PVALB, a new Hürthle adenoma diagnostic marker identified through gene expression

The Impact of Transcription Factor Prospero Homeobox 1 on the Regulation of Thyroid Cancer Malignancy

Transcription factor Prospero homeobox 1 (PROX1) is continuously expressed in the lymphatic endothelial cells, playing an essential role in their differentiation. Many reports have shown that PROX1 is implicated in cancer development and acts as an oncoprotein or suppressor in a tissue-dependent manner. Additionally, the PROX1 expression in many types of tumors has prognostic significance and is associated with patient outcomes. In our previous experimental studies, we showed that PROX1 is present in the thyroid cancer (THC) cells of different origins and has a high impact on follicular thyroid cancer (FTC) phenotypes, regulating migration, invasion, focal adhesion, cytoskeleton reorganization, and angiogenesis. Herein, we discuss the PROX1 transcript and protein structures, the expression pattern of PROX1 in THC specimens, and its epigenetic regulation. Next, we emphasize the biological processes and genes regulated by PROX1 in CGTH-W-1 cells, derived from squamous cell carcinoma of the thyroid gland. Finally, we discuss the interaction of PROX1 with other lymphatic factors. In our review, we aimed to highlight the importance of vascular molecules in cancer development and provide an update on the functionality of PROX1 in THC biology regulation.

Molecular Study of Thyroid Cancer in World Trade Center Responders

Thyroid cancer incidence is higher in World Trade Center (WTC) responders compared with the general population. It is unclear whether this excess in thyroid cancer is associated with WTC-related exposures or if instead there is an over-diagnosis of malignant thyroid cancer among WTC first responders due to enhanced surveillance and physician bias. To maximize diagnostic yield and determine the false positive rate for malignancy, the histological diagnoses of thyroid cancer tumors from WTC responders and age, gender, and histology matched non-WTC thyroid cancer cases were evaluated using biomarkers of malignancy. Using a highly accurate panel of four biomarkers that are able to distinguish benign from malignant thyroid cancer, our results suggest that over-diagnosis by virtue of misdiagnosis of a benign tumor as malignant does not explain the increased incidence of thyroid cancer observed in WTC responders. Therefore, rather than over-diagnosis due to physician bias, the yearly screening visits by the World Trade Center Health Program are identifying true cases of thyroid cancer. Continuing regular screening of this cohort is thus warranted.

FAM129A regulates autophagy in thyroid carcinomas in an oncogene-dependent manner

We previously proposed that high expression of FAM129A can be used as a thyroid carcinoma biomarker in preoperative diagnostic exams of thyroid nodules. Here, we identify that FAM129A expression is increased under nutrient and growth factor depletion in a normal thyroid cell line (PCCL3), overlapping with increased expression of autophagy-related protein and inhibition of AKT/mTOR/p70S6K. Supplementation of insulin, TSH and serum to the medium was able to reduce the expression of both FAM129A and autophagy-related protein and reestablish the AKT/mTOR/p70S6K axis. To determine the direct role of FAM129A on autophagy, FAM129A was transfected into PCCL3 cells. Its overexpression induced autophagic vesicles formation, evidenced by transmission electron microscopy. Co-expression of FAM129A and mCherry-EGFP-LC3B in PCCL3 showed an increased yellow puncta formation, suggesting that FAM129Ainduces autophagy. To further confirm its role on autophagy, we knockdown FAM129A in two thyroid carcinoma cell lines (TPC1 and FTC-236). Unexpectedly, FAM129A silencing increased autophagic flux, suggesting that FAM129A inhibits autophagy in these models. We next co-transfected PCCL3 cells with FAM129A and RET/PTC1 and tested autophagy in this context. Co-expression of FAM129A and RET/PTC1 oncogene in PCCL3 cells, inhibited RET/PTC1-induced autophagy. Together, our data suggest that, in normal cells FAM129A induces autophagy in order to maintain cell homeostasis and provide substrates under starvation conditions. Instead, in cancer cells, decreased autophagy may help the cells to overcome cell death. FAM129A regulates autophagy in a cell- and/or context-dependent manner. Our data reinforce the concept that autophagy can be used as a strategy for cancer treatment.

Diagnostic Utility of Molecular and Imaging Biomarkers in Cytological Indeterminate Thyroid Nodules

Indeterminate thyroid cytology (Bethesda III and IV) corresponds to follicular-patterned benign and malignant lesions, which are particularly difficult to differentiate on cytology alone. As ~25% of these nodules harbor malignancy, diagnostic hemithyroidectomy is still custom. However, advanced preoperative diagnostics are rapidly evolving.This review provides an overview of additional molecular and imaging diagnostics for indeterminate thyroid nodules in a preoperative clinical setting, including considerations regarding cost-effectiveness, availability, and feasibility of combining techniques. Addressed diagnostics include gene mutation analysis, microRNA, immunocytochemistry, ultrasonography, elastosonography, computed tomography, sestamibi scintigraphy, [18F]-2-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET), and diffusion-weighted magnetic resonance imaging.The best rule-out tests for malignancy were the Afirma® gene expression classifier and FDG-PET. The most accurate rule-in test was sole BRAF mutation analysis. No diagnostic had both near-perfect sensitivity and specificity, and estimated cost-effectiveness. Molecular techniques are rapidly advancing. However, given the currently available techniques, a multimodality stepwise approach likely offers the most accurate diagnosis, sequentially applying one sensitive rule-out test and one specific rule-in test. Geographical variations in cytology (e.g., Hürthle cell neoplasms) and tumor genetics strongly influence local test performance and clinical utility. Multidisciplinary collaboration and implementation studies can aid the local decision for one or more eligible diagnostics.

Identification of Driver Genes and Key Pathways of Pediatric Brain Tumors and Comparison of Molecular Pathogenesis Based on Pathologic Types

OBJECTIVE

This study is to identify pediatric brain tumors (PBT) driver genes and key pathways to detect the expression of the driver genes and also to clarify the relationship between patients' prognosis and expression of driver genes.

METHODS

The gene expression profile of GSE50161 was analyzed to identify the differentially expressed genes (DEGs) between tumor tissue and the normal tissue. Gene ontology, Kyoto Encyclopedia of Genes and Genomes analysis, and protein-protein interaction network analysis were conducted to identify the enrichment functions, pathways, and hub genes. After hub genes were identified, quantitative reverse transcription polymerase chain reaction was used to confirm the differential expression of these hub genes. Survival data of 325 patients' were analyzed to clarify the relationship between prognosis and expression levels of the mutual hub genes.

RESULTS

Gene ontology and Kyoto Encyclopedia of Genes and Genomes analysis showed that there were 13 common functions and 3 common pathways which were upregulated or downregulated among the 4 groups. Mutual hub genes were somatostatin (SST), glutamate decarboxylase 2 (GAD2), and single copy human parvalbumin gene (PVALB). The expression of SST, GAD2, and PVALB in glioma cells significantly decreased compared with normal glial cells (P < 0.05). In addition, survival analysis showed a favorable progression-free and overall survival in patients with glioma with SST, GAD2, and PVALB high expression (P < 0.05).

CONCLUSIONS

SST, GAD2, and PVALB significantly decrease in glioma cells compared with normal glial cells. Survival analysis suggests that patients with high-expressed SST, GAD2, and PVALB have a longer overall and progression-free survival. The differential expressed genes identified in this study provide novel targets for diagnosis and treatment.

A Unique Case of Bilateral Hürthle Cell Adenoma in an Adolescent

BACKGROUND

Hürthle cell (HC) neoplasms are rare among pediatric thyroid cancers. HC adenomas (HCA) are typically benign and localized unilaterally without recurrence, and they are thus treated by hemithyroidectomy. HC carcinomas (HCC) can be bilateral and are more aggressive, necessitating total thyroidectomy. Diagnosis relies upon surgical histopathology demonstrating invasion for classification as HCC or lack of invasion in HCA, since fine needle aspiration fails to differentiate between the two.

METHODS

We report a case of a 14-year-old adolescent female with bilateral HCA. She had an initial left hemithyroidectomy for a large nodule measuring 2 × 1.5 × 1.2 cm3 in the left lobe, while smaller subcentimeter nodules remained under surveillance in the right. One year later, a nodule in the right lobe doubled in size, necessitating a right hemithyroidectomy which also revealed HCA.

CONCLUSION

To our knowledge, this is the first reported case of bilateral HCA in pediatrics. It highlights the importance of close surveillance of persistent small nodules, even in patients with previously documented benign lesions such as HCA, which are typically thought to be unilateral and localized. Both HCA and HCC remain unpredictable in behavior, and treatment of HCA should be individualized.

PVALB diminishes [Ca2+] and alters mitochondrial features in follicular thyroid carcinoma cells through AKT/GSK3β pathway

We have identified previously a panel of markers (C1orf24, ITM1 and PVALB) that can help to discriminate benign from malignant thyroid lesions. C1orf24 and ITM1 are specifically helpful for detecting a wide range of thyroid carcinomas, and PVALB is particularly valuable for detecting the benign Hürthle cell adenoma. Although these markers may ultimately help patient care, the current understanding of their biological functions remains largely unknown. In this article, we investigated whether PVALB is critical for the acquisition of Hürthle cell features and explored the molecular mechanism underlying the phenotypic changes. Through ectopic expression of PVALB in thyroid carcinoma cell lines (FTC-133 and WRO), we demonstrated that PVALB sequesters free cytoplasmic Ca(2+), which ultimately lowers calcium levels and precludes endoplasmic reticulum (ER) Ca(2+) refilling. These results were accompanied by induced expression of PERK, an ER stress marker. Additionally, forced expression of PVALB reduces Ca(2+) inflow in the mitochondria, which can in turn cause changes in mitochondria morphology, increase mitochondria number and alter subcellular localization. These findings share striking similarity to those observed in Hürthle cell tumors. Moreover, PVALB inhibits cell growth and induces cell death, most likely through the AKT/GSK-3β. Finally, PVALB expression coincides with Ca(2+) deposits in HCA tissues. Our data support the hypothesis that the loss of PVALB plays a role in the pathogenesis of thyroid tumors.

microRNA-106b-mediated down-regulation of C1orf24 expression induces apoptosis and suppresses invasion of thyroid cancer

We previously showed that C1orf24 expression is increased in thyroid carcinomas. Nonetheless, the mechanism underlying C1orf24 deregulation is not fully understood. It has been widely demonstrated that microRNAs are involved in post-transcriptional gene regulation in several diseases, including cancer. Using in silico prediction approach, five microRNAs that bind to the 3'-untranslated region (3'-UTR) of C1orf24 were identified. The expression of two selected microRNAs (miR-17-5p, miR-106b) and the expression of C1orf24 were tested in 48 benign and malignant thyroid lesions and in five thyroid carcinoma cell lines. miR-106b was down-regulated in thyroid cancer specimens and thyroid carcinoma cell lines, while C1orf24 expression was markedly increased. To demonstrate that miR-106b reduces C1orf24 expression, follicular (WRO) and papillary (TPC1) thyroid carcinoma cell lines were transiently transfected with miR-106b mimic. Ectopic expression of the miR-106b mimic significantly inhibits C1orf24 mRNA and protein expression in both WRO and TPC1 cells. Dual-luciferase report assays demonstrated that miR-106b directly targets C1orf24 by binding its 3'-UTR. Moreover, miR-106b-mediated down-regulation of C1orf24 expression increased apoptosis and inhibited migration. We additionally demonstrated that siRNA against C1orf24 significantly decreased its expression, inhibited cell migration and cell cycle progression while induced apoptosis. In summary, our findings not only provide new insights into molecular mechanism associated with C1orf24 overexpression in thyroid carcinomas but also show that C1orf24 might increase proliferation and cell migration. Thus, decreasing C1orf24 levels, by restoring miR-106b function, may have therapeutic implications.

Gene expression signature in mouse thyroid tissue after (131)I and (211)At exposure

BACKGROUND

(131)I and (211)At are used in nuclear medicine and accumulate in the thyroid gland and may impact normal thyroid function. The aim of this study was to determine transcriptional profile variations, assess the impact on cellular activity, and identify genes with biomarker properties in thyroid tissue after (131)I and (211)At administration in mice.

METHODS

To further investigate thyroid tissue transcriptional responses to (131)I and (211)At administration, we generated a new transcriptional dataset that includes re-evaluated raw intensity values from our previous (131)I and (211)At studies. Differential transcriptional profiles were identified by comparing treated and mock-treated samples using Nexus Expression 3.0 software. Further data analysis was performed using R/Bioconductor and IPA.

RESULTS

A total of 1144 genes were regulated. Hierarchical clustering subdivided the groups into two clusters containing the lowest and highest absorbed dose levels, respectively, and revealed similar transcriptional regulation patterns for many kallikrein-related genes. Twenty-seven of the 1144 genes were recurrently regulated after (131)I and (211)At exposure and divided into six clusters. Several signalling pathways were affected, including calcium, integrin-linked kinase, and thyroid cancer signalling, and the peroxisomal proliferator-activated receptor network.

CONCLUSIONS

Substantial changes in transcriptional regulation were shown in (131)I and (211)At-treated samples, and 27 genes were identified as potential biomarkers for (131)I and (211)At exposure. Clustering revealed distinct differences between transcriptional profiles of both similar and different exposures, demonstrating the necessity for better understanding of radiation-induced effects on cellular activity. Additionally, ionizing radiation-induced changes in kallikrein gene expression and identified canonical pathways should be further assessed.

Performance of the Afirma Gene Expression Classifier in Hürthle Cell Thyroid Nodules Differs from Other Indeterminate Thyroid Nodules

BACKGROUND

The recently introduced Afirma gene expression classifier (AGEC) provides binary results (benign or suspicious) to guide management of cytologically indeterminate thyroid nodules. The AGEC is intended to reduce unnecessary surgeries for benign nodules, and management algorithms favor surgery for suspicious results. Limited data are available on the performance of this test for Hürthle cell nodules (HCNs). This study hypothesized that a predominance of Hürthle cells leads to an increased rate of suspicious AGEC results with a potential for overtreatment, despite a relatively low risk of malignancy.

METHODS

The pathology databases from three tertiary care facilities were queried from 2010 to 2014 for fine-needle aspirates (FNAs) diagnosed as suspicious for Hürthle cell neoplasm (SHCN) or atypia of undetermined significance/follicular lesion of undetermined significance concerning for Hürthle cell neoplasm (AFHCN). Cytology diagnoses were rendered internally prior to AGEC testing. The patient demographics, FNA diagnosis, AGEC result, surgical procedure, and pathologic outcomes were recorded.

RESULTS

The cohort consisted of 134 patients with HCNs. Prior to AGEC availability, 62 patients underwent surgery: 81% (50/62) of patients had surgery, and 34% (17/50) of the resected index nodules were malignant. After introduction of the AGEC, 72 patients underwent AGEC testing: 65% (47/72) of patients had surgery, and 13% (6/46) of the resected nodules were malignant. Thirty-two percent (23/72) of patients had a benign AGEC result and did not undergo surgery, and 4% (3/72) had surgery despite a benign AGEC result with benign final pathology, whereas 63% (45/72) of patients had suspicious AGEC results, with 96% of these patients (43/45) undergoing surgery, and 14% (6/43) of these index nodules were malignant.

CONCLUSIONS

While 32% of tested patients declined surgery based on a benign AGEC, 86% of patients with suspicious AGEC findings had unnecessary surgery, reflecting a substantially lower rate of malignancy from what was previously reported for all indeterminate nodules. Given the approximate pretest malignancy risk of 25-35% for an FNA diagnosis of SHCN or AFHCN, a suspicious AGEC diagnosis does not increase the probability of malignancy in an HCN, and patients should be counseled accordingly.

Preoperative serum thyroglobulin concentration as a predictive factor of malignancy in small follicular and Hürthle cell neoplasms of the thyroid gland

BACKGROUND

Cytologic examination of a fine-needle aspiration biopsy specimen cannot distinguish between benign and malignant follicular or Hürthle cell neoplasms. Serum thyroglobulin (Tg) concentrations are higher in follicular and Hürthle cell carcinomas than in benign follicular or Hürthle cell tumors, but preoperative measurement of Tg is not recommended for initial evaluation of thyroid nodules. The aim of this study was to find out whether preoperative serum Tg concentration is a predictive factor of malignant disease in patients with a follicular or Hürthle cell neoplasm with a diameter of 2 cm or less.

METHODS

From 1988 to 2013, a total of 244 patients (214 female, 30 male, age range 9 to 82 years, median age 52 years) had a surgical procedure at our institute because of follicular or Hürthle cell neoplasms with a tumor diameter of 2 cm or less. In these patients a preoperative concentration of Tg was determined and Tg-autoantibodies were negative. The risk factors for malignancy were identified by a chi-square test and multivariate logistic regression.

RESULTS

The histopathologic diagnoses were carcinoma, adenoma, and benign goiter in 62 (25.5%), 115 (47%), and 67 (27.5%) patients, respectively. The median preoperative Tg concentration in benign tumors, papillary carcinomas, follicular carcinomas, and Hürthle cell carcinomas was 41, 87, 72, and 106 ng/ml (P = 0.05), respectively. The predictive factors for carcinoma shown by the chi-square test were: sex, thyroid volume, and preoperative Tg concentration. The independent predictors of malignancy as shown by multivariate logistic regression were: male sex (odds ratio, 2.57; P = 0.02), and a Tg concentration of more than 80 ng/ml (odds ratio, 2.35; P = 0.005).

CONCLUSION

The independent predictors of malignancy in follicular or Hürthle cell neoplasms are sex and preoperative Tg concentration.

Employing genetic markers to improve diagnosis of thyroid tumor fine needle biopsy

Fine-Needle Aspiration (FNA) is the most widely used and cost-effective preoperative test for the initial evaluation of a thyroid nodule, although it has limited diagnostic accuracy for several types of tumors. Patients will often receive cytological report of indeterminate cytology and are referred to surgery for a more accurate diagnosis. An improved test would help physicians rapidly focus treatment on true malignancies and avoid some unnecessary treatment of benign tumors. This review will discuss current molecular markers that may improve thyroid nodule diagnosis.

The new molecular markers DDIT3, STT3A, ARG2 and FAM129A are not useful in diagnosing thyroid follicular tumors

Preoperative characterization of thyroid follicular lesions is challenging. Fine-needle aspiration specimens cannot differentiate follicular carcinomas from benign follicular neoplasias. Recently, promising markers have been detected using modern molecular techniques. We conducted a retrospective study to confirm the usefulness of immunohistochemical staining for the protein markers, DDIT3, STT3A (ITM1), ARG2 and FAM129A (C1orf24) in separating benign and malignant thyroid follicular lesions. Formalin-fixed, paraffin-embedded thyroid tissue from 30 in-house cases (15 follicular carcinomas and 15 follicular adenomas), as well as 8 follicular carcinomas and 21 follicular adenomas on tissue microarray slides were stained immunohistochemically for DDIT3, STT3A, ARG2 and FAM129A expression. Control tissue consisted of thyroid parenchyma adjacent to the tumors and 11 separate cases of normal thyroid parenchyma. All in-house cases of follicular adenomas, follicular carcinomas and adjacent normal thyroid tissue showed positive immunostaining with anti-DDIT3 and anti-STT3A. Anti-ARG2 and anti-FAM129A polyclonal antibodies showed positive staining in 20 and 60% of in-house follicular adenomas, and 40 and 87% of in-house follicular carcinomas, respectively. Monoclonal anti-FAM129A demonstrated positive staining in 13 and 33% of in-house follicular adenomas and follicular carcinomas, respectively. Polyclonal anti-DDIT3, -STT3A and -FAM129A antibodies showed positive staining in all tissue microarray slides of follicular carcinoma and in 76, 85 and 81% of the follicular adenomas, respectively. Monoclonal anti-STT3A stained 81% of the follicular adenoma cores. Anti-ARG2 stained positive in 13% of follicular carcinomas and 10% of follicular adenomas on the tissue microarray slides. In conclusion, DDIT3, STT3A, ARG2 and FAM129A immunohistochemistry does not appear to be useful in the diagnosis of thyroid follicular neoplasias, as they do not reliably distinguish follicular thyroid carcinoma from follicular thyroid adenoma.

The RET p.G533C mutation confers predisposition to multiple endocrine neoplasia type 2A in a Brazilian kindred and is able to induce a malignant phenotype in vitro and in vivo

BACKGROUND

We have previously described a p.G533C substitution in the rearranged during transfection (RET) oncogene in a large family with medullary thyroid carcinoma. Here, we explore the functional transforming potential of RET p.G533C mutation.

METHODS

Plasmids expressing RET mutants (p.G533C and p.C634Y) and RET wild type were stable transfected into a rat thyroid cell line (PCCL3). Biological and biochemical effects of RET p.G533C were investigated both in vitro and in vivo. Moreover, we report the first case of pheochromocytoma among the RET p.G533C-carriers in this Brazilian family and explore the RET mutational status in DNA isolated from pheochromocytoma.

RESULTS

Ectopic expression of RET p.G533C and p.C634Y activates RET/MAPK/ERK pathway at similar levels and significantly increased cell proliferation, compared with RET wild type. We additionally show that p.G533C increased cell viability, anchorage-independent growth, and micronuclei formation while reducing apoptosis, hallmarks of the malignant phenotype. RET p.G533C down-regulates the expression of thyroid specific genes in PCCL3. Moreover, RET p.G533C-expressing cells were able to induce liver metastasis in nude mice. Finally, we described two novel RET variants (G548V and S556T) in the DNA isolated from pheochromocytoma while they were absent in the DNA isolated from blood.

CONCLUSIONS

Our in vitro and in vivo analysis indicates that this mutation confers a malignant phenotype to PCCL3 cells. These findings, in association with the report of first case of pheochromocytoma in the Brazilian kindred, suggest that this noncysteine mutation may be more aggressive than was initially considered.

Oncocytic mania: a review of oncocytic lesions throughout the body

Oncocytic lesions are characterized pathologically by an abundance of oncocytes, that is by enlarged, eosinophilic, and finely granular cells enriched in mitochondria. They can arise in numerous organs and tissues, often in endocrine glands, and have been associated with hyperplasia, autoimmunity, and neoplasia. The causes and mechanisms that transform a normal cell into an oncocyte remain to be elucidated. Aim of this article is to review the most common oncocytic lesions, highlighting their key pathological features and clinical significance.