multifocality (p=0.032), and with marginal significance with capsular invasion (p=0.051).

CONCLUSIONS

FOXE1 overexpression and translocation to the cytoplasm are phenotypic hallmarks of tumor cells suggesting that FOXE1 is involved in the pathogenesis of PTC. Nuclear FOXE1 expression in tumor cells in the vicinity of the PTC border is associated with the presence of a risk allele of rs1867277 (c.-238G>A) in the 5' untranslated region of the FOXE1 gene, as well as with pathological characteristics of PTC, suggesting possible FOXE1 involvement in the facilitation of tumor development beginning at an early stage.

Diagnostic and prognostic implications of the PAX8-PPARγ translocation in thyroid carcinomas-a TMA-based study of 226 cases

AIMS

Follicular thyroid carcinoma (FTC) has been a diagnostic challenge for decades. The PAX8-PPARγ rearrangement has been detected in FTC and classic papillary thyroid carcinomas (PTCs). The aims of this study were to assess the presence of PAX8-PPARγ by using tissue microarrays in a large cohort of different thyroid neoplasms, and to assess its diagnostic and prognostic implications.

METHODS AND RESULTS

Fluorescence in-situ hybridization (FISH) analysis for PAX8-PPARγ was performed on 226 thyroid tumours, comprising FTCs (n = 59), PTCs (n = 126), poorly differentiated thyroid carcinomas (PDs; n = 34), follicular thyroid adenomas (FTAs; n = 5), and follicular tumours of unknown malignant potential (FTUMPs; n = 2). PAX8-PPARγ was detected in 12% of FTCs, 1% of PTCs, 7% of PDs, and in both cases of FTUMP. There was no correlation between the extent of capsular or vascular invasion and PAX8-PPARγ, or between lymph node or haematogenous metastasis and PAX8-PPARγ. Overall survival (OS), tumour-specific survival (TSS) and relapse-free-survival (RFS) were not influenced by PAX8-PPARγ.

CONCLUSIONS

In this study, we demonstrate for the first time the presence of PAX8-PPARγ in PDs and FTUMPs, whereas in FTCs and PTCs the prevalence of PAX8-PPARγ is lower than previously reported. PAX8-PPARγ did not correlate with invasiveness or affect prognosis in any tumour type.

Genomic dissection of Hurthle cell carcinoma reveals a unique class of thyroid malignancy

CONTEXT

Hurthle cell cancer (HCC) is an understudied cancer with poor prognosis.

OBJECTIVE

Our objective was to elucidate the genomic foundations of HCC.

DESIGN AND SETTING

We conducted a large-scale integrated analysis of mutations, gene expression profiles, and copy number alterations in HCC at a single tertiary-care cancer institution.

METHODS

Mass spectrometry-based genotyping was used to interrogate hot spot point mutations in the most common thyroid oncogenes: BRAF, RET, NRAS, HRAS, KRAS, PIK3CA, MAP2K1, and AKT1. In addition, common oncogenic fusions of RET and NTRK1 as well as PAX8/PPARγ and AKAP9-BRAF were also assessed by RT-PCR. Global copy number changes and gene expression profiles were determined in the same tumor set as the mutational analyses.

RESULTS

We report that the mutational, transcriptional, and copy number profiles of HCC were distinct from those of papillary thyroid cancer and follicular thyroid cancer, indicating HCC to be a unique type of thyroid malignancy. Unsupervised hierarchical clustering of gene expression showed the 3 groups of Hurthle tumors (Hurthle cell adenoma [HA], minimally invasive Hurthle cell carcinoma [HMIN], and widely invasive Hurthle cell carcinoma [HWIDE] clustered separately with a marked difference between HWIDE and HA. Global copy number analysis also indicated distinct subgroups of tumors that may arise as HWIDE and HMIN. Molecular pathways that differentiate HA from HWIDE included the PIK3CA-Akt-mTOR and Wnt/β-catenin pathways, potentially providing a rationale for new targets for this type of malignancy.

CONCLUSIONS

Our data provide evidence that HCC may be a unique thyroid cancer distinct from papillary and follicular thyroid cancer.

Genetic mutations, molecular markers and future directions in research

Recent molecular studies have described a number of abnormalities associated with the pathogenesis of thyroid carcinoma. These distinct molecular events are often associated with specific stages of tumor development and may serve as prognostic factors and therapeutic targets. A better understanding of the mechanisms involved in thyroid cancer pathogenesis, will hopefully help translate these discoveries to improved patient care.

Enlarging neck masses in the elderly - Histological and surgical considerations

INTRODUCTION

Anaplastic carcinoma of the thyroid is a rare but aggressive malignancy which can present with a rapidly enlarging neck mass or compressive sequelae of cough, dyspnoea, dysphagia and hoarseness. Treatment of such tumours is commonly palliative however they occasionally represent surgical challenges due to their rapid growth, diagnostic difficulty and locoregional spread.

PRESENTATION OF CASE

A 75 year-old retired veterinary surgeon was referred with a 2 month history of a painless, enlarging neck mass. The patient denied any secondary compressive symptoms or general symptoms of malignancy. On examination a large right-sided neck mass measuring 7cm×5cm was appreciated which was fixed, hard and irregular with associated adenopathy.

DISCUSSION

We discuss the diagnostic challenges posed by anaplastic carcinoma of the thyroid and the difficulties in selecting the appropriate intervention in this aggressive disease process.

CONCLUSION

Anaplastic carcinoma of the thyroid is encountered infrequently in clinical practice and can generate diagnostic and therapeutic challenges.

RET gene abnormalities and thyroid disease: who should be screened and when

Mutations in the RET proto-oncogene have been implicated in the pathogenesis of several forms of medullary thyroid cancer (MTC). Multiple endocrine neoplasia type 2 (MEN-2) is an autosomal dominant syndrome caused by germline activating mutations of the RET proto-oncogene and has been categorized into three distinct clinical forms. MEN-2A is associated with MTC, bilateral pheochromocytoma, and primary hyperparathyroidism. MEN-2B is associated with MTC, bilateral pheochromocytoma, and mucosal neuromas. The rarest clinical form of MEN-2 is familial MTC (FMTC), which is also associated with MTC, but other endocrinopathies are characteristically not present. Each clinical form of MEN-2 results from a specific RET gene mutation, with a strong correlation of phenotype expression with regard to the onset and course of MTC and the presence of other endocrine tumors and a corresponding genotype. Recommendations for screening of RET mutations are necessary as their presence or absence will influence interventional strategies such as the timing of a prophylactic thyroidectomy and extent of surgery. Timing of screenings and development of interventional strategies are extremely important in caring for patients with certain RET mutations as evidence of metastatic MTC has been documented as early as 6 years of age. Interventional strategies should consider the risks of complications of these interventions based on certain characteristics of each individual case such as age of the patient, course of disease in affected family members, and the invasiveness of any proposed surgical procedure.

Activated leukocyte cell adhesion molecule is a marker for thyroid carcinoma aggressiveness and disease-free survival

BACKGROUND

Currently, there are no protein biomarkers for aggressive subtypes of thyroid carcinomas (TC) in clinical use that would allow for early detection and patient management. We hypothesized that activated leukocyte cell adhesion molecule (ALCAM or CD166) expression in thyroid tissues will reveal ALCAM to be a potential diagnostic and/or prognostic marker for TC aggressiveness.

METHODS

Forty-five benign and 158 malignant thyroid tissues were analyzed for ALCAM expression using immunohistochemistry. ALCAM expression was correlated with different subtypes and clinicopathological features of TC, as well as patient disease-free survival.

RESULTS

Combined membranous and cytoplasmic (total) expression of ALCAM was significantly reduced in patients with poorly/undifferentiated (aggressive) TC as compared to well-differentiated (nonaggressive) tumors (p<0.001; area-under-curve=0.865, sensitivity=82%, specificity=74%). The decreased ALCAM expression in TC correlated significantly with extrathyroidal extension, distant metastasis, and TC histotype. Notably, Kaplan-Meier survival analysis for follow-up data of 134 patients revealed significantly reduced disease-free survival for patients with TC with decreased ALCAM membranous, cytoplasmic, and total expression. Median survival of patients with decreased cytoplasmic ALCAM expression was 6 years, as compared to 13.7 years for patients with higher ALCAM expression (p<0.001).

CONCLUSION

ALCAM has the potential to serve as a diagnostic and prognostic biomarker for aggressive TC. This protein can be taken forward for analysis in sera of patients with TC to determine its applicability as a minimally invasive serum biomarker for TC aggressiveness and patient disease-free survival.

Platelet-derived growth factor receptor-α promotes lymphatic metastases in papillary thyroid cancer

Lymph node metastases are common in papillary thyroid cancer (PTC) and can be resistant to surgical extirpation or radioiodine ablation. We examined the role of platelet-derived growth factor receptor (PDGFR) in mediating lymph node metastases in PTC. Clinical specimens of PTC (n = 137) were surveyed in a tissue array and by western blots to examine the relationship between expression of the α and β subunits of PDGFR and lymph node metastases. PDGFR-α was found at high levels in primary tumours with known lymphatic metastases but not in those tumours lacking nodal involvement (p < 0.0001). However, PDGFR-β expression was not linked to metastatic disease (p = 0.78) as it was found in virtually all PTC specimens. A matching analysis in fresh PTC specimens (n = 13) confirmed that PDGFR-α expression was strongly linked to metastatic spread (p = 0.0047). PDGFR-α and -β were not found in normal thyroid tissue (p < 0.0001). PTC cell lines selectively expressing PDGFR-α or -β were assessed for invasive potential and activation of downstream signal transduction pathways. PTC cell lines expressing PDGFR-α responded to PDGF-BB stimulation with increased invasive potential and this process can be blocked by the tyrosine kinase receptor inhibitor sunitinib (p < 0.009). Cell lines with only PDGFR-β, or no PDGFR, did not show significant changes in invasive potential. Activation of PDGFR-α led to downstream up-regulation of both the MAPK/ERK and PI3K/Akt pathways and disruption of either pathway is sufficient to block PDGFR-mediated increases in invasive potential. Thus, PDGFR-α is associated with lymph node metastases in papillary thyroid carcinoma and PDGFR-α promotes increased invasive potential in PTC cell lines. PDGFR-α is a strong candidate for a diagnostic biomarker to identify patients at risk of nodal metastases. Our results also strengthen the rationale for selection of tyrosine kinase receptor inhibitors that target PDGFR in the treatment of progressive, metastatic PTC.

Differentiated thyroid cancers: a comprehensive review of novel targeted therapies

Differentiated thyroid carcinoma (DTC) accounts for more than 90% of new thyroid cancer diagnoses, and includes papillary, follicular and Hürthle cell carcinoma. The prognosis for the vast majority of individuals diagnosed with DTC is excellent, with current treatment that includes surgery, radioactive iodine ablation and postoperative thyroid-stimulating hormone suppression. Unfortunately, the small proportion of individuals who develop radioactive iodine-resistant recurrent disease have few treatment options, and the vast majority will eventually die from their disease. Recently, several novel targets for anticancer agents have been identified and offer new hope for thyroid cancer patients diagnosed with progressive disease. In addition to targeting genes commonly altered in thyroid cancer, which include mutations in BRAF, RAS and RET, proangiogenic growth factor receptors and the sodium-iodide symporter have also been targeted. Several clinical trials evaluating tyrosine kinase and angiogenesis inhibitors for treatment of individuals diagnosed with metastatic or treatment-refractory DTC are currently underway. The objective of this review is to evaluate recent clinical trials that have studied novel targeted drugs for treatment of DTC.

Innovative in vitro chemo-hormonal drug therapy for refractory thyroid carcinomas

More than 95% of the thyroid carcinomas are well differentiated types showing favorable prognosis. However, only a few therapeutic options are available to treat the patients with undifferentiated thyroid carcinomas, especially with refractory thyroid carcinomas that are not amenable to surgery or radioiodine ablation. We investigated the anticancer effects of 20 chemotherapy and hormonal therapy drugs on 8 thyroid carcinoma cell lines. In vitro chemosensitivity was tested using the adenosine-triphosphate-based chemotherapy response assay (ATP-CRA). The tumor inhibition rate (TIR; or cell death rate) or half maximal inhibitory concentration (IC(50)) was analyzed to interpret the results. Of the 12 chemotherapy drugs, etoposide (178.9 index value in follicular carcinoma cell line) and vincristine (211.7 in Hürthle cell carcinoma cell line) were the most active drugs showing the highest chemosensitivity, and of the 8 additional drugs, trichostatin A (0.03 µg/mL IC(50) in follicular carcinoma cell line) showed favorable outcome having the anticancer effect. In our study, the result of etoposide and vincristine show evidence as active anticancer drugs in thyroid carcinoma cell lines and trichostatin A seems be the next promising drug. These drugs may become an innovative therapy for refractory thyroid carcinomas in near future.

The associations between RAS mutations and clinical characteristics in follicular thyroid tumors: new insights from a single center and a large patient cohort

BACKGROUND

Many studies on thyroid follicular tumors have reported the presence of somatic mutations to three forms of RAS: HRAS, KRAS, and NRAS. However, the frequency and clinical significance of these RAS mutations remain unclear, in large part due to the different methodologies being used for mutation analysis and the limited number of cases featured in studies. To clarify the significance of RAS mutations, we examined a large number of follicular adenomas and carcinomas obtained from a single institute using established methods for the analysis of RAS.

METHODS

Tumor samples from 40 follicular adenoma and 58 follicular carcinoma patients treated at the Kanagawa Cancer Center Hospital were analyzed. The three RAS mutations at codons 12 and 61 were assessed with a polymerase chain reaction-based loop-hybrid mobility shift assay followed by confirmation with direct sequencing. The relationships between mutation status and clinicopathological features at the time of the initial operation and the prognosis of the patients were also analyzed.

RESULTS

Twelve out of 40 (30%) adenomas harbored RAS mutations. In contrast, 33 out of 58 (57%) follicular carcinomas harbored RAS mutations, and the mutation was predominantly found in the NRAS codon 61 (22/33, 67%, p<0.01). The rate of gene mutations was significantly higher in the carcinomas than in the adenomas (p<0.01). The NRAS codon 61 mutation in follicular carcinomas was positively associated with distant metastases through the entire clinical course of the patients (p<0.05), and RAS mutations were associated with poor overall patient survival (p<0.05).

CONCLUSIONS

We investigated the frequency of RAS mutations in follicular thyroid tumors from a large number of cases obtained from a single institute. The predominance of NRAS codon 61 mutations as a feature of carcinomas indicates that the diagnosis of adenoma alongside the presence of this mutation should be made cautiously. Our study raises the possibility that follicular adenomas with the RAS mutations have an inherent malignant potential; however, the clinical significance of this finding should be further investigated in more patients and over a longer follow-up period.

BRAFV600E status and clinical characteristics in solitary and multiple papillary thyroid carcinoma: experience of 512 cases at a clinical center in China

Background

Papillary thyroid carcinoma (PTC) is one of the most frequent endocrine malignancies. In most cases, it often presents as multifocal tumor. It has been reported that multifocal tumors are associated with elevated risk of lymph node and distant metastases. Multifocality is also one of the factors predicting prognosis. Recent studies show that BRAF^V600E mutation occurs more frequently in aggressive PTC. The purpose of this study was to evaluate BRAF^V600E status and clinicopathological features in multiple and solitary PTC.

Methods

We performed a retrospective study to analyze 512 PTC cases who received surgery, including 376 solitary PTCs and 136 multiple PTCs.

Results

Multiple PTC is more related to lymph node metastasis and vascular invasion than solitary PTC. However, the distant metastasis rate and 10-year survival rate showed no difference between these two groups. BRAF^V600E mutation status was more frequent in multiple PTC patients with lymph node metastasis and late stage at diagnosis.

Conclusion

BRAF^V600E mutation is most commonly associated with extra-thyroidal extension and lymph node metastasis in PTC. Multiple PTC patients with young age, large tumors and BRAF^V600E mutation should be followed carefully. Our study provides useful information for PTC patients’ followup and treatment.

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.

Discovery of common variants associated with low TSH levels and thyroid cancer risk

To search for sequence variants conferring risk of nonmedullary thyroid cancer, we focused our analysis on 22 SNPs with a P < 5 × 10(-8) in a genome-wide association study on levels of thyroid stimulating hormone (TSH) in 27,758 Icelanders. Of those, rs965513 has previously been shown to associate with thyroid cancer. The remaining 21 SNPs were genotyped in 561 Icelandic individuals with thyroid cancer (cases) and up to 40,013 controls. Variants suggestively associated with thyroid cancer (P < 0.05) were genotyped in an additional 595 non-Icelandic cases and 2,604 controls. After combining the results, three variants were shown to associate with thyroid cancer: rs966423 on 2q35 (OR = 1.34; P(combined) = 1.3 × 10(-9)), rs2439302 on 8p12 (OR = 1.36; P(combined) = 2.0 × 10(-9)) and rs116909374 on 14q13.3 (OR = 2.09; P(combined) = 4.6 × 10(-11)), a region previously reported to contain an uncorrelated variant conferring risk of thyroid cancer. A strong association (P = 9.1 × 10(-91)) was observed between rs2439302 on 8p12 and expression of NRG1, which encodes the signaling protein neuregulin 1, in blood.

Differential expression of a set of genes in follicular and classic variants of papillary thyroid carcinoma

Fine-needle aspiration biopsy (FNA) is currently the best initial diagnostic test for evaluation of a thyroid nodule. FNA cytology cannot discriminate between benign and malignant thyroid nodules in up to 30% of thyroid nodules. Therefore, an adjunct to FNA is needed to clarify these lesions as benign or malignant. Using differential display-polymerase chain reaction method, the gene expression differences between follicular and classic variants of papillary thyroid carcinoma (PTC) and benign thyroid nodules were evaluated in a group of 42 patients. Computational gene function analyses via Cytoscape, FuncBASE, and GeneMANIA led us to a functional network of 17 genes in which a core sub-network of five genes coexists. Although the exact mechanisms underlying in thyroid cancer biogenesis are not currently known, our data suggest that the pattern of transformation from healthy cells to cancer cells of PTC is different in follicular variant than in classic variant.

Synthesis, characterization, and in vivo delivery of siRNA-squalene nanoparticles targeting fusion oncogene in papillary thyroid carcinoma

We report the conjugation of the natural lipid squalene (SQ) with a small interfering RNA (siRNA), against the junction oncogene RET/PTC1, usually found in papillary thyroid carcinoma (PTC). The acyclic isoprenoid chain of squalene has been covalently coupled with siRNA RET/PTC1 at the 3'-terminus of the sense strand via maleimide-sulfhydryl chemistry. Remarkably, the linkage of siRNA RET/PTC1 to squalene led to an amphiphilic molecule that self-organized in H(2)O as siRNA-SQ RET/PTC1 nanoparticles (NPs). The siRNA-SQ RET/PTC1 NPs, stable in H(2)O, were used for biological studies. In vitro, they did not show any cytotoxicity. Interestingly, in vivo, on a mice xenografted RET/PTC1 experimental model, RET/PTC1-SQ NPs were found to inhibit tumor growth and RET/PTC1 oncogene and oncoprotein expression after 2.5 mg/kg cumulative dose intravenous injections. In conclusion, these results showed that the "squalenoylation" offers a new noncationic plate-form for the siRNA delivery.

Clinicopathological and molecular characterization of nine cases of columnar cell variant of papillary thyroid carcinoma

The majority of papillary thyroid carcinoma is indolent and associated with long-term survival. The columnar cell variant, however, is a rare subtype that is variable in biological behavior; some are clinically aggressive, whereas others are more clinically indolent. Tumor size, tumor circumscription, and encapsulation may influence the behavior of columnar cell carcinomas. Other variables including genetic changes and putative biomarkers associated with malignant growth have not been thoroughly examined in these neoplasms. In this study, nine cases of columnar cell variant of papillary thyroid carcinoma from three institutions were classified as clinically indolent or aggressive based on pathological features, clinical history, and outcome. Indolent tumors were typically small, circumscribed or encapsulated, and from younger female patients, whereas aggressive tumors were large, locally aggressive, associated with regional and distant metastasis, and from older male patients. The missense mutation, V600E in the BRAF oncogene (BRAF(V600E)), was detected in three of nine of cases, of which two were clinically aggressive. Immunohistochemical evaluation of neoplasia-associated markers showed increased nuclear cyclin D1 expression, elevated Ki-67 proliferation indices, and predominantly weak nuclear p53 staining in both indolent and aggressive tumors. Expression of β-catenin was largely restricted to a membranous pattern in both tumor types. Cytoplasmic expression of bcl-2 was overall mildly reduced in indolent neoplasms. Nuclear expression of estrogen and progesterone receptors was increased in both indolent and aggressive neoplasms, but was without sex- or age-related differences; however, whereas progesterone receptor expression was diffuse and strong in clinically indolent carcinomas, its expression was diminished in aggressive neoplasms. Recognition of the clinicopathological characteristics and the molecular and immunophenotypic features of the columnar cell variant of papillary thyroid carcinoma may aid in characterizing neoplasms that behave indolently or aggressively.

Thyroid pathology in PTEN-hamartoma tumor syndrome: characteristic findings of a distinct entity

BACKGROUND

Phosphatase and tensin homolog deleted on chromosome ten (PTEN)-hamartoma tumor syndrome (PHTS) is a complex disorder caused by germline inactivating mutations of the PTEN tumor suppressor gene. PHTS includes Cowden syndrome (CS), Bannayan-Riley-Ruvalcaba syndrome (BRRS), and Proteus-like syndromes. Affected individuals develop both benign and malignant tumors in a variety of tissues, including the thyroid. This study is to better characterize and describe the thyroid pathology within the different entities of this syndrome, and examine whether there is an association between specific thyroid findings and different PTEN mutations.

METHODS

Twenty patients with known PTEN mutations, and/or clinical diagnosis of PHTS, and thyroid pathology were identified: 14 with CS and 6 with BRRS.

RESULTS

Thyroid pathology findings were as follows: multiple adenomatous nodules in a background of lymphocytic thyroiditis (LT) in 75%, papillary carcinoma in 60%, LT alone in 55%, follicular carcinoma in 45%, C-cell hyperplasia in 55%, and follicular adenomas in 25%. Within the papillary carcinoma group, there were 6 microcarcinomas, 5 follicular variants, and 1 classical type.

CONCLUSIONS

There were no morphologic differences between the thyroid findings in CS and BRRS. Also, there was no correlation between specific PTEN germline mutations (exons 5, 6, and 8) and pathologic findings. Distinctive and characteristic findings in PHTS include multiple unique adenomatous nodules in a background of LT, and C-cell hyperplasia; it is vital that pathologists recognize the classical histologic features of this syndrome to alert clinicians to the possibility of this syndrome in their patients.

Decreased 1-25 dihydroxyvitamin D3 concentration in peripheral blood serum of patients with thyroid cancer

BACKGROUND AND AIMS

Vitamin D(3), in addition to its role in calcium homeostasis, has been recognized as playing a role in human cancer development. However, little is known about the association between vitamin D status and the development of thyroid cancer. This study aimed to investigate vitamin D metabolism by measuring 25(OH) D(3), 1-25 (OH)(2) D(3), PTH and calcium concentrations in the peripheral blood of patients with different forms of thyroid tumors.

METHODS

The 25-hydroxyvitamin D(3) ,1-25- dihydoxyvitamin D(3), PTH and calcium serum levels of 50 consecutive patients with epithelial thyroid cancer 27 cases of papillary cancers (PTC), 16 follicular cancers (FTC), and seven cases of anaplastic cancers (ATC) and 34 multinodular nontoxic goiter (MNG) were measured by specific immunoassay. The control group consisted of 26 healthy volunteers.

RESULTS

Our results revealed significantly lower 1-25 (OH)(2) D(3) concentration in the PTC group (22.67 pg/mL +/- 8.12; p <0.05), FTC group (16.09 pg/mL +/- 6.15; p <0.02) and ATC group (9.48 pg/mL +/- 5.18; p <0.02). Levels of 1-25 (OH)(2) D(3) varied by cancer stage and were also significantly different. A significant decrease in circulating 1-25 (OH)(2) D(3) concentration was found in patients with stage I (24.12 pg/mL +/- 6.77; p <0.05), stage II (16.93 pg/mL +/- 4.55; p <0.05), stage III (12.44 +/- 8.98; p <0.02) and in stage IVa (6.18 +/- 2.22; p <0.01). There were no significant differences when comparing serum levels of 25(OH) D(3), PTH or calcium concentrations among individuals with multinodular goiter, thyroid cancer and age- and sex-matched control volunteers.

CONCLUSIONS

Our study revealed that impaired vitamin D(3) metabolism may play an important role in thyroid follicular cell oncogenesis.

Medullary thyroid carcinoma: The third most common thyroid cancer reviewed

Medullary thyroid cancer is a type of thyroid cancer of neuroendocrine origin. It occurs in hereditary and sporadic forms, and its aggressive behavior is associated with the clinical presentation and type of RET mutation. Total thyroidectomy remains the ideal choice of treatment. Early diagnosis and treatment are the fundamental for a 100% cure rate. In this study, we present our experience of 3 cases, along with a complete review of the literature derived from a Pubmed Database search.

Thyroid cancer of follicular cell origin in inherited tumor syndromes

Well-differentiated thyroid cancer accounts for 95% of thyroid malignancies. In contrast to medullary thyroid carcinoma, in which about 25% are familial, only 5% of follicular cell-derived thyroid carcinomas are a component of a familial cancer syndrome. The familial follicular cell-derived tumors or nonmedullary thyroid carcinoma encompass a heterogeneous group of diseases, and are classified into 2 distinct groups: syndromic-associated tumors, occurring in syndromes in which nonmedullary thyroid carcinomas are the predominant tumor encountered, and nonsyndromic tumors, those occurring in tumor syndromes in which thyroid involvement is a minor component. The first group, syndromic-associated tumors, includes phosphase and tensin (PTEN)-hamartoma tumor syndrome/Cowden syndrome, familial adenomatous polyposis/Gardner syndrome, Carney complex type 1, Werner syndrome, and Pendred syndrome. Other syndromes, as McCune Albright syndrome, Peutz-Jeghers syndrome, and Ataxia-teleangiectasia syndrome may be associated with the development of follicular cell-derived tumors, but the link is less established than the above syndromes. The syndromic-associated tumors are the focus of this review. The second group of familial follicular cell-derived tumors syndromes or nonsyndromic tumors, in which nonmedullary thyroid carcinomas are the major findings, include pure familial papillary thyroid carcinoma, with or without oxyphilia, familial papillary thyroid carcinoma with papillary renal cell carcinoma, and familial papillary thyroid carcinoma with multinodular goiter. This review will discuss the clinical and pathological findings of the patients with familial syndrome-associated tumors: PTEN-hamartoma tumor syndrome/Cowden syndrome, familial adenomatous polyposis syndrome, Carney complex type 1, Werner syndrome, and Pendred syndrome.

Diagnostic utility of immunohistochemical panel in various thyroid pathologies

BACKGROUND

For management of thyroid nodules, distinction between benign and malignant tumours is essential. The study was performed to evaluate the diagnostic value of molecular markers in different thyroid tumours.

MATERIALS AND METHODS

Immunohistochemistry for CD56, HBME-1, COX-2, Ki-67, p53 and E-cadherin (E-CAD) was performed in 113 benign and 35 malignant thyroid lesions including 36 follicular adenomas (FA), 77 colloid goitres, 26 papillary thyroid carcinomas (PTC) and 9 follicular carcinomas (FC). The results were scored semiquantitatively by staining intensity (0-3 scale) and percentage of positive cells.

RESULTS

PTC was characterised by decreased E-CAD and CD56 expression in contrast to surrounding benign thyroid tissues. HBME-1 expression was absent in benign thyroid tissues but was notably high in PTC and occasionally in FC. The expression of E-CAD and CD56 in FA was significantly higher than in the surrounding thyroid tissues. No expression of p53 was found in any group. The expression of COX-2 was low in all lesions. The proliferation activity by Ki-67 was generally low; however, it was significantly higher in cancers.

CONCLUSIONS

The panel consisting of three markers, HBME-1, E-CAD and CD56, can be recommended as an adjunct to morphology criteria. HBME-1 is found in malignant lesions only and is the most sensitive and specific single marker in PTC. Decreased expression of E-CAD and CD56 distinguishes PTC from FA and FC. Both FA and FC are characterised by high expression of E-CAD and CD56. The practical use of Ki-67 is difficult due to low values. The role of adhesion factors in thyroid malignancies may be superior in comparison with cell proliferation.

Update on recent developments in the therapy of differentiated thyroid cancer

In the past decade, the management of differentiated thyroid carcinoma changed significantly and thus contributed to the improvement of the already favorable prognosis of this malignant disease. Surgical treatment techniques improved and the extent of initial surgery is more individualized. Radioiodine therapy is an essential part of therapeutic regimens in almost all cases, and the use of recombinant human thyroid-stimulating hormone has established for ablation of remnant tissue, treatment of iodine-positive cancer, and sensitive thyroglobulin measurement during follow-up. Risk stratification has become more important to plan treatment and follow-up individually, particularly to evaluate the need for thyroid-stimulating hormone suppression therapy. Especially for inoperable and radioiodine-negative thyroid carcinomas, novel treatment options such as tyrosine kinase inhibitor therapy have emerged. This article deals with the current options of optimal therapy regimens in differentiated thyroid carcinoma.

Immunohistochemical expression of CXCR4 in thyroid carcinomas and thyroid benign lesions

In different tumor entities, expression of the chemokine receptor 4 (CXCR4) has been linked to tumor dissemination and poor prognosis. The aim of this study was to examine the immunohistochemical expression of CXCR4 in thyroid carcinomas and thyroid benign lesions. Using monoclonal anti-CXCR4 antibody, we performed immunohistochemical staining on tissue sections from 134 cases obtained from Ruijin Hospital affiliated with Shanghai Jiaotong University School of Medicine (Shanghai, China) between 2000 and 2007. In our study, the CXCR4 expression of the thyroid carcinoma group (including 16 papillary thyroid carcinomas, 18 follicular thyroid carcinomas, 9 poorly differentiated thyroid carcinomas, and 7 medullary thyroid carcinomas) was found to be higher than in the benign lesion group (including 19 cases of Hashimoto's thyroiditis, 15 nodular goiters, and 50 follicular adenomas) (p<0.0001). Within the carcinoma group, the more malignant thyroid carcinoma group (including 9 poorly differentiated thyroid carcinomas and 7 medullary thyroid carcinomas) showed a higher ratio of CXCR4 positivity compared to the less malignant thyroid carcinoma group (including 16 papillary thyroid carcinomas and 18 follicular thyroid carcinomas) (p<0.0001). Our study suggests that CXCR4 expression might be a frequent and cancer-specific event in thyroid carcinoma, and it might be involved in malignancy transformation during the progression of thyroid carcinoma.

Expression of the PAX8/PPARγ Fusion Protein Is Associated with Decreased Neovascularization In Vivo: Impact on Tumorigenesis and Disease Prognosis

The PAX8/PPARγ fusion protein (PPFP) occurs in 36% of human follicular thyroid carcinoma (FTC) and is associated with favorable prognosis. To elucidate the function of PPFP in FTC, we analyzed the consequences of PPFP expression in immortalized thyrocytes in vitro and in vivo via xenograft tumorigenesis. While PPFP-expressing cells exhibited oncogenic hallmarks, including increased growth and decreased apoptosis, in vitro, xenograft tumors were initiated but not sustained in vivo. PPFP xenograft tumors exhibited reduced CD31 staining and VEGF expression, suggesting that PPFP modulates neovascularization. Microarray analysis demonstrated increased expression of tissue inhibitor of metalloproteinase (TIMP-3), an inhibitor of angiogenesis, in PPFP cells and tumors, a finding confirmed by quantitative PCR and immunohistochemistry. Immunohistochemical staining of archival human thyroid tumors demonstrates a significant decrease in CD31 staining in all adenomas and carcinomas containing the PAX8/PPARγ rearrangement. Decreased angiogenesis in PPFP-containing tumors is directly correlated with our observations in the xenograft model and provides evidence for the first time that PPFP may impact FTC tumorigenesis by modulating angiogenesis in vivo.

Clinicopathologic and molecular disease prognostication for papillary thyroid cancer

Despite its increasing incidence over the last 30 years, the mortality rate of papillary thyroid cancer (PTC) has decreased significantly. Nevertheless, a minority of patients still present with an aggressive form of PTC that can lead to death, even after a prolonged period of survival. Many classifications exist that allow one to stratify the clinical risk of recurrence and death in patients with PTC; however, the parameters upon which they are established are pathological and molecular and, therefore, are revealed only after surgery. The preoperative identification of these aggressive variants of PTC would allow one to schedule a more aggressive operation (e.g., total thyroidectomy together with central and/or mono- or bi-lateral node dissections) in patients with high-risk PTC. This article reviews the parameters used most commonly to differentiate low-risk PTCs from their more aggressive variants and describes some of the newest molecular therapies for this latter group of tumors.

Encapsulated thyroid tumors of follicular cell origin with high grade features (high mitotic rate/tumor necrosis): a clinicopathologic and molecular study

Encapsulated thyroid tumors of follicular cell origin with high-grade features (EFHG) are unusual neoplasms. In current classification schemes, they are called atypical adenomas or follicular, papillary, or poorly differentiated carcinoma. When noninvasive, EFHG create a major therapeutic/diagnostic dilemma stemming from their rarity, low-stage, high-grade appearance, and lack of long-term follow-up studies. All cases of EFHG were defined as encapsulated tumors of follicular cell origin with at least 5 mitoses per 10 high-power fields and/or tumor necrosis. Available tissues were subjected to a thyroid carcinoma platform for mass spectrometry high-throughput genotyping, which consisted of 111 known mutations in 16 different genes: BRAF, RET, NRAS, HRAS, KRAS, PIK3CA, AKT1, and other related genes. Twenty-five cases met the selection criteria. Tumor necrosis was present in 56.0% (n = 14). Extensive vascular invasion was identified in 24.0% (n = 6). Eight (32%) of 25 tumors were noninvasive. Twenty-two patients (88%) were free of disease (median follow up: 8.5 years). All 8 noninvasive tumor did not recur despite focal/extensive tumor necrosis in 3 cases and a median follow-up of 11.9 years. EFHG with no vascular invasion did not recur. In patients without distant metastases at presentation (n = 24), 33% (2/6) of patients with extensive angioinvasion relapsed, whereas none of 18 with absent/focal vascular invasion recurred (P = .054). Mutations were found in 10 (45%) of 22 cases tested: 8 had NRAS codon 61, 1 KRAS codon 61, and 1 had coexistent BRAF V600E and AKT1. There was a higher frequency of RAS (9/22, 41%) than BRAF mutations (1/22, 4.5%) (P = .009). Noninvasive EFHG have an indolent behavior even in the presence of extensive tumor necrosis. EFHG with absent vascular invasion have an excellent prognosis despite the frequent occurrence of tumor necrosis. NRAS mutations are the most frequent oncogenic event in EFHG.

BRAFV600E mutation in papillary thyroid carcinoma: a potential target for therapy?

This article reviews the therapeutic significance of the close genotype-phenotype association in papillary thyroid carcinoma, namely regarding the association between genetic alterations in RET, BRAF or RAS genes and the histopathological variants of papillary thyroid carcinoma. Based upon the aforementioned review on morphology and molecular pathology, the most recent prognostic and therapeutic data are reviewed and the role of targeted therapies, namely those interfering with BRAF-activated pathways are discussed, which may play a role in the treatment of patients with papillary thyroid carcinoma unresponsive to radioactive iodine.

Papillary carcinoma of the breast lacks evidence of RET rearrangements despite morphological similarities to papillary thyroid carcinoma

Rare breast neoplasms resembling the tall-cell variant of papillary thyroid carcinoma have been reported. In addition, papillary carcinoma of the breast occasionally displays nuclear features reminiscent of papillary thyroid carcinoma. In this study, we evaluated 33 intraductal/intracystic papillary carcinomas of the breast for the presence and extent of nuclear overlap, grooves, clearing, and inclusions, as well as features of the tall-cell or columnar-cell variants of papillary thyroid carcinoma. RET rearrangements were assessed in a subset of these cases. Paired probes localizing to the centromeric and telomeric ends of the RET gene on chromosome 10 were used for FISH using a break-apart approach. Single round and nested PCR was performed to detect RET/PTC1, RET/PTC2, RET/PTC3 and ELKS-RET fusion transcripts. Nuclear overlap, grooves, stratification, and clearing were identified in 24 (73%), 14 (42%), 11 (33%), and 9 (27%) cases respectively, whereas nuclear inclusions and 'tall-cell' features were each seen in only one (3%) and two (6%) cases, respectively. Four of 19 tested cases displayed split FISH signals in a low percentage of cells and were considered borderline for RET rearrangement. All 19 tested cases with amplifiable RNA were negative for the four RET fusion transcripts evaluated by RT-PCR. Although papillary carcinomas of breast often display one or more cytoarchitectural features of papillary thyroid carcinoma, there is no evidence that RET rearrangements are involved.

Mitochondria and cancer

The authors review the role played by mutations in mitochondrial DNA and in nuclear genes encoding mitochondrial proteins in cancer development, with an emphasis on the alterations of the oxidative phosphorylation system and glycolysis.

Common variants on 9q22.33 and 14q13.3 predispose to thyroid cancer in European populations

In order to search for sequence variants conferring risk of thyroid cancer we conducted a genome-wide association study in 192 and 37,196 Icelandic cases and controls, respectively, followed by a replication study in individuals of European descent. Here we show that two common variants, located on 9q22.33 and 14q13.3, are associated with the disease. Overall, the strongest association signals were observed for rs965513 on 9q22.33 (OR = 1.75; P = 1.7 x 10(-27)) and rs944289 on 14q13.3 (OR = 1.37; P = 2.0 x 10(-9)). The gene nearest to the 9q22.33 locus is FOXE1 (TTF2) and NKX2-1 (TTF1) is among the genes located at the 14q13.3 locus. Both variants contribute to an increased risk of both papillary and follicular thyroid cancer. Approximately 3.7% of individuals are homozygous for both variants, and their estimated risk of thyroid cancer is 5.7-fold greater than that of noncarriers. In a study on a large sample set from the general population, both risk alleles are associated with low concentrations of thyroid stimulating hormone (TSH), and the 9q22.33 allele is associated with low concentration of thyroxin (T(4)) and high concentration of triiodothyronine (T(3)).

Molecular alterations in hereditary and sporadic thyroid and parathyroid diseases

Thyroid and parathyroid diseases are fairly common and can be either hereditary or sporadic in nature. Tumors and tumor-like processes account for the majority of surgical pathology specimens in both of these endocrine organs. Molecular alterations are well known to occur in both the hereditary and the sporadic settings, and include alterations in tumor suppressor genes and oncogenes. The genetic pathways of tumors of parathyroid and thyroid are beginning to be well understood and are proving to be useful diagnostic, prognostic, and potential therapeutic targets. The molecular alterations in parathyroid and thyroid tumors and tumor-like processes are reviewed, with a focus on the potentially clinically useful diagnostic markers.

Conventional and molecular cytogenetics of human non-medullary thyroid carcinoma: characterization of eight cell line models and review of the literature on clinical samples

Background

Cell lines are often poorly characterized from a genetic point of view, reducing their usefulness as tumor models. Our purpose was to assess the genetic background of eight commonly used human thyroid carcinoma models and to compare the findings with those reported for primary tumors of the gland.

Methods

We used chromosome banding analysis and comparative genomic hybridization to profile eight non-medullary thyroid carcinoma cell lines of papillary (TPC-1, FB2, K1 and B-CPAP), follicular (XTC-1) or anaplastic origin (8505C, C643 and HTH74). To assess the representativeness of the findings, we additionally performed a thorough review of cytogenetic (n = 125) and DNA copy number information (n = 270) available in the literature on clinical samples of thyroid carcinoma.

Results

The detailed characterization of chromosomal markers specific for each cell line revealed two cases of mistaken identities: FB2 was shown to derive from TPC-1 cells, whereas K1 cells have their origin in cell line GLAG-66. All cellular models displayed genomic aberrations of varying complexity, and recurrent gains at 5p, 5q, 8q, and 20q (6/7 cell lines) and losses at 8p, 13q, 18q, and Xp (4/7 cell lines) were seen. Importantly, the genomic profiles were compatible with those of the respective primary tumors, as seen in the meta-analysis of the existing literature data.

Conclusion

We provide the genomic background of seven independent thyroid carcinoma models representative of the clinical tumors of the corresponding histotypes, and highlight regions of recurrent aberrations that may guide future studies aimed at identifying target genes. Our findings further support the importance of routinely performing cytogenetic studies on cell lines, to detect cross-contamination mishaps such as those identified here.

Geographical mapping of a multifocal thyroid tumour using genetic alteration analysis & miRNA profiling

Background

Papillary thyroid carcinoma (PTC) frequently presents as multiple tumour-foci within a single thyroid gland or pluriform, with synchronous tumours comprising different histological variants, raising questions regarding its clonality. Among the genetic aberrations described in PTC, the BRAF V600E mutation and ret/PTC activation occur most commonly. Several studies have investigated the genetic alteration status of multifocal thyroid tumours, with discordant results.

To address the question of clonality this study examined disparate geographical and morphological areas from a single PTC (classic PTC, insular and anaplastic foci, and tumour cells adjacent to vascular invasion and lymphocytic infiltrate) for the presence of ret/PTC 1 or BRAF mutations. Moreover, we wanted to investigate the consistency of miRNA signatures within disparate areas of a tumour, and geographical data was further correlated with expression profiles of 330 different miRNAs. Putative miRNA gene targets were predicted for differentially regulated miRNAs and immunohistochemistry was performed on tissue sections in an effort to investigate phenotypic variations in microvascular density (MVD), and cytokeratin and p53 protein expression levels.

Results

All of the morphological areas proved negative for ret/PTC 1 rearrangement. Two distinct foci with classic morphology harboured the BRAF mutation. All other regions, including the insular and anaplastic areas were negative for the mutation.

MiRNA profiles were found to distinguish tumours containing the BRAF mutation from the other tumour types, and to differentiate between the more aggressive insular & anaplastic tumours, and the classic variant. Our data corroborated miRNAs previously discovered in this carcinoma, and additional miRNAs linked to various processes involved in tumour growth and proliferation.

Conclusion

The initial genetic alteration analysis indicated that pluriform PTC did not necessarily evolve from classic PTC progenitor foci. Analysis of miRNA profiles however provided an interesting variation on the clonality question. While hierarchical clustering analysis of miRNA expression supported the hypothesis that discrete areas did not evolve from clonal expansion of tumour cells, it did not exclude the possibility of independent mutational events suggesting both phenomena might occur simultaneously within a tumour to enhance cancer progression in geographical micro-environments within a tumour.