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Zhang L, Liu Y, Zhuang JG, Guo J, Li YT, Dong Y, Song G. Identification of key genes and biological pathways in lung adenocarcinoma by integrated bioinformatics analysis. World J Clin Cases 2023; 11:5504-5518. [PMID: 37637684 PMCID: PMC10450371 DOI: 10.12998/wjcc.v11.i23.5504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/29/2023] [Accepted: 07/25/2023] [Indexed: 08/16/2023] Open
Abstract
BACKGROUND The objectives of this study were to identify hub genes and biological pathways involved in lung adenocarcinoma (LUAD) via bioinformatics analysis, and investigate potential therapeutic targets. AIM To determine reliable prognostic biomarkers for early diagnosis and treatment of LUAD. METHODS To identify potential therapeutic targets for LUAD, two microarray datasets derived from the Gene Expression Omnibus (GEO) database were analyzed, GSE3116959 and GSE118370. Differentially expressed genes (DEGs) in LUAD and normal tissues were identified using the GEO2R tool. The Hiplot database was then used to generate a volcanic map of the DEGs. Weighted gene co-expression network analysis was conducted to cluster the genes in GSE116959 and GSE118370 into different modules, and identify immune genes shared between them. A protein-protein interaction network was established using the Search Tool for the Retrieval of Interacting Genes database, then the CytoNCA and CytoHubba components of Cytoscape software were used to visualize the genes. Hub genes with high scores and co-expression were identified, and the Database for Annotation, Visualization and Integrated Discovery was used to perform enrichment analysis of these genes. The diagnostic and prognostic values of the hub genes were calculated using receiver operating characteristic curves and Kaplan-Meier survival analysis, and gene-set enrichment analysis was conducted. The University of Alabama at Birmingham Cancer data analysis portal was used to analyze relationships between the hub genes and normal specimens, as well as their expression during tumor progression. Lastly, validation of protein expression was conducted on the identified hub genes via the Human Protein Atlas database. RESULTS Three hub genes with high connectivity were identified; cellular retinoic acid binding protein 2 (CRABP2), matrix metallopeptidase 12 (MMP12), and DNA topoisomerase II alpha (TOP2A). High expression of these genes was associated with a poor LUAD prognosis, and the genes exhibited high diagnostic value. CONCLUSION Expression levels of CRABP2, MMP12, and TOP2A in LUAD were higher than those in normal lung tissue. This observation has diagnostic value, and is linked to poor LUAD prognosis. These genes may be biomarkers and therapeutic targets in LUAD, but further research is warranted to investigate their usefulness in these respects.
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Affiliation(s)
- Lin Zhang
- Department of Critical Medicine, Hebei Provincial Hospital of Traditional Chinese Medicine, Shijiazhuang 050000, Hebei Province, China
| | - Yuan Liu
- Department of Critical Medicine, Hebei Provincial Hospital of Traditional Chinese Medicine, Shijiazhuang 050000, Hebei Province, China
| | - Jian-Guo Zhuang
- Department of Internal Medicine, Xiongxian Hospital of Traditional Chinese Medicine, Baoding 071800, Hebei Province, China
| | - Jie Guo
- Second Department of Respiratory Medicine, Hebei Provincial Hospital of Traditional Chinese Medicine, Shijiazhuang 050000, Hebei Province, China
| | - Yan-Tao Li
- Department of Critical Medicine, Hebei Provincial Hospital of Traditional Chinese Medicine, Shijiazhuang 050000, Hebei Province, China
| | - Yan Dong
- Department of Critical Medicine, Hebei Provincial Hospital of Traditional Chinese Medicine, Shijiazhuang 050000, Hebei Province, China
| | - Gang Song
- Second Department of Respiratory Medicine, Hebei Provincial Hospital of Traditional Chinese Medicine, Shijiazhuang 050000, Hebei Province, China
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Vitamin B6 Deficiency Promotes Loss of Heterozygosity (LOH) at the Drosophila warts (wts) Locus. Int J Mol Sci 2022; 23:ijms23116087. [PMID: 35682766 PMCID: PMC9181336 DOI: 10.3390/ijms23116087] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 05/26/2022] [Accepted: 05/27/2022] [Indexed: 02/04/2023] Open
Abstract
The active form of vitamin B6, pyridoxal 5'-phosphate (PLP), is a cofactor for more than 200 enzymes involved in many metabolic pathways. Moreover, PLP has antioxidant properties and quenches the reactive oxygen species (ROS). Accordingly, PLP deficiency causes chromosome aberrations in Drosophila, yeast, and human cells. In this work, we investigated whether PLP depletion can also cause loss of heterozygosity (LOH) of the tumor suppressor warts (wts) in Drosophila. LOH is usually initiated by DNA breakage in heterozygous cells for a tumor suppressor mutation and can contribute to oncogenesis inducing the loss of the wild-type allele. LOH at the wts locus results in epithelial wts homozygous tumors easily detectable on adult fly cuticle. Here, we found that PLP depletion, induced by two PLP inhibitors, promotes LOH of wts locus producing significant frequencies of wts tumors (~7% vs. 2.3%). In addition, we identified the mitotic recombination as a possible mechanism through which PLP deficiency induces LOH. Moreover, LOH of wts locus, induced by PLP inhibitors, was rescued by PLP supplementation. These data further confirm the role of PLP in genome integrity maintenance and indicate that vitamin B6 deficiency may impact on cancer also by promoting LOH.
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Identification of Significant Genes in Lung Cancer of Nonsmoking Women via Bioinformatics Analysis. BIOMED RESEARCH INTERNATIONAL 2021; 2021:5516218. [PMID: 34671675 PMCID: PMC8523254 DOI: 10.1155/2021/5516218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 08/26/2021] [Indexed: 11/24/2022]
Abstract
Background The aim of this study was to identify potential key genes, proteins, and associated interaction networks for the development of lung cancer in nonsmoking women through a bioinformatics approach. Methods We used the GSE19804 dataset, which includes 60 lung cancer and corresponding paracancerous tissue samples from nonsmoking women, to perform the work. The GSE19804 microarray was downloaded from the GEO database and differentially expressed genes were identified using the limma package analysis in R software, with the screening criteria of p value < 0.01 and ∣log2 fold change (FC) | >2. Results A total of 169 DEGs including 130 upregulated genes and 39 downregulated were selected. Gene Ontology and KEGG pathway analysis were performed using the DAVID website, and protein-protein interaction (PPI) networks were constructed and the hub gene module was screened through STING and Cytoscape. Conclusions We obtained five key genes such as GREM1, MMP11, SPP1, FOSB, and IL33 which were strongly associated with lung cancer in nonsmoking women, which improved understanding and could serve as new therapeutic targets, but their functionality needs further experimental verification.
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Abstract
Every microarray experiment is based on a common format. First, a large number of nucleotide "spots" are arrayed onto a substrate, typically a glass slide, a silicon chip, or microbeads. Second, a complex population of nucleic acids (isolated from cells, selected from in vitro-synthesized libraries, or obtained from another source) is labeled, typically with fluorescent dyes. Third, the labeled nucleic acids are allowed to hybridize to their complementary spot(s) on the microarray. Fourth, the hybridized microarray is washed, allowing the amount of hybridized label to then be quantified. Analysis of the raw data generates a readout of the levels of each species of RNA in the original complex population. This introduction includes several examples of microarray applications and provides a discussion of the basic steps of most microarray experiments.
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Peyvan K, Karouia F, Cooper JJ, Chamberlain J, Suciu D, Slota M, Pohorille A. Gene Expression Measurement Module (GEMM) for space application: Design and validation. LIFE SCIENCES IN SPACE RESEARCH 2019; 22:55-67. [PMID: 31421849 DOI: 10.1016/j.lssr.2019.07.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 07/05/2019] [Accepted: 07/07/2019] [Indexed: 06/10/2023]
Abstract
In order to facilitate studies on the impact of the space environment on biological systems, we have developed a prototype of GEMM (Gene Expression Measurement Module) - an automated, miniaturized, integrated fluidic system for in-situ measurements of gene expression in microbial samples. The GEMM instrument is capable of (1) lysing bacterial cell walls, (2) extracting and purifying RNA released from cells, (3) hybridizing the RNA to probes attached to a microarray and (4) providing electrochemical readout, all in a microfluidics cartridge. To function on small, uncrewed spacecraft, the conventional, laboratory protocols for both sample preparation and hybridization required significant modifications. Biological validation of the instrument was carried out on Synechococcus elongatus, a photosynthetic cyanobacterium known for its metabolic diversity and resilience to adverse conditions. It was demonstrated that GEMM yielded reliable, reproducible gene expression profiles. GEMM is the only high throughput instrument that can be deployed in near future on space platforms other than the ISS to advance biological research in space. It can also prove useful for numerous terrestrial applications in the field.
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Affiliation(s)
| | - Fathi Karouia
- University of California San Francisco, Department of Pharmaceutical Chemistry, San Francisco, CA 94158, USA; NASA Ames Research Center, Space Biosciences Research Branch, Moffett Field, CA 94035, USA; NASA Ames Research Center, Exobiology Branch, MS 239-4, Moffett Field, CA 94035, USA.
| | | | | | | | | | - Andrew Pohorille
- University of California San Francisco, Department of Pharmaceutical Chemistry, San Francisco, CA 94158, USA; NASA Ames Research Center, Exobiology Branch, MS 239-4, Moffett Field, CA 94035, USA.
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Yuen SC, Zhu H, Leung SW. Building Molecular Interaction Networks from Microarray Data for Drug Target Screening. Methods Mol Biol 2018; 1762:179-197. [PMID: 29594773 DOI: 10.1007/978-1-4939-7756-7_10] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Potential drug targets for the disease treatment can be identified from microarray studies on differential gene expression of patients and healthy participants. Here, we describe a method to use the information of differentially expressed (DE) genes obtained from microarray studies to build molecular interaction networks for identification of pivotal molecules as potential drug targets. The quality control and normalization of the microarray data are conducted with R packages simpleaffy and affy, respectively. The DE genes with adjusted P values less than 0.05 and log fold changes larger than 1 or less than -1 are identified by limma package to construct a molecular interaction network with InnateDB. The genes with significant connectivity are identified by the Cytoscape app jActiveModules. The interactions among the genes within a module are tested by psych package to determine their associations. The gene pairs with significant association and known protein structures according to the Protein Data Bank are selected as potential drug targets. As an example for drug target screening, we demonstrate how to identify potential drug targets from a molecular interaction network constructed with the DE genes of significant connectivity, using a microarray dataset of type 2 diabetes mellitus.
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Affiliation(s)
- Sze Chung Yuen
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Hongmei Zhu
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Siu-Wai Leung
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China.
- School of Informatics, University of Edinburgh, Edinburgh, UK.
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Wood SL, Pernemalm M, Crosbie PA, Whetton AD. Molecular histology of lung cancer: from targets to treatments. Cancer Treat Rev 2015; 41:361-75. [PMID: 25825324 DOI: 10.1016/j.ctrv.2015.02.008] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 02/02/2015] [Accepted: 02/13/2015] [Indexed: 01/06/2023]
Abstract
Lung cancer is the leading cause of cancer-related death worldwide with a 5-year survival rate of less than 15%, despite significant advances in both diagnostic and therapeutic approaches. Combined genomic and transcriptomic sequencing studies have identified numerous genetic driver mutations that are responsible for the development of lung cancer. In addition, molecular profiling studies identify gene products and their mutations which predict tumour responses to targeted therapies such as protein tyrosine kinase inhibitors and also can offer explanation for drug resistance mechanisms. The profiling of circulating micro-RNAs has also provided an ability to discriminate patients in terms of prognosis/diagnosis and high-throughput DNA sequencing strategies are beginning to elucidate cell signalling pathway mutations associated with oncogenesis, including potential stem cell associated pathways, offering the promise that future therapies may target this sub-population, preventing disease relapse post treatment and improving patient survival. This review provides an assessment of molecular profiling within lung cancer concerning molecular mechanisms, treatment options and disease-progression. Current areas of development within lung cancer profiling are discussed (i.e. profiling of circulating tumour cells) and future challenges for lung cancer treatment addressed such as detection of micro-metastases and cancer stem cells.
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Affiliation(s)
- Steven L Wood
- Faculty Institute of Cancer Sciences, University of Manchester, Manchester Academic Health Science Centre, Wolfson Molecular Imaging Centre, Manchester M20 3LJ, UK.
| | - Maria Pernemalm
- Faculty Institute of Cancer Sciences, University of Manchester, Manchester Academic Health Science Centre, Wolfson Molecular Imaging Centre, Manchester M20 3LJ, UK; Karolinska Institutet, Department of Oncology and Pathology, SciLifeLab, Tomtebodavägen 23A, 17165 Solna, Sweden
| | - Philip A Crosbie
- Faculty Institute of Cancer Sciences, University of Manchester, Manchester Academic Health Science Centre, Wolfson Molecular Imaging Centre, Manchester M20 3LJ, UK
| | - Anthony D Whetton
- Faculty Institute of Cancer Sciences, University of Manchester, Manchester Academic Health Science Centre, Wolfson Molecular Imaging Centre, Manchester M20 3LJ, UK
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El Ghannam D, Taalab MM, Ghazy HF, Eneen AF. DNMT3A R882 mutations in patients with cytogenetically normal acute myeloid leukemia and myelodysplastic syndrome. Blood Cells Mol Dis 2014; 53:61-6. [PMID: 24512939 DOI: 10.1016/j.bcmd.2014.01.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 01/07/2014] [Accepted: 01/07/2014] [Indexed: 01/22/2023]
Abstract
Several molecular markers have been described that help to classify patients with acute myeloid leukemia (AML), a heterogeneous hematopoietic tissue neoplasm, into risk groups. We determined the frequency of DNMT3A mutations, their associations with clinical and molecular characteristics and outcome, in primary, cytogenetically-normal AML (CN-AML) and CN-myelodysplastic syndrome (MDS). A total of 63 CN-AML and 16 CN-MDS patients were analyzed for mutations in DNMT3A, codon R822 by direct sequencing and mutation of NPM1 and FLT3/ITD. DNMT3A mutations were found in 17/63 (27%) of CN-AML and in 1/16 (6.3%) of CN-MDS patients. Patients with DNMT3A mutations were older (p=0.047), had higher white blood cell (WBC) counts (p=0.046), more often belonged to FAB groups M4 and M5 (p=0.017), and were more associated with NPM1 mutations (p=0.017), than those with wild-type DNMT3A. DNMT3A-mutated patients had shorter overall disease survival (p<0.001) and disease-free survival (p=0.014) when the entire patient cohort was considered, which remained significant in multivariate analysis. We conclude that DNMT3A R882 mutations are recurrent molecular aberrations in CN-AML, less frequent in CN-MDS, and that testing for R882 mutations may provide a useful tool for refining risk classification of CN-AML.
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Affiliation(s)
- Doaa El Ghannam
- Departments of Clinical Pathology, Faculty of Medicine, Mansoura University, Egypt.
| | - Mona M Taalab
- Clinical Hematology Unit, Internal Medicine Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Hayam F Ghazy
- Medical Oncology Unit, Internal Medicine Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Asmaa F Eneen
- Internal Medicine Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt
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Chang TH, Wu SL, Wang WJ, Horng JT, Chang CW. A novel approach for discovering condition-specific correlations of gene expressions within biological pathways by using cloud computing technology. BIOMED RESEARCH INTERNATIONAL 2014; 2014:763237. [PMID: 24579087 PMCID: PMC3919110 DOI: 10.1155/2014/763237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 11/18/2013] [Accepted: 12/15/2013] [Indexed: 11/18/2022]
Abstract
Microarrays are widely used to assess gene expressions. Most microarray studies focus primarily on identifying differential gene expressions between conditions (e.g., cancer versus normal cells), for discovering the major factors that cause diseases. Because previous studies have not identified the correlations of differential gene expression between conditions, crucial but abnormal regulations that cause diseases might have been disregarded. This paper proposes an approach for discovering the condition-specific correlations of gene expressions within biological pathways. Because analyzing gene expression correlations is time consuming, an Apache Hadoop cloud computing platform was implemented. Three microarray data sets of breast cancer were collected from the Gene Expression Omnibus, and pathway information from the Kyoto Encyclopedia of Genes and Genomes was applied for discovering meaningful biological correlations. The results showed that adopting the Hadoop platform considerably decreased the computation time. Several correlations of differential gene expressions were discovered between the relapse and nonrelapse breast cancer samples, and most of them were involved in cancer regulation and cancer-related pathways. The results showed that breast cancer recurrence might be highly associated with the abnormal regulations of these gene pairs, rather than with their individual expression levels. The proposed method was computationally efficient and reliable, and stable results were obtained when different data sets were used. The proposed method is effective in identifying meaningful biological regulation patterns between conditions.
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Affiliation(s)
- Tzu-Hao Chang
- Graduate Institute of Biomedical Informatics, College of Medical Science and Technology, Taipei Medical University, Taipei 110, Taiwan
| | - Shih-Lin Wu
- Department of Computer Science and Information Engineering, College of Engineering, Chang Gung University, Taoyuan 333, Taiwan
| | - Wei-Jen Wang
- Department of Computer Science and Information Engineering, National Central University, Taoyuan 320, Taiwan
| | - Jorng-Tzong Horng
- Department of Computer Science and Information Engineering, National Central University, Taoyuan 320, Taiwan
- Department of Biomedical Informatics, Asia University, Taichung 413, Taiwan
| | - Cheng-Wei Chang
- Department of Information Management, Hsing Wu University, New Taipei City 244, Taiwan
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Wood SL, Brown JE. The Application of ‘Omics’ Techniques for Cancers That Metastasise to Bone: From Biological Mechanism to Biomarkers. CANCER METASTASIS - BIOLOGY AND TREATMENT 2014:125-153. [DOI: 10.1007/978-94-007-7569-5_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2025]
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Marescalco MS, Capizzi C, Condorelli DF, Barresi V. Genome-wide analysis of recurrent copy-number alterations and copy-neutral loss of heterozygosity in head and neck squamous cell carcinoma. J Oral Pathol Med 2013; 43:20-7. [DOI: 10.1111/jop.12087] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/02/2013] [Indexed: 02/02/2023]
Affiliation(s)
| | - Carmela Capizzi
- Scuola Superiore di Catania; University of Catania; Catania Italy
| | - Daniele Filippo Condorelli
- Scuola Superiore di Catania; University of Catania; Catania Italy
- Department of Bio-Medical Sciences; Section of Biochemistry; University of Catania; Catania Italy
| | - Vincenza Barresi
- Scuola Superiore di Catania; University of Catania; Catania Italy
- Department of Bio-Medical Sciences; Section of Biochemistry; University of Catania; Catania Italy
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Gene-expression profiling to identify genes related to spontaneous tumor regression in a canine cancer model. Vet Immunol Immunopathol 2013; 151:207-16. [DOI: 10.1016/j.vetimm.2012.11.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 11/15/2012] [Accepted: 11/15/2012] [Indexed: 02/07/2023]
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Abstract
UNLABELLED Identification of common molecular mechanisms is needed to facilitate the development of new treatment options for patients with ileal carcinoids. PURPOSE OF REVIEW Recent profiling studies on ileal carcinoids were examined to obtain a comprehensive view of risk factors, genetic aberrations, and transcriptional alterations. Special attention was paid to mechanisms that could provide novel targets for therapy. RESULTS Genome-wide association studies have shown that single nucleotide polymorphisms (SNPs) at IL12A and DAD1 are associated with an increased risk of ileal carcinoids. Genomic profiling revealed distinct patterns of copy-number alterations in ileal carcinoids. Two groups of carcinoids could be identified by hierarchical clustering. A major group of tumors was characterized by loss on chromosome 18 followed by additional losses on chromosomes 3p, 11q, and 13. Three minimal common regions of deletions were identified at 18q21.1-q21.31, 18q22.1-q22.2, and 18q22.3-q23. A minor group of tumors was characterized by clustered gains on chromosomes 4, 5, 7, 14, and 20. Expression profiling identified three groups of ileal carcinoids by principal component analysis. Tumor progression was associated with changes in gene expression including downregulation of MIR133A. Candidate genes for targeted therapy included ERBB2/HER2, DAD1, PRKCA, RYBP, CASP1, CASP4, CASP5, VMAT1, RET, APLP1, OR51E1, GPR112, SPOCK1, RUNX1, and MIR133A. CONCLUSION Profiling of ileal carcinoids has revealed recurrent genetic alterations and distinct patterns of gene expression. Frequent alterations in cellular pathways and genes were identified, suggesting novel targets for therapy. Translational studies are needed to validate suggested molecular targets.
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Affiliation(s)
- Ola Nilsson
- Sahlgrenska Cancer Center, Institute of Biomedicine, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden.
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Valsesia A, Stevenson BJ, Waterworth D, Mooser V, Vollenweider P, Waeber G, Jongeneel CV, Beckmann JS, Kutalik Z, Bergmann S. Identification and validation of copy number variants using SNP genotyping arrays from a large clinical cohort. BMC Genomics 2012; 13:241. [PMID: 22702538 PMCID: PMC3464625 DOI: 10.1186/1471-2164-13-241] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 06/15/2012] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Genotypes obtained with commercial SNP arrays have been extensively used in many large case-control or population-based cohorts for SNP-based genome-wide association studies for a multitude of traits. Yet, these genotypes capture only a small fraction of the variance of the studied traits. Genomic structural variants (GSV) such as Copy Number Variation (CNV) may account for part of the missing heritability, but their comprehensive detection requires either next-generation arrays or sequencing. Sophisticated algorithms that infer CNVs by combining the intensities from SNP-probes for the two alleles can already be used to extract a partial view of such GSV from existing data sets. RESULTS Here we present several advances to facilitate the latter approach. First, we introduce a novel CNV detection method based on a Gaussian Mixture Model. Second, we propose a new algorithm, PCA merge, for combining copy-number profiles from many individuals into consensus regions. We applied both our new methods as well as existing ones to data from 5612 individuals from the CoLaus study who were genotyped on Affymetrix 500K arrays. We developed a number of procedures in order to evaluate the performance of the different methods. This includes comparison with previously published CNVs as well as using a replication sample of 239 individuals, genotyped with Illumina 550K arrays. We also established a new evaluation procedure that employs the fact that related individuals are expected to share their CNVs more frequently than randomly selected individuals. The ability to detect both rare and common CNVs provides a valuable resource that will facilitate association studies exploring potential phenotypic associations with CNVs. CONCLUSION Our new methodologies for CNV detection and their evaluation will help in extracting additional information from the large amount of SNP-genotyping data on various cohorts and use this to explore structural variants and their impact on complex traits.
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Affiliation(s)
- Armand Valsesia
- Department of Medical Genetics, University of Lausanne, Lausanne, Switzerland
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Abstract
Metastable and somatically heritable patterns of DNA methylation provide an important level of genomic regulation. In this article, we review methods for analyzing these genome-wide epigenetic patterns and offer a perspective on the ever-expanding literature, which we hope will be useful for investigators who are new to this area. The historical aspects that we cover will be helpful in interpreting this literature and we hope that our discussion of the newest analytical methods will stimulate future progress. We emphasize that no single approach can provide a complete view of the overall methylome, and that combinations of several modalities applied to the same sample set will give the clearest picture. Given the unexpected epigenomic patterns and new biological principles, as well as new disease markers, that have been uncovered in recent studies, it is likely that important discoveries will continue to be made using genome-wide DNA methylation profiling.
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Affiliation(s)
- Tao Zuo
- Division of Human Cancer Genetics, Department of Molecular Virology, Immunology and Medical Genetics, Comprehensive Cancer Center, Ohio State University, Columbus, OH 43210, USA.
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Lee TL, Rennert OM, Chan WY. Revealing the transcriptome landscape of mouse spermatogonial cells by tiling microarray. Methods Mol Biol 2012; 825:75-92. [PMID: 22144238 PMCID: PMC4156874 DOI: 10.1007/978-1-61779-436-0_7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
In the past decade, the advent of microarray technologies has allowed functional genomic studies of male germ cell development, resulting in the identification of genes governing various processes. A major limitation with conventional gene expression microarray is that results obtained are biased due to gene probe design. The gene probes for expression microarrays are usually represented by a small number of probes located at the 3' end of a transcript. Tiling microarrays eliminate such issue by interrogating the genome in an unbiased fashion through probes tiled across the entire genome. These arrays provide higher genomic resolution and allow the identification of novel transcripts. To reveal the complexity of the genomic landscape of developing male germ cells, we applied tiling microarray to evaluate the transcriptome in spermatogonial cells. Over 50% of all known mouse genes are expressed during testicular development. More than 47% of the transcripts are uncharacterized. The results suggested that the transcription machinery in spermaotogonial cells is more complex than previously envisioned.
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Affiliation(s)
- Tin-Lap Lee
- School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
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Hawthorn L, Cowell JK. Analysis of wilms tumors using SNP mapping array-based comparative genomic hybridization. PLoS One 2011; 6:e18941. [PMID: 21544195 PMCID: PMC3081321 DOI: 10.1371/journal.pone.0018941] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 03/25/2011] [Indexed: 12/18/2022] Open
Abstract
Wilms tumor (WT) has been a model to study kidney embryogenesis and tumorigenesis and, although associated with hereditary, cancer predisposition syndromes, the majority of tumors occur sporadically. To analyze genetic changes in WT we have defined copy number changes and loss of heterozygosity in 56 Wilms tumors using high resolution oligonucleotide arrays at a average resolution of ∼12 Kb. Consistent deletions were seen on chromosomes 1p, 4q, 7p, 9q, 11p, 11q, 14q, 16q, and 21q. High frequency gains were seen for 1q and lower frequency gains were seen on 7q and chromosomes 8, 12 and 18. The high resolution provided by the SNP mapping arrays has defined minimal regions of deletion for many of these LOH events. Analysis of CNAs by tumor stage show relatively stable karyotypes in stage 1 tumors and more complex aCGH profiles in tumors from stages 3–5.
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Affiliation(s)
- Lesleyann Hawthorn
- School of Medicine, MCG Cancer Center, Medical College of Georgia, Augusta, Georgia, United States of America.
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Dong L, Jensen RV, De Rienzo A, Gordon GJ, Xu Y, Sugarbaker DJ, Bueno R. Differentially expressed alternatively spliced genes in malignant pleural mesothelioma identified using massively parallel transcriptome sequencing. BMC MEDICAL GENETICS 2009; 10:149. [PMID: 20043850 PMCID: PMC2808307 DOI: 10.1186/1471-2350-10-149] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2009] [Accepted: 12/31/2009] [Indexed: 12/22/2022]
Abstract
Background Analyses of Expressed Sequence Tags (ESTs) databases suggest that most human genes have multiple alternative splice variants. The alternative splicing of pre-mRNA is tightly regulated during development and in different tissue types. Changes in splicing patterns have been described in disease states. Recently, we used whole-transcriptome shotgun pryrosequencing to characterize 4 malignant pleural mesothelioma (MPM) tumors, 1 lung adenocarcinoma and 1 normal lung. We hypothesized that alternative splicing profiles might be detected in the sequencing data for the expressed genes in these samples. Methods We developed a software pipeline to map the transcriptome read sequences of the 4 MPM samples and 1 normal lung sample onto known exon junction sequences in the comprehensive AceView database of expressed sequences and to count how many reads map to each junction. 13,274,187 transcriptome reads generated by the Roche/454 sequencing platform for 5 samples were compared with 151,486 exon junctions from the AceView database. The exon junction expression index (EJEI) was calculated for each exon junction in each sample to measure the differential expression of alternative splicing events. Top ten exon junctions with the largest EJEI difference between the 4 mesothelioma and the normal lung sample were then examined for differential expression using Quantitative Real Time PCR (qRT-PCR) in the 5 sequenced samples. Two of the differentially expressed exon junctions (ACTG2.aAug05 and CDK4.aAug05) were further examined with qRT-PCR in additional 18 MPM and 18 normal lung specimens. Results We found 70,953 exon junctions covered by at least one sequence read in at least one of the 5 samples. All 10 identified most differentially expressed exon junctions were validated as present by RT-PCR, and 8 were differentially expressed exactly as predicted by the sequence analysis. The differential expression of the AceView exon junctions for the ACTG2 and CDK4 genes were also observed to be statistically significant in an additional 18 MPM and 18 normal lung samples examined using qRT-PCR. The differential expression of these two junctions was shown to successfully classify these mesothelioma and normal lung specimens with high sensitivity (89% and 78%, respectively). Conclusion Whole-transcriptome shotgun sequencing, combined with a downstream bioinformatics pipeline, provides powerful tools for the identification of differentially expressed exon junctions resulting from alternative splice variants. The alternatively spliced genes discovered in the study could serve as useful diagnostic markers as well as potential therapeutic targets for MPM.
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Affiliation(s)
- Lingsheng Dong
- The Thoracic Surgery Oncology Laboratory and Division of Thoracic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
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High-throughput resequencing in the diagnosis of BRCA1/2 mutations using oligonucleotide resequencing microarrays. Breast Cancer Res Treat 2009; 122:287-97. [PMID: 19941162 DOI: 10.1007/s10549-009-0639-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2009] [Accepted: 11/05/2009] [Indexed: 10/20/2022]
Abstract
Breast cancer is the most frequent form of carcinoma in European females (incidence 65 per 100,000). In about 10% of all cases, pedigree analysis predicts a hereditary breast-ovarian cancer syndrome (HBOC) to be causative for the disease. Frequently, mutations in two genes, BRCA1 (Chr. 17q21) and BRCA2 (Chr. 13q12), are associated with HBOC. In females, mutations in these genes result in a lifetime risk of 80-85% for breast cancer and 54% (BRCA1) or 23% (BRCA2) for ovarian cancer. Current genetic diagnostic tools for BRCA1 and BRCA2 remain laborious and expensive. Here, we present the first oligonucleotide resequencing microarray covering the complete coding sequence of both genes. In total, 36 previously characterized DNAs were resequenced; all 11 patients with single-nucleotide mutations and, due to a special mutational design, eight patients with heterozygous deletions were detected correctly. In total, 47 different single-nucleotide variants (SNVs) were found. A newly developed software, SeqC, reduced the number of ambiguous calls with the help of a statistical module comparing the acquired data to an online-database. SeqC improved the average call rate to 99% (GSeq: 97%) and reduced time and efforts for manual analysis. SeqC confirmed the results obtained by GSeq and found an additional 33 sequences changes representing 14 SNVs. In total, 945 kb were screened and the overall turnaround time for each patient took approximately 3 days, including analysis.
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De Paoli P. Institutional shared resources and translational cancer research. J Transl Med 2009; 7:54. [PMID: 19563639 PMCID: PMC2711056 DOI: 10.1186/1479-5876-7-54] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2009] [Accepted: 06/29/2009] [Indexed: 02/06/2023] Open
Abstract
The development and maintenance of adequate shared infrastructures is considered a major goal for academic centers promoting translational research programs. Among infrastructures favoring translational research, centralized facilities characterized by shared, multidisciplinary use of expensive laboratory instrumentation, or by complex computer hardware and software and/or by high professional skills are necessary to maintain or improve institutional scientific competitiveness. The success or failure of a shared resource program also depends on the choice of appropriate institutional policies and requires an effective institutional governance regarding decisions on staffing, existence and composition of advisory committees, policies and of defined mechanisms of reporting, budgeting and financial support of each resource. Shared Resources represent a widely diffused model to sustain cancer research; in fact, web sites from an impressive number of research Institutes and Universities in the U.S. contain pages dedicated to the SR that have been established in each Center, making a complete view of the situation impossible. However, a nation-wide overview of how Cancer Centers develop SR programs is available on the web site for NCI-designated Cancer Centers in the U.S., while in Europe, information is available for individual Cancer centers. This article will briefly summarize the institutional policies, the organizational needs, the characteristics, scientific aims, and future developments of SRs necessary to develop effective translational research programs in oncology. In fact, the physical build-up of SRs per se is not sufficient for the successful translation of biomedical research. Appropriate policies to improve the academic culture in collaboration, the availability of educational programs for translational investigators, the existence of administrative facilitations for translational research and an efficient organization supporting clinical trial recruitment and management represent essential tools, providing solutions to overcome existing barriers in the development of translational research in biomedical research centers.
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Affiliation(s)
- Paolo De Paoli
- Centro di Riferimento Oncologico, IRCCS, I-33081 Aviano PN Aviano, Italy.
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Zanivan S, Gnad F, Wickström SA, Geiger T, Macek B, Cox J, Fässler R, Mann M. Solid tumor proteome and phosphoproteome analysis by high resolution mass spectrometry. J Proteome Res 2009; 7:5314-26. [PMID: 19367708 DOI: 10.1021/pr800599n] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Kinases play a prominent role in tumor development, pointing to the presence of specific phosphorylation patterns in tumor tissues. Here, we investigate whether recently developed high resolution mass spectrometric (MS) methods for proteome and phosphoproteome analysis can also be applied to solid tumors. As tumor model, we used TG3 mutant mice carrying skin melanomas. At total of 100 microg of solid tumor lysate yielded a melanoma proteome of 4443 identified proteins, including at least 88 putative melanoma markers previously found by cDNA microarray technology. Analysis of 2 mg of lysate from dissected melanoma with titansphere chromatography and 8 mg with strong cation exchange together resulted in the identification of more than 5600 phosphorylation sites on 2250 proteins. The phosphoproteome included many hits from pathways important in melanoma. One-month storage at -80 degrees C did not significantly decrease the number of identified phosphorylation sites. Thus, solid tumor can be analyzed by MS-based proteomics with similar efficiency as cell culture models and in amounts compatible with biopsies.
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Affiliation(s)
- Sara Zanivan
- Department of Proteomics and Signal Transduction, Max-Planck-Institute for Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
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Muggerud AA, Edgren H, Wolf M, Kleivi K, Dejeux E, Tost J, Sørlie T, Kallioniemi O. Data integration from two microarray platforms identifies bi-allelic genetic inactivation of RIC8A in a breast cancer cell line. BMC Med Genomics 2009; 2:26. [PMID: 19432969 PMCID: PMC2685142 DOI: 10.1186/1755-8794-2-26] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2008] [Accepted: 05/11/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Using array comparative genomic hybridization (aCGH), a large number of deleted genomic regions have been identified in human cancers. However, subsequent efforts to identify target genes selected for inactivation in these regions have often been challenging. METHODS We integrated here genome-wide copy number data with gene expression data and non-sense mediated mRNA decay rates in breast cancer cell lines to prioritize gene candidates that are likely to be tumour suppressor genes inactivated by bi-allelic genetic events. The candidates were sequenced to identify potential mutations. RESULTS This integrated genomic approach led to the identification of RIC8A at 11p15 as a putative candidate target gene for the genomic deletion in the ZR-75-1 breast cancer cell line. We identified a truncating mutation in this cell line, leading to loss of expression and rapid decay of the transcript. We screened 127 breast cancers for RIC8A mutations, but did not find any pathogenic mutations. No promoter hypermethylation in these tumours was detected either. However, analysis of gene expression data from breast tumours identified a small group of aggressive tumours that displayed low levels of RIC8A transcripts. qRT-PCR analysis of 38 breast tumours showed a strong association between low RIC8A expression and the presence of TP53 mutations (P = 0.006). CONCLUSION We demonstrate a data integration strategy leading to the identification of RIC8A as a gene undergoing a classical double-hit genetic inactivation in a breast cancer cell line, as well as in vivo evidence of loss of RIC8A expression in a subgroup of aggressive TP53 mutant breast cancers.
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Affiliation(s)
- Aslaug Aamodt Muggerud
- Department of Genetics, Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, 0310 Oslo, Norway.
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Abstract
PURPOSE OF REVIEW The proportion of breast cancers directly attributable to determinant hereditary factors is estimated to be 5-10%. A number of recent findings with regard to hereditary breast cancer should affect the criteria and scope of routine genetic testing and, soon, breast cancer therapy. RECENT FINDINGS The number of genes causing genetic cancer has expanded, mostly with genes that encode proteins that function in the BRCA1/2 pathways. The risk level associated with some genes is still under investigation, but is high for specific mutations. Some mutant alleles occur frequently, some are rare. High-throughput technologies will progressively allow investigating all genes involved in genetic (breast) cancer risks in all individuals for whom this information could be relevant. This and the emerging novel treatment options specific for cancers in mutation carriers will oblige us to progressively drop all currently used selection criteria such as familial phenotype for genomic testing. A major challenge remains the effective penetration of this knowledge in the professional and lay community, the broad application and financing of this high-throughput technology, and the identification of as yet unknown breast cancer predisposition genes. SUMMARY The assessment of breast cancer predisposition genes, previously only an optional predictive genetic test, is growing in importance as it also becomes a therapeutic predictive test.
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Seng KY, Glenny RW, Madtes DK, Spilker ME, Vicini P, Gharib SA. Comparison of statistical data models for identifying differentially expressed genes using a generalized likelihood ratio test. GENE REGULATION AND SYSTEMS BIOLOGY 2009; 2:125-139. [PMID: 19119428 PMCID: PMC2613008 DOI: 10.4137/grsb.s381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Currently, statistical techniques for analysis of microarray-generated data sets have deficiencies due to limited understanding of errors inherent in the data. A generalized likelihood ratio (GLR) test based on an error model has been recently proposed to identify differentially expressed genes from microarray experiments. However, the use of different error structures under the GLR test has not been evaluated, nor has this method been compared to commonly used statistical tests such as the parametric t-test. The concomitant effects of varying data signal-to-noise ratio and replication number on the performance of statistical tests also remain largely unexplored. In this study, we compared the effects of different underlying statistical error structures on the GLR test’s power in identifying differentially expressed genes in microarray data. We evaluated such variants of the GLR test as well as the one sample t-test based on simulated data by means of receiver operating characteristic (ROC) curves. Further, we used bootstrapping of ROC curves to assess statistical significance of differences between the areas under the curves. Our results showed that i) the GLR tests outperformed the t-test for detecting differential gene expression, ii) the identity of the underlying error structure was important in determining the GLR tests’ performance, and iii) signal-to-noise ratio was a more important contributor than sample replication in identifying statistically significant differential gene expression.
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Affiliation(s)
- Kok-Yong Seng
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
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25
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Cowell JK, Lo KC. Application of oligonucleotides arrays for coincident comparative genomic hybridization, ploidy status and loss of heterozygosity studies in human cancers. Methods Mol Biol 2009; 556:47-65. [PMID: 19488871 DOI: 10.1007/978-1-60327-192-9_5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Many oligonucleotide arrays comprise of spotted short oligonucleotides from throughout the genome under study. Hybridization of tumor DNA samples to these arrays will provide copy number estimates at each reference point with varying degrees of accuracy. In addition to copy number changes, however, tumors often undergo loss of heterozygosity for specific regions of the genome without copy number changes and these genetic changes can only be identified using arrays that identify polymorphic alleles at each reference point. In addition, because the hybridization intensity can be measured at each of the allelic variants, allelic ratios can be established which give indications of ploidy status in the tumor which is not generally possible using most other oligonucleotide array designs. The only arrays currently available that simultaneously report copy number, ploidy, and loss of heterozygosity are the Affymetrix SNP mapping arrays. In this review, the features of the SNP mapping arrays are described and computational tools explored which allow the maximum genetic information to be extracted from the experiment. Although the methodologies to generate the SNP data are now well established, approaches to interpret the data are only just being developed. From our experience using these arrays, we provide insights into how to evaluate the SNP data to report copy number changes, loss of heterozygosity, and ploidy in the same tumor samples using a single array.
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Affiliation(s)
- John K Cowell
- School of Medicine, Medical College of Georgia Cancer Center, Augusta, GA, USA
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Ravits J, Traynor BJ. Current and future directions in genomics of amyotrophic lateral sclerosis. Phys Med Rehabil Clin N Am 2008; 19:461-77, viii. [PMID: 18625410 PMCID: PMC3524513 DOI: 10.1016/j.pmr.2008.04.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
New knowledge of the structure and function of the human genome and novel genomic technologies are being applied to the study of sporadic amyotrophic lateral sclerosis (ALS). These studies can examine tens to hundreds of thousands of items at once, and depend on sophisticated computer processing. Current studies are focused on genetic susceptibility and gene expression and future studies will likely focus on structural variation, gene regulation and non-protein coding regions. The hope is that they will lead to deeper understanding of molecular aspects of the disease and to rational therapeutic targets.
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Affiliation(s)
- John Ravits
- Virginia Mason Medical Center, 1100 Ninth Avenue, Seattle, WA 98101, USA.
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27
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Ye X, Lotan R. Potential misinterpretation of data on differential gene expression in normal and malignant cells in vitro. BRIEFINGS IN FUNCTIONAL GENOMICS AND PROTEOMICS 2008; 7:322-6. [DOI: 10.1093/bfgp/eln021] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Mojica WD, Stein L, Hawthorn L. Universal Reference RNA is not a representative normal sample for oligonucleotide microarray studies. Pathol Oncol Res 2008; 14:243-51. [PMID: 18553159 DOI: 10.1007/s12253-008-9068-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2008] [Accepted: 05/16/2008] [Indexed: 12/31/2022]
Abstract
Translational research has been defined as the scientific study using human material that will ultimately generate patient specific data. A major caveat in human directed study is the availability of high quality and quantities of patient derived homogeneous cells for analysis. Whereas there exist sources for which tumor tissue and blood samples can be made available, the same cannot be said for normal tissue. The absence of normal control tissue has led to the creation of pooled cell lines and tissues for purchase known as "reference RNA". Although initially created for purposes of standardization, the difficulty associated with acquiring normal tissue has led some investigators to use sources of universal pooled RNA for comparative analysis with clinical tissue specimens. In order to study the effects of using Universal Reference RNA on expression profiling experiments we have evaluated the performance of universal RNA compared to RNA obtained from a purified population of colon epithelial cells in defining a set of altered transcripts in colon cancer.
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Affiliation(s)
- Wilfrido D Mojica
- Department of Pathology, University at Buffalo, State University of New York, Buffalo, NY 14203, USA.
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Comprehensive analysis of loss of heterozygosity events in glioblastoma using the 100K SNP mapping arrays and comparison with copy number abnormalities defined by BAC array comparative genomic hybridization. Genes Chromosomes Cancer 2008; 47:221-37. [DOI: 10.1002/gcc.20524] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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30
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Huang CJ, Chien CC, Yang SH, Chang CC, Sun HL, Cheng YC, Liu CC, Lin SC, Lin CM. Faecal ribosomal protein L19 is a genetic prognostic factor for survival in colorectal cancer. J Cell Mol Med 2008; 12:1936-43. [PMID: 18266979 PMCID: PMC4506161 DOI: 10.1111/j.1582-4934.2008.00253.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Ribosomal proteins are encoded by a gene family, members of which are overexpressed in human cancers. Many of them have been found, using oligonucleotide microarray hybridization, to be differentially expressed in the faeces of patients with various stages of col-orectal cancer (CRC). The gene encoding ribosomal protein L19 (RPL19), a prognostic marker for human prostate cancer, is differentially expressed in CRC patients. Measurement of faecal RPL19 mRNA might improve prognostic prediction for CRC patients. Using quantitative real-time reverse transcription PCR, levels of RPL19 mRNA were detected in samples of colonic tissues from 44 CRC patients, in the faeces of 54 CRC patients and 15 controls, and in 11 colonic cell lines. Seven of 24 patients with late-stage CRC (Dukes' stages C and D) expressed over 2-fold more RPL19 in colonic tumour tissues than in corresponding normal tissues (P= 0.038). The mean faecal RPL19 mRNA levels of late-staged patients were higher than those of controls (P= 0.003) and early-staged patients (P= 0.008). Patients with both high serum levels of carcinoembryonic antigen (CEA; >5 ng/mL) and high-faecal RPL19 mRNA (≥0.0069) had higher risk (odds ratio, 8.0; P= 0.015) and lower overall 48-month survival (33.8 ± 13.7%, P= 0.013). Oligonucleotide microarray hybridization analysis of faecal molecules identified gene transcripts differentially present in faeces. In conclusion, faecal RPL19 expression is associated with advanced tumour stages and addictive to serum CEA in predicting prognosis of CRC patients.
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Affiliation(s)
- C-J Huang
- Molecular Genetics and Biochemistry Laboratory, Cathay Medical Research Institute, Cathay General Hospital, Taipei, Taiwan
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Guindalini C, Tufik S. Uso de microarrays na busca de perfis de expressão gênica: aplicação no estudo de fenótipos complexos. BRAZILIAN JOURNAL OF PSYCHIATRY 2007; 29:370-4. [DOI: 10.1590/s1516-44462007000400014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Accepted: 10/23/2007] [Indexed: 11/21/2022]
Abstract
Com o advento do seqüenciamento de genoma humano, novas tecnologias foram desenvolvidas e despontaram como promissoras ferramentas metodológicas e científicas para o avanço na compreensão dos mecanismos envolvidos em várias doenças complexas. Dentre elas, a técnica de análise em larga escala (conhecida como microarrays ou chips de DNA) é particularmente eficaz em permitir uma visão global na busca de padrões de expressão gênica em amostras biológicas. Por meio da determinação da expressão de milhares de genes simultaneamente, a promissora tecnologia permite que pesquisadores comparem o comportamento molecular de diversos tipos de linhagens celulares e tecidos diferentes, quando expostos a uma determinada condição patológica ou experimental. A aplicação do método pode trazer novas perspectivas de análise de processos fisiológicos e facilitar a identificação de marcadores moleculares para o diagnóstico, prognóstico e para o tratamento farmacológico atual. Nesse artigo, apresentaremos conceitos teóricos e metodológicos que permeiam a tecnologia de microarrays, assim como suas vantagens, perspectivas e direcionamentos futuros. Com o intuito de exemplificar sua aplicabilidade e eficiência no estudo de fenômenos complexos, serão apresentados e também discutidos resultados iniciais sobre padrões de expressão gênica em amostra de cérebros post-mortem de pacientes psiquiátricos e sobre as conseqüências moleculares e funcionais de perturbações no sono, comumente associadas a transtornos psiquiátricos.
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Affiliation(s)
- Camila Guindalini
- Universidade Federal de São Paulo, Brasil; Universidade Federal de São Paulo, Brasil
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Abstract
PURPOSE OF REVIEW Gene expression profiling has highlighted the biologic heterogeneity of breast cancer and has begun to influence the ability of the medical community to individualize patient therapy. The review is intended to highlight the most important advances in the field over recent years with an emphasis on those most relevant to the practicing oncologist. RECENT FINDINGS Two prognostic profiling assays, the Mammaprint and Oncotype Dx, are in phase III clinical trials designed to evaluate their contribution to therapeutic decision making. Predictive profiles for both chemotherapy and targeted therapy are also in development. In addition, application of genetic profiling techniques to a variety of tumor types is starting to identify those processes, like proliferation, that are integral to carcinogenesis as a whole. SUMMARY The biologic heterogeneity of breast cancer has become clearer through genome-wide profiling technologies. Validation of the clinical utility of prognostic profiles may enable oncologists to better identify those patients whose prognosis justifies more intensive therapy, while predictive profiles may soon be able to determine which type of chemotherapy a patient should receive. In addition, profiling is starting to identify new therapeutic targets which will point the field of breast cancer oncology in new directions.
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Affiliation(s)
- Shannon R Morris
- GlaxoSmithKline, Research Triangle Park and Division of Hematology/Oncology, University of North Carolina, Chapel Hill, NC 27599-7305, USA
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Smith LT, Otterson GA, Plass C. Unraveling the epigenetic code of cancer for therapy. Trends Genet 2007; 23:449-56. [PMID: 17681396 DOI: 10.1016/j.tig.2007.07.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Revised: 06/06/2007] [Accepted: 07/24/2007] [Indexed: 01/03/2023]
Abstract
Alterations in the genome and the epigenome are common in most cancers. Changes in epigenetic signatures, including aberrant DNA methylation and histone deacetylation, are among the most prevalent modifications in cancer and lead to dramatic changes in gene expression patterns. Because DNA methylation and histone deacetylation are reversible processes, they have become attractive as targets for cancer epigenetic therapy, both as single agents and as 'enhancing' agents for other treatment strategies. In this review we discuss our current view of the mammalian epigenome, this view has changed over the years because of the availability of novel technologies. We further demonstrate how the profound understanding of epigenetic alterations in cancer will help develop novel strategies for epigenetic therapies.
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Affiliation(s)
- Laura T Smith
- Division of Human Cancer Genetics, Department of Molecular Virology, Immunology and Medical Genetics, OH, USA
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Henderson G, Bradley M. Functional peptide arrays for high-throughput chemical biology based applications. Curr Opin Biotechnol 2007; 18:326-30. [PMID: 17681464 DOI: 10.1016/j.copbio.2007.05.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2007] [Revised: 05/08/2007] [Accepted: 05/09/2007] [Indexed: 10/23/2022]
Abstract
Constant advancements in printing technology, informatics, surface modification strategies and peptide chemistries mean that peptide arrays have, like DNA arrays, become even more miniaturised and complex in terms of not only the numbers of peptides immobilised but also their lengths. As a result peptide-based arrays have become a powerful tool in the interrogation, examination and perturbation of a host of biological systems.
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Affiliation(s)
- Graham Henderson
- EaStCHEM, School of Chemistry, King's Buildings, University of Edinburgh, Edinburgh EH9 3JJ, United Kingdom
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