Long non-coding RNA MALAT 1 and PHOX2B expression in olfactory neuroblastomas and sympathetic neuroblastomas.

Long noncoding RNAs (lncRNAs) participate in transcriptional, epigenetic, and post-transcriptional regulation of gene expression and may influence carcinogenesis. MALAT1 is a lncRNA that is expressed in endocrine and many other neoplasms and it has been shown to have oncogenic and/or tumor suppressor effects in tumor development. Olfactory neuroblastomas arise in the nasal cavity while sympathetic neuroblastomas are present mainly in the adrenal and periadrenal regions. These neoplasms have overlapping histopathological features. Rare cases of sympathetic neuroblastomas metastatic to the nasal cavity have been reported. PHOX2B has been shown to be relatively specific for sympathetic neuroblastomas, but only a limited number of cases of olfactory neuroblastomas have been examined for PHOX2B expression. This study aimed to explore the potential utilization of MALAT1 and PHOX2B in distinguishing these two entities. Tissue microarrays (TMA) were created for olfactory neuroblastomas (n = 26) and sympathetic neuroblastomas (n = 52). MALAT1 lncRNA expression was assessed by in situ hybridization using RNAScope technology. TMA slides were scanned by Vectra multispectral imaging system and image analysis and quantification were performed with inForm software. PHOX2B expression was analyzed by immunohistochemistry. MALAT1 showed predominantly nuclear expression in both tumor types and MALAT1 expression was 2-fold higher in olfactory neuroblastomas compared to sympathetic neuroblastomas (p < 0.0001). PHOX2B showed nuclear staining in most sympathetic neuroblastomas (51/52, 98 %) while only 1 olfactory neuroblastoma (3.8 %) was focally positive for this marker. These findings suggest immunostaining of PHOX2B could be an excellent marker in distinguishing between these two tumor types.

Somatostatin Receptor Type 2 and Thyroid-Stimulating Hormone Receptor Expression in Oncocytic Thyroid Neoplasms: Implications for Prognosis and Treatment.

Somatostatin receptor type 2 (SSTR2) and thyroid-stimulating hormone receptor (TSHR) display variable expression in primary thyroid tumors and have been implicated as theranostic targets. This study was designed to explore the differential expression of SSTR2 and TSHR in oncocytic (Hurthle cell) carcinoma (OC) vs oncocytic adenoma (OA). We performed a retrospective review for oncocytic neoplasms treated at our institution from 2012 to 2019. Formalin-fixed paraffin-embedded tissue blocks were used for tissue microarray construction. Tissue microarray blocks were cut into 5-µm sections and stained with anti-SSTR2 and anti-TSHR antibodies. Immunostains were analyzed by 3 independent pathologists. χ2 and logistic regression analysis were used to analyze clinical and pathologic variables. Sixty-seven specimens were analyzed with 15 OA and 52 OC. The mean age was 57 years, 61.2% were women, and 70% were White. SSTR2 positivity was noted in 2 OA (13%) and 15 OC (28%; 10 primary, 4 recurrent, and 1 metastatic) (P = .22). TSHR positivity was noted in 11 OA (73%) and 32 OC (62%; 31 primary and 1 metastatic) (P = .40). Those who presented with or developed clinical recurrence/metastasis were more likely to be SSTR2-positive (50% vs 21%; P = .04) and TSHR-negative (64.3% vs 28.9%; P = .02) than primary OC patients. Widely invasive OC was more likely to be SSTR2-positive compared to all other OC subtypes (minimally invasive and angioinvasive) (P = .003). For all patients with OC, TSHR positivity was inversely correlated with SSTR2 positivity (odds ratio, 0.12; CI, 0.03-0.43; P = .006). This relationship was not seen in the patients with OA (odds ratio, 0.30; CI, 0.01-9.14; P = .440). Our results show that recurrent/metastatic OC was more likely to be SSTR2-positive and TSHR-negative than primary OC. Patients with OC displayed a significant inverse relationship between SSTR2 and TSHR expression that was not seen in patients with OA. This may be a key relationship that can be used to prognosticate and treat OCs.

Epigenomic and somatic mutations of pituitary tumors with clinical and pathological correlations in 111 patients.

OBJECTIVE: To profile clinically non-aggressive and aggressive pituitary adenomas (PAs)/pituitary neuroendocrine tumours (PitNETs) and pituitary carcinomas for somatic mutations and epigenetic alterations of genes involved in cell proliferation/differentiation, microRNAs (miRNA)/long noncoding RNA (LncRNA)-post-transcriptional regulators and therapy targets. DESIGN: Retrospective observational study. PATIENTS AND MEASUREMENTS: A total of 64 non-aggressive and 41 aggressive PAs/PitNETs and 6 pituitary carcinomas treated by endoscopic surgery with ≥1-year follow-up were included. Somatic mutations of 17 genes and DNA methylation of 22 genes were assessed. Ten normal pituitaries were used as control. RESULTS: We found at least one mutation in 17 tumours, including 6/64 non-aggressive, 10/41 aggressive PAs/PitNETs, and 1/6 pituitary carcinoma. AIP (N = 6) was the most frequently mutated gene, followed by NOTCH (4), and TP53 (3). Hypermethylation of PARP15, LINC00599, ZAP70 was more common in aggressive than non-aggressive PAs/PITNETs (p < .05). Lower levels of methylation of AIP, GNAS and PDCD1 were detected in aggressive PAs/PITNETs than non-aggressive ones (p < .05). For X-linked genes, males presented higher level of methylation of FLNA, UXT and MAGE family (MAGEA11, MAGEA1, MAGEC2) genes in aggressive vs. non-aggressive PAs/PITNETs (p < .05). In pituitary carcinomas, methylation of autosomal genes PARP15, LINC00599, MIR193 and ZAP70 was higher than in PAs/PITNETs, while X-linked genes methylation level was lower. CONCLUSIONS: Somatic mutations and methylation levels of genes involved in cell proliferation/differentiation, miRNA/LncRNA-post-transcriptional regulators and targets of antineoplastic therapies are different in non-aggressive and in aggressive PAs/PitNETs. Methylation profile also varies according to gender. Combined genetic-epigenetic analysis, in association with clinico-radiological-pathological data, may be of help in predicting PA/PitNET behaviour.

LncRNA expression and SDHB mutations in pheochromocytomas and paragangliomas.

Although pheochromocytomas and paragangliomas (PPGLs) are usual low-grade neoplasms, the metastatic forms of these lesions are associated with high morbidity and mortality. Recent studies have discovered multiple aberrantly expressed long non-coding RNAs (lncRNAs) in cancers that may have regulatory roles in tumor pathogenesis and metastasis; however, the roles of some lncRNAs in PPGLs are still unknown. The expression levels of lncRNAs including metastasis-associated lung adenocarcinoma transcript (MALAT1), prostate cancer antigen 3 (PCA3), and HOX transcript antisense intergenic RNA (HOTAIR) in PPGLs were analyzed by in situ hybridization, using two tissue microarrays (TMAs). The pheochromocytoma (PCC) TMA consisted of normal adrenal medulla (N = 25), non-metastatic PCCs (N = 76) and metastatic PCCs (N = 5) while the paraganglioma (PGL) TMA had 73 non-metastatic PGLs and 5 metastatic PGLs. Immunohistochemical staining was performed on all samples with an anti-SDHB antibody. The correlations between lncRNA expression, loss of SDHB expression and clinical characteristics including tumor progression and disease prognosis were investigated. The expression levels of MALAT1 and PCA3 were significantly elevated (2.5-3.9 folds) in both non-metastatic and metastatic PCCs compared to normal adrenal medulla, although there were no significant differences between the non-metastatic and metastatic neoplasms. In contrast to non-metastatic PGLs, metastatic PGLs had significantly upregulated expression of MALAT1, PCA3, and HOTAIR. SDHB loss was more frequently observed in PGLs (25 of 78), especially in metastatic PGLs (5 of 5), compared to PCCs (2 of 81) and in 0 of 5 metastatic PCCs. Patients with SDHB loss, in contrast to SDHB retained, were younger at diagnosis, had higher rates of tumor recurrence, metastatic disease, and mortality. In addition, PGLs with SDHB loss had significantly increased expression of PCA3 compared to tumors with intact SDHB expression. Our findings suggest that specific lncRNAs may be involved in the SDHx signaling pathways in the tumorigenesis and in the development of PPGL.

In situ hybridization: Introduction to techniques, applications and pitfalls in the performance and interpretation of assays.

In situ hybridization (ISH) has become a common laboratory technique used for the analysis of gene expression and for the localization of specific DNA and RNA molecules in cells. Many different methods of performing ISH have been described. These techniques have evolved into important tools in basic scientific research and in clinical diagnoses. One of the goals of ISH is to localize gene sequences in situ and to visualize the products within cells while preserving cell integrity. This allows for meaningful anatomical and histological interpretation of the localized product(s) within heterogeneous tissues. Because of the possibility of false positive and false negative results that may occur with ISH assays, familiarity with the pathophysiology of the molecules that are analyzed and the cellular processes involved as well as with limitations of the assays can help to avoid erroneous diagnoses with clinical specimens.

Mortalin (GRP75/HSPA9) Promotes Survival and Proliferation of Thyroid Carcinoma Cells.

We previously reported that upregulation of mortalin (HSPA9/GRP75), the mitochondrial HSP70 chaperone, facilitates tumor cell proliferation and survival in human medullary thyroid carcinoma (MTC), proposing mortalin as a novel therapeutic target for MTC. In this report, we show that mortalin is also upregulated in other thyroid tumor types, including papillary thyroid carcinoma (PTC), follicular thyroid carcinoma (FTC), and anaplastic thyroid carcinoma (ATC), and that mortalin depletion can effectively induce growth arrest and cell death in human PTC (TPC-1), FTC (FTC133), and ATC (8505C and C643) cells in culture. Intriguingly, mortalin depletion induced varied effects on cell cycle arrest (G0/G1 phase arrest in TPC-1 and C643, G2/M phase arrest in 8505C, and mild G2/M phase arrest with increased sub-G0/G1 population in FTC133) and on the levels of TP53, E2F-1, p21CIP1, p27KIP1, and poly (ADP-ribose) polymerase cleavage in these cells, suggesting that thyroid tumor cells respond to mortalin depletion in a cell type-specific manner. In these cells, we also determined the efficacy of triphenyl-phosphonium-carboxy-proxyl (Mito-CP) because this mitochondria-targeted metabolism interfering agent exhibited similar tumor suppressive effects as mortalin depletion in MTC cells. Indeed, Mito-CP also induced robust caspase-dependent apoptosis in PTC and ATC cell lines in vitro, exhibiting IC50 lower than PLX4032 in 8505C cells and IC50 lower than vandetanib and cabozantinib in TPC-1 cells. Intriguingly, Mito-CP-induced cell death was partially rescued by mortalin overexpression, suggesting that Mito-CP may inactivate a mechanism that requires mortalin function. These findings support the significance of mortalin and mitochondrial activity in a broad spectrum of thyroid cancer.

Thyroid cancer stem-like cell exosomes: regulation of EMT via transfer of lncRNAs.

Thyroid cancers are the most common endocrine malignancy and approximately 2% of thyroid cancers are anaplastic thyroid carcinoma (ATC), one of the most lethal and treatment resistant human cancers. Cancer stem-like cells (CSCs) may initiate tumorigenesis, induce resistance to chemotherapy and radiation therapy, have multipotent capability and may be responsible for recurrent and metastatic disease. The production of CSCs has been linked to epithelial-mesenchymal transition (EMT) and the acquisition of stemness. Exosomes are small (30-150 nm) membranous vesicles secreted by most cells that play a significant role in cell-to-cell communication. Many non-coding RNAs (ncRNA), such as long-non-coding RNAs (lncRNA), can initiate tumorigenesis and the EMT process. Exosomes carry ncRNAs to local and distant cell populations. This study examines secreted exosomes from two in vitro cell culture models; an EMT model and a CSC model. The EMT was induced in a papillary thyroid carcinoma (PTC) cell line by TGFß1 treatment. Exosomes from this model were isolated and cultured with naïve PTC cells and examined for EMT induction. In the CSC model, exosomes were isolated from a CSC clonal line, cultured with a normal thyroid cell line and examined for EMT induction. The EMT exosomes transferred the lncRNA MALAT1 and EMT effectors SLUG and SOX2; however, EMT was not induced in this model. The exosomes from the CSC model also transferred the lncRNA MALAT1 and the transcription factors SLUG and SOX2 but additionally transferred linc-ROR and induced EMT in the normal thyroid cells. Preliminary siRNA studies directed towards linc-ROR reduced invasion. We hypothesize that CSC exosomes transfer lncRNAs, importantly linc-ROR, to induce EMT and inculcate the local tumor microenvironment and the distant metastatic niche. Therapies directed towards CSCs, their exosomes and/or the lncRNAs they carry may reduce a tumor's metastatic capacity.

Recent Advances in the Classification of Low-grade Papillary-like Thyroid Neoplasms and Aggressive Papillary Thyroid Carcinomas: Evolution of Diagnostic Criteria.

Papillary thyroid carcinomas account for ∼80% of well-differentiated thyroid tumors. During the past decade, several new variants of papillary-like thyroid neoplasms and papillary thyroid carcinomas have been recognized. Some of these neoplasms that were previously classified as malignant have been reclassified as low-grade neoplasms, as the diagnostic criteria have evolved. Similarly, some of the papillary thyroid carcinomas that were previously classified as conventional or classic papillary thyroid carcinomas have now been recognized as more aggressive variants of papillary thyroid carcinomas. Recognizing these differences becomes more important for the proper medical, surgical, and radiotherapeutic management of patients with these neoplasms.

Insulinoma-associated 1: A novel nuclear marker in Merkel cell carcinoma (cutaneous neuroendocrine carcinoma).

Merkel cell carcinoma (MCC) is a rare, clinically aggressive, cutaneous neuroendocrine (NE) neoplasm. As a tumor with small, round, blue cells, the histologic differential diagnosis for MCC can include melanoma, metastatic small cell carcinoma (SCC), nodular hematopoietic tumors, basal cell carcinoma (BCC), atypical variants of squamous carcinoma and the uncommon occurrence of primary cutaneous Ewing sarcoma. In cases with atypical histology or without the classic immunophenotype, the diagnosis can be challenging. Ultimately, immunohistochemistry (IHC) is essential to the definitive diagnosis of MCC and in difficult cases, the diagnosis may hinge entirely on the immunophenotype of the tumor cells. Insulinoma-associated 1 (INSM1) is a transcription factor expressed in tissues undergoing terminal NE differentiation. As a nuclear protein tied to both differentiation and the cell cycle, INSM1 may offer additional utility in comparison to traditional, cytoplasmic markers of NE differentiation.

The evolving concept of cancer stem-like cells in thyroid cancer and other solid tumors.

The cancer stem-like cell (CSC) hypothesis postulates that a small population of cells in a cancer has self-renewal and clonal tumor initiation properties. These cells are responsible for tumor initiation, growth, recurrence and for resistance to chemotherapy and radiation therapy. CSCs can be characterized using markers such as SSEA-1, SSEA-4, CD44, CD24, ALDEFLUOR and others. CSCs form spheres when they are cultured in serum-free condition in low attachment plates and can generate tumors when injected into immune-deficient mice. During epithelial to mesenchymal transition (EMT), cells lose cellular adhesion and polarity and acquire an invasive phenotype. Recent studies have established a relationship between EMT and increased numbers of CSCs in some solid malignancies. Non-coding RNAs such as microRNAs and long non-coding RNAs (lncRNAs) have been shown to have important roles during EMT and some of these molecules also have regulatory roles in the proliferation of CSCs. Specific lncRNAs enhanced cell migration and invasion in breast carcinomas, which was associated with the generation of stem cell properties. The tumor microenvironment of CSCs also has an important role in tumor progression. Recent studies have shown that the interaction between tumor cells and the local microenvironment at the metastatic site leads to the development of premetastatic niche(s) and allows for the proliferation of the metastatic cells during colonization. The role of exosomes in the microenvironment during the EMT program is currently a major area of research. This review examines CSCs and the relationship between EMT and CSCs in solid tumors with emphasis on thyroid CSCs. The role of non-coding RNAs and of the microenvironment in EMT and in tumor progression are also examined. This review also highlights the growing number of studies that show the close association of EMT and CSCs and the role of exosomes and other elements of the tissue microenvironment in CSC metastasis. A better understanding of these mechanisms will lead to more effective targeting of primary and metastatic malignancies.

Notch3 expression correlates with thyroid cancer differentiation, induces apoptosis, and predicts disease prognosis.

BACKGROUND: Thyroid tumorigenesis is characterized by a progressive loss of differentiation exhibited by a range of disease variants. The Notch receptor family (1-4) regulates developmental progression in both normal and cancerous tissues. This study sought to characterize the third Notch isoform (Notch3) across the various differentiated states of thyroid cancer, and determine its clinical impact. METHODS: Notch3 expression was analyzed in a tissue microarray of normal and pathologic thyroid biopsies from 155 patients. The functional role of Notch3 was then investigated by upregulating its expression in a follicular thyroid cancer (FTC) cell line. RESULTS: Notch3 expression regressed across decreasingly differentiated, increasingly malignant thyroid specimens, correlated with clinicopathological attributes reflecting poor prognosis, and independently predicted survival following univariate and multivariate analyses. Overexpression of the active Notch3 intracellular domain (NICD3) in a gain-of-function FTC line led to functional activation of centromere-binding protein 1, while increasing thyroid-specific gene transcription. NICD3 induction also reduced tumor burden in vivo and initiated the intrinsic apoptotic cascade, alongside suppressing cyclin and B-cell lymphoma 2 family expression. CONCLUSIONS: Loss of Notch3 expression may be fundamental to the process of dedifferentiation that accompanies thyroid oncogenesis. Conversely, activation of Notch3 in thyroid cancer exerts an antiproliferative effect and restores elements of a differentiated phenotype. These findings provide preclinical rationale for evaluating Notch3 as a disease prognosticator and therapeutic target in advanced thyroid cancer. Cancer 2017;123:769-82. © 2016 American Cancer Society.

Generation of Novel Thyroid Cancer Stem-Like Cell Clones: Effects of Resveratrol and Valproic Acid.

Anaplastic thyroid cancer is an aggressive and highly lethal cancer for which conventional therapies have proved ineffective. Cancer stem-like cells (CSCs) represent a small fraction of cells in the cancer that are resistant to chemotherapy and radiation therapy and are responsible for tumor reoccurrence and metastasis. We characterized CSCs in thyroid carcinomas and generated clones of CSC lines. Our study showed that anaplastic thyroid cancers had significantly more CSCs than well-differentiated thyroid cancers. We also showed that Aldefluor-positive cells revealed significantly higher expression of stem cell markers, self-renewal properties, thyrosphere formation, and enhanced tumorigenicity. In vivo passaging of Aldefluor-positive cells resulted in the growth of larger, more aggressive tumors. We isolated and generated two clonal spheroid CSC lines derived from anaplastic thyroid cancer that were even more enriched with stem cell markers and more tumorigenic than the freshly isolated Aldefluor-positive cells. Resveratrol and valproic acid treatment of one of the CSC lines resulted in a significant decrease in stem cell markers, Aldefluor expression, proliferation, and invasiveness, with an increase in apoptosis and thyroid differentiation markers, suggesting that these cell lines may be useful for discovering new adjuvant therapies for aggressive thyroid cancers. For the first time, we have two thyroid CSC lines that will be useful tools for the study of thyroid CSC targeted therapies.

Encapsulated follicular variant of papillary thyroid cancer: are these tumors really benign?

BACKGROUND: Recent studies suggest that the encapsulated form of follicular variant of papillary thyroid cancer (eFVPTC) behaves more similarly to benign lesions and can be treated with thyroid lobectomy alone instead of total thyroidectomy. To distinguish aggressive cancers from more benign lesions more clearly, the objective of this study was to determine if the eFVPTC behaves less aggressively than the nonencapsulated variant (neFVPTC). METHODS: A prospectively collected endocrine surgery database in our institution was reviewed for all patients with FVPTC on surgical pathology from 1999 to 2012. Samples were rereviewed to determine if the tumor was eFVPTC or neFVPTC, which were correlated with patient outcomes. RESULTS: Of the 68 patients, 59 (87%) had eFVPTC and 9 (13%) had neFVPTC. The mean age was 48 y and 63% were female. Fifty-four of 64 patients (84%) who had a total thyroidectomy received radioactive iodine. The eFVPTC group had lower rates of cervical LN involvement (5% versus 22%, P = 0.2504). The median follow-up time was 3 y (0-13 y) and only two patients had recurrence, one with eFVPTC and one with neFVPTC. None of the patients had distant metastasis or died of their disease. CONCLUSIONS: eFVPTCs appear to have a lower rate of cervical lymph node metastases compared with neFVPTCs, but recurrent disease may be seen in both subtypes. These findings suggest eFVPTC can be managed more conservatively.

AKT activity is elevated in aggressive thyroid neoplasms where it promotes proliferation and invasion.

The PI3K/AKT/mTOR signaling pathway controls major cellular processes such as cell growth, proliferation and survival. Stimulation of this pathway leads to AKT phosphorylation and activation, resulting in phosphorylation of mTOR and myriad other targets. AKT upregulation has been implicated in thyroid cancer pathogenesis and is a candidate treatment target for patients with advanced disease that has not responded to traditional therapies. Here we evaluate a large series of benign and malignant thyroid tumors for AKT activity and intracellular distribution. We also deplete AKT from multiple thyroid cancer cell lines, including putative cancer stem cell lines, and measure the effect on proliferation and invasion in vitro. We show that active AKT has a predominantly nuclear distribution and its expression is highest in anaplastic thyroid carcinomas and papillary thyroid carcinomas, including encapsulated and invasive follicular variants. Depletion of AKT in thyroid carcinoma cell lines led to greatly reduced proliferative capacity and resulted in a reduction of invasive potential. A reduction in invasion was also observed in the cancer stem cell compartment. Targeting AKT activity in the clinical setting may slow the growth and spread of aggressive thyroid neoplasms, and target the tumor stem cell compartment.

MicroRNA-21 and long non-coding RNA MALAT1 are overexpressed markers in medullary thyroid carcinoma.

BACKGROUND: Non-coding RNAs, including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), are well-recognized post-transcriptional regulators of gene expression. This study examines the expression of microRNA-21 (miR-21) and lncRNA MALAT1 in medullary thyroid carcinomas (MTCs) and their effects on tumor behavior. METHODS: Tissue microarrays (TMAs) were constructed using normal thyroid (n=39), primary tumors (N=39) and metastatic MTCs (N=18) from a total of 42 MTC cases diagnosed between 1987 and 2016. In situ hybridization with probes for miR-21 and MALAT1 was performed. PCR quantification of expression was performed in a subset of normal thyroid (N=10) and primary MTCs (N=32). An MTC-derived cell line (MZ-CRC-1) was transfected with small interfering RNAs (siRNAs) targeting miR-21 and MALAT1 to determine the effects on cell proliferation and invasion. RESULTS: In situ hybridization (ISH) showed strong (2+ to 3+) expression of miR-21 in 17 (44%) primary MTCs and strong MALAT1 expression in 37 (95%) primary MTCs. Real-time PCR expression of miR-21 (P<0.001) and MALAT1 (P=0.038) in primary MTCs were significantly higher than in normal thyroid, supporting the ISH findings. Experiments with siRNAs showed inhibition of miR-21 and MALAT1 expression in the MTC-derived cell line, leading to significant decreases in cell proliferation (P<0.05) and invasion (P<0.05). CONCLUSION: There is increased expression of miR-21 and MALAT1 in MTCs. This study also showed an in vitro pro-oncogenic effect of MALAT1 and miR-21 in MTCs. The results suggest that overexpression of miR-21 and MALAT1 may regulate MTC progression.

The roles of the epithelial-mesenchymal transition marker PRRX1 and miR-146b-5p in papillary thyroid carcinoma progression.

Thyroid carcinoma is the most common endocrine malignancy, and papillary thyroid carcinoma represents the most common thyroid cancer. Papillary thyroid carcinomas that invade locally or metastasize are associated with a poor prognosis. We found that, during epithelial-mesenchymal transition (EMT) induced by transforming growth factor-ß1 (TGF-ß1), papillary thyroid carcinoma cells acquired increased cancer stem cell-like features and the transcription factor paired-related homeobox protein 1 (PRRX1; alias PRX-1), a newly identified EMT inducer, was markedly up-regulated. miR-146b-5p was also transiently up-regulated during EMT, and in siRNA experiments miR-146b-5p had an inhibitory role on cell proliferation and invasion during TGF-ß1-induced EMT. We conclude that papillary thyroid carcinoma tumor cells exhibit increased cancer stem cell-like features during TGF-ß1-induced EMT, that miR-146b-5p has a role in cell proliferation and invasion, and that PRRX1 plays an important role in papillary thyroid carcinoma EMT and disease progression.

Lymph node metastases do not impact survival in follicular variant papillary thyroid cancer.

INTRODUCTION: Follicular variant of papillary thyroid cancer (FVPTC) is the most common and fastest growing subtype of papillary thyroid cancer (PTC) with features of both PTC and follicular thyroid cancer (FTC). The purpose of this study was to determine the patient and tumor features associated with lymph node metastases (LNM) in FVPTC. METHODS: This was a retrospective review of adult (≥18) patients with histologically confirmed diagnoses of FVPTC within the SEER database between 1988 and 2009. LNM were defined by at least two lymph nodes with metastatic disease. To determine factors associated with LNM, we constructed a multivariate logistic regression model from significant variables (p < 0.05) identified on univariate analysis. Similarly, we used a Cox proportional hazards model to understand the relative importance of LNM in determining disease-specific mortality (DSM). RESULTS: Of the 20,357 cases of FVPTC with lymph node data available, 1,761 (8.7%) had LNM; 61.1% of these LNM were located in the central neck and 38.9% were in the lateral neck. Extrathyroidal extension (odds ratio [OR] 2.6, 95% confidence interval [CI] 2.2-3.0, p < 0.01) and multifocality (OR 3.0, 95% CI 2.5-3.6, p < 0.01) were the strongest predictors of LNM. Importantly, LNM did not independently predict DSM (p = 0.52). Tumor size >4 cm (hazards ratio [HR] 5.3, 95% CI 2.2-12.8, p < 0.01) and extrathyroidal extension (HR 8.2, 95% CI 3.0-22.0, p < 0.01) were the strongest predictors of DSM. CONCLUSIONS: LNM occur in less than 10% of patients with FVPTC but do not impact DSM. Instead, DSM in FVPTC is related to size and local invasion.

Pheochromocytomas and Paragangliomas: An Update on Recent Molecular Genetic Advances and Criteria for Malignancy.

Pheochromocytomas are uncommon neuroendocrine tumors arising in the adrenal medulla, whereas paragangliomas arise from chromaffin cells in sympathetic and parasympathetic locations outside of the adrenal gland. Molecular genetic studies in the past few years have identified >10 genes involved in the pathogenesis of pheochromocytomas and paragangliomas, including RET oncogene, involved in the pathogenesis of multiple endocrine neoplasia (MEN) 2A and 2B, von Hippel-Lindau tumor-suppressor gene, neurofibromatosis type 1 gene, succinate dehydrogenase, THEM127, and several others. The presence of genetic alterations in some of these genes such as in MEN 2A and 2B can be used to diagnose these disorders clinically, and other mutations such as succinate dehydrogenase can be used in the pathologic prediction of benign and malignant pheochromocytomas and paragangliomas. Although it has been difficult to separate benign and malignant pheochromocytomas and paragangliomas, recent studies that may predict the behavior of these chromaffin-derived neoplasms have been reported. The Pheochromocytoma of the Adrenal Scale Score and the Grading system for Adrenal Pheochromocytoma and Paraganglioma scoring system are also discussed.

Novel approaches in anaplastic thyroid cancer therapy.

Anaplastic thyroid cancer (ATC), accounting for less than 2% of all thyroid cancer, is responsible for the majority of death from all thyroid malignancies and has a median survival of 6 months. The resistance of ATC to conventional thyroid cancer therapies, including radioiodine and thyroid-stimulating hormone suppression, contributes to the very poor prognosis of this malignancy. This review will cover several cellular signaling pathways and mechanisms, including RET/PTC, RAS, BRAF, Notch, p53, and histone deacetylase, which are identified to play roles in the transformation and dedifferentiation process, and therapies that target these pathways. Lastly, novel approaches and agents involving the Notch1 pathway, nuclear factor κB, Trk-fused gene, cancer stem-like cells, mitochondrial mutation, and tumor immune microenvironment are discussed. With a better understanding of the biological process and treatment modality, the hope is to improve ATC outcome in the future.

Thyroid-stimulating hormone receptor (TSHR) as a target for imaging differentiated thyroid cancer.

BACKGROUND: Of the half a million cases of thyroid cancer diagnosed annually, 95% are differentiated thyroid cancers. Although clinical guidelines recommend surgical resection followed by radioactive iodine ablation, loss of sodium-iodine symporter expression causes up to 20% of differentiated thyroid cancers to become radioactive iodine refractory. For patients with radioactive iodine refractory disease, there is an urgent need for new diagnostic and therapeutic approaches. We evaluated the thyroid-stimulating hormone receptor as a potential target for imaging of differentiated thyroid cancer. METHODS: We immunostained tissue microarrays containing 52 Hurthle cell carcinomas to confirm thyroid-stimulating hormone receptor expression. We radiolabeled chelator deferoxamine conjugated to recombinant human thyroid-stimulating hormone analog superagonist TR1402 with 89Zr (t1/2 = 78.4 h, ß+ =22.7%) to produce [89Zr]Zr-TR1402. We performed in vitro uptake assays in high-thyroid-stimulating hormone receptor and low-thyroid-stimulating hormone receptor-expressing THJ529T and FTC133 thyroid cancer cell lines. We performed in vivo positron emission tomography/computed tomography and biodistribution studies in male athymic nude mice bearing thyroid-stimulating hormone receptor-positive THJ529T tumors. RESULTS: Immunohistochemical analysis revealed 62% of patients (27 primary and 5 recurrent) were thyroid-stimulating hormone receptor membranous immunostain positive. In vitro uptake of 1nM [89Zr]Zr-TR1402 was 38 ± 17% bound/mg in thyroid-stimulating hormone receptor-positive THJ529T thyroid cancer cell lines compared to 3.2 ± 0.5 in the low-expressing cell line (P < .01), with a similar difference seen in FTC133 cell lines (P < .0001). In vivo and biodistribution studies showed uptake of [89Zr]Zr-TR1402 in thyroid-stimulating hormone receptor-expressing tumors, with a mean percentage of injected dose/g of 1.9 ± 0.4 at 3 days post-injection. CONCLUSION: Our observation of thyroid-stimulating hormone receptor expression in tissue microarrays and [89Zr]Zr-TR1402 accumulation in thyroid-stimulating hormone receptor-positive thyroid cancer cells and tumors suggests thyroid-stimulating hormone receptor is a promising target for imaging of differentiated thyroid cancer.