Diagnostic and prognostic value of cell-cycle regulatory genes in malignant thyroid neoplasms

Early diagnostic and prognostic biomarkers for gastric cancer: systems-level molecular basis of subsequent alterations in gastric mucosa from chronic atrophic gastritis to gastric cancer

PURPOSE

It is important to comprehend how the molecular mechanisms shift when gastric cancer in its early stages (GC). We employed integrative bioinformatics approaches to locate various biological signalling pathways and molecular fingerprints to comprehend the pathophysiology of the GC. To facilitate the discovery of their possible biomarkers, a rapid diagnostic may be made, which leads to an improved diagnosis and improves the patient's prognosis.

METHODS

Through protein-protein interaction networks, functional differentially expressed genes (DEGs), and pathway enrichment studies, we examined the gene expression profiles of individuals with chronic atrophic gastritis and GC.

RESULTS

A total of 17 DEGs comprising 8 upregulated and 9 down-regulated genes were identified from the microarray dataset from biopsies with chronic atrophic gastritis and GC. These DEGs were primarily enriched for CDK regulation of DNA replication and mitotic M-M/G1 phase pathways, according to KEGG analysis (p > 0.05). We discovered two hub genes, MCM7 and CDC6, in the protein-protein interaction network we obtained for the 17 DEGs (expanded with increased maximum interaction with 110 nodes and 2103 edges). MCM7 was discovered to be up-regulated in GC tissues following confirmation using the GEPIA and Human Protein Atlas databases.

CONCLUSION

The elevated expression of MCM7 in both chronic atrophic gastritis and GC, as shown by our comprehensive investigation, suggests that this protein may serve as a promising biomarker for the early detection of GC.

DNA replication: Mechanisms and therapeutic interventions for diseases

Accurate and integral cellular DNA replication is modulated by multiple replication-associated proteins, which is fundamental to preserve genome stability. Furthermore, replication proteins cooperate with multiple DNA damage factors to deal with replication stress through mechanisms beyond their role in replication. Cancer cells with chronic replication stress exhibit aberrant DNA replication and DNA damage response, providing an exploitable therapeutic target in tumors. Numerous evidence has indicated that posttranslational modifications (PTMs) of replication proteins present distinct functions in DNA replication and respond to replication stress. In addition, abundant replication proteins are involved in tumorigenesis and development, which act as diagnostic and prognostic biomarkers in some tumors, implying these proteins act as therapeutic targets in clinical. Replication-target cancer therapy emerges as the times require. In this context, we outline the current investigation of the DNA replication mechanism, and simultaneously enumerate the aberrant expression of replication proteins as hallmark for various diseases, revealing their therapeutic potential for target therapy. Meanwhile, we also discuss current observations that the novel PTM of replication proteins in response to replication stress, which seems to be a promising strategy to eliminate diseases.

Exonucleases: Degrading DNA to Deal with Genome Damage, Cell Death, Inflammation and Cancer

Although DNA degradation might seem an unwanted event, it is essential in many cellular processes that are key to maintaining genomic stability and cell and organism homeostasis. The capacity to cut out nucleotides one at a time from the end of a DNA chain is present in enzymes called exonucleases. Exonuclease activity might come from enzymes with multiple other functions or specialized enzymes only dedicated to this function. Exonucleases are involved in central pathways of cell biology such as DNA replication, repair, and death, as well as tuning the immune response. Of note, malfunctioning of these enzymes is associated with immune disorders and cancer. In this review, we will dissect the impact of DNA degradation on the DNA damage response and its links with inflammation and cancer.

The Immunohistochemical Expression of MCM-3, -5, and -7 Proteins in the Uterine Fibroids

Uterine fibroids are the most common mesenchymal uterine neoplasms; their prevalence is estimated in 40%–60% of women under 35 and in 70%–80% of women over 50 years of age. The current research aims to focus on the etiopathogenesis of uterine fibroids, the factors that affect their growth, and markers with diagnostic and prognostic properties. The MCM (minichromosome maintenance) protein family consists of peptides whose primary function is participation in the molecular mechanism of creating replication forks while regulating DNA synthesis. The aim of this work was to determine the proliferative potential of uterine fibroid cells based on the expression of the Ki-67 antigen and the MCMs—i.e., MCM-3, MCM-5, and MCM-7. In addition, the expression of estrogen (ER) and progesterone (PgR) receptors was evaluated and correlated with the expression of the abovementioned observations. Ultimately, received results were analyzed in terms of clinical and pathological data. Materials and methods: In forty-four cases of uterine fibroids, immunohistochemical reactions were performed. A tissue microarray (TMA) technique was utilized and analyzed cases were assessed in triplicate. Immunohistochemistry was performed using antibodies against Ki-67 antigen, ER, PgR, MCM-3, MCM-5, and MCM-8 on an automated staining platform. Reactions were digitalized by a histologic scanner and quantified utilizing dedicated software for nuclear analysis. Assessment was based on quantification expression of the three histiospots, each representing one case in TMA. Results: In the study group (uterine fibroids), statistically significant stronger expression of all the investigated MCMs was observed, as compared to the control group. In addition, moderate and strong positive correlations were found between all tested proliferative markers. The expression of the MCM-7 protein also correlated positively with ER and PgR. With regard to clinical and pathological data, there was a negative correlation between the expression of MCMs and the number of both pregnancies and births. Significant reductions in MCM-5 and MCM-7 expression were observed in the group of women receiving oral hormonal contraceptives, while smoking women showed an increase in MCM-7, ER, and PgR. Conclusions: Uterine fibroid cells have greater proliferative potential, as evaluated by expression of the Ki-67 antigen and MCMs, than unaltered myometrial cells of the uterine corpus. The expression of MCM-7 was found to have strong or moderate correlations in all assessed relations. In the context of the clinical data, as well evident proliferative potential of MCMs, further studies are strongly recommended.

Diagnostic performance of HMGA2 gene expression for differentiation of malignant thyroid nodules: A systematic review and meta-analysis

OBJECTIVE

The purpose of the current study was to investigate the diagnostic performance of high mobility group A2 (HMGA2) gene expression for differentiation of malignant thyroid nodules through a systematic review and meta-analysis.

DESIGN

The MEDLINE/PubMed and EMBASE database, from the earliest available date of indexing through 10 April 2018, were searched for studies evaluating the diagnostic performance of HMGA2 expression for differentiation of thyroid nodules.

METHODS

We determined the sensitivities and specificities across studies, calculated positive and negative likelihood ratios (LR+ and LR-), and constructed summary receiver operating characteristic (ROC) curves.

RESULTS

Across 7 studies, the pooled sensitivity for HMGA2 expression was 0.78 (95% CI; 0.67-0.86) with heterogeneity (I²  = 86.6) and a pooled specificity of 0.94 (95% CI: 0.85-0.98) with heterogeneity (I²  = 94.7). Likelihood ratio (LR) syntheses gave an overall positive likelihood ratio (LR+) of 12.6 (95% CI: 5.1-31.3) and negative likelihood ratio (LR-) of 0.24 (95% CI: 0.15-0.36). The pooled diagnostic odds ratio (DOR) was 53 (95% CI: 18-159). Hierarchical summary ROC curve indicates that the areas under the curve were 0.92 (95% CI: 0.89-0.94). In meta-regression analysis, no definite variable was the source of the study heterogeneity.

CONCLUSION

The current meta-analysis showed the moderate sensitivity and high specificity of HMGA2 expression for differentiation of malignant thyroid nodules. The likelihood ratio scatter-gram suggested that HMGA2 expression analysis could be useful for confirmation of the presence of malignant thyroid nodules. Considering the heterogeneity of included studies, further large prospective studies are necessary to confirm these results.

The role of MCM5 expression in cervical cancer: Correlation with progression and prognosis

Minichromosome maintenance protein 5 (MCM5) has been suggested overexpressed in cervical cancer, but the clinical value and biological function of MCM5 in cervical cancer is still unknown. In our study, MCM5 mRNA and protein were significantly overexpressed in cervical cancer tissues and cell lines compared with normal cervical tissues and cell lines, and were obviously increased in cervical adenocarcinoma tissues and cell lines in comparison to cervical squamous cell carcinoma tissues and cell lines. In cervical adenocarcinoma patients, we firstly found that MCM5 expression was closely correlated with clinical stage, lymph node metastasis, distant metastasis and histological grade. Univariate and multivariate analysis showed MCM5 high-expression was an independent unfavorable prognostic factor. In conclusion, MCM5 is associated with the malignant status and poor prognosis in cervical adenocarcinoma patients, and modulates cervical adenocarcinoma cells proliferation.

Pre-RC Protein MCM7 depletion promotes mitotic exit by Inhibiting CDK1 activity

MCM7, a subunit of mini-chromosome maintenance proteins (MCM) complex, plays an important role in initiating DNA replication during the G1 phase and extending DNA strands during the S phase. Here, we demonstrated that MCM7 is not only sustained but maintains association with chromatin during M phase. Remarkably, MCM7 siRNA can accelerate mitotic exit. MCM7 depletion leads to CDK1 inactivation and promotes subsequent cohesin/RAD21 cleavage, which eventually leads to sister chromatin segregation. Moreover, MCM7 is co-localized with tubulin in the mitotic cells and MCM7 depletion results in aberrant mitosis. Our results indicate that MCM7 may exert certain functions on spindle formation to prevent cytokinesis during early mitosis by regulating CDK1 activity.

MCM5 as a target of BET inhibitors in thyroid cancer cells

Anaplastic thyroid carcinoma (ATC) is an extremely aggressive thyroid cancer subtype, refractory to the current medical treatment. Among various epigenetic anticancer drugs, bromodomain and extra-terminal inhibitors (BETis) are considered to be an appealing novel class of compounds. BETi target the bromodomain and extra-terminal of BET proteins that act as regulators of gene transcription, interacting with histone acetyl groups. The goal of this study is to delineate which pathway underlies the biological effects derived from BET inhibition, in order to find new potential therapeutic targets in ATC. We investigated the effects of BET inhibition on two human anaplastic thyroid cancer-derived cell lines (FRO and SW1736). The treatment with two BETis, JQ1 and I-BET762, decreased cell viability, reduced cell cycle S-phase, and determined cell death. In order to find BETi effectors, FRO and SW1736 were subjected to a global transcriptome analysis after JQ1 treatment. A significant portion of deregulated genes belongs to cell cycle regulators. Among them, MCM5 was decreased at both mRNA and protein levels in both tested cell lines. Chromatin immunoprecipitation (ChIP) experiments indicate that MCM5 is directly bound by the BET protein BRD4. MCM5 silencing reduced cell proliferation, thus underlining its involvement in the block of proliferation induced by BETis. Furthermore, MCM5 immunohistochemical evaluation in human thyroid tumor tissues demonstrated its overexpression in several papillary thyroid carcinomas and in all ATCs. MCM5 was also overexpressed in a murine model of ATC, and JQ1 treatment reduced Mcm5 mRNA expression in two murine ATC cell lines. Thus, MCM5 could represent a new target in the therapeutic approach against ATC.

Correlation between levels of expression of minichromosome maintenance proteins, Ki-67 proliferation antigen and metallothionein I/II in laryngeal squamous cell cancer

MCM2, MCM3 and MCM7 are minichromosome maintenance proteins found in dividing cells and they play a role in DNA synthesis. Increased MCM expression level is observed in cells of different cancer types. Additionally, metallothioneins (MT-I/II) are involved in control of cell proliferation and differentiation and changes of their expression are observed in many types of cancer. Ki-67 is known cancer cell proliferation antigen currently used in prognostic evaluation. The study material consisted of 83 laryngeal squamous cell cancer (LSCC) cases and 10 benign hypertrophic lesions of larynx epithelium as a control group. For the present study, laryngeal cancer cell line HEp-2 and human keratinocytes were employed, and to evaluate expression of all the markers, immunohistochemical method (IHC), immunofluorescence (IF) and western blot analysis were used. Statistical analysis showed strong positive correlation between expression of MCM2, MCM3, MCM7 and Ki-67 antigen in LSCC. Additionally, moderate positive correlation was observed between MCM3 and MT-I/II expression. In cancer cells, the level of expression of MCM3, MCM2, MCM7 and Ki-67 markers was increasing with the grade of LSCC malignancy. IF and western blot analysis showed higher MCM2, MCM3, MCM7 expression in HEp-2 cells in comparison to their expression in keratinocytes. MCM proteins might be useful markers of cell proliferation in LSCC.

Over expression of hRad9 protein correlates with reduced chemosensitivity in breast cancer with administration of neoadjuvant chemotherapy

Human Rad 9 (hRad9), part of the Rad9-Hus1-Rad1 complex plays an important role in DNA damage repair as an up-stream regulator of checkpoint signaling, however little is known about its role in response to chemotherapy of breast cancer and whether hRad9 inhibition can potentiate the cytotoxic effects of chemotherapy on breast cancer cells remains to be elucidated. Fifty cases of breast cancer receiving neoadjuvant therapy were collected. All these cases were revised and classified into chemotherapy sensitive (CS) or chemotherapy resistant (CR) group according to the Miller and Payne (MP) grading system. Immunohistochemically, hRad9 positive tumours showed nuclear and/or cytoplasmic staining. hRad9 over-expression was associated with an impaired neoadjuvant chemotherapy response. A significant correlation was found between expression of hRad9 and Cyclin D1. In vitro, hRad9 was knocked down using siRNA in breast cancer cell line MCF-7 and MDA-MB-231. Deregulated expression of Rad9 accompanied by down expression of chk1 enhanced the sensitivity of human breast cancer cells to doxorubicin. Our work suggests that hRad9 might be a potential predictor for the response to chemotherapy in patients with breast cancer and its clinical value as a target for improving chemosensitivity needs further exploration.

MCM7 serves as a prognostic marker in diffuse-type gastric adenocarcinoma and siRNA-mediated knockdown suppresses its oncogenic function

MCM7 (mini-chromosome maintenance protein 7) is essential for the initiation of genomic replication as a component of the pre-replication complex. The present study aimed to analyze its expression, clinical significance and biological functions in gastric adenocarcinoma (GAC). The MCM7 protein was upregulated in all 9 GAC cell lines. In 6 paired primary GACs, MCM7 was upregulated in tumor compared with the corresponding non-tumorous gastric tissues. In normal gastric epithelium tissue, MCM7 was strictly expressed in the proliferative compartment. MCM7 knockdown by siRNA in gastric cancer cell line AGS and NCI-N87 significantly suppressed cell proliferation, inhibited monolayer colony formation, reduced cell invasion and induced late apoptosis. Its nuclear expression correlated with advanced age and poorer disease specific survival in diffuse-type GACs. All the findings supported that MCM7 might play an oncogenic role in gastric tumorigenesis. It serves as a potential prognostic marker and therapeutic target in diffuse-type GACs.

hRAD9 functions as a tumor suppressor by inducing p21-dependent senescence and suppressing epithelial-mesenchymal transition through inhibition of Slug transcription

Senescence and epithelial-mesenchymal transition (EMT) have opposing roles in tumor progression, in that, one is a barrier against tumorigenesis, whereas the other is required for invasive malignancies. Here, we report that the DNA damage response (DDR) protein hRAD9 contributes to induction of senescence and inhibition of EMT. Our data show that hRAD9 is frequently downregulated in breast and lung cancers. Loss of hRAD9 expression is associated with tumor stage in breast and lung cancers, as well as with acquisition of an invasive phenotype. Ectopic hRAD9 expression in highly invasive cancer cell lines, H1299 and MDA-MB 231, with low endogenous hRAD9 induced senescence by upregulation of nuclear p21, independent of the p53 status. Ectopic expression of hRAD9 also significantly attenuated cellular migration and invasion in vitro and tumor growth in a xenograft mouse model in vivo. In contrast, silencing hRAD9 in lower invasive cancer cell lines, A549 and MCF7, with high endogenous hRAD9 dramatically increased their migration and invasion abilities, and simultaneously activated EMT. Knockdown of hRAD9 increased, whereas ectopic expression of hRAD9 decreased, the expression of Slug. Moreover, hRAD9 directly bound to the promoter region of slug gene and repressed its transcriptional activity. Taken together, these results suggest that hRAD9 is a potential tumor suppressor in breast and lung cancers and that it is likely to function by upregulating p21 and inhibiting Slug to regulate tumorigenesis.

Interaction of MCM7 and RACK1 for activation of MCM7 and cell growth

MCM7 is one of the pivotal DNA replication licensing factors in controlling DNA synthesis and cell entry into S phase. Its expression and DNA copy number are some of the most predictive factors for the growth and behavior of human malignancies. In this study, we identified that MCM7 interacts with the receptor for activated protein kinase C 1 (RACK1), a protein kinase C (PKC) adaptor, in vivo and in vitro. The RACK1 binding motif in MCM7 is located at the amino acid 221-248. Knocking down RACK1 significantly reduced MCM7 chromatin association, DNA synthesis, and cell cycle entry into S phase. Activation of PKC by 12-O-tetradecanoylphorbol-13-acetate dramatically decreased MCM7 DNA replication licensing and induced cell growth arrest. Activation of PKC induced redistribution of RACK1 from nucleus to cytoplasm and decreased RACK1-chromatin association. The MCM7 mutant that does not bind RACK1 has no DNA replication licensing or oncogenic transformation activity. As a result, this study demonstrates a novel signaling mechanism that critically controls DNA synthesis and cell cycle progression.

Contributions of Rad9 to tumorigenesis

Rad9 plays a crucial role in maintaining genomic stability by regulating cell cycle checkpoints, DNA repair, telomere stability, and apoptosis. Rad9 controls these processes mainly as part of the heterotrimeric 9-1-1 (Rad9-Hus1-Rad1) complex. However, in recent years it has been demonstrated that Rad9 can also act independently of the 9-1-1 complex as a transcriptional factor, participate in immunoglobulin class switch recombination, and show 3'-5' exonuclease activity. Aberrant Rad9 expression has been associated with prostate, breast, lung, skin, thyroid, and gastric cancers. High expression of Rad9 is causally related to, at least, human prostate cancer growth. On the other hand, deletion of Mrad9, the mouse homolog, is responsible for increased skin cancer incidence. These results reveal that Rad9 can act as an oncogene or tumor suppressor. Which of the many functions of Rad9 are causally related to initiation and progression of tumorigenesis and the mechanistic details by which Rad9 induces or suppresses tumorigenesis are presently not known, but are crucial for the development of targeted therapeutic interventions.

Adaptation to statins restricts human tumour growth in Nude mice

BACKGROUND

Statins have long been used as anti-hypercholesterolemia drugs, but numerous lines of evidence suggest that they may also bear anti-tumour potential. We have recently demonstrated that it was possible to isolate cancer cells adapted to growth in the continuous presence of lovastatin. These cells grew more slowly than the statin-sensitive cells of origin. In the present study, we compared the ability of both statin-sensitive and statin-resistant cells to give rise to tumours in Nude mice.

METHODS

HGT-1 human gastric cancer cells and L50 statin-resistant derivatives were injected subcutaneously into Nude mice and tumour growth was recorded. At the end of the experiment, tumours were recovered and marker proteins were analyzed by western blotting, RT-PCR and immunohistochemistry.

RESULTS

L50 tumours grew more slowly, showed a strong decrease in cyclin B1, over-expressed collagen IV, and had reduced laminin 332, VEGF and CD34 levels, which, collectively, may have restricted cell division, cell adhesion and neoangiogenesis.

CONCLUSIONS

Taken together, these results showed that statin-resistant cells developed into smaller tumours than statin-sensitive cells. This may be reflective of the cancer restricting activity of statins in humans, as suggested from several retrospective studies with subjects undergoing statin therapy for several years.

MicroRNA expression profiling is a potential diagnostic tool for thyroid cancer

BACKGROUND

Approximately 30% of fine-needle aspiration (FNA) biopsies of thyroid nodules are indeterminate or nondiagnostic. Recent studies suggest microRNA (miRNA, miR) is differentially expressed in malignant tumors and may have a role in carcinogenesis, including thyroid cancer. The authors therefore tested the hypothesis that miRNA expression analysis would identify putative markers that could distinguish benign from malignant thyroid neoplasms that are often indeterminate on FNA biopsy.

METHODS

A miRNA array was used to identify differentially expressed genes (5-fold higher or lower) in pooled normal, malignant, and benign thyroid tissue samples. Real-time quantitative polymerase chain reaction was used to confirm miRNA array expression data in 104 tissue samples (7 normal thyroid, 14 hyperplastic nodule, 12 follicular variant of papillary thyroid cancer, 8 papillary thyroid cancer, 15 follicular adenoma, 12 follicular carcinoma, 12 Hurthle cell adenoma, 20 Hurthle cell carcinoma, and 4 anaplastic carcinoma cases), and 125 indeterminate clinical FNA samples. The diagnostic accuracy of differentially expressed genes was determined by analyzing receiver operating characteristics.

RESULTS

Ten miRNAs showed >5-fold expression difference between benign and malignant thyroid neoplasms on miRNA array analysis. Four of the 10 miRNAs were validated to be significantly differentially expressed between benign and malignant thyroid neoplasms by quantitative polymerase chain reaction (P < .002): miR-100, miR-125b, miR-138, and miR-768-3p were overexpressed in malignant samples of follicular origin (P < .001), and in Hurthle cell carcinoma samples alone (P < .01). Only miR-125b was significantly overexpressed in follicular carcinoma samples (P < .05). The accuracy for distinguishing benign from malignant thyroid neoplasms was 79% overall, 98% for Hurthle cell neoplasms, and 71% for follicular neoplasms. The miR-138 was overexpressed in the FNA samples (P = .04) that were malignant on final pathology with an accuracy of 75%.

CONCLUSIONS

MicroRNA expression differs for normal, benign, and malignant thyroid tissue. Expression analysis of differentially expressed miRNA could help distinguish benign from malignant thyroid neoplasms that are indeterminate on thyroid FNA biopsy.

Reduced mRNA and protein expression of the genomic caretaker RAD9A in primary fibroblasts of individuals with childhood and independent second cancer

Background

The etiology of secondary cancer in childhood cancer survivors is largely unclear. Exposure of normal somatic cells to radiation and/or chemotherapy can damage DNA and if not all DNA lesions are properly fixed, the mis-repair may lead to pathological consequences. It is plausible to assume that genetic differences, i.e. in the pathways responsible for cell cycle control and DNA repair, play a critical role in the development of secondary cancer.

Methodology/Findings

To identify factors that may influence the susceptibility for second cancer formation, we recruited 20 individuals who survived a childhood malignancy and then developed a second cancer as well as 20 carefully matched control individuals with childhood malignancy but without a second cancer. By antibody microarrays, we screened primary fibroblasts of matched patients for differences in the amount of representative DNA repair-associated proteins. We found constitutively decreased levels of RAD9A and several other DNA repair proteins in two-cancer patients, compared to one-cancer patients. The RAD9A protein level increased in response to DNA damage, however to a lesser extent in the two-cancer patients. Quantification of mRNA expression by real-time RT PCR revealed lower RAD9A mRNA levels in both untreated and 1 Gy γ-irradiated cells of two-cancer patients.

Conclusions/Significance

Collectively, our results support the idea that modulation of RAD9A and other cell cycle arrest and DNA repair proteins contribute to the risk of developing a second malignancy in childhood cancer patients.

Predicting malignancy in thyroid nodules: molecular advances

Over the last several years, a clearer understanding has developed of the genetic alterations underlying thyroid carcinogenesis. This knowledge can be used to tackle 1 of the challenges facing thyroidologists: management of the indeterminate thyroid nodule. Despite the accuracy of fine-needle aspiration cytology, many patients undergo surgery to diagnose malignancy and better diagnostic tools are required. A number of biomarkers have recently been studied and show promise in this setting. In particular, BRAF, RAS, PAX8-PPARγ, microRNAs, and loss of heterozygosity have each been demonstrated as useful molecular tools for predicting malignancy and can potentially guide decisions regarding surgical management of nodular thyroid disease. This review summarizes the current literature surrounding each of these markers, highlights our institution's prospective analysis of these markers, and describes the subsequent incorporation of molecular markers into a management algorithm for thyroid nodules.

The role of RAD9 in tumorigenesis

RAD9 regulates multiple cellular processes that influence genomic integrity, and for at least some of its functions the protein acts as part of a heterotrimeric complex bound to HUS1 and RAD1 proteins. RAD9 participates in DNA repair, including base excision repair, homologous recombination repair and mismatch repair, multiple cell cycle phase checkpoints and apoptosis. In addition, functions including the transactivation of downstream target genes, immunoglobulin class switch recombination, as well as 3'-5' exonuclease activity have been reported. Aberrant RAD9 expression has been linked to breast, lung, thyroid, skin and prostate tumorigenesis, and a cause-effect relationship has been demonstrated for the latter two. Interestingly, human RAD9 overproduction correlates with prostate cancer whereas deletion of Mrad9, the corresponding mouse gene, in keratinocytes leads to skin cancer. These results reveal that RAD9 protein can function as an oncogene or tumor suppressor, and aberrantly high or low levels can have deleterious health consequences. It is not clear which of the many functions of RAD9 is critical for carcinogenesis, but several alternatives are considered herein and implications for the development of novel cancer therapies based on these findings are examined.

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.

Oncogenic activity of MCM7 transforming cluster

The miniature chromosome maintenance (MCM) complex is a group of proteins that are essential for DNA replication licensing and control of cell cycle progression from G1 to S phase. Recent studies suggest that MCM7 is overexpressed and amplified in a variety of human malignancies. MCM7 genome sequence contains a cluster of miRNA that has been shown to downregulate expression of several tumor suppressors including p21, E2F1, BIM and pTEN. The oncogenic potential of MCM7 and its embedded miRNA has been demonstrated vigorously in in vitro experiments and in animal models, and they appear to cooperate in initiation of cancer. MCM7 protein also serves as a critical target for oncogenic signaling pathways such as androgen receptor signaling, or tumor suppressor pathways such as integrin α7 or retinoblastoma signaling. This review analyzes the transforming activity and signaling of MCM7, oncogenic function of miRNA cluster that is embedded in the MCM7 genome, and the potential of gene therapy that targets MCM7.

Well differentiated follicular thyroid neoplasia: impact of molecular and technological advances on detection, monitoring and treatment

Our understanding of the molecular mechanisms responsible for follicular thyroid cell oncogenesis has been advanced significantly in recent years. Specific genetic alterations and the molecular pathways they affect have been associated with particular histologic subtypes of well-differentiated thyroid cancer and are now being evaluated for their utility as clinical tools with diagnostic, prognostic and even therapeutic relevance. This paper focuses on the most common and clinically relevant genetic alterations shown to be consistently associated with well-differentiated thyroid carcinoma. We review the impact of recent molecular and technological advances on thyroid cancer standard of care and the practice of clinical medicine.

Inhibition of prostate cancer growth and metastasis using small interference RNA specific for minichromosome complex maintenance component 7

Minichromosome complex maintenance component 7 (MCM7) is a critical component of DNA replication licensing. Amplification and overexpression of MCM7 leads to high rate of prostate cancer metastasis. Recent studies indicate that MCM7 genome encodes a putative 'super-oncogene' cluster including MCM7 oncogene and a miRNA cluster that knocks down the expression of several critical tumor-suppressor genes. In this study, we constructed a vector that constitutively expresses small interference RNA (siRNA) specific for MCM7. Introduction of this vector into prostate cancer cell lines PC3 or Du145 decreases the expression of MCM7 by 80%. The vector inhibits DNA synthesis and generates growth arrest of these cancer cells. Severe combined immunodeficient mice were xenografted PC3 or Du145 tumors, and subsequently treated with this vector through tail vein injection with polyethylenimine. The animals had dramatically smaller tumor volume, less metastasis and better survival rate in comparison with the controls. As a result, intervention of MCM7 expression using siRNA approach may hold the promise for treating androgen refractory prostate cancer.

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.

Molecular markers in thyroid cancer diagnostics

Although fine-needle aspiration biopsy (FNA) remains the mainstay of the preoperative workup of thyroid nodules, it does not provide a diagnosis in up to 20% of nodules. This group of indeterminate lesions, including lesions with cellular atypia, suspicious cytology, and demonstrating a follicular pattern, provides one of the greatest challenges to researchers in thyroid cancer today. Over the last 2 decades, considerable work has been done to find molecular markers to resolve this diagnostic dilemma. This article explores some of the markers including galectin-3, HBME-1, BRAF, RET/PTC, PAX8-PPARgamma, hTERT, telomerase, miRNA, and microarray and multigene assays. Although no one marker has proven to be a panacea, several combinations of markers have shown great promise as an adjunct to FNA.

Potential utility and limitations of thyroid cancer cell lines as models for studying thyroid cancer

BACKGROUND

Tumor-derived cell lines are widely used to study the mechanisms involved in thyroid carcinogenesis but recent studies have reported redundancy among thyroid cancer cell lines and identification of some "thyroid cell lines" that are likely not of thyroid origin.

SUMMARY

In this review, we have summarized the uses, the limitations, and the existing problems associated with the available follicular cell-derived thyroid cancer cell lines. There are some limitations to the use of cell lines as a model to "mimic" in vivo tumors. Based on the gene expression profiles of thyroid cell lines originating from tumors of different types it has become apparent that some of the cell lines are closely related to each other and to those of undifferentiated carcinomas. Further, many cell lines have lost the expression of thyroid-specific genes and have altered karyotypes, while they exhibit activation of several oncogenes (BRAF, v-raf murine sarcoma viral oncogene homolog B1; RAS, rat sarcoma; and RET/PTC, rearranged in transformation/papillary thyroid carcinoma) and inactivation of tumor suppressor gene (TP53) which is known to be important for thyroid tumorigenesis.

CONCLUSIONS

A careful selection of thyroid cancer cell lines that reflect the major characteristics of a particular type of thyroid cancer being investigated could be used as a good model system to analyze the signaling pathways that may be important in thyroid carcinogenesis. Further, the review of literature also suggests that some of the limitations can be overcome by using multiple cell lines derived from the same type of tumor.

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.

Mitogen-inducible gene-6 expression correlates with survival and is an independent predictor of recurrence in BRAF(V600E) positive papillary thyroid cancers

BACKGROUND

Mitogen-inducible gene-6 (Mig-6) is an immediate early response gene that negatively regulates signaling. EGFR overexpression and activating mutations in MAPK signaling effectors are common events in papillary thyroid cancer (PTC). The purpose of this study was to determine if Mig-6 expression is associated with EGFR expression or surgical outcomes in PTC.

METHODS

We determined Mig-6 transcript levels from a microarray in 19 patients with PTC who underwent thyroidectomy. We established a maximally selected cutoff to discriminate Kaplan-Meier survival estimates. For cross-validation, we performed quantitative RT-PCR on resected well-differentiated PTC from an additional 106 patients.

RESULTS

Mig-6 and EGFR mRNA levels correlated directly (P < .0001). Mig-6 expression above the cutoff of 1.10 (2;-dCt[Mig6-GUS]) was associated with greater survival (P = .008). When this cutoff was applied in the cross-validation, high Mig-6 expression was associated with longer survival (P = .03) and disease-free survival (P = .07). Furthermore, high Mig-6 expression was independently predictive of greater disease-free survival in BRAF(V600E)-positive PTC.

CONCLUSION

High Mig-6 expression in PTC is associated with favorable outcomes. Mig-6 is a novel tumor suppressor that may be a candidate for targeted cancer therapeutics in patients with PTC refractory to conventional therapy.

Molecular phenotyping of thyroid tumors identifies a marker panel for differentiated thyroid cancer diagnosis

BACKGROUND

Currently, a large proportion of individuals undergo thyroidectomy as a diagnostic procedure for cancer. The objective of this work was to evaluate the molecular phenotype of differentiated thyroid cancer (DTC) and benign thyroid lesions to identify molecular markers that allow for accurate thyroid cancer diagnosis.

METHODS

Tissue microarrays consisting of 100 benign and 105 malignant thyroid lesions, plus 24 lymph node samples, were stained for a panel of 57 molecular markers. Significant associations between marker staining and tumor pathology (DTC versus benign) were determined using contingency table and Mann-Whitney U (MU) tests. A Random Forests classifier algorithm was also used to identify useful/important molecular classifiers.

RESULTS

Of the 57 diagnostic markers evaluated 35 (61%) were significantly associated with a DTC diagnosis after multiple testing correction. Of these, in DTC compared with benign thyroid tumors, 8 markers were downregulated and 27 upregulated. The most significant markers for DTC diagnosis were: Galectin-3, Cytokeratin 19, Vascular Endothelial Growth Factor, Androgen Receptor, p16, Aurora-A, and HBME-1. Using the entire molecular marker panel, a Random Forests algorithm was able to classify tumors as DTC or benign with an estimated sensitivity of 87.9%, specificity of 94.0%, and an accuracy of 91.0%.

CONCLUSION

Evaluation of the DTC and benign thyroid tumor molecular phenotype has allowed for identification of a marker panel, composed of both established and novel markers, useful for thyroid cancer diagnosis. These results suggest that further study of the molecular profile of thyroid tumors is warranted, and a diagnostic molecular marker panel may potentially improve patient selection for thyroid surgery.

The extracellular matrix protein 1: its molecular interaction and implication in tumor progression

The extracellular matrix protein 1 (ECM1) is expressed around blood vessels, which suggest a role for ECM1 in angiogenesis. Recombinant ECM1 stimulates proliferation of cultured endothelial cells and promotes blood vessel formation in the chorioallantoic membrane of chicken embryos. These observations make ECM1 a possible trigger for angiogenesis, tumor progression and malignancies. Interaction of ECM1 with perlecan, MMP-9 and fibulin-1C/D contributes to this hypothesis. However, the importance of ECM1 in cancer biology has been neglected so far. Nevertheless, a survey of ECM1 expression in different tumors indicated that ECM1, although not tumor specific, is significantly elevated in many malignant epithelial tumors that give rise to metastases, emphasizing its relevance in the cancer process.

Recent developments in the clinical application of thyroid cancer biomarkers

PURPOSE OF REVIEW

The aim of this article is to provide an update on the status of the clinical application of thyroid cancer biomarkers.

RECENT FINDINGS

Our understanding of the tumor cell biology of thyroid cancer of follicular cell origin has improved and modern genomic technological tools are providing new data that may have clinical ramifications. The common somatic genetic changes in thyroid cancer of follicular cell origin (RET/PTC, NTRK, RAS, BRAF, PAX8-PPARgamma) are generally mutually exclusive, with distinct genotype-histologic subtype of thyroid cancer and genotype-phenotype associations observed. Mutation analysis in thyroid nodule fine needle aspiration biopsy has been applied to improve the diagnostic accuracy of fine needle aspiration biopsy and cytologic examination. Gene expression profiling studies have identified numerous diagnostic biomarkers of thyroid cancer that are beginning to be applied in fine needle aspiration biopsy samples to improve diagnosis. The BRAF mutation has recently been shown to be associated with disease aggressiveness, and as an independent prognostic biomarker.

SUMMARY

There has been significant progress toward identifying biomarkers that could improve the accuracy of fine needle aspiration biopsy in the evaluation of patients with thyroid nodule and predicting disease aggressiveness. Future clinical trials evaluating the accuracy and cost-effectiveness of applying these biomarkers in the management of thyroid neoplasm should be considered.

Upregulation of HMGA2 in thyroid carcinomas: a novel molecular marker to distinguish between benign and malignant follicular neoplasias

The identification of molecular markers allowing to differentiate between benign and malignant thyroid tumors remains a diagnostic challenge. Herein, we have used the expression of the high mobility group protein gene HMGA2 and its protein, respectively, as a possible marker detecting malignant growth of thyroid tumors. HMGA2 belongs to the high mobility group proteins, i.e. small, highly charged DNA-binding proteins. While HMGA2 is highly expressed in most embryonic tissues, its expression in adult tissues is very low. However, a reactivation of HMGA2 expression has been described for various malignant tumors and often correlates with the aggressiveness of the tumors. The aim of this study was to investigate whether the HMGA2 expression can be used to detect malignant thyroid tumors. RNA from 64 formalin-fixed paraffin-embedded thyroid tissues including normal tissue (n = 3), thyroiditis (n = 2), and follicular adenomas (n = 19) as well as follicular (n = 9), papillary (n = 28), and anaplastic (n = 3) carcinomas was reverse transcribed. Finally, real-time quantitative RT-PCR was performed. Expression differences of up to 400-fold were detected between benign and malignant thyroid tumors. Based on HMGA2 expression alone, it was possible to distinguish between benign and malignant thyroid tissues with a sensitivity of 95.9% and a specificity of 93.9%. There was a highly significant (P < 0.001) difference with histology of the tumors being the gold standard between the benign lesions and malignant tumors. Our results show that even as a stand-alone marker HMGA2 expression has a high potential to improve diagnoses of follicular neoplasms of the thyroid.

Incidentally discovered tumors of the endocrine glands

Clinically inapparent masses, or ‘incidentalomas’ of the endocrine glands are increasingly common owing to continued advancements in medical imaging. Incidentalomas of the adrenal glandS have received substantial attention in the literature, whereas lesions of the thyroid and endocrine pancreas, though frequently encountered in the clinic, have received relatively little attention. We review the detection and subsequent management of incidentalomas of the thyroid, adrenal and pancreas, with specific attention paid to the mode of detection and risk stratification of lesions.