The role of cell cycle regulatory proteins, cyclin D1, cyclin E, and p27 in thyroid carcinogenesis

Designed hybrid anticancer nuclear-localized peptide inhibits aggressive cancer cell proliferation

Cell proliferation is a crucial step that might promote cancer if deregulated. Therefore, this vital segment is critically controlled by a complicated cell-cycle process in normal cells that is regulated by some regulatory proteins. It has been observed that p16 protein, playing a crucial role in cell-cycle progression/regulation, remains inactivated in different cancer cells. This inactivity of p16 protein leads to the enhancement of cancer cell proliferation by allowing uncontrolled cancer cell division. Hence, the activity of p16 protein needs to be restored using new viral vectors, small molecules as well as peptides to control/suppress this type of abnormal cell proliferation. In this work, we have taken an interesting approach to increase the efficiency and bio-availability of p16 peptide (functional part of p16 protein) to be an aggressive anti-leukemia therapeutic agent by conjugating a nuclear-localized signal (NLS) sequence and a short peptide (AVPI) with it. Moreover, this newly designed NLS attached hybrid peptide greatly affects XIAP expressing but p16 lower expressing human chronic myelogenous leukemia (CML) cell proliferation by targeting both nuclear (CDK4/cyclin D) and cellular factors (XIAP) and promoting the caspase-3 dependent apoptosis pathway.

Influence of thyroid hormone in the expression of the marker pro-apoptosis BID, in spite of the predominance of anti-apoptosis activation in intratiroidal lymphocytic infiltration in Hashimoto's thyroiditis

Cell destruction in Hashimoto's thyroiditis (HT) involves autoantibodies and cytotoxic T lymphocytes. Thyrocytes maintenance occurs by pro-apoptotic, anti-apoptotic and cell proliferation balance.

OBJECTIVES

To characterize factors related to the mechanisms of apoptosis and cell proliferation in thyroid cells and intrathyroid lymphocytic infiltrate in HT.

METHODS

We assessed lymphocytic infiltrate and thyroid cells from HT and normal thyroid by immunohistochemical analysis of cell proliferation (Ki-67), antiproliferation (p27Kip1), pro-apoptosis (Fas, Fas-ligand, BID) and anti-apoptosis (MCL-1, BCL2) markers.

RESULTS

Lymphocytic infiltrate presented BCL2 and MCL-1 higher expression, Ki-67 and p27kip1 balance. Thyrocytes exhibited Fas and FasL balance, higher BID expression; MCL-1, BCL-2, Ki-67 similar to the normal thyroid. T4 and higher lymphocytes BID expression were associated.

CONCLUSIONS

In lymphocytic infiltrate predominated anti-apoptosis in relation to pro-apoptosis except for BID. Thyrocytes presented pro-apoptosis and anti-apoptosis balance and cell proliferation similar to normal thyroid. T4-associated BID expression in HT lymphocytes suggests the influence of thyroid hormone as a signal to up-regulate the BID pro-apoptotic protein and thus increase lymphocytic apoptosis rates.

Co-Occurrence of Differentiated Thyroid Cancer and Second Primary Malignancy: Correlation with Expression Profiles of Mismatch Repair Protein and Cell Cycle Regulators

Simple Summary

Although the incidence of thyroid cancer is increasing, improvements in treatment have resulted in more patients being confirmed to have a second primary cancer. However, studies on potential biomarkers for predicting the risk of second primary malignancy are extremely limited. Therefore, our objective was to establish molecular biomarkers for the risk prediction of second primary malignancy using routinely collected formalin-fixed paraffin-embedded tissue specimens. Our results suggest that the deficient mismatch repair phenotype, the expression of pRb, and the lack of CDK4 or CDK6 are significantly associated with co-occurrence of nonthyroid malignancy. The predictive value of these immunohistochemical profiles for the co-occurrence of nonthyroid malignancy was also assessed. The combined evaluation of a four-biomarker signature model may provide the most important predictive innovation. Our study proposes the first tissue-based screening tool for risk stratification and further active surveillance in patients with thyroid cancer.

Abstract

Some patients with thyroid cancer develop a second primary cancer. Defining the characteristics of patients with double primary cancers (DPCs) is crucial and needs to be followed. In this study, we examine molecular profiles in DPC. We enrolled 71 patients who received thyroid cancer surgery, 26 with single thyroid cancer (STC), and 45 with DPC. A retrograde cohort was used to develop immunohistochemical expressions of mismatch repair (MMR) proteins and cell-cycle-related markers from tissue microarrays to produce an equation for predicting the occurrence of DPC. The multivariate logistic model of 67 randomly selected patients (24 with STC and 43 with DPC) identified that the expression of deficient MMR (dMMR) (odds ratio (OR), 10.34; 95% confidence interval (CI), 2.17–49.21) and pRb (OR, 62.71; 95% CI, 4.83–814.22) were significantly associated with a higher risk of DPC. In contrast, the expression of CDK4 (OR, 0.19; 95% CI, 0.04–0.99) and CDK6 (OR, 0.03; 95% CI, 0.002–0.44) was significantly associated with a lower risk of DPC. Collectively, dMMR, pRb, CDK4, and CDK6 have a sensitivity of 88.9% (95% CI, 75.1–95.8) and a specificity of 69.2% (95% CI, 48.1–84.9) for occurrence of DPC in all 71 patients. This is the first report to demonstrate the molecular differentiation of STC and DPC. Overall, the integral molecular profile performed excellent discrimination and denoted an exponential function to predict the probability of DPC.

Assessment of Biomarkers for Clinical Diagnosis of Papillary Thyroid Carcinoma with Distant Metastasis

Early diagnosis and treatment of thyroid cancers are critical for better prognosis and better survival rates. The purpose of this study was to identify potential diagnostic markers for papillary thyroid carcinomas with distant metastasis. Fifty-eight papillary thyroid tumor specimens (27 papillary thyroid carcinomas with distant metastasis and 31 without metastasis) were examined, and protein expression of pituitary tumor-transforming gene (PTTG), E-cadherin, p27kip1, vascular endothelial growth factor (VEGF)-C, metalloproteinase (MMP) 2, MMP9, chemokine receptor CXCR4, and basic fibroblast growth factor (bFGF) in these tumors was assessed by immunohistochemistry. The clinicopathological variables with diagnostic significance were determined by multivariate analysis, and their diagnostic values were evaluated by ROC curve analysis. PTTG, VEGF-C, MMP2, MMP9, CXCR4, and bFGF were overexpressed in metastatic papillary thyroid carcinomas, whereas p27kip1 expression was elevated only in carcinomas lacking metastasis. Multiple-factor binary ordinal logistic regression analysis revealed that PTTG, VEGF-C, MMP2, and bFGF were independently related to biological metastatic behavior in thyroid tumors, suggesting their potential use as biomarkers. ROC curve analysis showed that among these four proteins, VEGF-C and bFGF were the best diagnostic biomarkers. A VEGF-C and bFGF cluster was the most useful factor for the differential diagnosis between metastatic and non-metastatic papillary thyroid cancers. Thus, the combined use of VEGF-C and bFGF as biomarkers may improve the diagnostic accuracy of papillary thyroid carcinoma and may be useful in multimodal screening programs for the clinical diagnosis of papillary thyroid carcinoma and early detection of papillary thyroid carcinoma with distant metastasis.

A selective cyclin-dependent kinase 4, 6 dual inhibitor, Ribociclib (LEE011) inhibits cell proliferation and induces apoptosis in aggressive thyroid cancer

The RB-E2F1 pathway is an important mechanism of cell-cycle control, and deregulation of this pathway is one of the key factors contributing to tumorigenesis. Cyclin-dependent kinases (CDKs) and Cyclin D have been known to increase in aggressive thyroid cancer. However, there has been no study to investigate effects of a selective CDK 4/6 inhibitor, Ribociclib (LEE011), in thyroid cancer. Performing Western blotting, we found that RB phosphorylation and the expression of Cyclin D are significantly higher in papillary thyroid cancer (PTC) cell lines as well as anaplastic thyroid cancer (ATC) cell lines, compared with normal thyroid cell line and follicular thyroid cancer cell line. LEE011 dose-dependently inhibited RB phosphorylation and also decreased the expressions of its target genes such as FOXM1, Cyclin A1, and Myc in ATC. Furthermore, LEE011 induced cell cycle arrest in G0-G1 phase and cell apoptosis, and inhibited cell proliferation in ATC. Consistently, oral administration of LEE011 to ATC xenograft models strongly inhibited tumor growth with decreased expressions of pRB, pAKT and Ki-67, and also significantly increased tumor cell apoptosis. Taken together, our data support the rationale for clinical development of the CDK4/6 inhibitor as a therapy for patients with aggressive thyroid cancer.

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.

Simultaneous Targeting of Bladder Tumor Growth, Survival, and Epithelial-to-Mesenchymal Transition with a Novel Therapeutic Combination of Acetazolamide (AZ) and Sulforaphane (SFN)

BACKGROUND

Current chemotherapies for advanced stage metastatic bladder cancer often result in severe side effects, and most patients become drug resistant over time. Thus, there is a need for more effective therapies with minimal side effects.

OBJECTIVE

The acid/base balance in tumor cells is essential for tumor cell functioning. We reasoned that simultaneous targeting of pH homeostasis and survival pathways would improve therapeutic efficacy. We evaluated the effectiveness of targeting pH homeostasis with the carbonic anhydrase inhibitor acetazolamide (AZ) in combination with the survival pathway targeting isothiocyanate sulforaphane (SFN) on the HTB-9 and RT112(H) human bladder tumor cell lines.

MATERIALS AND METHODS

We assessed viability, proliferation, and survival in vitro and effect on xenografts in vivo.

RESULTS

Combination AZ + SFN treatment induced dose-dependent suppression of growth, produced a potent anti-proliferative and anti-clonogenic effect, and induced apoptosis through caspase-3 and PARP activation. The anti-proliferative effect was corroborated by significant reductions in Ki-67, pHH3, cyclin D1, and sustained induction of the cell cycle inhibitors, p21 and p27. Both active p-Akt (Ser473) and p-S6 were significantly downregulated in the AZ + SFN combination treated cells with a concomitant inhibition of Akt kinase activity. The inhibitory effects of the AZ + SFN combination treatment showed similar efficacy as the dual PI3K/mTOR pathway inhibitor NVP-BEZ235, albeit at an expected higher dose. In terms of the effect on the metastatic potential of these bladder cancers, we found downregulated expression of carbonic anhydrase 9 (CA9) concomitant with reductions in both E-cadherin, N-cadherin, and vimentin proteins mitigating the epithelial-to-mesenchymal transition (EMT), suggesting negation of this program.

CONCLUSION

We suggest that reductions in these components could be linked with downregulation of the survival mediated Akt pathway and suggested an active role of the Akt pathway in bladder cancer. Altogether, our in vitro and pre-clinical model data support the potential use of an AZ + SFN combination for the treatment of bladder cancer.

Five Top Stories in Thyroid Pathology

CONTEXT

Thyroid carcinoma is the most common malignant tumor of endocrine organs, yet it only accounts for approximately 1% of all cancers in the United States with more than 35,000 new cases diagnosed each year and more than 450,000 people living with this disease. While most tumors can be diagnosed without much difficulty, a few tumor types, especially tumors with follicular pattern, sometimes pose a diagnostic challenge.

OBJECTIVE

To discuss morphologic, immunohistochemical, and molecular features of thyroid tumors. We also explore the clinicopathologic features of papillary microcarcinoma and medullary microcarcinoma and how the latter is related and differentiated from C-cell hyperplasia. Finally with the ever-growing list of organ systems involved in immunoglobulin (Ig) G4-related diseases, we discuss the still not completely explored IgG-4-related thyroid disease.

DATA SOURCES

Data were obtained from review of the pertinent peer-reviewed literature and institutional experience.

CONCLUSIONS

Histomorphologic evaluation still remains the gold standard for diagnosis in most cases of thyroid diseases. The application of ancillary studies such as immunohistochemistry and molecular diagnosis, including next-generation sequencing, is becoming more common.

Effects of BP-14, a novel cyclin-dependent kinase inhibitor, on anaplastic thyroid cancer cells

Anaplastic thyroid carcinoma (ATC) is an extremely aggressive human malignancy characterized by a marked degree of invasiveness, absense of features of thyroid differentiation and resistance to current medical treatment. It is well known that ATCs are characterized by deregulation of genes related to cell cycle regulation, i.e., cyclin-dependent kinases (CDKs) and endogenous cyclin-dependent kinase inhibitors (CDKIs). Therefore, in the present study, the effect of a novel exogenous cyclin-dependent kinase inhibitor, BP-14, was investigated in three human ATC cell lines. The ATC-derived cell lines FRO, SW1736 and 8505C were treated with BP-14 alone or in combination with the mTOR inhibitor everolimus. In all ATC cell lines, treatment with BP-14 decreased cell viability and, in two of them, BP-14 modified expression of genes involved in epithelial-mesenchymal transition. Thus, our data indicate that BP-14 is a potential new compound effective against ATC. Combined treatment with BP-14 and the mTOR inhibitor everolimus had a strong synergistic effect on cell viability in all three cell lines, suggesting that the combined used of CDK and mTOR inhibitors may be a useful strategy for ATC treatment.

Immunohistochemical Subcellular Localization of Protein Biomarkers Distinguishes Benign from Malignant Thyroid Nodules: Potential for Fine-Needle Aspiration Biopsy Clinical Application

BACKGROUND

It is of critical clinical importance to select accurately for surgery thyroid nodules at risk for malignancy and avoid surgery on those that are benign. Using alterations in subcellular localization for seven putative biomarker proteins (identified by proteomics), this study aimed to define a specific combination of proteins in surgical tissues that could distinguish benign from malignant nodules to assist in future surgical selection by fine-needle aspiration biopsy (FNAB).

METHODS

Immunohistochemical subcellular localization (IHC) analyses of seven proteins were retrospectively performed on surgical tissues (115 benign nodules and 114 papillary-based thyroid carcinomas [TC]), and a risk model biomarker panel was developed and validated. The biomarker panel efficacy was verified in 50 FNAB formalin-fixed and paraffin-embedded cell blocks, and 26 cytosmears were prepared from fresh surgically resected thyroid nodules.

RESULTS

Selection modeling using these proteins resulted in nuclear phosphoglycerate kinase 1 (PGK1) loss and nuclear Galectin-3 overexpression as the best combination for distinguishing TC from benign nodules (area under the curve [AUC] 0.96 and 0.95 in test and validation sets, respectively). A computed malignancy score also accurately identified TC in benign and indeterminate nodules (test and validation sets: AUC 0.94, 0.90; specificity 98%, 99%). Its efficacy was confirmed in surgical FNAB cell blocks and cytosmears.

CONCLUSION

Using surgical tissues, it was observed that a combination of PGK1 and Galectin-3 had high efficiency for distinguishing benign from malignant thyroid nodules and could improve surgical selection for TC among indeterminate nodules. Further validation in prospective preoperative FNAB will be required to confirm such a clinical application.

Application of Immunohistochemistry in Thyroid Pathology

Context

Accurate classification of follicular-patterned thyroid lesions is not always an easy task on routine surgical hematoxylin-eosin–stained or cytologic fine-needle aspiration specimens. The diagnostic challenges are partially due to differential diagnostic criteria that are often subtle and subjective. In the past decades, tremendous advances have been made in molecular gene profiling of tumors and diagnostic immunohistochemistry, aiding in diagnostic accuracy and proper patient management.

Objective

To evaluate the diagnostic utility of the most commonly studied immunomarkers in the field of thyroid pathology by review of the literature, using the database of indexed articles in PubMed (US National Library of Medicine) from 1976–2013.

Data Sources

Literature review, authors' research data, and personal practice experience.

Conclusions

The appropriate use of immunohistochemistry by applying a panel of immunomarkers and using a standardized technical and interpretational method may complement the morphologic assessment and aid in the accurate classification of difficult thyroid lesions.

Immunohistochemical Diagnosis of Thyroid Tumors

Recent insight into the molecular mechanisms of thyroid carcinogenesis has led to studies involving newly directed antibodies. With the introduction of new molecular targeted therapies, these antibodies may represent useful predictors of therapeutic response in tumors unresponsive to radioiodine or insensitive to conventional antitumor therapies. These markers complement the development of markers that are able to discern benign from malignant entities, including hyalinizing trabecular tumors, oncocytic neoplasms, and follicular variant of papillary thyroid carcinoma. The use of antibodies directed to proteins generated by mutated genes may represent a cost-effective method for diagnosing and managing patients affected by thyroid tumors.

CCND1 gene polymorphic variants in patients with differentiated thyroid carcinoma

Alterations in the CCND1 gene affect the cell cycle and are frequently observed in a variety of cancers. While the most frequent mutations that occur in thyroid tumor tissue have been characterized, the genetic factors that predispose individuals to differentiated thyroid cancer (DTC) remain to be elucidated. The present study examined whether the CCND1 c.723G>A (rs9344; p.Pro241=) and c.669C>T (rs3862792; p.Phe223=) variants have an impact on DTC susceptibility. A cohort consisting of 652 patients diagnosed with DTC were analyzed and comapred with a reference group of 799 subjects from the general population. Pyrosequencing was used as the genotyping technique. In order to determine the statistical significance of differences observed in the genotypic and allelic frequencies between the compared groups, GraphPad Prism 4 was used. At the rs9344 locus in the DTC patients, a higher frequency of allele A [P=0.032; odds ratio (OR), 1.18; 95% confidence interval (CI), 1.014–1.361] and the AA homozygous genotype (P=0.028; OR, 1.41; 95% CI, 1.059–1.989) was observed compared with the control population group. The differences were stronger for papillary carcinomas (OR 1.45; 95% CI, 1.059–1.989), but were not significant in follicular tumors. No statistically significant differences were noted in the frequency of genotypes or alleles at the rs3862792 locus in the examined groups. The present findings indicate that the c.723A variant of the CCDN1 gene may be a susceptibility low penetrance allele in the development of papillary thyroid cancer in the population studied, however it does not impact on multifocality, metastatic ability or age at diagnosis. A cumulative effect of the analyzed CCND1 gene variants was also excluded.

Cyclin E involved in early stage carcinogenesis of esophageal adenocarcinoma by SNP DNA microarray and immunohistochemical studies

Background

Cyclin E is a cell cycle regulator which is critical for driving G1/S transition. Abnormal levels of cyclin E have been found in many cancers. However, the level changes of cyclin E in esophageal adenocarcinoma and its precancerous lesion have not been well studied. Here, we focus on the gene amplification and expression of cyclin E in these lesions, and aim to ascertain the relationship with clinicopathological characteristics.

Methods

Genomic DNA was analyzed from 116 esophageal adenocarcinoma and 26 precancerous lesion patients using Affymetrix SNP 6.0 arrays. The protein overexpression of cyclin E was also detected using immunohistochemistry from tissue microarrays containing esophageal adenocarcinoma and precancerous lesions. Patient survival and other clinical data were collected and analyzed. The intensity and percentage of the cyclin E expressing cells in tissue microarrays were scored by two pathologists. Fisher exact tests and Kaplan-Meier methods were used to analyze data.

Results

By genomic analysis, cyclin E was amplified in 19.0% of the EAC samples. By immunohistochemistry, high expression of cyclin E was observed in 2.3% of squamous mucosa tissues, 3.7% in columnar cell metaplasia, 5.8% in Barrett’s esophagus, 19.0% in low grade dysplasia, 35.7% in high grade dysplasia, and 16.7% in esophageal adenocarcinoma. The differences in cyclin E high expression between neoplastic groups and non-dysplasia groups are statistically significant (p < 0.05). The prognosis for patients with high cyclin E expression appeared slightly better than for those with low cyclin E expression although this was not statistically significant (p = 0.13).

Conclusions

The expression of cyclin E significantly increases from non-dysplasia esophageal lesion to low and high grade dysplasia, suggesting that cyclin E plays an important role in the early stage of carcinogenesis. Importantly, cyclin E is also amplified and highly expressed in a subset of esophageal adenocarcinoma patients, but this increase is not associated with worse prognosis.

Cyclin D1 expression in benign and differentiated malignant tumors of the thyroid gland: diagnostic and biologic implications

Cyclin D1 expression was examined in benign and differentiated malignant thyroid tumors to determine diagnostic utility and correlation with tumor type, size, and nodal status; 29 follicular adenomas (FA), 23 follicular carcinomas (FCA) and 43 papillary thyroid carcinomas (PTC) (22 with and 21 without nodal metastases) were stained. PTCs included 27 classical (PTCC) and 16 follicular variants (PTCFV). A statistically significant association was found between tumor type and cyclin D1 staining, distribution, and intensity. There were fewer cyclin D1-positive FAs than PTCs (52% vs. 88% respectively; P<0.001) and stain distribution was greater in PTC than FA (P=0.032). More PTCs were positive than FCAs (88% vs. 61%, respectively; P=0.013). All significant comparisons remained significant after adjusting for tumor size. FA did not differ from FCA in staining/intensity. There were fewer cyclin D1-positive FAs than PTCC (52% vs. 89%, respectively; P=0.003) and PTCFV (52% vs. 88%, respectively; P=0.023). FCA also differed significantly from PTCC in staining (61% vs. 89%, respectively; P=0.044) and intensity (P=0.024). In terms of cyclin D1 intensity, FA had significantly less intense staining than PTCC (P=0.004). No significant associations were found between PTC nodal status and any cyclin D1 characteristic. In conclusion, cyclin D1 shows heterogeneity in distribution and intensity in benign and malignant thyroid tumors, which disqualifies it as a primary diagnostic marker in these tumors; however, it may be helpful in distinguishing FA from PTC, especially PTCFV. Its expression by thyroid tumors suggests a role in tumor development and may be an early event in thyroid neoplasia.

Multifaceted suppression of aggressive behavior of thyroid carcinoma by all-trans retinoic acid induced re-differentiation

Since all-trans retinoic acid (ATRA) has shown promising results in differentiation therapy, the present study was designed to investigate the effects of ATRA on thyroid carcinoma and to evaluate the effectiveness of ATRA in redifferentiation induction of thyroid carcinoma. Therefore, we investigated cell growth rate, morphological and nuclear: cytoplasmic ratio, adherent-dependent growth, response to chemotherapy drug following differentiation, T3 and T4 measurement, and critical genes expression pattern. Papillary cell line showed more growth inhibition by ATRA, in addition, mesenchymal and spindle-shape of 8305C cells changed to polygonal. Additionally, high nuclear: cytoplasmic ratio of anaplastic decreased significantly. Redifferentiation significantly suppressed the anchorage-dependent growth in the both cell lines in a dose-dependent manner, potentiated the arsenic trioxide (ATO) effects in anaplastic and papillary cell lines. Furthermore, reduction in the expression of stemness, and invasion related genes was observed in the both cell lines. Altogether, ATRA treatment could hold the aggressive behavior of thyroid carcinoma in restraint and/or potentiate the effect of chemotherapy drug ATO.

Differential expression of cyclin D1 in human pituitary tumors: relation to MIB-1 and p27/Kip1 labeling indices

BACKGROUND

Pituitary tumors are a common form of endocrine neoplasia. However few studies assessed the expression of the principal cyclin regulating checkpoint exit, cyclin D1. Cyclin D1 expression in pituitary tumors and its possible relation to MIB-1 and p27/Kip1 labeling indices (LIs) was explored.

DESIGN

We studied a total of 199 pituitaries, including normal pituitaries (n=7), pituitary adenomas (n=187), and pituitary carcinoma (n=5). All tissues were tested as cores of archived tissue microarrays that were immunostained for cyclin D1, MIB-1 and p27 using a standard technique. Tissue cores were subjected to automated analysis to evaluate the staining LIs.

RESULTS

No cyclin D1 positive cells in the normal anterior pituitary gland was found. Sparse nuclear staining was noted in pituitary tumors. Higher expression of cyclin D1 was noted in pituitary carcinomas compared to adenomas (p<0.001), in non-functioning adenomas compared to functioning ones (p<0.001) in macroadenomas versus microadenomas (p=0.017) and in recurrent non recurrent adenomas (p<0.001). Cyclin D1 LI and MIB-1 LI were related among adenomas (p<0.001) and carcinomas (p=0.041). p27 LI was neither related to pituitary adenoma recurrence nor invasion.

CONCLUSIONS

Expression of cyclin D1 in pituitary tumors is related to cell proliferation, recurrence, and metastatic potential. Nuclear cyclin D1 expression is a good marker of aggressive behavior in pituitary tumors.

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

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

Expression of cell-cycle regulators (cyclin D1, cyclin E, p27kip1, p57kip2) in papillary thyroid carcinoma

Objective: To evaluate the expression of cell-cycle regulators in papillary thyroid carcinoma in relation to lymph node metastatic features, and to determine whether immunohistochemical staining of cell-cycle markers can predict lymph node metastasis.

Study Design: Cross-sectional study of prior surgical specimens.

Setting: Academic tertiary referral center.

Subjects and Methods: We reviewed the clinical records of patients who had undergone surgery for thyroid cancer and follicular adenoma between January 2005 and May 2008 at our clinic. Among these cases, 92 patients, comprising 28 patients with follicular adenoma, 32 with papillary thyroid carcinoma without lymph node metastasis, and 32 with papillary thyroid carcinoma with lymph node metastasis, were selected randomly. Formalin-fixed, paraffin-embedded tissues from the 92 patients were immunohistochemically stained for cyclin D1, cyclin E, p27kip1, and p57kip2, and protein expression levels were quantified and compared among the groups.

Results: Tumor specimens from the papillary thyroid carcinoma group had significantly higher expression levels of cyclin D1 and cyclin E, and cytoplasmic expression of p57kip2 than the other two groups ( P < 0.05). In particular, all malignant cases expressed cyclin D1, and cytoplasmic p57kip2 was expressed only in malignant cases. Furthermore, differences in the grade of cyclin D1 expression according to lymph node metastasis were statistically significant ( P < 0.05).

Conclusion: Our results suggest that immunohistochemistry of certain cell-cycle regulators may be helpful in the diagnosis of papillary thyroid carcinoma, and that cyclin D1 in particular may be a useful marker for evaluating lymph node metastasis.

Tunicamycin enhances TRAIL-induced apoptosis by inhibition of cyclin D1 and the subsequent downregulation of survivin

TNF-related apoptosis-inducing ligand (TRAIL) has been proposed as a promising cancer therapy that preferentially induces apoptosis in cancer cells, but not most normal tissues. However, many cancers are resistant to TRAIL by mechanisms that are poorly understood. In this study, we showed that tunicamycin, a naturally occurring antibiotic, was a potent enhancer of TRAIL-induced apoptosis through downregulation of survivin. The tunicamycin-mediated sensitization to TRAIL was efficiently reduced by forced expression of survivin, suggesting that the sensitization was mediated at least in part through inhibition of survivin expression. Tunicamycin also repressed expression of cyclin D1, a cell cycle regulator commonly overexpressed in thyroid carcinoma. Furthermore, silencing cyclin D1 by RNA interference reduced survivin expression and sensitized thyroid cancer cells to TRAIL; in contrast, forced expression of cyclin D1 attenuated tunicamycin-potentiated TRAIL-induced apoptosis via over-riding downregulation of survivin. Collectively, our results demonstrated that tunicamycin promoted TRAIL-induced apoptosis, at least in part, by inhibiting the expression of cyclin D1 and subsequent survivin. Of note, tunicamycin did not sensitize the differentiated thyroid epithelial cells to TRAIL-induced apoptosis. Thus, combined treatment with tunicamycin and TRAIL may offer an attractive strategy for safely treating resistant thyroid cancers.

Expression of cell cycle biomarkers and telomere length in papillary thyroid carcinoma: a comparative study between radiation-associated and spontaneous cancers

OBJECTIVE

Radiation exposure during childhood is the only well-established risk factor for papillary thyroid carcinoma (PTC). To better define the biologic profile of radiation-induced and sporadic PTC, we compared in these two groups of PTC the expression of cell cycle regulatory proteins and telomere length.

METHODS

Cell cycle markers (cyclin A, B1, D1, E, and Ki67) were evaluated on 100 PTC specimens (26 radiation-induced and 74 sporadic PTCs). The expression of cell cycle regulators was studied using immunohistochemistry; telomere length heterogeneity was studied using in situ hybridization in a subset of 16 formalin-fixed samples (8 radiation-induced and 8 sporadic PTCs).

RESULTS

At multivariate analysis, only cytoplasmic cyclin E staining was overexpressed in sporadic cases (P = 0.006). The other cell cycle markers and telomere length did not differ significantly between sporadic PTC and radiation-induced PTC.

CONCLUSIONS

These markers cannot be used to differentiate radiation-induced from sporadic PTCs.

Cyclin D1 and p27 expression as prognostic factor in papillary carcinoma of thyroid: association with clinicopathological parameters

AIM

To determine the prognostic value of cell cycle regulators cyclin D1 and p27 for papillary thyroid carcinomas.

METHODS

Analysis included 180 patients with papillary thyroid carcinoma who underwent surgery at Split University Hospital Center between 1999 and 2001. Clinical data were obtained from clinical charts and histopathology reports. Immunohistochemistry was performed on formalin-fixed, paraffin-embedded tissue by antibody p27 and cyclin D1. Quantification was based on the intensity and distribution of nuclear staining.

RESULTS

Univariate analysis showed that sex (P=0.019) and capsular invasion (P=0.010) were significant predictors of lymph node metastases, whereas age (P=0.96), histopathological variant (P=0.075), size (P=0.556) and multifocality (P=0.131) were not. Univariate analysis also showed that overexpression of cyclin D1 (P<0.001) and underexpression of p27 (P<0.001) predicted lymph node metastases in papillary thyroid carcinomas. There was a significant correlation between cyclin D1 (P=0.024) and p27 (P=0.029) expression in two prognostic groups of low and high risk. Low risk group was cyclin D1 negative and p27 positive, while high risk group was cyclin D1 positive and p27 negative. Multivariate analysis confirmed that sex (P=0.041), capsular invasion (P=0.027), and p27 (P<0.001) were strong independent predictors of lymph node metastases in the high-risk group.

CONCLUSIONS

Immunohistochemical analysis of p27 expression may be a valuable tool for identifying risk of lymph node metastases and more aggressive behavior of papillary thyroid carcinoma.

Insulin-like growth factor mRNA binding protein 3 (IMP3) is differentially expressed in benign and malignant follicular patterned thyroid tumors

Insulin-like growth factor mRNA binding protein 3 (IMP3) is an mRNA-binding protein that regulates transcription of insulin-like growth factor II affecting cell proliferation during embryogenesis. It is highly expressed in carcinomas of the pancreas, stomach, colon, rectum, kidneys, uterine cervix, lung, and ovary. The purpose of our study was to evaluate IMP3 expression in thyroid follicular lesions, to determine whether it has a role in differentiating among these lesions, and to understand their biological relationships. We immunostained 219 thyroid lesions selected from our surgical pathology archives including 14 hyperplastic colloid nodules (CN), 19 Hashimoto's thyroiditis (HT), two Graves disease (GD), ten Hürthle cell adenoma (HCA), 20 follicular adenoma (FA), 37 conventional papillary thyroid carcinoma (PTC), 60 follicular variant of papillary carcinoma (FVPC), 19 Hürthle cell carcinoma (HCC), 32 follicular carcinoma (FC), and six poorly differentiated/anaplastic carcinoma. Immunohistochemistry was performed on formalin-fixed sections using monoclonal antibody to IMP3. Clinicopathological data were also reviewed. In all cases, residual thyroid tissue, CN, HT, GD, HCA, and FA were completely negative for IMP3 staining. Of the 60 FVPC, 23 tumors (38%) were positive for IMP3, with 13 of these (22%) showing very strong staining (3+). Of the 32 FC, 22 tumors (69%) were positive, with seven (22%) showing very strong staining (3+). Furthermore, 33 out of 37 cases (89%) of PTC were negative for IMP3. In all four PTC cases that did stain positive, staining was weak-moderate (1-2+). Similarly, 15 out of 19 cases (79%) of HCC were negative. No significant correlation was found between pathologic tumor characteristics and IMP3 expression in differentiated follicular pattern thyroid carcinoma. With 100% specificity and 69% sensitivity for FC as compared to FA and 100% specificity for FVPC, again compared to FA, IMP3 has the potential to be diagnostically useful in differentiating malignant and benign follicular pattern thyroid lesions. This study also points to a possible common biological relationship between FC and FVPC that requires further investigation.

Expression of p21cip1, p27kip1, and p16INk4a cyclin-dependent kinase inhibitors in papillary thyroid carcinoma: correlation with clinicopathological factors

In a variety of human malignancies, aberrant expression of proteins involved in the control of cell-cycle progression has been reported. In this study, p21cip1, p27kip1, and p16INk4a cyclin-dependent kinase inhibitors were analyzed to evaluate their usefulness in clinical management of papillary thyroid carcinoma (PTC). Archived material derived from 46 cases of PTC was analyzed immunohistochemically. Protein expression was ascertained on tissue microarrays, and results were correlated with clinicopathological features of the patients. Positive immunostaining was observed in 14 (30,4%) p21cip1, 26 (56,5%) p27kip1, and 14 (30,4%) p16INk4a cases. No significant correlation between p21cip1 or p27kip1 and clinical factors was found. In contrast, p16INk4a expression showed a significant correlation with initial extension of the disease. Therefore, 45.8% of patients with loco-regional extension were p16INk4a positive, whereas overexpression was only seen in 15.7% of cases with intrathyroid disease (p < 0.05). Moreover, all patients with simultaneous p16INk4a positivity and lack of p27kip1 staining (four patients) presented lymph node metastases. In contrast, only 12 (28.5%) of the remaining patients showed lymph node tumor involvement. In conclusion, p16INk4a expression suggests extrathyroid neck extension of PTC. This effect is enhanced when p27kip1 is negative. We think that their analysis by immunohistochemistry could be useful in the management of patients with PTC.

Cell cycle regulators show diagnostic and prognostic utility for differentiated thyroid cancer

BACKGROUND

Differentiated thyroid cancer (DTC) generally has a favorable outcome, but some patients develop local recurrence and/or distant metastases and ultimately die of their disease. Molecular markers that accurately predict tumor behavior are lacking. This study's aim was to ascertain the role of cell cycle regulators in predicting malignant histology and tumor behavior in DTC.

METHODS

Tissue microarrays consisting of 100 benign and 105 malignant thyroid lesions, plus 24 lymph node samples, were stained for p16, p21, p27, p53, p57, p63, cyclin D1, cyclin E, and mdm2. Statistical analysis was used to compare the expression of the markers in benign versus DTC lesions and correlate their expression with clinicopathologic characteristics.

RESULTS

p16, p21, cyclin D1, and cyclin E showed significantly (P < .001) increased expression in DTCs compared with benign thyroid lesions (54.7% vs. 5%, 71.7% vs. 38%, 87.1% vs. 45.7%, and 72.3% vs. 37.4%, respectively). There was no significant difference in expression between benign lesions and DTC for the remaining markers. p16 expression correlated significantly with extrathyroidal tumor extension (P = .02) and the presence of cancer in lymph nodes (P = .03). A total of 73% vs. 45% of the cancers of patients with and without lymph node involvement, respectively, stained positive for p16 (P = .01).

CONCLUSIONS

There is a statistically significant difference in the expression of p16, p21, cyclin D1, and cyclin E between DTCs and benign thyroid lesions, and p16 expression correlates with clinicopathologic variables predicting poor outcomes for DTC. These results suggest that evaluation of cell cycle derangement in thyroid tumors may serve as a useful tool for both DTC diagnosis and prognosis.

Diagnostic value of galectin-3, HBME-1, cytokeratin 19, high molecular weight cytokeratin, cyclin D1 and p27(kip1) in the differential diagnosis of thyroid nodules

The distinction between benign and malignant thyroid tumors is critical for the management of patients with thyroid nodules. We applied immunohistochemical staining for galectin-3, HBME-1, cytokeratin 19 (CK19), high molecular weight cytokeratin (HMWCK), cyclin D1 and p27(kip1) in 295 thyroid lesions to determine their diagnostic accuracy. The expression of all markers was significantly associated with differentiated thyroid carcinoma (DTC). The sensitivity for the diagnosis of DTC was 94.7% with galectin-3, 91.3% with HBME-1, and 90.3% with CK19. The specificities of these markers were 95.5%, 69.7%, and 83.1%, respectively. Combining these markers, co-expression of galectin-3 and CK19 or galectin-3 and HBME-1 was seen in 93.2% of carcinomas but in none of the benign nodules. Comparing follicular variant of papillary carcinoma (FVPC) with follicular carcinoma (FC), the expression of galectin-3, CK19, and HMWCK was significantly higher in FVPC. When comparing FC with FA, the expression of galectin-3 and HBME-1 was significantly higher in FC. These results suggest that 1) galectin-3 is a useful marker in the distinction between benign and malignant thyroid tumors, 2) the combined use of HBME-1 and CK19 can increase the diagnostic accuracy, and 3) the use of CK19 and HMWCK can aid in the differential diagnosis between PC and FC.

Papillary thyroid carcinoma with lymph node metastases

Papillary thyroid cancer (PTC) is the most frequently occurring human thyroid cancer with good prognosis following appropriate treatment. Lymph node (LN) metastases are the main way through which PTC spread cancer cells. The mechanisms underlying PTC with local invasion, LN metastases and distant metastases are not well investigated. Tumor secrete cytokines, such as vascular endothelial growth factor (VEGF)-C and -D bind to VEGF receptors on lymphatic endothelial cells and induce proliferation (budding) from nearby lymphatic capillaries and growth of new lymphatic capillaries. About one-third of patients can be diagnosed at the time of surgical findings. Different image studies, such as ultrasonography with fine needle aspiration cytology, scintigraphic localization and positron emission tomography were reported to detect LN metastases. Important factors in predicting LN metastases are vascular invasion, male gender, absence of tumor capsule, and perithyroid involvement. Tumor recurrence in LN after primary treatment of PTC had an independent and highly significant negative effect on survival in patients over 45 year-old. Recombinant adeno-associated virus-mediated gene transfer of sVEGFR3-Fc is a feasible therapeutic scheme for blocking lymphogenous metastasis. In conclusion, aggressive surgical procedures performed by experienced surgeons or postoperative radioactive iodine therapy to minimize local recurrence of LN for PTC patients with high risk.

Cyclin D1 protein expression in human thyroid gland and thyroid cancer

Cell cycle progression is facilitated by cyclin dependent kinases (CDKs) that are activated by cyclins, including Cyclin D1 and inhibited by CDK inhibitors. Evidence of the involvement of cyclin gene alterations and over expression of various cyclins in human cancer is growing. The role of Cyclin D1 in malignant progression of papillary carcinomas of the thyroid has yet to be established. We therefore studied the expression of Cyclin D1 protein in thyroid carcinomas of young Kuwaiti patients (36 cases of conventional papillary thyroid carcinoma, 12 cases of its follicular variant, one case of tall cell thyroid carcinoma and one case of medullary carcinoma) using immunohistochemistry. In 23 patients (46%) circumscribed areas of cells were detected that showed a distinct to strong nuclear staining for immunoreactive Cyclin D1 whereas the remaining bulk of the carcinoma cells were negative or only showed a slight cytoplasmic staining. None of the tested clinical or path histological parameters showed a statistically significant correlation with the focal immunostaining. This does not rule out that the detected foci with positive nuclear Cyclin D1 immunostaining are areas where a progressive transformation to a more malignant phenotype occurs which eventually leading to lymph node and distant metastases.

Accumulation of p27(kip1) is associated with cyclin D3 overexpression in the oxyphilic (Hurthle cell) variant of follicular thyroid carcinoma

BACKGROUND

The down regulation of protein p27(kip1) (p27) in most cases of thyroid cancer has relevant diagnostic and prognostic implications. However, the oxyphilic (Hurthle cell) variant of follicular thyroid carcinoma expresses more p27 than benign oxyphilic lesions do.

AIM

To evaluate the mechanism underlying this difference in expression of p27.

METHODS

Because high levels of cyclin D3 lead to p27 accumulation in cell lines and clinical samples of thyroid cancer, the immunocytochemical pattern of cyclin D3 in oxyphilic (n = 47) and non-oxyphilic (n = 70) thyroid neoplasms was investigated.

RESULTS

In the whole study sample, there was a significant correlation between p27 and cyclin D3 expression (Spearman's r: 0.64; p<0.001). The expression of cyclin D3 and p27 was significantly higher in the oxyphilic variant of follicular carcinomas than in non-oxyphilic carcinomas (p<0.001). In the former, cyclin D3 overexpression and p27 accumulation were observed in a median of 75% and 55% of cells, respectively. In co-immunoprecipitation experiments, the level of p27-bound cyclin D3 was much higher in oxyphilic neoplasias than in normal thyroids and other thyroid tumours.

CONCLUSION

These results show that increased p27 expression in the oxyphilic (Hurthle cell) variant of follicular thyroid carcinoma results from cyclin D3 overexpression.

Role of Immunohistochemistry in the Diagnosis and Progression of Follicular Epithelium-Derived Thyroid Carcinoma

Thyroid carcinoma derived from the thyroid hormone-producing follicular epithelium is the most common thyroid malignancy. While the morphologic diagnosis of conventional papillary thyroid carcinoma is simple, thyroid tumors with a follicular pattern are sometimes a diagnostic challenge. It is in the latter group of thyroid neoplasms that ancillary diagnostic tests such as immunohistochemistry may be of great help. Furthermore, while most differentiated thyroid carcinomas have an excellent prognosis, a subset of these tumors may progress to a poorly or undifferentiated phenotype indicating an aggressive biologic behavior that may lead to systemic spread and death. Application of immunohistochemistry to identify a subset of thyroid carcinoma that may progress to a biologically aggressive phenotype may help in the management of patients with thyroid carcinoma. This review discusses the role of immunohistochemistry in the diagnosis and progression of thyroid carcinoma is discussed.

Altered expression of cyclins and cell cycle inhibitors in papillary thyroid cancer: prognostic implications

Currently we lack biochemical or molecular markers that predict recurrence and metastases in thyroid cancer. Recent studies in a number of other human malignancies indicate that expression and/or subcellular localization of certain cell cycle regulators has prognostic utility. We have investigated the expression of cyclins D1 and E and of cyclin-dependent kinase inhibitor's p21 and p27 in papillary thyroid cancer (PTC) and correlated this with clinical/histological stage at diagnosis and with clinical outcome. PTCs were compared to normal thyroid, adenomas, and undifferentiated thyroid cancers (UTCs). Our studies indicate that PTCs and UTCs demonstrate low nuclear expression of cyclin E and p27, allowing a clear distinction between adenomas and these carcinomas (p < 0.004). A pattern of low nuclear expression of all four markers was observed in stage IV PTCs and UTCs, while stage I PTCs had low D1 and E accompanied by high p21 or p27. Expression of cytoplasmic cyclin D1 was significantly lower in stage IV PTCs and UTCs than in stage I-III PTC's (p </= 0.020), and appeared to correlate inversely with poor outcome in PTCs (p = 0.010). These studies suggest that evaluation of a panel of these markers and attention to their subcellular localization may be a useful adjunct in differentiating benign from malignant thyroid neoplasms and in predicting tumor behavior.

Patterns of Cyclin E, Retinoblastoma Protein, and p21Cip1/WAF1 Immunostaining in the Oncogenesis of Papillary Thyroid Carcinoma

Purpose: Uncontrolled cell proliferation, a hallmark of cancer, may result from an increased expression of cell cycle up-regulators, and/or from a reduced expression of cell cycle down-regulators. In the present study, we analyzed, by immunohistochemistry, the expression of a panel of three proteins: cyclin E and two cell cycle inhibitors, p21Cip1/WAF1 and retinoblastoma protein (pRb) product, in different stages of papillary thyroid carcinomas (PTC).

Experimental Design: We investigated immunostaining patterns of the proteins in question in 51 resected PTC in pathologic stages, ranging from pT1a to pT4, taking into consideration their relation to clinicohistopathologic factors.

Results: We observed a significant, progressive loss of expression of p21Cip1/WAF1 with advancing tumor grade. The differences reached values of significance between pT1a [papillary thyroid microcarcinomas (PMC)] and pT2 and between PMC and pT4 stages of PTC. pRb presented a similar immunostaining pattern to that of p21Cip1/WAF1 and the differences reached values of significance between pT1a and pT2, and between PMC and pT4 stages of PTC. The results of cyclin E immunostaining corresponded to our recently published result, and a negative correlation was observed between the immunostaining index of cyclin E and pRb.

Conclusions: The results of the present study suggest that cyclin E expression and suppression of pRb and p21Cip1/WAF1 may be characteristic patterns of immunostaining for PTC with a tendency to early metastasizing. If our results are confirmed in a larger study, the diagnostic panel, constructed of the antibodies against these proteins, may become a valuable tool in predicting the metastatic potential in PTC.

Expression profile of malignant and non-malignant diseases of the thyroid gland reveals altered expression of a common set of genes in goiter and papillary carcinomas

Using cDNA microarrays with 3800 cDNA fragments, we determined the expression profile of normal thyroid tissue, goiter, adenoma and papillary carcinoma (10 samples from each class). After background correction and statistical analysis, we identified a set of 160 genes as being differentially expressed in all pair-wise comparisons. Here we demonstrate that, at least on the basis of these differentially expressed genes, a positive correlation between goiter and papillary carcinomas could be observed. We identified a common set of genes whose expression is diminished in both goiter and papillary carcinomas as compared to normal thyroid tissue. Moreover, no genes with inverse correlation in samples from goiter and papillary carcinomas could be detected. Using Real-Time PCR and/or tissue microarrays, we confirmed the altered expression of some of the identified genes. Of notice, we demonstrate that the reduced mRNA levels of p27(kip1) observed in papillary carcinomas as compared to either goiter or normal thyroid tissues (P<0.001) is accompanied by an altered protein distribution within the cell. In papillary carcinomas, P27(KIP1) is preferentially cytoplasmic as opposed to goiter or normal thyroid tissue, where P27(KIP1) is preferentially located in the nucleus. The exploitation of the data presented here could contribute to the understanding of the molecular events related to thyroid diseases and gives support to the notion that common molecular events might be related to the frequent observation of areas of papillary carcinomas in the gland of patients with goiter.

Cyclin E expression in papillary thyroid carcinoma: Relation to staging

Cyclin E plays a pivotal role in the regulation of G1-S transition and relates to malignant transformation of the cells. However, the clinical significance of cyclin E expression in patients with papillary thyroid carcinoma (PTC) remains unknown. We examined by immunohistochemistry the expression of cyclin E in 41 resected PTCs in pathologic stages from pT1a to pT4 and analyzed its relation to clinicohistopathologic factors. The positive staining was divided into 3 grades: no expression if less than 10%, expression if 11-50% and overexpression if more than 50% of the nuclei of tumor cells were stained positively. Cylin E expressions were observed in 75.6% of analyzed PTCs but only 60% of papillary microcarcinomas (PMCs) were immunopositive for cyclin E expression. However, cyclin E staining was observed in 90.4% of PTCs in a group with TNM higher than pT1a. The staining index was significantly different between the PMCs and the rest of the cancers investigated (14.91% +/- 14.4% vs. 34.03% +/- 23.44%, respectively; p < 0.005) and we observed positive relation between the staining index and factor T of staging of PTCs. All the lymph node metastases coexisted with cyclin E expression and most, but not all, of them coexisted with cyclin E overexpression. These findings indicate that cyclin E may play a key role for the oncogenesis and biologic behavior of PTC. If our results are confirmed in a larger study, a high level of cyclin E expression may become a new prognostic marker for PTCs.

Molecular pathogenesis of thyroid cancer

A number of molecular abnormalities have been described in association with the progression from normal thyroid tissue to benign adenomas to well-differentiated and finally anaplastic epithelial thyroid cancer. These include upregulation of proliferative factors, such as growth hormones and oncogenes, downregulation of apoptotic and cell-cycle inhibitory factors, such as tumor suppressors, disruption of normal cell-to-cell interactions, and cellular immortalization. The progression model for thyroid carcinoma has not been proven, but evidence suggests that an evolutionary molecular process is involved, especially in the development of follicular thyroid cancers for which there are distinct intermediate phenotypes. We present a comprehensive evaluation of factors involved in thyroid tumorigenesis and attempt to describe preliminary attributes of a progression model. The organization of this model should also provide a template for the incorporation of new information as it is derived from large-scale genomic studies.

CD10 expression is useful in the diagnosis of follicular carcinoma and follicular variant of papillary thyroid carcinoma

CD10/neutral endopeptidase 24.11(NEP) is a membrane-bound zinc metalloproteinase the expression of which represents a useful tool in the classification and diagnosis of malignant leukemia and lymphoma. Recently, CD10 has been found to be expressed in nonhematopoietic tissues and various types of neoplasms. In this study, we examined CD10 immunostaining in paraffin sections of 70 distinct lesions to investigate whether CD10 is a useful diagnostic marker for thyroid neoplasms. CD10 was not detected in normal thyroid tissue, benign lesions (15 follicular lesions and 15 adenomatous goiters), and pure papillary carcinomas except for follicular variants. In contrast, CD10 was expressed in 8 of 10 (80%) follicular carcinomas and 7 of 9 (77%) follicular variant of papillary thyroid carcinomas. This appears to be the first report on the expression of this member of a newly identified gene family in thyroid tumors. In conclusion, immunohistochemistry of CD10 in paraffin sections is valuable in the classification of thyroid follicular lesions into benign and malignant groups and in the diagnosis of follicular variant of papillary thyroid carcinoma.

Ras stimulates aberrant cell cycle progression and apoptosis in rat thyroid cells

Abundant evidence supports the ability of Ras to stimulate thyroid cell proliferation. Stable expression of activated Ras enhances the sensitivity of thyroid cells to apoptosis. We report that apoptosis is a primary and general response of rat thyroid cells to acute expression of activated Ras in the absence or presence of thyrotropin, insulin, and serum, survival factors for thyroid cells. Ras induced apoptosis in quiescent and cycling cells. Concomitantly, Ras stimulated S phase entry in quiescent cells and enhanced G1/S transition in cycling cells. Ras effects on the cell cycle were characterized by delayed progression through S phase and an apparent failure to proceed through G2/M phase. Unlike thyroid cell mitogens, Ras markedly decreased cyclin D1 expression. Although acute expression of Ras decreased cyclin D1 protein levels, cells selected to survive chronic Ras expression exhibited a selective increase in cyclin D1 expression. In summary, thyroid cells harbor an apoptotic program activated by Ras that outstrips the protective effects of thyrotropin, insulin, and serum. Apoptosis is accompanied by dysregulated cell cycle progression, suggesting that cell death may arise, at least in part, as a consequence of inappropriate proliferative cues.

Immunohistochemical expression of cyclin D1, E2F-1, and Ki-67 in benign and malignant thyroid lesions

Cyclin D1 and E2F-1 proteins are essential for the regulation of the G1/S transition through the cell cycle. Cyclin D1, a product of the bcl-1 gene, phosphorylates the retinoblastoma protein, releasing E2F-1, which in turn activates genes involved in DNA synthesis. Expression patterns of E2F-1 protein in thyroid proliferations have not been reported. This study used monoclonal antibodies for cyclin D1 and E2F-1 proteins to immunostain sections of normal thyroid, hyperplastic (cellular) nodules, follicular adenomas, follicular carcinomas, and papillary carcinomas. The proliferation rate was examined using an antibody specific for the Ki-67 antigen. Fluorescence in situ hybridization (FISH) methods and chromosome 11-specific probes were also employed to determine chromosome copy number and to assess for evidence of amplification at the 11q13 locus in papillary and follicular carcinomas with cyclin D1 overexpression. Concurrent overexpression of Ki-67, cyclin D1, and E2F-1 was found in the majority of benign and malignant thyroid lesions, compared with normal thyroid tissue. Cyclin D1 up-regulation was not due to extra copies of chromosome 11, or bcl-1 gene amplification. Malignant tumours showed the highest expression for all three markers, particularly papillary carcinomas. E2F-1 was detected at the same or slightly lower levels than cyclin D1. It was only found when cyclin D1 was overexpressed. Because cyclin D1 normally activates E2F-1, up-regulation of cyclin D1 may lead to E2F-1 overexpression in benign and malignant thyroid lesions.

Cyclin D1 protein expression predicts metastatic behavior in thyroid papillary microcarcinomas but is not associated with gene amplification

Overexpression of cyclin D1 occurs in several malignancies, often due to gene amplification, and this has been associated with aggressive tumor behavior, a higher incidence of lymph node metastases, and a poorer prognosis. The role of cyclin D1 in the pathogenesis of thyroid malignancy is unknown; however, cyclin D1 expression has been reported to occur in a proportion of well differentiated thyroid carcinomas. Micropapillary carcinomas of the thyroid are common incidental findings that almost always behave in an indolent manner and remain quiescent. However, rare microcarcinomas behave aggressively and metastasize early, giving rise to clinically significant disease. We hypothesized that cyclin D1 might play a role in the aggressive behavior of metastasizing papillary microcarcinomas. We reviewed the histopathology reports of 2,000 patients who underwent thyroid surgery at our institution between 1995-1999 and identified 22 patients who presented with gross regional metastases from a primary papillary microcarcinoma. These patients formed the index cohort for this analysis. As controls, we selected 34 patients with nonmetastasizing microcarcinomas. We studied these tumors for immunoreactivity to cyclin D1 on immunohistochemistry and analyzed 13 tumors that diffusely expressed cyclin D1 for gene amplification by differential PCR. Twenty of the 22 (90.9%) metastasizing papillary microcarcinomas expressed cyclin D1, compared with 3 of the 34 (8.8%) nonmetastasizing papillary microcarcinomas (P < 0.001). However, of the 13 tumors that showed diffuse immunoreactivity for cyclin D1 on immunohistochemistry, none showed amplification of the cyclin D1 gene on differential PCR. We conclude that cyclin D1 is significantly overexpressed in metastasizing papillary microcarcinomas of the thyroid. This is likely due to mechanisms other than gene amplification. Cyclin D1 immunohistochemistry may be a valuable tool in predicting metastatic potential in papillary microcarcinomas.

Overexpression of cyclin D1 and underexpression of p27 predict lymph node metastases in papillary thyroid carcinoma

Lymph node metastasis in papillary thyroid carcinoma increases the morbidity of treatment and the risk of local regional relapse and may also affect cure rates and survival. Factors that predict lymph node metastasis are, however, unclear. We analyzed 125 patients with papillary thyroid carcinoma for factors that predict lymph node metastasis. On univariate analysis, age, extrathyroidal extension, tumor focality, overexpression of cyclin D1, and underexpression of p27 predicted lymph node metastasis, whereas patient gender and tumor size did not. On multivariate analysis, extrathyroidal extension, overexpression of cyclin D1, and underexpression of p27 proved to be strong independent predictors of lymph node metastasis. We suggest that immunohistochemistry for cyclin D1 and p27 will prove valuable in identifying papillary thyroid carcinomas with metastatic potential.

Vitamin D arrests thyroid carcinoma cell growth and induces p27 dephosphorylation and accumulation through PTEN/akt-dependent and -independent pathways

We investigated the effects of 1,25-dihydroxycholecalciferol vitamin D(3) (VD) and its noncalciomimetic analog EB1089 on thyroid carcinoma cell growth. VD and EB1089 exhibited anti-proliferative effects in a dose-dependent manner as determined by [(3)H]thymidine incorporation and MIB-1 immunolabeling. VD or EB1089 resulted in similar G(1)-phase arrest. Neither apoptosis nor differentiation was affected. VD and EB1089 induced increased nuclear protein expression of the cyclin-dependent kinase inhibitor, p27(kip1) (p27). VD/EB1089 effects paralleled but were not additive to those of the proteasome inhibitor LLnL, consistent with reduced p27 degradation. As p27 phosphorylation and association with Skp2 is a key step in its degradation, we examined the effects of VD/EB1089 on this reaction. Despite increased total p27, the pThr content of p27 remained unaffected, an effect confirmed by diminished association with Skp2 as well as in situ phosphorylation. Moreover, phosphatase inhibition abrogated the effect of VD/EB1089 on p27 accumulation consistent with a role for phosphatase action in mediating this VD effect. Although VD/EB1089 resulted in comparable increases in p27 in WRO and NPA cells, only WRO but not NPA cells demonstrated a change in the phosphatase PTEN and its downstream target pAkt/PKB in response to VD/EB1089. Transfection of PTEN resulted in p27 accumulation and was partially additive to the effect of VD/EB1089. Moreover, treatment with PI-3 kinase inhibitors decreased pAkt/PKB and increased p27 in both WRO and NPA cells highlighting the potential role of this downstream pathway in regulating p27 in the thyroid. These findings point to a novel mechanism of action for VD/EB1089 inhibition of thyroid carcinoma cell growth by p27 hypophosphorylation, diminished association with Skp2, and consequent accumulation. This effect can be mediated but is not essentially dependent on the phosphatase PTEN/Akt/PKB pathway. These properties support the potential utility of VD analogs in the treatment of thyroid carcinomas irrespective of their PTEN/pAkt status.

The meanings of markers: ancillary techniques in diagnosis of thyroid neoplasia

This review article primarily discusses immunohistochemical markers used to aid the diagnosis of thyroid neoplasia. The review concentrates on high molecular weight cytokeratins, cytokertain 19, HBME-1, and galectin-3. Diagnostic uses of proliferation markers such as p27(kip1) and Ki-67 are discussed along with the oncogene ret in relation to papillary carcinomas and PAX8-peroxisome proliferator-activated receptor gamma1 in relation to follicular carcinoma. The diagnostic use of retinoblastoma tumor suppressor gene product is also discussed. The sensitivities and specificities as well as the pitfalls of these techniques are reviewed. On the basis of the literature, the most highly recommended of these markers to aid in diagnosis are HBME-1 and galectin-3.

Immunohistochemical expression of cell cycle proteins E2F-1, Cdk-2, Cyclin E, p27(kip1), and Ki-67 in normal placenta and gestational trophoblastic disease

The role of cell cycle protein expression in gestational trophoblastic disease is poorly understood. In this study we investigated the immunostaining patterns of G(1) restriction point and G(1)-S regulatory proteins E2F-1, Cdk2, cyclin E, p27(kip1), and the proliferation marker Ki-67 on routinely processed sections of 29 hydatidiform moles (10 partial moles and 19 complete moles, including 9 persistent moles), 7 choriocarcinomas, and 7 normal placentas. Ki-67 trophoblast staining decreased with increasing gestational age of the placenta, and showed maximal expression in gestational trophoblastic disease. Cyclin-dependent kinase activity, as reflected by Cdk2 expression patterns, also decreased with placental maturation. E2F-1 was uniquely expressed by trophoblasts of moles and choriocarcinoma. Cyclin E was maximally expressed by complete moles and choriocarcinomas, and showed an inverse relationship with the cyclin-dependent kinase inhibitor p27(kip1). Abnormal trophoblastic proliferations may be mediated through interactions of Cdk-2, E2F-1, cyclin E, and p27(kip1). Overexpression of cyclin E was associated with more aggressive forms of gestational trophoblastic disease. However, we did not find distinguishing features between complete moles that spontaneously resolved after evacuation and persistent moles that required chemotherapy. The different expression patterns of cyclin E and E2F-1 in partial and complete moles may be useful in distinguishing these two entities. Furthermore, loss of p27(kip1) in malignant trophoblast may represent a necessary step in the development of choriocarcinoma.

Regulation of thyroid cell proliferation by TSH and other factors: a critical evaluation of in vitro models

TSH via cAMP, and various growth factors, in cooperation with insulin or IGF-I stimulate cell cycle progression and proliferation in various thyrocyte culture systems, including rat thyroid cell lines (FRTL-5, WRT, PC Cl3) and primary cultures of rat, dog, sheep and human thyroid. The available data on cell signaling cascades, cell cycle kinetics, and cell cycle-regulatory proteins are thoroughly and critically reviewed in these experimental systems. In most FRTL-5 cells, TSH (cAMP) merely acts as a priming/competence factor amplifying PI3K and MAPK pathway activation and DNA synthesis elicited by insulin/IGF-I. In WRT cells, TSH and insulin/IGF-I can independently activate Ras and PI3K pathways and DNA synthesis. In dog thyroid primary cultures, TSH (cAMP) does not activate Ras and PI3K, and cAMP must be continuously elevated by TSH to directly control the progression through G(1) phase. This effect is exerted, at least in part, via the cAMP-dependent activation of the required cyclin D3, itself synthesized in response to insulin/IGF-I. This and other discrepancies show that the mechanistic logics of cell cycle stimulation by cAMP profoundly diverge in these different in vitro models of the same cell. Therefore, although these different thyrocyte systems constitute interesting models of the wide diversity of possible mechanisms of cAMP-dependent proliferation in various cell types, extrapolation of in vitro mechanistic data to TSH-dependent goitrogenesis in man can only be accepted in the cases where independent validation is provided.

Analyses of MYC, ERBB2, and CCND1 genes in benign and malignant thyroid follicular cell tumors by real-time polymerase chain reaction

The roles of the MYC, ERBB2, and CCND1 genes in thyroid carcinogenesis are poorly known. We used real-time quantitative polymerase chain reaction (PCR) assays based on fluorescent TaqMan methodology to quantify MYC, ERBB2, and CCND1 gene amplification and expression in 24 benign tumors (adenomas and goiter nodules) and 12 carcinomas (9 papillary, 2 follicular, and 1 anaplastic) of the thyroid. Real-time PCR is a recently developed method for nucleic acid quantification in homogeneous solutions, and has the potential to become a reference in terms of performance, accuracy, sensitivity, wide dynamic range, excellent interlaboratory agreement, and high throughput capacity, while avoiding the need for tedious post-PCR processing. Overexpression (>5 standard deviations above mean for normal thyroid tissues) of the ERBB2 and CCND1 genes was observed (3.2- to 5.2-fold and 3.8- to 8.4-fold, respectively) in 5 (14%) and 13 (36%) of 36 neoplastic thyroid RNA samples, respectively. Overexpression of the CCND1 gene was observed in both the benign and malignant thyroid tumors, whereas the ERBB2 gene was mainly overexpressed in malignant thyroid tumors. None of the neoplastic thyroid samples overexpressed MYC. No MYC, ERBB2, or CCND1 gene amplification was identified. These results suggest that the CCND1 gene plays an early role and the ERBB2 gene a later role in thyroid tumorigenesis.