Recent developments in the clinical application of thyroid cancer biomarkers

Ferroptosis in thyroid cancer: Potential mechanisms, effective therapeutic targets and predictive biomarker

Thyroid cancer is a prevalent endocrine malignancy whose global incidence has risen over the past several decades. Ferroptosis, a regulated form of cell death distinguished by the excessive buildup of iron-dependent lipid peroxidates, stands out from other programmed cell death pathways in terms of morphological and molecular characteristics. Increasing evidence suggests a close association between thyroid cancer and ferroptosis, that is, inducing ferroptosis effectively suppresses the proliferation of thyroid cancer cells and impede tumor advancement. Therefore, ferroptosis represents a promising therapeutic target for the clinical management of thyroid cancer in clinical settings. Alterations in ferroptosis-related genes hold potential for prognostic prediction in thyroid cancer. This review summarizes current studies on the role of ferroptosis in thyroid cancer, elucidating its mechanisms, therapeutic targets, and predictive biomarkers. The findings underscore the significance of ferroptosis in thyroid cancer and offer valuable insights into the development of innovative treatment strategies and accurate predictors for the thyroid cancer.

Papillary Thyroid Cancer Prognosis: An Evolving Field

Simple Summary

Over the last couple of decades, the prognostic stratification systems of differentiated thyroid cancer (DTC) patients have been revised several times in an attempt to achieve a tailored clinical management reflecting the single patients’ needs. Such revisions are likely to continue in the near future, since the prognostic value of a number of promising clinicopathological features and new molecular biomarkers are being evaluated. Here, we will review the current staging systems of thyroid cancer patients and discuss the most relevant clinicopathological parameters and new molecular markers that are potentially capable of refining the prognosis.

Abstract

Over the last few years, a great advance has been made in the comprehension of the molecular pathogenesis underlying thyroid cancer progression, particularly for the papillary thyroid cancer (PTC), which represents the most common thyroid malignancy. Putative cancer driver mutations have been identified in more than 98% of PTC, and a new PTC classification into molecular subtypes has been proposed in order to resolve clinical uncertainties still present in the clinical management of patients. Additionally, the prognostic stratification systems have been profoundly modified over the last decade, with a view to refine patients’ staging and being able to choose a clinical approach tailored on single patient’s needs. Here, we will briefly discuss the recent changes in the clinical management of thyroid nodules, and review the current staging systems of thyroid cancer patients by analyzing promising clinicopathological features (i.e., gender, thyroid auto-immunity, multifocality, PTC histological variants, and vascular invasion) as well as new molecular markers (i.e., BRAF/TERT promoter mutations, miRNAs, and components of the plasminogen activating system) potentially capable of ameliorating the prognosis of PTC patients.

Malignant and benign thyroid nodule differentiation through the analysis of blood plasma with terahertz spectroscopy

The liquid and lyophilized blood plasma of patients with benign or malignant thyroid nodules and healthy individuals were studied by terahertz (THz) time-domain spectroscopy and machine learning. The blood plasma samples from malignant nodule patients were shown to have higher absorption. The glucose concentration and miRNA-146b level were correlated with the sample's absorption at 1 THz. A two-stage ensemble algorithm was proposed for the THz spectra analysis. The first stage was based on the Support Vector Machine with a linear kernel to separate healthy and thyroid nodule participants. The second stage included additional data preprocessing by Ornstein-Uhlenbeck kernel Principal Component Analysis to separate benign and malignant thyroid nodule participants. Thus, the distinction of malignant and benign thyroid nodule patients through their lyophilized blood plasma analysis by terahertz time-domain spectroscopy and machine learning was demonstrated.

Clinical Utility of BRAF, NRAS, and TERT Promoter Mutation in Preoperative Thyroid Fine-Needle Aspiration Biopsy: A Diagnostic Study From Dharmais Cancer Hospital

Objective:

Molecular testing of thyroid nodules becomes important for improving the accuracy of fine-needle aspiration biopsy (FNAB). This study aimed to investigate the diagnostic utility of BRAF, NRAS, and TERT promoter mutation in thyroid nodules at Dharmais Cancer Hospital.

Methods:

We performed a prospective diagnostic study involving 50 patients with thyroid nodules who needed surgery between September 2013 and August 2014. Mutational hotspots in BRAF exon 15, NRAS exon 3, and TERT promoter region were analyzed by Sanger sequencing from FNAB specimens. Cytology and molecular data were compared to histopathology results.

Results:

Of the 50 cases included in the analysis, 39 cases (78%) were thyroid malignancies. Mutations of BRAF, NRAS, and TERT promoter were detected in 31% (12/39), 18% (7/39), and 13% (5/39) cases, respectively. BRAF and NRAS mutations were found mutually exclusive, while all of TERT promoter mutation was found coexistent either with BRAF (40%) or NRAS (60%). The combination of FNAB cytology and molecular testing resulted in 69% sensitivity, 100% specificity, 100% positive predictive value, 48% negative predictive value, and 76% accuracy.

Conclusion:

Molecular testing of BRAF, NRAS, and TERT mutations improve the sensitivity of thyroid FNAB and is beneficial for more definitive treatment in selective cases. However, the NPV is relatively low to avoid the need for diagnostic surgery. Therefore, further studies to identify more sensitive methods and more comprehensive molecular markers in the diagnosis of thyroid nodules are needed.

Thyroid Carcinoma: Do We Need to Treat Men and Women Differently?

BACKGROUND

For differentiated thyroid carcinoma, gender-specific differences exist in regard to incidence, age at onset, tumor stage, and recurrence, but causative factors remain to be elucidated. Possible and likely contributors are genetic and hormonal differences. While some of these factors are known to be differently distributed between the sexes, like, for example, BRAF-mutation and estrogen levels, their role in thyroid cancer initiation or promotion awaits further investigation.

SUMMARY

Apart from generally accepted risk factors for differentiated thyroid carcinoma, an apparent gender disparity of thyroid cancer with a general female predominance, an age-dependent difference in growth acceleration during the reproductive years, and a peak at the time of entering menopause have been demonstrated. Hormonal status and hormonal receptor mediation seem to be most likely to contribute to the differences in thyroid cancer phenotypes of males and females. However, specific cause-and-effect pathways have not yet been determined.

KEY MESSAGES

Female gender is overrepresented in the incidence of differentiated thyroid carcinoma, as it is in the more favorable tumor stages. Besides the assumption of gender-specific differences in general health awareness and behavior, hormonal age-dependent and gender-specific factors appear to be contributory. In the advanced stage of thyroid cancer, males are overrepresented. Therefore, the real cause of gender differences in thyroid cancer is likely due to a mixed effect. Present knowledge does not favor different treatment modalities of thyroid carcinoma according to gender.

Combined quantitation of HMGA2 mRNA, microRNAs, and mitochondrial-DNA content enables the identification and typing of thyroid tumors in fine-needle aspiration smears

Background

Analysis of molecular markers in addition to cytological analysis of fine-needle aspiration (FNA) samples is a promising way to improve the preoperative diagnosis of thyroid nodules. Nonetheless, in clinical practice, applications of existing diagnostic solutions based on the detection of somatic mutations or analysis of gene expression are limited by their high cost and difficulties with clinical interpretation.

The aim of our work was to develop an algorithm for the differential diagnosis of thyroid nodules on the basis of a small set of molecular markers analyzed by real-time PCR.

Methods

A total of 494 preoperative FNA samples of thyroid goiters and tumors from 232 patients with known histological reports were analyzed: goiter, 105 samples (50 patients); follicular adenoma, 101 (48); follicular carcinoma, 43 (28); Hürthle cell carcinoma, 25 (11); papillary carcinoma, 121 (56); follicular variant of papillary carcinoma, 80 (32); and medullary carcinoma, 19 (12). Total nucleic acids extracted from dried FNA smears were analyzed for five somatic point mutations and two translocations typical of thyroid tumors as well as for relative concentrations of HMGA2 mRNA and 13 microRNAs and the ratio of mitochondrial to nuclear DNA by real-time PCR. A decision tree–based algorithm was built to discriminate benign and malignant tumors and to type the thyroid cancer. Leave-p-out cross-validation with five partitions was performed to estimate prediction quality. A comparison of two independent samples by quantitative traits was carried out via the Mann–Whitney U test.

Results

A minimum set of markers was selected (levels of HMGA2 mRNA and miR-375, − 221, and -146b in combination with the mitochondrial-to-nuclear DNA ratio) and yielded highly accurate discrimination (sensitivity = 0.97; positive predictive value = 0.98) between goiters with benign tumors and malignant tumors and accurate typing of papillary, medullary, and Hürthle cell carcinomas. The results support an alternative classification of follicular tumors, which differs from the histological one.

Conclusions

The study shows the feasibility of the preoperative differential diagnosis of thyroid nodules using a panel of several molecular markers by a simple PCR-based method. Combining markers of different types increases the accuracy of classification.

Do Helper T Cell Subtypes in Lymphocytic Thyroiditis Play a Role in the Antitumor Effect?

BACKGROUND

Papillary thyroid carcinoma (PTC) is frequently accompanied by lymphocytic thyroiditis (LT). Some reports claim that Hashimoto's thyroiditis (the clinical form of LT) enhances the likelihood of PTC; however, others suggest that LT has antitumor activity. This study was aimed to find out the relationship between the patterns of helper T cell (Th) cytokines in thyroid tissue of PTC with or without LT and the clinicopathological manifestation of PTC.

METHODS

Fresh surgical samples of PTC with (13 cases) or without (10 cases) LT were used. The prognostic parameters (tumor size, extra-thyroidal extension of PTC, and lymph node metastasis) were analyzed. The mRNA levels of two subtypes of Th cytokines, Th1 (tumor necrosis factor α [TNF-α], interferon γ [IFN-γ ], and interleukin [IL] 2) and Th2 (IL-4 and IL-10), were analyzed. Because most PTC cases were microcarcinomas and recent cases without clinical follow-up, negative or faint p27 immunoreactivity was used as a surrogate marker for lymph node metastasis.

RESULTS

PTC with LT cases showed significantly higher expression of TNF-α (p = .043), IFN-γ (p < .010), IL-4 (p = .015) than those without LT cases. Although the data were not statistically significant, all analyzed cytokines (except for IL-4) were highly expressed in the cases with higher expression of p27 surrogate marker.

CONCLUSIONS

These results indicate that mixed Th1 (TNF-α, IFN-γ , and IL-2) and Th2 (IL-10) immunity might play a role in the antitumor effect in terms of lymph node metastasis.

LDOC1 inhibits proliferation and promotes apoptosis by repressing NF-κB activation in papillary thyroid carcinoma

Background

The incidence of thyroid cancer has progressively increased over the past few decades, and the most frequent types of this cancer are papillary thyroid carcinoma (PTC) and small primary tumors. In PTC, oncogene activation is known to occur at a high frequency. However, the potential roles of tumor suppressor genes in thyroid carcinogenesis remain unclear. LDOC1 was first identified as a gene encoding a leucine zipper protein whose expression was decreased in a series of pancreatic and gastric cancer cell lines. In this study, we aimed to determine the status of LDOC1 in PTC and identify its mechanistic role in PTC pathogenesis.

Methods

LDOC1 expression was evaluated in fresh samples and stored specimens of human PTC and contralateral normal tissues by performing quantitative reverse transcription-PCR and immunohistochemical staining. The correlation to nuclear p65 content in the stored specimens was analyzed. Moreover, the basal level of LDOC1 in two human PTC-derived cell lines (BCPAP and TPC-1) compared with normal thyroid tissue was determined. Human LDOC1 cDNA was inserted into a lentiviral vector and transduced into TPC-1 cells. TPC-1 cells overexpressing LDOC1/GFP (Lv-LDOC1) or negative control GFP (Lv-NC) were stimulated with TNFα or recombinant TGF-β1, and then cell proliferation, cell cycle distribution, and apoptosis were assessed. Western blotting was used to examine the expression of p65, IκBα, c-Myc, Bax, and Bcl-xL, and a luciferase reporter assay was used to measure NF-κB activity stimulated by TNFα. Statistical significance was determined using Student’s t tests or ANOVA and Newman-Keuls multiple comparison tests. Pearson chi-square test was used to analyze possible associations.

Results

LDOC1 expression was significantly downregulated in PTC specimens as compared with the expression in normal thyroid tissues, and this downregulation was associated with an increase in tumor size (P < 0.05). There is a correlation between LDOC1 and nuclear P65 expression in human PTC tissues (P < 0.01). Lentivirus-mediated restoration of LDOC1 expression in TPC-1 cells characterized by low level of LDOC1 expression suppressed proliferation and induced apoptosis by inhibiting NF-κB activation, and LDOC1-overexpressing TPC-1 cells recovered responsiveness to TGF-β1 antiproliferative signaling.

Conclusions

LDOC1 might function as a tumor suppressor gene in PTC by inhibiting NF-κΒ signaling, and thus might represent a promising therapeutic target in patients with PTC.

Expression Levels of miR-30a-5p in Papillary Thyroid Carcinoma: A Comparison Between Serum and Fine Needle Aspiration Biopsy Samples

BACKGROUND

Fine needle aspiration biopsy (FNAB) is a useful tool in the diagnosis of thyroid nodules. However, some limitations exist as approximately 25% of the cases cannot be distinguished with this method. Therefore, identification of novel diagnostic markers is very important in improving the papillary thyroid carcinoma (PTC) diagnosis. microRNAs (miRNAs) are small regulatory RNA molecules that have been involved in a variety of biological processes, including tumorigenesis. Moreover, determination of miRNAs with prognostic, diagnostic, and therapeutic potential is of a great interest today.

AIMS

In the present study, we evaluated the expression level of miR-30a-5p in serum and FNAB samples of PTC patients.

METHODS

A total of 60 cases were included in the study, with the patients subdivided into four groups; benign, atypical cells of undetermined significance (ACUS), malignant group, including Hurthle cell PTC (HC-PTC), and malignant without Hurthle cell PTC (non-HC-PTC). Peripheral blood and FNAB samples of the cases were collected. The serum and FNAB expression levels of miR-30a-5p among the groups were compared. The miR-30a-5p expression level was determined using real-time polymerase chain reaction (RT-PCR).

RESULTS

According to both pre- and postoperative pathological diagnosis, miR-30a-5p levels were significantly increased in both serum and FNAB samples of HC-PTC and non-HC-PTC groups compared to other groups. This increase was more evident in the non-HC-PTC group (p=0.0245 for FNAB, p=0.0166 for serum).

CONCLUSIONS

The results of this study suggest that miR-30a-5p might be a novel diagnostic marker candidate in PTC. Further studies are required to investigate this possibility.

Deregulated expression of Aurora kinases is not a prognostic biomarker in papillary thyroid cancer patients

A number of reports indicated that Aurora-A or Aurora-B overexpression represented a negative prognostic factor in several human malignancies. In thyroid cancer tissues a deregulated expression of Aurora kinases has been also demonstrated, but no information regarding its possible prognostic role in differentiated thyroid cancer is available. Here, we evaluated Aurora-A and Aurora-B mRNA expression and its prognostic relevance in a series of 87 papillary thyroid cancers (PTC), with a median follow-up of 63 months. The analysis of Aurora-A and Aurora-B mRNA levels in PTC tissues, compared to normal matched tissues, revealed that their expression was either up- or down-regulated in the majority of cancer tissues. In particular, Aurora-A and Aurora-B mRNA levels were altered, respectively, in 55 (63.2%) and 79 (90.8%) out of the 87 PTC analyzed.A significant positive correlation between Aurora-A and Aurora-B mRNAs was observed (p=0.001). The expression of both Aurora genes was not affected by the BRAFV600E mutation. Univariate, multivariate and Kaplan-Mayer analyses documented the lack of association between Aurora-A or Aurora-B expression and clinicopathological parameters such as gender, age, tumor size, histology, TNM stage, lymph node metastasis and BRAF status as well as disease recurrences or disease-free interval. Only Aurora-B mRNA was significantly higher in T(3-4) tissues, with respect to T(1-2) PTC tissues. The data reported here demonstrate that the expression of Aurora kinases is deregulated in the majority of PTC tissues, likely contributing to PTC progression. However, differently from other human solid cancers, detection of Aurora-A or Aurora-B mRNAs is not a prognostic biomarker in PTC patients.

Emerging molecular markers for the prognosis of differentiated thyroid cancer patients

Epithelial thyroid cancers are represented by the differentiated papillary and follicular thyroid carcinomas which, following dedifferentiation, are thought to give rise to the highly aggressive and incurable anaplastic thyroid carcinomas. Although derived from the same cell type, the different thyroid tumors show specific histological features, biological behavior and degree of differentiation as a consequence of different genetic alterations. Over the last few years, our knowledge regarding the molecular alterations underlying thyroid cell malignant transformation and cancer progression has considerably increased; however, the prognosis of differentiated thyroid cancer patients still relies on high-risk clinic-pathological variables. In particular, the actual staging systems provides only a rough prediction for cancer mortality and risk of recurrences, including in each risk group patients with highly different tumor-specific progression, disease-free interval and survival time. In order to improve DTC patient's risk stratification, both the European and the American Thyroid Associations proposed practical guidelines to integrate the actual staging systems with additional clinical features such as the tumor histological variant, the results of post-ablative whole body scan and the serum thyroglobulin levels. Despite that, patients within the same risk group still show a very heterogeneous behavior in terms of disease-free interval. As a consequence, the identification of new prognostic molecular biomarkers able to testify tumor aggressiveness is highly required. Here we'll review recently characterized new molecular markers potentially able to ameliorate the prognosis in DTC patients.

The Beneficial Effects of Valproic Acid in Thyroid Cancer Are Mediated through Promoting Redifferentiation and Reducing Stemness Level: An In Vitro Study

Valproic acid (VPA) has been identified as a histone deacetylase inhibitor, inducing differentiation in transformed cells. However, no study has shown the effect of VPA in the redifferentiation induction and stemness of anaplastic thyroid. The main objective of this study was to evaluate the efficacy of VPA as a differentiation therapy agent in human thyroid cancer based on its effect on stemness and differentiation process. Indications for differentiation of 8305C and B-CPAP cell lines following VPA treatment were obtained by analyzing cell proliferation rate, morphological changes, adherent-dependent colony formation, and Hoechst 33342 staining. The expressions of stemness, differentiation, and aggressiveness specific marker genes were measured by quantitative RT-PCR. VPA treatment effectively showed growth inhibition in both cell lines. The high nuclear-cytoplasmic (N : C) ratio of 8305C cells markedly decreased and treated cells became more epithelial-like. Treated cells showed stronger Hoechst 33342 fluorescence compared with control cells. The hTERT and OCT-4 reduction was paralleled with adherent-dependent colony formation decrement in both cell lines. VPA effectively induced NIS and TTF-1 in anaplastic cells, it whereas showed no clear pattern in papillary cell line. VPA treatment also resulted in the reduction of MMP-2 and MMP-9. These finding suggest that VPA could redifferentiate the anaplastic thyroid cancer cells.

Deregulation of microRNA expression in thyroid tumors

MicroRNAs (miRNAs or miRs) are endogenous non-coding RNAs that negatively regulate gene expression by binding to the 3' non-coding regions of target mRNAs, resulting in their cleavage or blocking their translation. miRNAs may have an impact on cell differentiation, proliferation, and survival, and their deregulation can be inclined to diseases and cancers, including thyroid tumors. The purpose of this review is to summarize the existing findings of deregulated miRNAs in different types of thyroid tumors and to exhibit their potential target genes, especially to demonstrate those involved in tumor invasion and metastasis. In addition, new findings of circulating miRNA expression profiles, single nucleotide polymorphism (SNP) in thyroid tumors, and the correlation of somatic mutations with deregulated miRNA expression in thyroid tumors were all included in this review.

Diagnostic value of B-RAF(V600E) in difficult-to-diagnose thyroid nodules using fine-needle aspiration: systematic review and meta-analysis

Fine-needle aspiration (FNA) is routinely used in the preoperative evaluation of thyroid nodules. However, approximately 5-20% of thyroid nodules are considered indeterminate or suspicious cases that do not meet clinical standards. The B-RAF(V600E) mutation has been reported in FNA specimens. We conducted a systematic review to evaluate the diagnostic value of testing for B-RAF(V600E) in thyroid nodules that are difficult to diagnose by FNA. A systematic literature search was performed from January 1, 2002 to June 30, 2012. Articles were obtained by searching two electronic databases (MEDLINE and EMBASE), hand searching selected journals, and contacting authors. Article quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool. Sensitivity, specificity, and other measures of accuracy were pooled using random effects models. Summary receiver operating characteristic (SROC) curves were used to summarize overall diagnostic accuracy. A total of 16 studies incorporating 1131 patients were included in a meta-analysis on diagnostic accuracy of B-RAF(V600E) tests. Pooled sensitivity was 0.60 (95% confidence interval [CI]: 0.556-0.634), pooled specificity was 0.99 (95% CI 0.976-0.997), and the area under the curve of the SROC curve was 0.8376. Q index value was 0.7696. Our data suggest a potentially useful adjunct to evaluating thyroid nodules that are difficult to diagnose. The B-RAF(V600E) test has a high positive predictive value and could help clinicians formulate a more individualized treatment schedule. When supplemented with other noninvasive test methods, the B-RAF(V600E) test could be a powerful adjunct with extensive clinical applications.

MCM3 protein expression in follicular and classical variants of papillary thyroid carcinoma

Minichromosome maintenance (MCM) proteins are needed as licensors in the DNA replication of eukaryotic cells and transcriptional control of MCM genes has critical role in the regulation of MCM functions. Different MCM protein family members are proposed as diagnostic or prognostic markers in various cancers due to their increased proliferative potential. Among MCM family members, minichromosome maintenance protein 3 (MCM3) expressions in both mRNA and protein levels were shown to be associated with papillary thyroid carcinoma (PTC). But, the usability of MCM3 in some histological variants of PTC might be controversial due to tissue specific molecular heterogeneities. In follicular variant of papillary thyroid carcinoma (FVPTC), a number of genes including MCM3 were shown to be differentially expressed which were specific to this kind of variant. Using immunohistochemistry method, MCM3 protein expression levels were compared in FVPTC, classic variant of papillary thyroid carcinoma (CVPTC), and multi-nodular goiter (MNG) tissues in a group of 32 cases. There was meaningful differences between MNG vs. FVPTC (p = 0.016) and MNG vs. CVPTC (p = 0.019) while there was no significant difference in the comparison FVPTC vs. CVPTC (p = 0.15). Four of the 5 CVPTC cases having surrounding tissue invasion had high expression values. For FVPTC and CVPTC, MCM3 protein expression results were parallel to our previous mRNA expression study while there was downregulation in protein expression despite the increased expression of MCM3 mRNA in MNG suggesting tissue-specific post-transcriptional events in benign thyroid neoplasms of which should be focused on. Moreover, the relatively lower MCM3 protein expression in FVPTC comparing to CVPTC could be due to a different tumorigenic pathway favored in this type of tissue.

RTN4IP1 is down-regulated in thyroid cancer and has tumor-suppressive function

CONTEXT

Previously we identified RTN4IP1 to be differentially expressed in thyroid cancer by sex and the gene is located on chromosome 6q21, a chromosomal region frequently deleted or with loss of heterozygosity in a variety of human malignancies including thyroid cancer.

OBJECTIVE

Because the expression and function of this gene is unknown, we sought to characterize its expression in normal, hyperplastic, and benign and malignant thyroid tissue samples and to evaluate its function in cancer cells.

DESIGN

RTN4IP1 expression was analyzed in normal and hyperplastic thyroid tissue and benign and malignant thyroid tissue samples. In 3 thyroid cancer cell lines (TPC1 from a papillary thyroid cancer, FTC133 from a follicular thyroid cancer, XTC1 from a Hürthle cell carcinoma), small interfering RNA knockdown of RTN4IP1 was used to determine its role in regulating the hallmarks of malignant cell phenotype (cellular proliferation, migration, apoptosis, invasion, tumor spheroid formation, anchorage independent growth).

RESULTS

We found RTN4IP1 mRNA expression was significantly down-regulated in follicular and papillary thyroid cancer as compared with normal, hyperplastic, and benign thyroid neoplasms (P < .05). Moreover, RTN4IP1 mRNA expression was significantly lower in larger papillary thyroid cancers (P < .05). Small interfering RNA knockdown of RTN4IP1 expression increased cellular proliferation (2- to 4-fold) in all 3 of the cell lines tested and increased cellular invasion (1.5- to 3-fold) and migration (2- to 7.5-fold), colony formation (3- to 6-fold), and tumor spheroid formation (P < .05) in 2 of the 3 cell lines tested (FTC-133 and XTC1).

CONCLUSIONS

This is the first study to characterize the expression and function of RTN4IP1 in cancer. Our results demonstrate RTN4IP1 is down-regulated in thyroid cancer and is associated with larger papillary thyroid cancer and that it regulates malignant cell phenotype. These findings, taken together, suggest that RTN4IP1 has a tumor-suppressive function and may regulate thyroid cancer progression.

In papillary thyroid carcinoma BRAFV600E is associated with increased expression of the urokinase plasminogen activator and its cognate receptor, but not with disease-free interval

CONTEXT

It has been suggested that patients with papillary thyroid cancer (PTC) harbouring the BRAF(V600E) mutation have a worse prognosis. We showed in PTC that high levels of urokinase plasminogen activator (uPA) and its cognate receptor (uPAR) inversely correlate with disease-free interval (DFI).

OBJECTIVES

To investigate the effects of BRAF(V600E) on the expression of uPA and uPAR and to evaluate the prognostic relevance of BRAF(V600E) alone or in combination with uPA and uPAR. DESIGN/SETTING/PATIENTS/INTERVENTION: The case study included 91 patients with PTC. All patients underwent thyroidectomy and radioiodine therapy. Follow-up was available for 75 patients.

MAIN OUTCOME MEASURES

The BRAF(V600E) mutation was analysed by sequencing and mutant allele-specific PCR amplification; uPA and uPAR expression by quantitative RT-PCR.

RESULTS

BRAF(V600E) was found in 44 of the 91 patients and associated with older age, but not with high-risk clinicopathological features. Urokinase PA and uPAR mRNA levels were higher in tumour tissues by 9·51 ± 1·30 and 4·64 ± 0·44 fold, respectively, compared to normal matched tissues, being significantly higher in BRAF(V600E) -positive patients. In vitro induction of BRAF(V600E) in PCCL3 cells caused a significant increase in both uPA and uPAR mRNAs. Higher levels of uPA and uPAR correlated with lymph node metastases, TNM stage and disease recurrences. Kaplan-Meier and multivariate analyses demonstrated that uPA and uPAR were associated with shorter DFI, while the BRAF(V600E) was not.

CONCLUSION

In PTC, BRAF(V600E) induces uPA and uPAR expression. The latter, but not BRAF(V600E) , associates with advanced stages and shorter DFI. If confirmed in larger case studies, they may represent reliable prognostic markers for more accurate risk stratification and postoperative decision-making in patients with PTC.

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

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

BRAF mutation in papillary thyroid cancer and its value in tailoring initial treatment: a systematic review and meta-analysis

Clinicians have long sought to characterize biological markers of neoplasia as objective indicators of tumor presence, pathogenicity, and prognosis. Armed with data that correlate biomarker activity with disease presence and progression, clinicians can develop treatment strategies that address risks of disease recurrence or persistence and progression. The B-type Raf kinase (BRAF V600E) mutation in exon 15 of the BRAF gene has been noted to be a putative prognostic marker of the most prevalent form of thyroid cancer, papillary thyroid cancer (PTC)--a tumor type with high proclivity for recurrence or persistence. There has been a remarkable interest in determining the association of BRAF mutation with PTC recurrence or persistence. Using many new studies that have been published recently, we performed a meta-analysis to investigate correlations of BRAF mutation status with PTC prognosis, focusing on the recurrence or persistence of the disease after initial treatment. The study was based on published studies included in the PubMed and Embase databases addressing the BRAF mutation and the frequency of recurrence of PTC. We selected studies with data that enabled measurement of the risk ratio for recurrent disease. We also analyzed the factors that are classically known to be associated with recurrence. These factors included lymph node metastasis, extrathyroidal extension, distant metastasis, and American Joint Committee on Cancer (AJCC) stages III/IV. We used 14 articles that included an analysis of these factors as well as PTC recurrence data, with a total of 2470 patients from 9 different countries. The overall prevalence of the BRAF mutation was 45%. The risk ratios in BRAF mutation-positive patients were 1.93 (95% confidence interval [CI], 1.61-2.32; Z = 7.01; p < 0.00001) for PTC recurrence, 1.32 (95% CI, 1.20-1.45; Z = 5.73; p < 0.00001) for lymph node metastasis, 1.71 (95% CI, 1.50-1.94; Z = 8.09; p < 0.00001) for extrathyroidal extension, 0.95 (95% CI, 0.63-1.44; Z = 0.23; p = 0.82) for distant metastasis, and 1.70 (95% CI, 1.45-1.99; Z = 6.46; p < 0.00001) for advanced stage AJCC III/IV. Thus, in this meta-analysis, the BRAF mutation in PTC was significantly associated with PTC recurrence, lymph node metastasis, extrathyroidal extension, and advanced stage AJCC III/IV. Patients with PTC harboring mutated BRAF are likely to demonstrate factors that are associated with an increased risk for recurrence of the disease, offering new prospects for optimizing and tailoring initial treatment strategies to prevent recurrence.

A high percentage of BRAFV600E alleles in papillary thyroid carcinoma predicts a poorer outcome

CONTEXT

BRAF(V600E) is considered a negative prognostic marker in papillary thyroid carcinoma (PTC), but unexplained conflicting results are present in the literature. In light of the new finding that most PTC consist of a mixture of tumor cells with wild-type and mutant BRAF, we examined the associations between the percentage of BRAF(V600E) alleles and both the clinicopathological parameters at time of diagnosis and the disease outcome in a large series of PTCs.

STUDY DESIGN

Tumors from 168 patients with PTC were genotyped for BRAF(V600E) using BigDye Terminator sequencing and pyrosequencing, and the clinical parameters were analyzed. The associations between clinicopathological characteristics, including disease recurrence at follow-up (median 5.1 yr) and the percentage of mutant BRAF alleles were assessed.

RESULTS

The observed prevalence of BRAF(V600E) was higher when using pyrosequencing then when using BigDye Terminator sequencing (53.6 vs. 36.9%). In the PTC positive for BRAF(V600E), the percentage of mutant alleles ranged from 5.1 to 44.7% of the total BRAF alleles, with a median of 20.6%. The presence or the percentage of BRAF(V600E) alleles did not correlate significantly with sex, multicentricity, lymph node metastasis, or tumor stage. The percentage of BRAF(V600E) alleles directly correlated with age at diagnosis and tumor volume (R(2) = 0.223, P = 0.039, and R(2) = 0.166, P < 0.001, respectively). The percentage of BRAF(V600E) alleles (P = 0.014), tumor volume (P = 0.012), and lymph node metastasis (P = 0.008) predicted the disease outcome. The odds ratio of recurrence for PTC with BRAF(V600E) alleles of 30% or greater, compared with that for PTC with BRAF(V600E) alleles of less than 30%, was 5.31 (P = 0.002).

CONCLUSIONS

A high percentage of BRAF(V600E) alleles defines a PTC molecular subtype and predicts a poorer disease outcome. The analysis of BRAF mutations by pyrosequencing is useful to refine the risk stratification of patients with PTC.

A high-resolution melting protocol for rapid and accurate differential diagnosis of thyroid nodules

A large majority of thyroid nodules are benign, and only 5% have malignant features on cytological examination. Unfortunately, fine-needle aspiration is inconclusive in approximately 30% of all thyroid biopsies, because the cytological features are indeterminate (suspicious for malignancy but not completely diagnostic or nondiagnostic). Wide panels of somatic mutations have been identified in thyroid cancers, and detection of genetic alterations in fine-needle aspirate has been demonstrated to improve diagnostic accuracy. Nevertheless, the relatively high number of genetic targets to be investigated, in comparison with the low percentage of malignant samples, makes the usual diagnostic protocol both time-consuming and expensive. We developed a reliable and sensitive protocol based on high-resolution melting analysis for the rapid screening of mutations of KRAS, HRAS, NRAS, and BRAF oncogenes in thyroid fine-needle aspirations. The entire procedure can be completed in approximately 48 hours, with a dramatic reduction in costs. The proposed protocol was applied to the analysis of 260 consecutive fine-needle aspiration biopsy (FNAB) samples. In 35 of 252 samples, 36 sequence variants were detected for BRAF (17 samples), NRAS (6 samples), HRAS (3 samples), KRAS codon 12 (9 samples), and KRAS codon 61 (1 sample).

Evaluation of candidate diagnostic microRNAs in thyroid fine-needle aspiration biopsy samples

BACKGROUND

Thyroid cancer diagnosis in the United States has increased by 2.3-folds in the last three decades. Up to 30% of thyroid fine-needle aspiration biopsy (FNAB) results are inconclusive. Several differentially expressed microRNAs (miRNAs) have been identified as candidate diagnostic markers for thyroid nodules. We hypothesized that these differentially expressed miRNAs may improve the accuracy of FNAB in difficult to diagnose thyroid nodules.

METHODS

Expression levels of four miRNAs (miR-7, -126, -374a, and let-7g) were analyzed using quantitative real-time reverse transcription-polymerase chain reaction in 95 FNAB samples as the training set. A predictor model was formulated based on the most differentially expressed miRNA (miR-7) ΔCt value and the model was applied on a separate cohort of 59 FNAB samples as the validation set.

RESULTS

miR-7 was the best predictor to distinguish benign from malignant thyroid FNAB samples. The other three miRNAs were co-expressed and did not significantly contribute to the predictor model. miR-7 had a sensitivity of 100%, specificity of 29%, positive predictive value (PPV) of 36%, negative predictive value (NPV) of 100%, and overall accuracy of 76% when applied to the validation set. In subgroup analysis of preoperative nondiagnostic, indeterminate, or suspicious FNAB samples, the predictor model had an overall accuracy of 37% with sensitivity of 100%, specificity of 20%, PPV of 25%, and NPV of 100%.

CONCLUSIONS

miR-7 may be a helpful adjunct marker to thyroid FNAB in tumor types which are inconclusive. Given the high NPV of miR-7, a patient with a benign result based on the predictor model may be followed as opposed to performing an immediate diagnostic thyroidectomy. Future prospective clinical trials evaluating its accuracy in a larger cohort are warranted to determine its clinical utility.

Expression profiling of difficult-to-diagnose thyroid histologic subtypes shows distinct expression profiles and identify candidate diagnostic microRNAs

BACKGROUND

The incidence of thyroid cancer is increasing worldwide. The findings of up to 30% of thyroid fine-needle aspiration biopsies (FNAB) are inconclusive, primarily as a result of several thyroid histologic subtypes with overlapping cytologic features. MicroRNAs (miRNAs) are small noncoding RNAs and have been implicated in carcinogenesis. We hypothesized that there are miRNAs that are differentially expressed between benign and malignant thyroid tumors that are difficult to distinguish by FNAB.

METHODS

The expression of 1263 human miRNAs was profiled in 47 tumor samples representing difficult to diagnose histologic subtypes of thyroid neoplasm (21 benign, 26 malignant). Differentially expressed miRNAs were validated by quantitative real-time reverse transcriptase-polymerase chain reaction. The area under the receiver operating characteristic curve (AUC) was used to determine the diagnostic accuracy of differentially expressed miRNAs.

RESULTS

Supervised hierarchical cluster analysis demonstrated grouping of 2 histologies (papillary and follicular thyroid carcinoma). A total of 34 miRNAs were differentially expressed in malignant compared to benign thyroid neoplasms (P<0.05). A total of 25 of the 34 nonproprietary miRNAs were selected for validation, and 15 of the 25 miRNAs were differentially expressed between benign and malignant samples with P-value<0.05. Seven miRNAs had AUC values of >0.7. miR-7 and miR-126 had the highest diagnostic accuracy with AUCs values of 0.81 and 0.77, respectively.

CONCLUSION

To our knowledge, this is the first study to evaluate the diagnostic accuracy of miRNAs in thyroid histologies that are difficult to distinguish as benign or malignant by FNAB. miR-126 and miR-7 had high diagnostic accuracy and could be helpful adjuncts to thyroid FNAB.

Controversies in the management of papillary thyroid cancer revisited

The debate on the appropriate treatment of patients with papillary thyroid cancer (PTC) has persisted for several decades. The main controversies focus on the extent of surgery, the timing of central neck dissection, and the indications for radioactive iodine ablation. These controversies continue, for the most part, due to the good prognosis of PTC patients and the questionable effect these treatment modalities have on patient survival. This paper addresses these three controversies and the role of molecular tumor markers in the appropriate treatment selection.

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

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

Thyroid cancer gender disparity

Cancer gender disparity in incidence, disease aggressiveness and prognosis has been observed in a variety of cancers. Thyroid cancer is one of the fastest growing cancer diagnoses worldwide. It is 2.9-times more common in women than men. The less aggressive histologic subtypes of thyroid cancer are more common in women, whereas the more aggressive histologic subtypes have similar gender distribution. The gender disparity in incidence, aggressiveness and prognosis is well established for thyroid cancer but the cause of the disparity is poorly understood. The aim of this article is to evaluate the current evidence on the cause of thyroid cancer gender disparity. Dietary and environmental factors do not appear to have a significant role in thyroid cancer gender disparity. Common somatic mutations in BRAF, rearranged in transformation/papillary thyroid carcinomas (RET/PTC) and neurotrophin receptor-tyrosine kinase (NTRK) also do not account for the gender disparity in thyroid cancer. While reproductive factors would seem a logical hypothesis to account for the gender disparity, there appears to be no conclusive effect on the risk of developing thyroid cancer. Recent studies on estrogen receptor status in thyroid cancer show a difference in the receptor subtypes expressed based on the histology of thyroid cancer. Moreover, the response to estrogen is dependent on the specific estrogen receptor expressed in thyroid cancer cells. However, what determines the tumor-specific sex hormone receptor expression is unclear. No established molecular factors appear to explain gender differences in thyroid cancer. Therefore, the application of high-throughput genomic and proteomic approaches to the study of thyroid cancer gender disparity could be helpful for better understanding the molecular basis for gender differences in thyroid and other cancers.

Molecular testing for somatic mutations improves the accuracy of thyroid fine-needle aspiration biopsy

Background

Thyroid fine-needle aspiration (FNA) biopsy is indeterminate or suspicious in up to 30% of cases and these patients are commonly subjected to at least a diagnostic hemithyroidectomy. If malignant on histology, a completion thyroidectomy is usually performed, which may be associated with higher morbidity. To determine the clinical utility of genetic testing in thyroid FNA biopsy, we conducted a prospective clinical trial.

Methods

Four hundred seventeen patients with 455 thyroid nodules were enrolled and had genetic testing for common somatic mutations (BRAF, NRAS, KRAS) and gene rearrangements (RET/PTC1, RET/PTC3, RAS, TRK1) by PCR and direct sequencing and by nested PCR, respectively. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of genetic testing in thyroid FNA biopsy were determined based on the histologic diagnosis.

Results

One hundred twenty-five of 455 thyroid nodule FNA biopsies were indeterminate or suspicious on cytologic examination. Overall, 50 mutations were identified (23 BRAF, 4 RET/PTC1, 2 RET/PTC3, 21 NRAS) in the thyroid FNA biopsies. There were significantly more mutations detected in malignant thyroid nodules than in benign (P = 0.0001). For thyroid FNA biopsies that were indeterminate or suspicious, genetic testing had a sensitivity of 12%, specificity of 98%, PPV of 38%, and NPV of 65%.

Conclusions

Genetic testing for somatic mutations in thyroid FNA biopsy samples is feasible and identifies a subset of malignant thyroid neoplasms that are indeterminate or suspicious on FNA biopsy. Genetic testing for common somatic genetic alterations thus could allow for more definitive initial thyroidectomy in those with positive results.

High expression of the urokinase plasminogen activator and its cognate receptor associates with advanced stages and reduced disease-free interval in papillary thyroid carcinoma

CONTEXT

The urokinase plasminogen activating system is implicated in neoplastic progression, and high tissue levels of urokinase plasminogen activating system components correlate with poor prognosis in various human cancers.

OBJECTIVE

The objective of the study was to investigate the prognostic relevance of the urokinase plasminogen activator (uPA), its cognate receptor (uPAR), and the plasminogen activator inhibitor 1 (PAI-1) in human papillary thyroid cancer (PTC).

DESIGN

The expression of uPA, uPAR, and PAI-1 genes was analyzed in PTC and normal matched tissues by quantitative RT-PCR. The case study consisted of 99 patients (21 males and 78 females) affected by PTC including 77 classical, 15 follicular, four tall cell, and three oncocytic variants. Forty-one patients had lymph node metastases at the time of diagnosis. All the patients underwent thyroidectomy and radioiodine therapy followed by thyroid hormone replacement therapy. Follow-up data were available for 76 patients up to 64 months.

RESULTS

The uPA, uPAR, and PAI-1 mRNA levels were significantly higher in PTC compared with normal matched tissues by 9.63 ± 1,29-, 4.82 ± 0.45-, and 5.64 ± 0.71-fold, respectively. The increased expression of uPA and uPAR correlated statistically with advanced pT and N status. The uPA was also significantly associated with advanced tumor node metastasis stages. The Kaplan-Meier analysis showed a significant association of uPA and uPAR levels with reduced patient disease-free interval (DFI), and this association was stronger in stage I patients.

CONCLUSION

The study demonstrated that in PTC the increased gene expression of uPA and uPAR is associated with tumor invasiveness, advanced stages, and shorter DFI, suggesting their prognostic relevance. These observations warrant further investigation in larger patient populations with longer follow-up.

A prospective study evaluating the accuracy of using combined clinical factors and candidate diagnostic markers to refine the accuracy of thyroid fine needle aspiration biopsy

BACKGROUND

Approximately 30% of fine needle aspiration biopsies of the thyroid have inconclusive results. We conducted a prospective trial to determine whether clinical and molecular markers could be used in combination to improve the accuracy of thyroid fine needle aspiration biopsy.

METHODS

Clinical, tumor genotyping for common somatic mutations (BRAF V600E, NRAS, KRAS, RET/PTC1, RET/PTC3, and NTRK1), and the gene expression levels of 6 candidate diagnostic markers were analyzed by univariate and multivariate methods in 341 patients to determine whether they could distinguish reliably benign from malignant thyroid neoplasms, and a scoring model was derived.

RESULTS

By a multivariate analysis, fine needle aspiration biopsy cytology classification, the presence of a NRAS mutation, and the tissue inhibitor of metalloproteinase 1 expression level were associated jointly with malignancy. The overall accuracy of the scoring model, including these 3 variables, to distinguish benign from malignant thyroid tumors was 91%, including 67% for the indeterminate and 77% for the suspicious FNA subgroups.

CONCLUSION

Fine needle aspiration biopsy cytology classification, the presence of NRAS mutation, and tissue inhibitor of metalloproteinase 1 messenger RNA expression levels in combination provide a greater diagnostic accuracy than fine needle aspiration biopsy cytology alone to allow selection of more definitive initial operative treatment. The sensitivity of the scoring model, however, was too low to avoid the need for diagnostic thyroidectomies for indeterminate fine needle aspiration biopsy findings.

Tumorigenic and metastatic activity of human thyroid cancer stem cells

Thyroid carcinoma is the most common endocrine malignancy and the first cause of death among endocrine cancers. We show that the tumorigenic capacity in thyroid cancer is confined in a small subpopulation of stem-like cells with high aldehyde dehydrogenase (ALDH(high)) activity and unlimited replication potential. ALDH(high) cells can be expanded indefinitely in vitro as tumor spheres, which retain the tumorigenic potential upon delivery in immunocompromised mice. Orthotopic injection of minute numbers of thyroid cancer stem cells recapitulates the behavior of the parental tumor, including the aggressive metastatic features of undifferentiated thyroid carcinomas, which are sustained by constitutive activation of cMet and Akt in thyroid cancer stem cells. The identification of tumorigenic and metastagenic thyroid cancer cells may provide unprecedented preclinical tools for development and preclinical validation of novel targeted therapies.

Surgical implications of B-RafV600E mutation in fine-needle aspiration of thyroid nodules

BACKGROUND

Management of patients with thyroid nodules is based on establishing an accurate diagnosis; however, differentiating benign from malignant lesions preoperatively is not always possible using current cytological techniques. Novel molecular testing on cytological material could lead to clearer treatment algorithms. B-Raf(V600E) mutation is the most common genetic alteration in thyroid cancer, specifically found in papillary thyroid cancer (PTC), and usually reported to be associated with aggressive disease.

DATA SOURCE

A literature search using PubMed identified all the pertinent literature on the identification and utilization of the B-Raf(V600E) mutation in thyroid cancer.

CONCLUSIONS

The utility of using B-Raf mutation testing for nodules with indeterminate cytology is limited since many of those nodules (benign and malignant) do not harbor B-Raf mutations. However, when the pathologist sees cytological features suspicious for PTC, B-Raf(V600E) mutation analysis may enhance the assessment of preoperative risks for PTC, directing a more aggressive initial surgical management when appropriate.

The evolution of biomarkers in thyroid cancer-from mass screening to a personalized biosignature

Thyroid cancer is the most common malignancy of the endocrine system. The diagnosis of thyroid nodules, made by neck examination and ultrasonography, is a common event occurring in over 50% of the patient population over the age of 50. Yet, only 5% of these patients will be diagnosed with cancer. Fine needle aspiration biopsy is the gold standard for diagnosing thyroid nodules. However, 10–15% of these biopsies are inconclusive, ultimately requiring a diagnostic thyroid lobectomy. Consequently, research in thyroid biomarkers has become an area of active interest. In the 40 years since calcitonin was first described as the biomarker for medullary thyroid cancer, new biomarkers in thyroid cancer have been discovered. Advances in genomic and proteomic technologies have defined many of these novel thyroid biomarkers. The purpose of this article is to provide a comprehensive literature review of how these biomarkers have evolved from simple screening tests into a complex array of multiple markers to help predict the malignant potential and genetic signature of thyroid neoplasms.

Targeted therapies in thyroid cancer

Differentiated thyroid carcinoma is the most frequent neoplasm of the endocrine system. Although thyroid cancer usually has an excellent prognosis, no therapeutic options are available for patients that develop metastases and are or became resistant to radioiodine therapy. The deeper knowledge of molecular aberrations that characterize tumor growth has provided novel targets in cancer therapy. Several proteins have been implicated as having a crucial role in the carcinogenesis of differentiated thyroid cancer, such as those involved in RET/PTC-RAS-RAF-MAPK pathway. Moreover, vascular aberrations and angiogenesis equilibrium have also been related to tumor growth. The development of new, targeted therapies and their encouraging initial results have opened a hopeful opportunity of treatment for these orphan therapy tumor patients.

Assessment of morphology, antigenicity, and nucleic acid integrity for diagnostic thyroid pathology using formalin substitute fixatives

BACKGROUND

With the advent of the formaldehyde standard law in France, and because of the impact of new methods for diagnosis and prognosis in pathology, formalin replacement in surgical pathology laboratories is currently being discussed in France. However, a set of criteria must be assessed before introducing a formalin substitute fixative. The objective of this study was to compare formalin substitute fixation with formalin fixation and cryoconservation of tissues from several benign and malignant thyroid pathologies with respect to morphology, antigenicity, and nucleic acid (RNA, DNA, microRNA) integrity.

METHODS

Calibrated specimens (200 mg, 1 cm(2) each) from four conventional papillary thyroid carcinomas, four follicular variant of papillary thyroid carcinomas, three minimally invasive follicular carcinomas, four thyroid adenomas, five thyroid nodular hyperplasias, and five normal thyroid tissues were fixed for 6, 12, or 24 hours, in different fixatives (formalin, Glyo-Fixx, FineFIX, ExcellPlus, RCL2) at room temperature or at 4 degrees C. Tissues were stained (hematoxylin-eosin, periodic acid Schiff, trichromic Masson, and Sweet-Gordon staining) and their antigenicity determined by immunohistochemistry (performed with HBME-1, galectin-3, CK19, vimentin, CD31, and KL1 antibodies). Evaluation by four pathologists was made blinded. The quantity and quality of DNA, RNA, and two representative microRNA extracted from deparaffinized sections of paraffin embedded specimen were compared with that of cryosections.

RESULTS

The staining and morphology were not altered by the use of different fixatives. However, formalin, FineFIX, and RCL2 gave the best results for immunohistochemistry. Moreover, FineFIX and RCL2 gave the highest amount of nucleic acids and of the best quality.

CONCLUSIONS

All the formalin substitute fixatives used in this study provided good histomorphologic quality for the different stained thyroid tissues, but individually, some fixatives performed better for immunohistochemical and molecular biological procedures for different thyroid pathologies.

Diagnostic markers and prognostic factors in thyroid cancer

There has been considerable progress identifying biomarkers in thyroid tumors that improve the accuracy of fine-needle aspiration biopsy and also help predict tumor aggressiveness or behavior. In this review we address both the clinical potential of molecular biomarkers and their usefulness, based on the most recent literature. We describe the current best clinical staging systems and the common somatic mutations in thyroid cancer. The BRAF mutation is the most common mutation in papillary thyroid cancer and has recently been reported to be associated with disease aggressiveness; it is also an independent predictor of tumor behavior. Combined testing of RET/PTC, NTRK, RAS and PAX8–PPARγ, which are mutually exclusive mutations, helps improve the accuracy of fine-needle aspiration biopsy. Gene-expression profiling studies have identified a variety of potential molecular markers to help distinguish benign from malignant thyroid neoplasms. Expression analysis of differentially expressed microRNAs also appears to be a promising diagnostic approach for distinguishing benign from malignant thyroid neoplasm. It is especially useful for indeterminate nodules by fine-needle aspiration biopsy.

Multiple genetic alterations in papillary thyroid cancer are associated with younger age at presentation

BACKGROUND

There is a significant gender and age disparity in thyroid cancer incidence and outcome. The molecular basis for these divergent clinical presentations and outcome are essentially unknown.

METHODS

The primary tumor genotype in 217 patients with papillary thyroid cancer was determined for six common somatic genetic alterations (RET/PTC1, RET/PTC3, and NTRK1 rearrangements, and BRAF V600E, KRAS, and NRAS hotspot mutations) by PCR and direct sequencing, and nested PCR. Univariate and multivariate analyses were performed to determine the association of genetic changes and age, gender, and other clinicopathologic factors.

RESULTS

One hundred twenty-one of the 190 conventional papillary thyroid carcinoma samples (63.7%) had at least one genetic alteration, and 27 of the samples (14.2%) had more than one alteration. In the follicular variant of papillary thyroid carcinomas, 13 of the 27 samples (48.1%) had at least one genetic alteration and three of the 27 samples (11.1%) had more than one. The presence of multiple genetic alterations was associated with younger age at diagnosis (P=0.034), mean difference of 8 y earlier. We found no significant association with the number or type of genetic alterations present by gender, tumor size, extent of tumor differentiation, multicentricity, lymph node metastasis, distant metastases, TNM stage, and the AMES risk group. The association of multiple genetic alterations and younger age were independent of tumor size, lymph node or distant metastasis, TNM stage, or AMES risk group.

CONCLUSIONS

Multiple genetic alterations are more common in younger patients with papillary thyroid cancer, but there is no difference in the type or number of genetic alterations by gender. Our findings suggest that multiple genetic alterations in thyroid cancer may be associated with earlier disease initiation and or progression.

BRAFV600E mutation and X-linked inhibitor of apoptosis expression in papillary thyroid carcinoma

BACKGROUND

The BRAF mutation V600E (BRAF(V600E)) is the most common genetic alteration in papillary thyroid carcinoma (PTC), while overexpression of X-linked inhibitor of apoptosis (XIAP) has been found in various tumors. Both of these events are implicated in carcinogenesis, tumor progression, recurrence, etc. There are few reports, however, of the BRAF(V600E) mutation and XIAP overexpression in PTC patients. The aim of this study was to investigate the frequency of the BRAF(V600E) mutation in PTC and its relationship to clinicopathological parameters and the expression of XIAP.

METHODS

Genomic DNA was extracted from 123 paraffin-embedded PTC tumor tissue samples and amplified for analysis of the V600E mutation in exon 15 of the BRAF gene by polymerase chain reaction. XIAP expression was examined by immunohistochemical methods in 46 PTCs, 18 benign nodular goiters, and 10 Hashimoto's thyroiditis samples.

RESULTS

The BRAF(V600E) mutation was found in 34.1% of PTC, and was especially prevalent in the classic type. BRAF(V600E) was significantly correlated with younger age at diagnosis (p = 0.026), tumor size (p = 0.009), and histological variants (p = 0.024). There was a trend towards association with extrathyroidal invasion (p = 0.067). By logistic regression analysis, a significant relationship was found between tumor size and the BRAF(V600E) mutation (p = 0.03). XIAP was expressed in 82.6% of PTCs, which was a higher percentage than observed in the group of benign thyroid disorders (35.7%, p < 0.001). Neither the intensity (p = 0.611) nor the extent (p = 0.723) of XIAP staining was correlated with the presence of BRAF(V600E) in PTC patients.

CONCLUSIONS

These data indicate that BRAF(V600E) is associated some of the aggressive clinicopathological features of PTC including younger age at diagnosis, larger tumor size, and classic histological type, as well as also extrathyroidal invasion. XIAP-positive staining was more prevalent in PTCs than in the benign thyroid disorders. Although BRAF(V600E) and XIAP expression are commonly seen in PTC, their presence together seems unrelated.

Recent developments in predicting thyroid malignancy

PURPOSE OF REVIEW

To provide an update on potential predictors of thyroid malignancy and how their use may alter clinical management.

RECENT FINDINGS

As thyroid nodules become more prevalent clinicians are increasingly impelled to identify the optimal predictor(s) of thyroid malignancy, with the goal of guiding management based on assessed risk. The gold standard evaluation for thyroid nodules is ultrasound-guided fine-needle aspiration biopsy. Fine-needle aspiration biopsy is not perfect and adjuncts which complement its predictive value are being investigated from several innovative perspectives. These include large tumor size (> or =4 cm), which appears to be an independent predictor of thyroid malignancy; 18F-fluorodeoxyglucose positron emission tomography, which appears to facilitate exclusion of malignancy in cytologically indeterminate thyroid nodules; and peripheral blood and fine-needle aspiration biopsy analysis of molecular markers, which may help to identify malignant thyroid nodules with greater specificity.

SUMMARY

Fine-needle aspiration biopsy of large thyroid nodules has a high false-negative rate and should be considered for diagnostic lobectomy. Nodule size appears to be an independent factor predicting malignancy and indeterminate lesions at least 4 cm should be considered for initial total thyroidectomy. Nuclear imaging may aid exclusion of malignancy in thyroid nodules and molecular markers have great promise in predicting thyroid malignancy with higher specificity.