S100A4 expression is associated with lymph node metastasis in papillary microcarcinoma of the thyroid

Single Cell RNA Sequencing of Papillary Cancer Mesenchymal Stem/Stromal Cells Reveals a Transcriptional Profile That Supports a Role for These Cells in Cancer Progression

Papillary thyroid cancer (PTC) contains mesenchymal stem/stromal cells (MSCs), but their contribution to PTC progression is not clear. In this study, we compared the transcriptional signatures of normal thyroid (NT) and PTC-derived MSCs with the aim of determining if these have distinct transcriptomes that might influence PTC progression. We used flow cytometry in combination with a panel of MSC clusters of differentiation (CD) markers and showed that both thyroid MSC populations expressed MSC markers and lacked expression of markers not normally expressed by MSCs. In addition, we determined that both MSC populations could differentiate to adipocytes and osteocytes. Analysis of single cell RNA sequencing data from both MSC populations revealed, regardless of tissue of origin, that both contained similar numbers of subpopulations. Cluster analysis revealed similarity in expression of both MSC populations for stromal markers, the vascular marker VEGFA and the smooth muscle marker CALD1, while smaller subpopulations expressed markers of more lineage-committed thyroid cells. PTC MSCs also showed upregulated expression of 28 genes, many of which are known to be involved in epithelial-mesenchymal transition (EMT) and/or disease progression in several types of cancers, including but not limited to breast cancer, gastric cancer, cervical carcinoma, bladder cancer and thyroid cancer. This included several members of the S100 and IGFBP gene families. Taken together, these data support a role for PTC MSCs in PTC progression.

S100A4-dependent glycolysis promotes lymphatic vessel sprouting in tumor

Tumor-induced lymphangiogenesis promotes the formation of new lymphatic vessels, contributing to lymph nodes (LNs) metastasis of tumor cells in both mice and humans. Vessel sprouting appears to be a critical step in this process. However, how lymphatic vessels sprout during tumor lymphangiogenesis is not well-established. Here, we report that S100A4 expressed in lymphatic endothelial cells (LECs) promotes lymphatic vessel sprouting in a growing tumor by regulating glycolysis. In mice, the loss of S100A4 in a whole body (S100A4^-/-), or specifically in LECs (S100A4^ΔLYVE1) leads to impaired tumor lymphangiogenesis and disrupted metastasis of tumor cells to sentinel LNs. Using a 3D spheroid sprouting assay, we found that S100A4 in LECs was required for the lymphatic vessel sprouting. Further investigations revealed that S100A4 was essential for the position and motility of tip cells, where it activated AMPK-dependent glycolysis during lymphatic sprouting. In addition, the expression of S100A4 in LECs was upregulated under hypoxic conditions. These results suggest that S100A4 is a novel regulator of tumor-induced lymphangiogenesis. Targeting S100A4 in LECs may be a potential therapeutic strategy for lymphatic tumor metastasis.

Association of BRAFV600E Mutation with the Aggressive Behavior of Papillary Thyroid Microcarcinoma: A Meta-Analysis of 33 Studies

An association between the BRAF^V600E mutation and the clinicopathological progression of papillary thyroid microcarcinoma (PTMC) has been suggested. We aimed to summarize the relevant literature and determine the predictive value of BRAF^V600E mutation in predicting clinical outcomes and risk stratification in patients with PTMC. A systematic search using PubMed, Cochrane, and Embase up to February 2020 was performed. A total of 33 studies met the inclusion criteria, resulting in a pool of 8838 patients, of whom 5043 (57.1%) patients were positive for BRAF^V600E mutation. Tumors with positive BRAF^V600E mutation had a higher tendency for multifocality (RR = 1.09, 95%CI = 1.03-1.16), extrathyroidal extension (RR = 1.79, 95%CI = 1.37-2.32), and lymph node metastasis (RR = 1.43, 95%CI = 1.19-1.71). Patients with BRAF^V600E mutation were at increased risk of disease recurrence (RR = 1.90, 95%CI = 1.43-2.53). PTMC in patients positive for the BRAF^V600E mutation is more aggressive than wild-type BRAF PTMC. Since BRAF-mutated PTMC is generally more resistant to radioiodine treatment, patients with BRAF^V600E-mutated PTMC may require earlier management, such as a minimally invasive ablative intervention. Conservative management by active surveillance may be suitable for patients with wild-type BRAF^V600E PTMC.

BRAF Status in Papillary Microcarcinomas of the Thyroid Gland: a Brief Review

Papillary thyroid microcarcinoma (PTMC) is defined by the World Health Organization as papillary cancer measuring 10 mm or less in diameter. Generally, PTMC shows an indolent clinical behavior with a good prognosis, although a minority of PTMC is characterized by an aggressive course. However, efforts to identify this aggressive subset of PTMC after surgery remain inconclusive. Several oncogenic pathways have been identified in thyroid cancer and have been applied translationally to improve prognosis and clinical management. In particular, the BRAFV600E mutation was found more frequently in large, aggressive, recurrent and advanced tumors. We aimed at reviewing studies on BRAFV600E mutation as a prognostic factor in PTMC.

Effect of shRNA-mediated regulation of S100A4 gene expression on proliferation and apoptosis of KLE endometrial cancer cells

PURPOSE

To investigate the effect of shRNA-regulated S100A4 expression on the proliferation and apoptosis in KLE endometrial cancer cells.

METHODS

S100A4-OVER and S100A4-shRNA were transfected into KLE endometrial cancer cells using lentiviral sh-RNA technology. Passive OVER-NC cell line and shRNA-NC cell line were used as a negative control group and non-transfected Control cell line as a blank control group. After 48 h of transfection, the expressions of S100A4 and protein were detected by real-time fluorescence quantitative PCR and Western blotting, respectively. CCK-8 detection and flow cytometer were used to detect cell proliferation and apoptosis, respectively.

RESULTS

Compared with the normal control group and the negative control group, the transfection efficiency and shRNA targeting of the shRNA-interfered S100A4 gene were verified at the levels of mRNA and protein expression. The expression of the disrupted S100A4 gene at S100A4 mRNA and protein levels in endometrial cancer cells was determined. The proliferation efficiency of KLE cells in S100A4-OVER group was significantly higher than that in other four groups; the proliferation rate of S100A4-shRNA cells decreased slightly;, the apoptotic rate of KLE cells in S100A4-shRNA group increased significantly, and the apoptotic rate of KLE cells in S100A4-OVER group decreased compared with NC group.

CONCLUSION

Specific regulation of S100A4 gene expression:, the enhanced expression of the S100A4 gene may promote the proliferation of KLE endometrial cancer cells; the inhibited expression of the S100A4 gene may promote the apoptosis of KLE endometrial cancer cells. S100A4 expression is closely related to the biological characteristics of endometrial cancer.

A meta-analysis evaluating the relationship between B-type Raf kinase mutation and cervical lymphatic metastasis in papillary thyroid cancer

BACKGROUND

B-type Raf kinase (BRAF) mutation is proved to be a critical predictive factor in papillary thyroid cancer (PTC) with aggressive characteristics. However, the association between BRAF mutation and cervical lymphatic metastasis in PTC is controversial.

METHODS

We searched papers on the study of BRAF mutation and cervical lymphatic metastasis in PTC patients through PubMed, Web of Science, Embase, and Cochranelibrary. The BRAF (+) cases, BRAF (-) cases, and cervical lymphphatic metastatic cases in both BRAF (+) and BRAF (-) groups were collected. After Quality assessment, statistical Analysis (funnel plot and Harbord evaluation, Random-effect model, heterogeneity, subgroup analysis, sensitivity analysis, and metacum analysis) were done by the Review Manager (RevMan) 5.3 and stata14 statistical software.

RESULTS

There were 78 cross-section studies which met our inclusion criteria. And all of them had no selection bias, publication bias, or any other bias. A significant association existed between BRAF mutation and cervical lymph node metastasis (LNM) (odds ratio [OR] = 1.63; 95% confidence interval [CI]: 1.44-1.84; P < .05). Overall, 46 studies were conducted among East Asians. Twenty four articles had provided the data of central lymph node metastasis (CLNM), 11 articles with the data of lateral lymph node metastasis (LLNM), and classic/conventional PTC (CPTC) was analyzed in 10 studies. Subgroup analyses were performed based on ethnicity, metastatic site, and subtype of PTC. Significant association between BRAF (+) mutation and cervical LNM were indicated in East Asians (OR = 1.73; 95% CI: 1.49-2.02; P < .05), in non-East Asians (OR = 1.57; 95% CI: 1.26-1.96; P < .05), and in CLNM (OR = 1.80; 95% CI: 1.56-2.07; P < .05). While no significant association was found in LLNM (OR = 1.37; 95% CI: 0.76-2.48; P = .29 > .05) and in CPTC (OR = 1.32; 95% CI: 0.97-1.80; P = .08 > .05). We did not find any other major changes when sensitivity analysis was performed. The metacum analysis showed no significant association existed before 2012. While a significant association began to exist between BRAF mutation and LNM from 2012, and this association became stable from 2017.

CONCLUSIONS

We consider that a significant association exists between BRAF mutation and cervical LNM. Further meta-analysis on subgroup may reveal some valuable factors between BRAF gene mutation and LNM. And we do not recommend that BRAF (+) as the biomarker for LNM in PTC.

Genomic and Transcriptomic Characterization of Papillary Microcarcinomas With Lateral Neck Lymph Node Metastases

CONTEXT

Most papillary microcarcinomas (PMCs) are indolent and subclinical. However, as many as 10% can present with clinically significant nodal metastases.

OBJECTIVE AND DESIGN

Characterization of the genomic and transcriptomic landscape of PMCs presenting with or without clinically important lymph node metastases.

SUBJECTS AND SAMPLES

Formalin-fixed paraffin-embedded PMC samples from 40 patients with lateral neck nodal metastases (pN1b) and 71 patients with PMC with documented absence of nodal disease (pN0).

OUTCOME MEASURES

To interrogate DNA alterations in 410 genes commonly mutated in cancer and test for differential gene expression using a custom NanoString panel of 248 genes selected primarily based on their association with tumor size and nodal disease in the papillary thyroid cancer TCGA project.

RESULTS

The genomic landscapes of PMC with or without pN1b were similar. Mutations in TERT promoter (3%) and TP53 (1%) were exclusive to N1b cases. Transcriptomic analysis revealed differential expression of 43 genes in PMCs with pN1b compared with pN0. A random forest machine learning-based molecular classifier developed to predict regional lymph node metastasis demonstrated a negative predictive value of 0.98 and a positive predictive value of 0.72 at a prevalence of 10% pN1b disease.

CONCLUSIONS

The genomic landscape of tumors with pN1b and pN0 disease was similar, whereas 43 genes selected primarily by mining the TCGA RNAseq data were differentially expressed. This bioinformatics-driven approach to the development of a custom transcriptomic assay provides a basis for a molecular classifier for pN1b risk stratification in PMC.

Mts1 Up-regulation is Associated With Aggressive Pathological Features in Thyroid Cancer

BACKGROUND/AIM

Thyroid cancer is the most common type of endocrine cancer and its incidence and mortality are increasing. However, few studies on the molecular factors related to its poor prognosis have been performed. The aim of our study was to identify a poor prognostic factor for thyroid cancer to reduce its overtreatment, recurrence, and mortality.

MATERIALS AND METHODS

The present study is a retrospective study of 55 patients who were diagnosed with papillary thyroid cancer and operated in Korea from September 2013 to November 2015.

RESULTS

Mts1 is a member of the S100 protein family and is involved in tumor progression and metastasis. Mts1 was highly expressed in patients with thyroid cancer and high Mts1 levels were related to poor prognoses such as lymph node metastasis.

CONCLUSION

Mts1 is associated with aggressive pathological features in thyroid cancer, and may be a poor prognostic factor for thyroid cancer.

Clinical effect of MUC1 and its relevance to BRAF V600E mutation in papillary thyroid carcinoma: a case-control study

AIM

To investigate the clinical effects of MUC1 on papillary thyroid cancer (PTC) and explore the relationship between MUC1 expression and BRAF mutation.

METHODS

The data of 69 patients subjected to fine-needle aspiration biopsy in our hospital and 486 patient data downloaded from The Cancer Genome Atlas (TCGA) database were used. Univariate and multivariate analyses were performed.

RESULTS

The results on the 486 patients recorded in the TCGA indicated that high MUC1 expression was independently related to BRAF mutation, lymph node metastasis (LNM), and unifocal type. In the 69 fine-needle aspiration biopsy patients with PTC, high MUC1 expression was significantly related to LNM and extrathyroid extension (ETE). The result of Pearson's correlation coefficient showed that BRAF mutation and MUC1 expression were moderately correlated. Moreover, in the subgroup with low MUC1 expression, the patients with BRAF mutation had higher ETE frequency and LNM than those without BRAF mutation. In the subgroup with BRAF mutation, patients with high MUC1 expression exhibited higher ETE frequency than those with low MUC1 expression, and high MUC1 expression occurred in older patients. In the subgroup with BRAF wild-type mutation, patients with high MUC1 expression had a higher incidence of ETE and LNM than those with low expression.

CONCLUSION

We demonstrated that the MUC1 is an important oncogene in PTC and may have great significance on therapeutic cancer vaccine development.

Circulating tumor cells in thyroid carcinoma - the prognostic role of this biomarker. Review of the literature

Thyroid cancer is a disease with a good prognosis and high survival rates, but having a marked growth of incidence all over the world in the last years. This fact requires special attention of researchers for understanding the behavior of this disease and to establish a correct therapy. Analysis of circulating tumor cells in patients with different malignancies is nowadays a new and exciting research tool, which can improve the diagnosis and prevent the metastatic disease. In the case of thyroid carcinoma there are few studies which explore these biomarkers and investigate the prognostic significance of circulating tumor cells. With this review we seek to emphasize the role of these cells to better understand the mechanisms of invasion or metastasis and to establish a new research base to treat aggressive forms of this type of cancer. Most of the included studies demonstrate the efficacy of these markers for diagnosis and follow up.

Clinicopathological significance of loss of p27kip1 expression in papillary thyroid carcinoma

INTRODUCTION

A meta-analysis was done to investigate the clinicopathological significance of the loss of p27kip1 expression in papillary thyroid carcinoma (PTC).

METHODS

The meta-analysis involving 17 studies included 1,652 PTC and 328 benign cases. The rate of p27kip1 expression loss in PTC and benign lesions, and the correlations between p27kip1 expression loss and clinicopathological characteristics of PTC were determined.

RESULTS

The estimated rate of p27kip1 expression loss was 0.557 (95% confidence interval [CI] 0.443-0.665) and 0.139 (95% CI 0.062-0.283) in PTC and benign lesions, respectively. In subgroup analysis, the rates of p27kip1 expression loss were 0.683, 0.393, and 0.414 in the classical variant, follicular variant, and papillary thyroid microcarcinoma, respectively. Loss of p27kip1 expression was significantly correlated with lymph node metastasis and distant metastasis (odds ratio 3.559, 95% CI 1.146-11.056 and 4.735, 95% CI 1.322-16.960, respectively). Extrathyroidal extension was correlated with loss of p27kip1 expression, but not in a statistically significant way (p = 0.051). There were no significant correlations between loss of p27kip1 expression and sex, tumor size, BRAFV600E mutation, and tumor multifocality.

CONCLUSIONS

Loss of p27kip1 expression is frequently found in PTC compared with benign lesions and normal thyroid tissue. When present in PTC, it is correlated with aggressive tumor behavior.

The Genetics of Papillary Microcarcinomas of the Thyroid: Diagnostic and Prognostic Implications

Papillary microcarcinoma of the thyroid (mPTC) is defined by the WHO as a papillary thy-roid cancer measuring 10mm or less in diameter and it is nowadays a topic of intense debate among the members of the medical community due to its apparent “epidemic” rise. Although these tumors follow almost always an indolent clinical course and carry an excellent prognosis, it is known that a small sub-set may display a potentially aggressive behavior. Nevertheless, we still lack an accurate way of predict-ing those which will cause significant disease. In an attempt to address this problem, a number of clini-co-pathologic features have been studied as poor prognostic markers in mPTC, and their association with known genetic alterations in thyroid cancer has been evaluated. Herein we review the present knowledge concerning mPTC’s genetic profile, namely the prevalence of BRAF (V600E), RAS and TERT promoter mutations and RET/PTC and PAX8-PPARG rearrangements and report the results of the evaluation in the putative prognostic value of these genetic alterations in mPTC.

Knockdown of S100A4 blocks growth and metastasis of anaplastic thyroid cancer cells in vitro and in vivo

Anaplastic thyroid cancer (ATC) is a locally aggressive type of thyroid tumor with high rate of distant metastases. It is often incurable because it does not respond to radioiodine, radiotherapy, or chemotherapy. With conventional treatment, the median survival is about 6 months; therefore, new treatment options are needed. S100A4 is a calcium-binding protein related to the metastatic potential of carcinoma. Previous study has found S100A4 was overexpressed in human papillary thyroid carcinomas (PTC) tissues, and overexpression of S100A4 is associated with thyroid tumour invasion and metastasis. In the present study, we first examined S100A4 protein expression in 14 ATC tissues, 20 PTC tissues and 14 normal thyroid tissue by immunohistochemistry analysis. We then knocked down of S100A4 expression by RNA interference (S100A4 siRNA) and investigated its effects on growth and metastasis in two human ATC cell lines 8505C (BRAFV600E) and Cal-62 (BRAFwt) in vitro and in vivo. S100A4 and BRAFV600E protein expression was evaluated by western blot assay and immunohistochemistry analysis. Using immunohistochemistry, we found that high levels of S100A4 were detected in ATC specimens and PTC specimens. No S100A4 staining was observed in normal thyroid tissues. S100A4 siRNA significantly decreased proliferation and increased apoptosis, and inhibited the invasive potential of the two cells in vitro. In addition, S100A4 siRNA could effectively inhibit BRAFV600E expression in the 8505C cells, and treatment with 100 ng/ml human recombinant BRAF V600E in S100A4 siRNA/8505C cells could partly restore its proliferative and invasive ability. Results of implantation in vivo showed S100A4 shRNA could significantly inhibit abdominal cavity metastasis and tumor growth in vivo. Furthermore, knockdown of S100A4 has significant role on invasion, metastasis and growth inhibition in the 8505C cells than that of in the Cal-62 cells. These results support the hypothesis that S100A4 contributes significantly to growth and metastasis, and that down-regulation of S100A4 expression decreases the metastatic potential of ATC cells. Furthermore, down-regulation of S100A4 expression is more marked in BRAFV600E cells than that of in the BRAFwt cells.

Prognostic Significance of TERT Promoter Mutations in Papillary Thyroid Carcinomas in a BRAF(V600E) Mutation-Prevalent Population

BACKGROUND

The role of telomerase reverse transcriptase (TERT) promoter mutations in differentiated thyroid cancer has been well established. These mutations have a significantly higher prevalence in aggressive thyroid tumors, including widely invasive oncocytic carcinomas, poorly differentiated carcinomas, and anaplastic thyroid carcinomas. Interestingly, in some studies, TERT mutations were found to be more common in tumors with a BRAF(V600E) mutation. However, mutational analysis of TERT promoter mutations in thyroid tumors has not been previously performed for patients in Korea, where the BRAF(V600E) mutation in papillary thyroid carcinoma (PTC) is particularly prevalent. This study analyzed TERT promoter mutations in various thyroid tumors and examined their relationship with clinicopathologic factors and the BRAF(V600E) mutation in PTC cases.

METHODS

Using 242 preoperative fine-needle aspiration biopsy specimens (including 207 PTCs) with confirmed histopathological diagnosis of the biopsied thyroid nodules, the TERT promoter status (C228T and C250T) was analyzed, and the relationship with clinicopathologic factors and the BRAF(V600E) mutation in PTC cases was examined.

RESULTS

Of 242 patients, 14.5% (30/207), 26.7% (4/15), 50% (1/2), and 60% (2/5) of PTCs, follicular thyroid carcinomas, poorly differentiated carcinomas, and anaplastic thyroid carcinomas harbored a TERT(C228T) mutation, respectively. The TERT(C228T) mutation was associated with recurrence (p = 0.03). However, no association with other clinicopathologic factors in PTC was found. Coexistence of TERT(C228T) and BRAF(V600E) mutations was found in 13.0% of PTCs and was significantly associated with older age and advanced stage compared with the group negative for either mutation. The TERT(C228T) mutation status was an independent prognostic factor for recurrence-free survival (hazard ratio = 3.08 [confidence interval 1.042-9.079]; p = 0.042) in patients with PTC in multivariate analysis.

CONCLUSIONS

Identification of TERT promoter mutations in preoperative fine-needle aspiration biopsy specimens may help in better characterizing the prognosis and triaging thyroid cancer patients for appropriate treatment.

BRAF(V⁶⁰⁰E) mutation and its association with clinicopathological features of papillary thyroid microcarcinoma: A meta-analysis

Recent studies have demonstrated that the BRAF(V600E) mutation is associated with aggressive clinicopathological features of papillary thyroid carcinoma (PTC). However, the BRAF mutation as a prognostic biomarker in papillary thyroid microcarcinoma (PTMC) is unclear. A systematic search of the electronic databases, including Medline, Scopus, CNKI and the Cochrane Library was performed up to July 1, 2014. Outcomes of interest included age, gender, concomitant hashimoto thyroiditis or nodular goiter, tumor size, pathological stage, tall cell variant of PTMC (TCVPTMC), multifocality, extrathyroidal extension (ETE) and lymph node metastasis (LNM). A total of 19 studies published from 2008 to 2014 comprising 2253 patients fulfilled the inclusion criteria and were included in the meta-analysis, and 1143 (50.7%) of these patients were BRAF mutation positive. BRAF mutation was associated with larger tumor size (OR: 1.64; 95% CI: 1.16-2.32), multifocality (OR: 1.58; 95% CI: 1.25-2.00), ETE (OR: 2.59; 95% CI: 2.03-3.29), LNM (OR: 1.73; 95% CI: 1.14-2.62), advanced stage (OR: 2.03; 95% CI: 1.14-3.64) and TCVPTMC (OR: 5.07; 95% CI: 1.49-17.27; P=0.009). Additionally, the BRAF mutation was found to be not associated with age, gender, concomitant hashimoto thyroiditis or nodular goiter (P>0.05 for all). This meta-analysis revealed that in patients with PTMC, BRAF mutation is associated with tumor size, multifocality, ETE, LNM, advanced stage and TCVPTMC, and it may be used as a predictive factor for prognosis of PTMC.

Knockdown of ILK inhibits glioma development via upregulation of E-cadherin and downregulation of cyclin D1

Integrin-linked kinase (ILK) is a highly conserved serine-threonine protein kinase that interacts with cytoplasmic domains of integrin subunits in tumor tissues. However, the relationship between gliomas and ILK is elusive. The present study aimed to investigate the role of ILK in a human glioma cell line (U251). ILK stable expressing vector, U251ILK-PGFP-V-RS-shRNA, was established and named as U251-si. The empty-PGFP-V-RS-shRNA (U251-N) was employed as the control. Quantitative real-time PCR and western blot analysis were used to detect ILK and E-cadherin mRNA and protein expression, respectively. Cell cycle analysis was employed to examine the cell cycle distribution. Cell migration was detected using a wound healing assay, and cell invasion was detected using a Transwell invasion assay. Tumor size and weight were also examined. The results indicated that ILK was expressed at a lower level at both the mRNA and protein levels in the U251-si group compared with the U251-N group (p<0.01). ILK knockdown suppressed cell proliferation of the glioma cells. Knockdown of ILK reduced the migratory and invasive potentials of the glioma cells. Inhibition of ILK expression upregulated E-cadherin and downregulated cyclin D1 in the glioma cells compared to the U251-N group (p<0.05). Knockdown of ILK in the U251 cells attenuated the ability of U251 cells to form tumors in nude mice and impaired glioma cell in vivo tumorigenicity. In conclusion, knockdown of ILK inhibits glioma cell migration, invasion and proliferation through upregulation of E-cadherin and downregulation of cyclin D1. Our results suggest that ILK may serve as a promising therapeutic target for glioma.

RAGE Mediates the Pro-Migratory Response of Extracellular S100A4 in Human Thyroid Cancer Cells

BACKGROUND

Expression of the small calcium-binding protein S100A4 is associated with poor prognosis in patients with thyroid cancer (TC). The authors have previously shown that S100A4 is a target for relaxin and insulin-like peptide 3 signaling in TC cells and that S100A4 is secreted from human TC cells. Although the pro-migratory role of intracellular S100A4 in binding to non-muscle myosin is well known, this study investigated here whether extracellular S100A4 contributes to TC migration.

METHODS

Human cell lines of follicular, papillary, and undifferentiated thyroid cancer, primary patient TC cells, and TC tissues were utilized to discover the presence of the receptor of advanced glycation end products (RAGE) in TC cells and TC tissues. Fluorescence imaging, protein pull-down assays, Western blot, siRNA protein silencing, small GTPase inhibitors, cell proliferation, and cell migration assays were used to investigate the interaction of extracellular S100A4 with RAGE in promoting a TC migratory response.

RESULTS

It was demonstrated that RAGE served as receptor for extracellular S100A4 mediating cell migration in TC cells. The RAGE-mediated increase in cell migration was dependent on the intracellular RAGE signaling partner diaphanous-1 (Dia-1) and involved the activation of the small GTPases Cdc42 and RhoA. Although extracellular S100A4 consistently activated ERK signaling in TC cells, it was shown that ERK signaling was not mediated by RAGE and not essential for the migratory response in TC cells.

CONCLUSION

The data have identified the RAGE/Dia-1 signaling system as a mediator for the pro-migratory response of extracellular S100A4 in human TC. Thus, therapeutic targeting of the RAGE/Dia-1/small GTPases signaling may successfully reduce local invasion and metastasis in TC.

BRAFV600E mutation in papillary thyroid microcarcinoma: a meta-analysis

The prognostic value of the BRAFV600E mutation, resulting in poor clinical outcomes of papillary thyroid carcinoma, has been generally confirmed. However, the association of BRAFV600E with aggressive clinical behaviors of papillary thyroid microcarcinoma (PTMC) has not been firmly established in individual studies. We performed this meta-analysis to examine the relationship between BRAFV600E mutation and the clinicopathological features of PTMC. We conducted a systematic search in PubMed, EMBASE, and the Cochrane library for relevant studies. We selected all the studies that reported clinicopathological features of PTMC patients with information available on BRAFV600E mutation status. Nineteen studies involving a total of 3437 patients met these selection criteria and were included in the analyses. The average prevalence of the BRAFV600E mutation was 47.48%, with no significant difference with respect to patient sex (male versus female) and age (younger than 45 years versus 45 years or older). Compared with the WT BRAF gene, the BRAFV600E mutation was associated with tumor multifocality (odds ratio (OR) 1.38; 95% CI, 1.04-1.82), extrathyroidal extension (OR 3.09; 95% CI, 2.24-4.26), lymph node metastases (OR 2.43; 95% CI, 1.28-4.60), and advanced stage (OR 2.39; 95% CI, 1.38-4.15) of PTMC. Thus, our findings from this large meta-analysis definitively demonstrate that BRAFV600E-mutation-positive PTMC are more likely to manifest with aggressive clinicopathological characteristics. In appropriate clinical settings, testing for the BRAFV600E mutation is likely to be useful in assisting the risk stratification and management of PTMC.

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

BACKGROUND

The BRAF(V600E) mutation is the most common genetic alteration in papillary thyroid carcinoma (PTC). The aim of this study is to analyze the clinicopathologic correlations of the BRAF(V600E) mutation, BRAF V600E immunohistochemistry (IHC) and BRAF RNA in situ hybridization (ISH) in PTC.

METHODS

This study included 467 patients with PTC who underwent surgical resection. We studied the BRAF(V600E) mutation using real-time PCR and BRAF V600E and BRAF RNA ISH using tissue microarray (TMA).

RESULTS

The frequencies of a positive BRAF(V600E) mutation by real-time PCR, positive BRAF V600E IHC, and high BRAF RNA ISH were 84%, 86%, and 70%, respectively, in PTC. Conventional PTC had higher positive rates in all three tests than other histologic types. The BRAF(V600E) mutation, BRAF V600E IHC, low ΔCt, and high BRAF RNA ISH were significantly associated with lymph node metastasis. The BRAF(V600E) mutation was significantly associated with positive immunostaining for BRAF V600E mutant protein (P<0.001) overall, with high BRAF RNA ISH only in the follicular variant (P=0.035). No significant correlation was noted between BRAF V600E IHC and BRAF RNA ISH. The sensitivity of BRAF V600E IHC for the BRAF(V600E) mutation was 95%, and the specificity was 61% overall, 96% and 54% in the conventional type, and 85% and 70% in the follicular variant.

CONCLUSIONS

Our results showed that positive BRAF V600E IHC significantly correlated with the BRAF(V600E) mutation. This suggests its clinical utility as a screening tool for the BRAF(V600E) mutation. In addition, a high BRAF RNA ISH score could be a candidate marker of aggressive behavior in BRAF(V600E) mutation-positive cases of PTC.

MUC1 expression in papillary thyroid carcinoma is associated with BRAF mutation and lymph node metastasis; the latter is the most important risk factor of relapse

BACKGROUND

The incidence of papillary thyroid carcinoma (PTC) has increased over the past 30 years in Western countries. PTC is usually associated with a good prognosis, but there is a wide range of aggressiveness, and some patients develop distant metastasis and/or resistance to standard treatment. Early identification of these high-risk tumors is a current challenge for appropriate patient management. MUC1 expression has been studied previously in thyroid cancer, but its prognostic value remains controversial. Here, we correlated MUC1 expression in PTC with clinical and pathological features and with the presence of the BRAF(V600E) mutation.

METHODS

We performed a clinical and morphological analysis of 190 thyroid tumors (95 PTCs and 95 adenomas). MUC1 immunohistochemistry was carried out on a tissue microarray using different antibodies. The presence of the BRAF(V600E) mutation was investigated by pyrosequencing. MUC1 mRNA levels were assessed by quantitative reverse transcription polymerase chain reaction on a subset of PTC.

RESULTS

MUC1 expression was observed in 49% of PTCs and was found to correlate with the presence of papillary architecture, a stromal lymphoid infiltrate, aggressive histological subtypes, extrathyroidal extension, lymph node metastasis, nuclear pseudoinclusions, lymphovascular invasion, and the presence of the BRAF(V600E) mutation (p<0.0001). MUC1 was abundant in nuclear pseudoinclusions. Multivariate analysis showed a strong association of MUC1 expression with the presence of the BRAF(V600E) mutation and lymph node metastasis (p<0.0001). Lymph node metastasis was the most important risk factor of relapse.

CONCLUSIONS

Our study shows an association between MUC1 expression and the presence of the BRAF(V600E) mutation in PTC. Analysis of MUC1 expression could improve the risk stratification of PTCs.

Clinical outcome in differentiated thyroid carcinoma and microcarcinoma

INTRODUCTION

Due to the frequent use of neck ultrasonography, the incidence of differentiated thyroid microcarcinoma (DTMC), defined as a lesion with greatest dimension ≤1 cm, is increasing worldwide. Although DTMC generally has a lower aggressivity and a better prognosis than differentiated thyroid carcinoma (DTC), some cases of clinically aggressive DTMC were found. The aim of this study is to compare the rate of recurrence in DTMC and DTC, during a 3-year follow-up.

METHODS

Patients with differentiated thyroid carcinoma, who underwent total thyroidectomy and postoperative (131)I-RAI ablation, were stratified according to lesion diameter (DTC for diameter > 1 cm or DTMC ≤ 1 cm). After surgery, patients underwent a 3-year follow-up. Recurrent disease was defined on the basis of positive biochemical (Tg > 2 ng/ml under TSH-suppression or after rhTSH-stimulation) and/or imaging (US, WBS, CT, PET/CT) findings.

RESULTS

449 patients have been included in the final analysis. Linfoadenectomy rate and RAI ablative dose were significantly higher in DTC than in DTMC (32.7% vs. 22.4%, p = 0.018 and 112.3 ± 21 vs. 68.3 ± 24.1 mCi, p < 0.001). During the follow-up, 50 carcinoma recurrences occurred, more frequent in DTC than in DTMC (15.6% vs. 7.6%, p = 0.010). After adjustment for gender, age, rate of lymph node dissection and 131I dose of RAI treatment, the difference in the risk of recurrence was no longer significant among DTC and DTMC patients (HR: 1.585, 95% CI 0874-2877, p = 0.130).

CONCLUSIONS

The prediction of disease severity cannot be based exclusively on lesion diameter. A more careful therapeutic approach and follow-up should be recommended in DTMC patients.

Papillary thyroid microcarcinoma: how to diagnose and manage this epidemic?

The incidence of papillary thyroid microcarcinoma (PTmC) has been increasing everywhere due to the improvement of imaging and morphological diagnoses and probably also due to environmental alterations. Despite this, the mortality caused by thyroid cancer has not increased, reflecting the low clinical aggressiveness of most papillary thyroid carcinomas (PTCs) and the quality of the available treatment. The criteria used to classify PTmC remain questionable, making the clinical risk evaluation of these lesions very difficult. There is no solid basis for establishing the most appropriate tumor size (currently <10 mm) to distinguish PTmC from PTC. Moreover, PTmCs encompass all sorts of PTC histotypes, thus turning the whole group of PTmC genetically and biologically heterogeneous. In this review, we address the 2 most interesting issues from a practical standpoint: Are there any specific morphological or molecular features distinguishing PTmC from PTC? Is it possible to predict the clinical behavior of PTmC in fine needle aspiration biopsy and in surgical specimens, using morphological and/or molecular markers?

Correlation of immunohistochemical markers and BRAF mutation status with histological variants of papillary thyroid carcinoma in the Korean population

Several pathologic characteristics are associated with an adverse clinical outcome in papillary thyroid carcinoma (PTC), including the histological variant. This study aimed to investigate immunohistochemical expression and BRAF mutation status based on the histological variant and evaluated potential markers of aggressive behavior of PTC in Korean patients. In all, 407 PTC cases were classified to each histological variant, and the 94 representative cases were subjected to immunohistochemistry and BRAF mutation analysis. The classic type, follicular variant (FV) and tall cell variant (TCV) represented 76.9%, 14.2% and 6%, respectively. TCV showed a larger tumor size (P = 0.009), frequent extrathyroidal extension (P = 0.022) and cervical lymph node (LN) metastasis (P = 0.018). TCV and FV showed the reduced expression of galectin-3 (P = 0.003) and HBME1 (P = 0.114). Regardless of histology, PTEN loss and diffuse S100A4 expression were associated with LN metastasis (P = 0.007, P = 0.013). All TCVs harbored BRAF V600E mutation, and FV harbored less BRAF V600E mutation (P = 0.043). Immunohistochemical evaluation showed characteristic patterns in histological variants. PTEN and S100A4 expression are suggested as indicators of regional lymph node metastasis.

Immunohistochemical analysis based Ep-ICD subcellular localization index (ESLI) is a novel marker for metastatic papillary thyroid microcarcinoma

Background

Thyroid cancer is among the fastest growing malignancies; almost fifty-percent of these rapidly increasing incidence tumors are less than or equal to 1cm in size, termed papillary thyroid microcarcinoma (PTMC). The management of PTMC remains a controversy due to differing natural history of these patients. Epithelial cell adhesion molecule (EpCAM) is comprised of an extracellular domain (EpEx), a single transmembrane domain and an intracellular domain (Ep-ICD). Our group reported nuclear Ep-ICD correlated with poor prognosis in thyroid cancer (Ralhan et al., BMC Cancer 2010,10:331). Here in, we hypothesized nuclear and cytoplasmic accumulation of Ep-ICD and loss of membranous EpEx may aid in distinguishing metastatic from non-metastatic PTMC, which is an important current clinical challenge. To test our hypothesis, Ep-ICD and EpEx expression levels were analyzed in PTMC and the staining was correlated with metastatic potential of these carcinomas.

Methods

Thirty-six PTMC patients (tumor size 0.5 - 1cm; metastatic 8 cases and non-metastatic 28 cases) who underwent total thyroidectomy were selected. The metastatic group consisted of patients who developed lymph node or distant metastasis at diagnosis or during follow up. The patients’ tissues were stained for Ep-ICD and EpEx using domain specific antibodies by immunohistochemistry and evaluated.

Results

PTMC patients with metastasis had higher scores for nuclear and cytoplasmic Ep-ICD immunostaining than the patients without metastasis (1.96 ± 0.86 vs. 1.22 ± 0.45; p = 0.007 and 5.37 ± 0.33 vs. 4.72 ± 1.07; p = 0.016, respectively). Concomitantly, the former had lower scores for membrane EpEx than the non-metastatic group (4.64 ± 1.08 vs. 5.64 ± 1.51; p = 0.026). An index of aggressiveness, Ep-ICD subcellular localization index (ESLI), was defined as sum of the IHC scores for accumulation of nuclear and cytoplasmic Ep-ICD and loss of membranous EpEx; ESLI = [Ep − ICD_nuc + Ep − ICD_cyt + loss of membranous EpEx]. Notably, ESLI correlated significantly with lymph node metastasis in PTMC (p = 0.008).

Conclusion

Nuclear and cytoplasmic Ep-ICD expression and loss of membranous EpEx were found to correlate positively with metastasis in PTMC patients. In addition, ESLI had the potential to identify metastatic behavior in PTMC which could serve as a valuable tool for solving a current dilemma in clinical practice.

American Thyroid Association consensus review and statement regarding the anatomy, terminology, and rationale for lateral neck dissection in differentiated thyroid cancer

BACKGROUND

Cervical lymph node metastases from differentiated thyroid cancer (DTC) are common. Thirty to eighty percent of patients with papillary thyroid cancer harbor lymph node metastases, with the central neck being the most common compartment involved. The goals of this study were to: (1) identify appropriate methods for determining metastatic DTC in the lateral neck and (2) address the extent of lymph node dissection for the lateral neck necessary to control nodal disease balanced against known risks of surgery.

METHODS

A literature review followed by formulation of a consensus statement was performed.

RESULTS

Four proposals regarding management of the lateral neck are made for consideration by organizations developing management guidelines for patients with thyroid nodules and DTC including the next iteration of management guidelines developed by the American Thyroid Association (ATA). Metastases to lateral neck nodes must be considered in the evaluation of the newly diagnosed thyroid cancer patient and for surveillance of the previously treated DTC patient.

CONCLUSIONS

Lateral neck lymph nodes are a significant consideration in the surgical management of patients with DTC. When current guidelines formulated by the ATA and by other international medical societies are followed, initial evaluation of the DTC patient with ultrasound (or other modalities when indicated) will help to identify lateral neck lymph nodes of concern. These findings should be addressed using fine-needle aspiration biopsy. A comprehensive neck dissection of at least nodal levels IIa, III, IV, and Vb should be performed when indicated to optimize disease control.

Genome-wide analysis of Pax8 binding provides new insights into thyroid functions

Background

The transcription factor Pax8 is essential for the differentiation of thyroid cells. However, there are few data on genes transcriptionally regulated by Pax8 other than thyroid-related genes. To better understand the role of Pax8 in the biology of thyroid cells, we obtained transcriptional profiles of Pax8-silenced PCCl3 thyroid cells using whole genome expression arrays and integrated these signals with global cis-regulatory sequencing studies performed by ChIP-Seq analysis

Results

Exhaustive analysis of Pax8 immunoprecipitated peaks demonstrated preferential binding to intragenic regions and CpG-enriched islands, which suggests a role of Pax8 in transcriptional regulation of orphan CpG regions. In addition, ChIP-Seq allowed us to identify Pax8 partners, including proteins involved in tertiary DNA structure (CTCF) and chromatin remodeling (Sp1), and these direct transcriptional interactions were confirmed in vivo. Moreover, both factors modulate Pax8-dependent transcriptional activation of the sodium iodide symporter (Nis) gene promoter. We ultimately combined putative and novel Pax8 binding sites with actual target gene expression regulation to define Pax8-dependent genes. Functional classification suggests that Pax8-regulated genes may be directly involved in important processes of thyroid cell function such as cell proliferation and differentiation, apoptosis, cell polarity, motion and adhesion, and a plethora of DNA/protein-related processes.

Conclusion

Our study provides novel insights into the role of Pax8 in thyroid biology, exerted through transcriptional regulation of important genes involved in critical thyrocyte processes. In addition, we found new transcriptional partners of Pax8, which functionally cooperate with Pax8 in the regulation of thyroid gene transcription. Besides, our data demonstrate preferential location of Pax8 in non-promoter CpG regions. These data point to an orphan CpG island-mediated mechanism that represents a novel role of Pax8 in the transcriptional output of the thyrocyte.

Clinical outcome, role of BRAF(V600E), and molecular pathways in papillary thyroid microcarcinoma: is it an indolent cancer or an early stage of papillary thyroid cancer?

Most human thyroid cancers are differentiated papillary carcinomas (PTC). Papillary thyroid microcarcinomas (PTMC) are tumors that measure 1 cm or less. This class of small tumors has proven to be a very common clinical entity in endocrine diseases. PTMC may be present in 30-40% of human autopsies and is often identified incidentally in a thyroid removed for benign clinical nodules. Although PTMC usually has an excellent long-term prognosis, it can metastasize to neck lymph nodes; however deaths related to this type of thyroid tumor are very rare. Few data exist on molecular pathways that play a role in PTMC development; however, two molecules have been shown to be associated with aggressive PTMC. S100A4 (calcium-binding protein), which plays a role in angiogenesis, extracellular matrix remodeling, and tumor microenvironment, is over-expressed in metastatic PTMC. In addition, the BRAF(V600E) mutation, the most common genetic alteration in PTC, is present in many PTMC with extra thyroidal extension and lymph node metastasis. Importantly, recently developed selective [e.g., PLX4720, PLX4032 (Vemurafenib, also called RG7204)] or non-selective (e.g., Sorafenib) inhibitors of BRAF(V600E) may be an effective treatment for patients with BRAF(V600E)-expressing PTMCs with aggressive clinical-pathologic features. Here, we summarize the clinical outcome, cancer genetics, and molecular mechanisms of PTMC.

Src kinase pathway is involved in NFAT5-mediated S100A4 induction by hyperosmotic stress in colon cancer cells

S100A4 is associated with the progression of many types of cancers as well as several nonmalignant conditions. However, how it is regulated by intracellular signaling and/or at the transcriptional level has not been extensively studied. We recently demonstrated that S100A4 is partially regulated by nuclear factor in activated T cell 5 (NFAT5) downstream of integrin α6β4. NFAT5 is a mammalian osmotic regulator. To study the regulation of S100A4 by NFAT5 in a more readily inducible model, colon cancer cells were subjected to hyperosmotic stress. We found that S100A4 is induced in a subset of colon cancer cell lines, and the ability to induce S100A4 depends on the methylation status of S100A4. The osmotic stress response elements were identified in the first intron region of S100A4 by S100A4 luciferase reporter assays. Depletion of NFAT5 by small interfering RNA abolished S100A4 induction. Furthermore, chromatin immunoprecipitation assays showed that NFAT5 is induced to bind to the first intron region. Inhibition of Src kinase pathways reduced S100A4 induction by affecting NFAT5 transactivation and protein levels. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to study the function of S100A4 induction in colon cancer cells under the condition of hyperosmotic stress; the results suggest that S100A4 induction contributes to cell survival. In conclusion, this study demonstrates that hyperosmotic stress induces S100A4 through NFAT5, and Src and chromatin remodeling are involved. In addition, the induction of S100A4 contributes to cell survival. Given that the gastrointestinal tract is periodically exposed to hyperosmotic stress, this study may uncover a novel signaling pathway that could contribute to GI cancer progression.

Identification of proteins overexpressed in papillary thyroid tumors

A modified method of proteome comparative analysis based on preliminary removal of cell structural proteins by extraction using salt buffer and subsequent separation of extracts by two-dimensional gel electrophoresis was developed. Identification of differentially expressed proteins by mass spectrometry has revealed three proteins with noticeably increased level of synthesis in most samples of papillary thyroid tumors compared to normal tissues. An increase in ubiquitin content was found for the first time. Oncomarker search efficiencies by two-dimensional gel electrophoresis and bioinformatic search were compared.

S100A4 over-expression underlies lymph node metastasis and poor prognosis in colorectal cancer

AIM: To develop lymph node metastasis (LNM)-associated biomarkers for colorectal cancer (CRC) using quantitative proteome analysis.

METHODS: Differences in protein expression between primary CRC with LNM (LNM CRC) and without LNM (non-LNM CRC) were assessed using methyl esterification stable isotope labeling coupled with 2D liquid chromatography followed by tandem mass spectrometry (2D-LC-MS/MS). The relationship to clinicopathological parameters and prognosis of candidate biomarkers was examined using an independent sample set.

RESULTS: Forty-three proteins were found to be differentially expressed by at least 2.5-fold in two types of CRC. S100A4 was significantly upregulated in LNM CRC compared with non-LNM CRC, which was confirmed by Western blotting, immunohistochemistry and real-time quantitative polymerase chain reaction. Further immunohistochemistry on another 112 CRC cases showed that overexpression of S100A4 frequently existed in LNM CRC compared with non-LNM CRC (P < 0.001). Overexpression of S100A4 was significantly associated with LNM (P < 0.001), advanced TNM stage (P < 0.001), increased 5-year recurrence rate (P < 0.001) and decreased 5-year overall survival rate (P < 0.001). Univariate and multivariate analyses indicated that S100A4 expression was an independent prognostic factor for recurrence and survival of CRC patients (P < 0.05).

CONCLUSION: S100A4 might serve as a powerful biomarker for LNM and a prognostic factor in CRC.

Muc-1 expression may help characterize thyroid nodules but does not predict patients' outcome

Our purpose was to evaluate MUC1 clinical utility in the diagnosis and prognosis of thyroid cancer patients. We studied the protein expression of MUC1 in 289 thyroid carcinomas and 121 noncancerous thyroid nodules. There were 41 follicular carcinomas (FC) and 248 papillary thyroid carcinomas (PTC) including 149 classic (CPTC), 20 tall cell (TCPTC) and 79 follicular variants (FVPTC). In addition, we used a quantitative real-time PCR (q-PCR) method to measure MUC1 mRNA expression levels in 108 carcinomas, 23 hyperplasias, and 19 FA. According to their serum Tg levels and other evidences of recurrence/metastasis, the patients were classified as free-of-disease (185 cases) or bad outcome (56 cases, 10 deaths). MUC1 protein was identified in 80.2% PTC; 48.8% FC; 68.3% FVPTC; 70% TCPTC; 21.8% FA; 30% hyperplasias and 6% normal thyroid tissues. MUC1 distinguished benign from malignant thyroid tissues (sensitivity = 89%; specificity = 53%). MUC1 also differentiated FC from FA (p = 0.0083). q-PCR mRNA expression of MUC1 also distinguished malignant from benign nodules (Mann-Whitney test, p < 0.0001). However, neither IHC nor mRNA MUC1 expression was associated with any clinical or pathological feature of aggressiveness or outcome. We suggest that MUC1 expression may help differentiate follicular patterned thyroid lesions.

Unique patterns of tumor growth related with the risk of lymph node metastasis in papillary thyroid carcinoma

Although many attempts have been made to predict the occurrence of lymph node metastases from papillary thyroid carcinoma, there are currently no reliable means to accurately predict cervical nodal metastasis. In this study, we present a novel prediction system for the lymph node metastasis based on the histological and cyclin D1 staining features. The frequency of lymph node metastases from a series of 210 papillary thyroid carcinomas was analyzed according to the clinicopathological variables, cyclin D1 staining patterns and BRAF(V600E) mutation in tumor tissue. A total of 113 (54%) patients had lymph node metastasis. Cyclin D1 was constantly expressed at the invasive tumor front and revealed well-defined isolated glands of tumor cells in the extra-tumoral region (isolated glands) and laterally spreading tubular growth along the fibrous septa around the invasive front of the tumor (lateral tubular growth). Upon univariate analysis, an age of less than 45 years (P<0.001), tumor size of 10 mm or more (P<0.001), non-follicular variant (P=0.005), invasive growth pattern (P=0.007), extrathyroid extension (P=0.006), isolated glands (P<0.001), lateral tubular growth (P<0.001) and tumor multiplicity (P=0.005) predicted lymph node metastasis, whereas BRAF(V600E) mutation did not. Upon multivariate analysis, age (P=0.001, odds ratio (OR)=5.146), tumor size (P=0.034, OR=3.119), isolated glands (P<0.001, OR=21.042) and lateral tubular growth (P<0.001, OR=24.652) were found to be strong independent predictors of lymph node metastasis. Cyclin D1 staining of papillary thyroid carcinoma is very useful for identifying the intrathyroidal spreading or multifocality of the tumors. Tumor growth patterns verified by cyclin D1 staining can be used for the identification of papillary thyroid carcinomas with metastatic potential.

INSL3 has tumor-promoting activity in thyroid cancer

The functional role of INSL3 and its receptor RXFP2 in carcinogenesis is largely unknown. We have previously demonstrated (pro-)cathepsin-L as a target of INSL3 in human thyroid cancer cells facilitating penetration of tumor cells through elastin matrices. We demonstrate the expression of RXFP2 in human thyroid tissues and in mouse follicular thyroid epithelial cells using Cre-recombinase transgene driven by Rxfp2 promoter. Recombinant and secreted INSL3 increased the motility of thyroid carcinoma (TC) cells in an autocrine/paracrine manner. This effect required the presence of RXFP2. We identified S100A4 as a novel INSL3 target molecule and showed that S100A4 facilitated INSL3-induced enhanced motility. Stable transfectants of the human follicular TC cell line FTC-133 expressing and secreting bioactive human INSL3 displayed enhanced anchorage-independent growth in soft agar assays. Xenotransplant experiments in nude mice showed that INSL3, but not EGFP-mock transfectants, developed fast-growing and highly vascularized xenografts. We used human umbilical vein endothelial cells in capillary tube formation assays to demonstrate increased 2-dimensional tube formations induced by recombinant human INSL3 and human S100A4 comparable to the effect of vascular endothelial growth factor used as positive control. We conclude that INSL3 is a powerful and multifunctional promoter of tumor growth and angiogenesis in human thyroid cancer cell xenografts. INSL3 actions involve RXFP2 activation and the secretion of S100A4 and (pro-)cathepsin-L.

Visually discernible [18F]fluorodeoxyglucose uptake in papillary thyroid microcarcinoma: a potential new risk factor

CONTEXT

A significant number of papillary thyroid microcarcinomas (PTMCs), despite excellent prognosis, show aggressive features such as extrathyroidal extension (EE) and lymph node metastasis (LNM) that may not always be detected preoperatively or intraoperatively. The relapse rate appears also substantial.

OBJECTIVE

To assess the value of [(18)F]fluorodeoxyglucose (FDG) uptake in PTMC as a potential risk factor for preoperative risk stratification.

METHODS

This retrospective study included 87 patients (17 males and 70 females; mean age = 51.2 yr, range 29-74 yr) with a unifocal PTMC who underwent preoperative FDG-positron emission tomography (PET)/computed tomography (CT)and total thyroidectomy and central lymph node dissection. Statistical analyses were performed to compare the gender, age, tumor size, and FDG uptake in PTMC with the presence of histopathologically proven EE and central LNM (cLNM).

RESULTS

Of the 87 patients, 44 (51%) had EE, and 27 (31%) had cLNM. PET/CT showed visually discernible FDG uptake in 46 PTMCs (53%). FDG positivity of PTMCs was the only significant variable correlated with both EE and cLNM; there was a significant difference in the prevalence of both EE (70 vs. 29%) and cLNM (41 vs. 19.5%) between the FDG-positive and FDG-negative groups. In contrast, other already known risk factors, i.e. gender, age, and size, showed a correlation with only one or neither of EE and cLNM.

CONCLUSION

The results indicate that visual FDG positivity in PTMCs is a potential risk factor that can be useful for preoperative risk stratification. Prospective studies would be warranted to assess the long-term benefit and cost effectiveness of preoperative FDG-PET/CT.

Subcellular distribution of S100A4 and its transcriptional regulation under hypoxic conditions in gastric cancer cell line BGC823

It is well known that S100A4 is overexpressed in many tumors and involved in tumor invasion and metastasis. But the regulation of it is ill understood. We previously found that hypoxia mimicking cobalt chloride (CoCl(2)) enhanced the mRNA and protein expressions of the S100A4 gene in the gastric cancer cell line BGC823. In this study we found that S100A4 also displayed increased expression in BGC823 cells after exposure to real hypoxia (2.5% O(2)) as that by CoCl(2) treatment. Moreover, S100A4 protein showed different subcellular distribution under real hypoxia compared with that by CoCl(2) treatment or in normoxic conditions. To investigate the underlying molecular mechanism by which hypoxia regulates the expression of S100A4, we analyzed the regulatory sequences of the genes by bioinformatics and found a putative hypoxia responsive element (HRE) motif in the first intron of S1004. Furthermore, luciferase reporter assay showed that it is responsive to hypoxia. Electrophoretic mobility shift assay and chromatin immunoprecipitation assays demonstrated that hypoxia-inducible factor 1 (HIF-1) binds to the functional HRE in vitro and in vivo. The results provide evidence that S100A4 is a hypoxia-inducible gene, whose transcription is stimulated at least partly through the interaction of HIF-1 and HRE located at +329 to +334 of S100A4.

Molecular markers of aggressiveness of thyroid cancer

PURPOSE OF REVIEW

To review recent progress at defining molecular markers that predict the biological behavior of thyroid cancer.

RECENT FINDINGS

Thyroid cancer behavior is defined by the effects of the initiating oncogene as well as secondary events in tumor cells and the tumor microenvironment that are both genetic and epigenetic. Over the past several years, there has been intense focus on identifying molecular markers to better predict the aggressiveness of thyroid cancers and also to define therapeutic targets. The results of recent articles in this area of work are summarized with a focus of differentiated follicular-cell-derived forms of thyroid cancer.

SUMMARY

Clinical staging predicts tumor behavior in many cases, but does not allow true 'personalization' of initial therapy or identify potential therapeutic targets for patients with progressive disease that does not respond to standard therapies. Recent data point to several new opportunities to refine thyroid cancer treatment based on molecular information. Several highlighted articles have begun to apply this information with clinical intent.

RNA interference targeting against S100A4 suppresses cell growth and motility and induces apoptosis in human pancreatic cancer cells

S100A4 protein belongs to the S100 subfamily, which has grown to be one of the large subfamilies of the EF-hand Ca(2+)-binding proteins, and overexpression of S100A4 is suggested to associate with cell proliferation, invasion, and metastasis. We observed frequent overexpression of S100A4 in pancreatic cancer cell lines and further analyzed RNAi-mediated knockdown to address the possibility of its use as a therapeutic target for pancreatic cancer. The specific knockdown of S100A4 strongly suppressed cell growth, induced G2 arrest and eventual apoptosis, and decreased cell migration. Furthermore, microarray analyses revealed that knockdown of S100A4 induced expression of the tumor suppressor genes PRDM2 and VASH1. Our present results suggest the possibility that the inhibition of S100A4 can be utilized in antitumor applications for patients with pancreatic cancer.

Immunogenicity of HLA-A1-restricted peptides derived from S100A4 (metastasin 1) in melanoma patients

S100A4 (metastasin 1) belongs to the S100 family of Ca(2+) binding proteins. While not present in most differentiated adult tissues, S100A4 is upregulated in the micromilieu of tumors. It is primarily expressed by tumor-associated macrophages, fibroblasts, and tumor endothelial cells. Due to its strong induction in tumors S100A4 is a promising target for cancer immunotherapy. By reverse immunology, using epitope prediction programs, we identified 3 HLA-A1-restricted peptide epitopes (S100A4 A1-1, A1-2, and A1-3) which are subject to human T cell responses as detected in peripheral blood of melanoma patients by means of IFN-gamma ELISPOT and cytotoxicity assays. In addition, IFN-gamma responses to S100A4 A1-2 can not only be induced by stimulation of T cells with peptide-loaded DC but also by stimulation with S100A4 protein-loaded DC, indicating that this epitope is indeed generated by processing of the endogenously expressed protein. In addition, S100A4 A1-2 reactive T cells demonstrate lysis of HLA-A1(+) fibroblasts in comparison to HLA-A1(-) fibroblasts. In summary, this HLA-A1-restricted peptide epitope is a candidate for immunotherapeutical approaches targeting S100A4-expressing cells in the tumor stroma.

Increased incidence of papillary thyroid microcarcinoma with decreased tumor size of thyroid cancer

The prevalence of papillary thyroid microcarcinoma (PTMC) in thyroid cancer varies from 20.0% to 42.8% with a mean of 30.0%. Most of these patients have benign clinical courses and receive less aggressive therapeutic procedures in most medical centers. This study retrospectively reviewed 30 years data in one institute and compared it with recent publications to illustrate change in trends and influence of PTMC. Incidental PTMC is usually diagnosed as a postoperative microcarcinoma following thyroidectomy for presumably benign thyroid lesions. Subtotal thyroidectomy or lobectomy without radioactive iodide treatment is sufficient to treat incidental PTMC. In contrast, aggressive surgical treatment with (131)I therapy is indicated for non-incidental PTMC. Those with PTMC in the absence of extra-thyroid invasion diagnosed by postoperative permanent section received follow-up if they had initially received subtotal thyroidectomy. In long-term follow-up studies, cancer-specific mortality for PTMC ranged from 0% to 4%. Most of the mortality cases had distant metastasis at the time of surgery. The clinical course and therapeutic strategies for the non-incidental PTMC patients depend on the TNM stage at the time of diagnosis. One-third of PTMC with clinically aggressive behavior cannot be treated as indolent disease. Invasive tumor markers or larger tumor size are useful to predict tumor recurrence or distant metastasis for PTMC.

The therapeutic management of differentiated thyroid cancer

BACKGROUND

The management of thyroid cancer is difficult because the tumors comprise a wide range of biologic behaviors, from small papillary thyroid microcarcinomas that pose little or no threat to survival for the patient, to anaplastic thyroid cancers that are arguably the most lethal tumor. Although it may be difficult initially to determine at which end of the prognostic spectrum a patient resides, one can ordinarily estimate a patient's risk for tumor recurrence and mortality based on a triad of features as simple as the patient's age at the time of diagnosis, the tumor stage at presentation, and its initial response to therapy. While staging systems are available to assist in the management process, all are inexact and leave wide gaps in the treatment plan for a given patient. This is largely because randomized controlled trials are lacking as a result of the low incidence and generally favorable prognosis of the disease. As a practical matter, it may sometimes be difficult to reassure a patient, given the generally favorable prognosis of this group of tumors, knowing that without adequate therapy some become unexpectedly aggressive and recur years after initial management. The treatment of these tumors rests on a fine balance of providing care that reflects the anticipated course of the disease without overtreating the patient or providing reassurance that is unfounded.

OBJECTIVE

To outline the treatment strategy for patients with differentiated thyroid cancer based on the available literature and to guide clinicians through a management algorithm utilizing patient and tumor characteristics.

METHODS

This review is limited to the treatment of patients with differentiated thyroid cancer - papillary and follicular thyroid cancer - and the standard therapy required for the majority of patients.

RESULTS/CONCLUSION

The treatment of differentiated thyroid cancer requires a multidisciplinary approach, involving an experienced surgeon, radiologists and an endocrinologist. There are many unanswered questions in the management algorithm and ongoing research is needed to further define the best treatment strategy for patients with differentiated thyroid cancer.