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Lewis KA, Tollefsbol TO. Regulation of the Telomerase Reverse Transcriptase Subunit through Epigenetic Mechanisms. Front Genet 2016; 7:83. [PMID: 27242892 PMCID: PMC4860561 DOI: 10.3389/fgene.2016.00083] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Accepted: 04/22/2016] [Indexed: 12/21/2022] Open
Abstract
Chromosome-shortening is characteristic of normal cells, and is known as the end replication problem. Telomerase is the enzyme responsible for extending the ends of the chromosomes in de novo synthesis, and occurs in germ cells as well as most malignant cancers. There are three subunits of telomerase: human telomerase RNA (hTERC), human telomerase associated protein (hTEP1), or dyskerin, and human telomerase reverse transcriptase (hTERT). hTERC and hTEP1 are constitutively expressed, so the enzymatic activity of telomerase is dependent on the transcription of hTERT. DNA methylation, histone methylation, and histone acetylation are basic epigenetic regulations involved in the expression of hTERT. Non-coding RNA can also serve as a form of epigenetic control of hTERT. This epigenetic-based regulation of hTERT is important in providing a mechanism for reversibility of hTERT control in various biological states. These include embryonic down-regulation of hTERT contributing to aging and the upregulation of hTERT playing a critical role in over 90% of cancers. Normal human somatic cells have a non-methylated/hypomethylated CpG island within the hTERT promoter region, while telomerase-positive cells paradoxically have at least a partially methylated promoter region that is opposite to the normal roles of DNA methylation. Histone acetylation of H3K9 within the promoter region is associated with an open chromatin state such that transcription machinery has the space to form. Histone methylation of hTERT has varied control of the gene, however. Mono- and dimethylation of H3K9 within the promoter region indicate silent euchromatin, while a trimethylated H3K9 enhances gene transcription. Non-coding RNAs can target epigenetic-modifying enzymes, as well as transcription factors involved in the control of hTERT. An epigenetics diet that can affect the epigenome of cancer cells is a recent fascination that has received much attention. By combining portions of this diet with epigenome-altering treatments, it is possible to selectively regulate the epigenetic control of hTERT and its expression.
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Affiliation(s)
- Kayla A Lewis
- Department of Biology, University of Alabama at Birmingham, Birmingham AL, USA
| | - Trygve O Tollefsbol
- Department of Biology, University of Alabama at Birmingham, BirminghamAL, USA; Comprehensive Center for Healthy Aging, University of Alabama at Birmingham, BirminghamAL, USA; Comprehensive Cancer Center, University of Alabama at Birmingham, BirminghamAL, USA; Nutrition Obesity Research Center, University of Alabama at Birmingham, BirminghamAL, USA; Comprehensive Diabetes Center, University of Alabama at Birmingham, BirminghamAL, USA
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Hashimoto Y, Zumwalt TJ, Goel A. DNA methylation patterns as noninvasive biomarkers and targets of epigenetic therapies in colorectal cancer. Epigenomics 2016; 8:685-703. [PMID: 27102979 DOI: 10.2217/epi-2015-0013] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Aberrant DNA methylation is frequently detected in gastrointestinal tumors, and can therefore potentially be used to screen, diagnose, prognosticate, and predict colorectal cancers (CRCs). Although colonoscopic screening remains the gold standard for CRC screening, this procedure is invasive, expensive, and suffers from poor patient compliance. Methylated DNA is an attractive choice for a biomarker substrate because CRCs harbor hundreds of aberrantly methylated genes. Furthermore, abundance in extracellular environments and resistance to degradation and enrichment in serum, stool, and other noninvasive bodily fluids, allows quantitative measurements of methylated DNA biomarkers. This article describes the most important studies that investigated the efficacy of serum- or stool-derived methylated DNA as population-based screening biomarkers in CRC, details several mechanisms and factors that control DNA methylation, describes a better use of prevailing technologies that discover novel DNA methylation biomarkers, and illustrates the diversity of demethylating agents and their applicability toward clinical impact.
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Affiliation(s)
- Yutaka Hashimoto
- Center for Translational Genomics & Oncology, Baylor Scott & White Research Institute & Sammons Cancer Center, Baylor University Medical Center, Dallas, TX, USA
| | - Timothy J Zumwalt
- Center for Translational Genomics & Oncology, Baylor Scott & White Research Institute & Sammons Cancer Center, Baylor University Medical Center, Dallas, TX, USA
| | - Ajay Goel
- Center for Translational Genomics & Oncology, Baylor Scott & White Research Institute & Sammons Cancer Center, Baylor University Medical Center, Dallas, TX, USA
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Coppedè F, Tannorella P, Stoccoro A, Chico L, Siciliano G, Bonuccelli U, Migliore L. Methylation analysis of DNA repair genes in Alzheimer's disease. Mech Ageing Dev 2016; 161:105-111. [PMID: 27080585 DOI: 10.1016/j.mad.2016.04.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 03/30/2016] [Accepted: 04/07/2016] [Indexed: 10/22/2022]
Abstract
There is substantial evidence of impaired DNA repair activities in Alzheimer's disease (AD) neurons and peripheral tissues, inducing some investigators to speculate that this could partially result from promoter hypermethylation of DNA repair genes, resulting in gene silencing in those tissues. In the present study a screening cohort composed by late-onset AD (LOAD) patients and healthy matched controls was evaluated with a commercially available DNA methylation array for the assessment of the methylation levels of a panel of 22 genes involved in major DNA repair pathways in blood DNA. We then applied a cost-effective PCR based methylation-sensitive high-resolution melting (MS-HRM) technique, in order to evaluate the promoter methylation levels of the following DNA repair genes: OGG1, PARP1, MRE11A, BRCA1, MLH1, and MGMT. The analysis was performed in blood DNA from 56 LOAD patients and 55 matched controls, including the samples previously assessed with the DNA methylation array as validating samples. Both approaches revealed that all the investigated genes were largely hypomethylated in LOAD and control blood DNA, and no difference between groups was observed. Collectively, present data do not support an increased promoter methylation of some of the major DNA repair genes in blood DNA of AD patients.
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Affiliation(s)
- Fabio Coppedè
- Department of Translational Research and New Technologies in Medicine and Surgery, Section of Medical Genetics, University of Pisa, Via Roma 55, 56126 Pisa, Italy.
| | - Pierpaola Tannorella
- Department of Translational Research and New Technologies in Medicine and Surgery, Section of Medical Genetics, University of Pisa, Via Roma 55, 56126 Pisa, Italy
| | - Andrea Stoccoro
- Department of Translational Research and New Technologies in Medicine and Surgery, Section of Medical Genetics, University of Pisa, Via Roma 55, 56126 Pisa, Italy; Doctoral School in Genetics Oncology and Clinical Medicine, University of Siena, Siena, Italy
| | - Lucia Chico
- Unit of Neurology, Department of Neuroscience, Pisa University Hospital, Via Roma 67, 56126 Pisa, Italy
| | - Gabriele Siciliano
- Unit of Neurology, Department of Neuroscience, Pisa University Hospital, Via Roma 67, 56126 Pisa, Italy; Department of Clinical and Experimental Medicine, University of Pisa, Neurological Clinic, Via Roma 67, 56126 Pisa, Italy
| | - Ubaldo Bonuccelli
- Unit of Neurology, Department of Neuroscience, Pisa University Hospital, Via Roma 67, 56126 Pisa, Italy; Department of Clinical and Experimental Medicine, University of Pisa, Neurological Clinic, Via Roma 67, 56126 Pisa, Italy
| | - Lucia Migliore
- Department of Translational Research and New Technologies in Medicine and Surgery, Section of Medical Genetics, University of Pisa, Via Roma 55, 56126 Pisa, Italy.
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Neumann JHL, Jung A, Kirchner T. [Molecular pathology of colorectal cancer]. DER PATHOLOGE 2016; 36:137-44. [PMID: 25777075 DOI: 10.1007/s00292-015-0005-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In recent years, several predictive and prognostic biomarkers have been established in colorectal cancer (CRC). The RAS-mutation status is widely applied in the daily routine diagnostic as predictive biomarker for treatment with EGFR-inhibitors. A BRAF- mutation has no predictive value in this context. The detection of high-grade microsatellite instability (MSI-H) is a predictive biomarker for response to 5-Fluoruracil-monotherapy. Prognostic biomarkers in CRC are the MSI-status and the mutational status of BRAF. According to the current WHO classification poorly and undifferentiated CRC and MSI-associated special morphological subtypes are molecular graded depending on their MSI-status. The detection of a BRAF-mutation in the context of microsatellite stability (MSS) is associated with a very poor prognosis and thus represents the most aggressive molecular subtype of CRC. In patients with positive Bethesda criteria a stepwise immunohistochemical and molecular diagnostic scheme is proposed.
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Affiliation(s)
- J H L Neumann
- Pathologisches Institut, Ludwig-Maximilians-Universität München, Thalkirchner Straße 36, 80337, München, Deutschland,
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Lakshminarasimhan R, Liang G. The Role of DNA Methylation in Cancer. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 945:151-172. [PMID: 27826838 PMCID: PMC7409375 DOI: 10.1007/978-3-319-43624-1_7] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The malignant transformation of normal cells is driven by both genetic and epigenetic changes. With the advent of next-generation sequencing and large-scale multinational consortium studies, it has become possible to profile the genomes and epigenomes of thousands of primary tumors from nearly every cancer type. From these genome-wide studies, it became clear that the dynamic regulation of DNA methylation is a critical epigenetic mechanism of cancer initiation, maintenance, and progression. Proper control of DNA methylation is not only crucial for regulating gene transcription, but its broader consequences include maintaining the integrity of the genome and modulating immune response. Here, we describe the aberrant DNA methylation changes that take place in cancer and how they contribute to the disease phenotype. Further, we highlight potential clinical implications of these changes in the context of prognostic and diagnostic biomarkers, as well as therapeutic targets.
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Affiliation(s)
- Ranjani Lakshminarasimhan
- Department of Urology, University of Southern California, Norris Comprehensive Cancer Center, Los Angeles, CA, 90089, USA
| | - Gangning Liang
- Department of Urology, University of Southern California, Norris Comprehensive Cancer Center, Los Angeles, CA, 90089, USA.
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Levine AJ, Phipps AI, Baron JA, Buchanan DD, Ahnen DJ, Cohen SA, Lindor NM, Newcomb PA, Rosty C, Haile RW, Laird PW, Weisenberger DJ. Clinicopathologic Risk Factor Distributions for MLH1 Promoter Region Methylation in CIMP-Positive Tumors. Cancer Epidemiol Biomarkers Prev 2015; 25:68-75. [PMID: 26512054 DOI: 10.1158/1055-9965.epi-15-0935] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 10/14/2015] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND The CpG island methylator phenotype (CIMP) is a major molecular pathway in colorectal cancer. Approximately 25% to 60% of CIMP tumors are microsatellite unstable (MSI-H) due to DNA hypermethylation of the MLH1 gene promoter. Our aim was to determine if the distributions of clinicopathologic factors in CIMP-positive tumors with MLH1 DNA methylation differed from those in CIMP-positive tumors without DNA methylation of MLH1. METHODS We assessed the associations between age, sex, tumor-site, MSI status BRAF and KRAS mutations, and family colorectal cancer history with MLH1 methylation status in a large population-based sample of CIMP-positive colorectal cancers defined by a 5-marker panel using unconditional logistic regression to assess the odds of MLH1 methylation by study variables. RESULTS Subjects with CIMP-positive tumors without MLH1 methylation were significantly younger, more likely to be male, and more likely to have distal colon or rectal primaries and the MSI-L phenotype. CIMP-positive MLH1-unmethylated tumors were significantly less likely than CIMP-positive MLH1-methylated tumors to harbor a BRAF V600E mutation and significantly more likely to harbor a KRAS mutation. MLH1 methylation was associated with significantly better overall survival (HR, 0.50; 95% confidence interval, 0.31-0.82). CONCLUSIONS These data suggest that MLH1 methylation in CIMP-positive tumors is not a completely random event and implies that there are environmental or genetic determinants that modify the probability that MLH1 will become methylated during CIMP pathogenesis. IMPACT MLH1 DNA methylation status should be taken into account in etiologic studies.
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Affiliation(s)
- A Joan Levine
- Stanford Cancer Institute, Stanford University, Palo Alto, California.
| | - Amanda I Phipps
- Epidemiology Department, University of Washington, Seattle, Washington. Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - John A Baron
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Daniel D Buchanan
- Colorectal Oncogenomics Group, Genetic Epidemiology Laboratory, Centre for Epidemiology and Biostatistics and Department of Pathology, The University of Melbourne, Victoria, Australia
| | - Dennis J Ahnen
- University of Colorado School of Medicine, Denver, Colorado
| | - Stacey A Cohen
- Division of Oncology, University of Washington, Seattle, Washington. Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Noralane M Lindor
- Clinical and Molecular Genetics, Department of Health Science Research, Mayo Clinic Arizona, Scottsdale, Arizona
| | - Polly A Newcomb
- Epidemiology Department, University of Washington, Seattle, Washington. Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Christophe Rosty
- Envoi Pathology, Brisbane, QLD, The University of Melbourne, Melbourne, Australia. Department of Pathology, The University of Melbourne, Melbourne, Australia
| | - Robert W Haile
- Stanford Cancer Institute, Stanford University, Palo Alto, California
| | - Peter W Laird
- Center for Epigenomics, Van Andel Research Institute, Grand Rapids, Michigan
| | - Daniel J Weisenberger
- Department of Biochemistry and Molecular Biology, University of Southern California/Norris Comprehensive Cancer Center, Los Angeles, California
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Santos JC, Ribeiro ML. Epigenetic regulation of DNA repair machinery in Helicobacter pylori-induced gastric carcinogenesis. World J Gastroenterol 2015; 21:9021-9037. [PMID: 26290630 PMCID: PMC4533035 DOI: 10.3748/wjg.v21.i30.9021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 06/02/2015] [Accepted: 07/08/2015] [Indexed: 02/06/2023] Open
Abstract
Although thousands of DNA damaging events occur in each cell every day, efficient DNA repair pathways have evolved to counteract them. The DNA repair machinery plays a key role in maintaining genomic stability by avoiding the maintenance of mutations. The DNA repair enzymes continuously monitor the chromosomes to correct any damage that is caused by exogenous and endogenous mutagens. If DNA damage in proliferating cells is not repaired because of an inadequate expression of DNA repair genes, it might increase the risk of cancer. In addition to mutations, which can be either inherited or somatically acquired, epigenetic silencing of DNA repair genes has been associated with carcinogenesis. Gastric cancer represents the second highest cause of cancer mortality worldwide. The disease develops from the accumulation of several genetic and epigenetic changes during the lifetime. Among the risk factors, Helicobacter pylori (H. pylori) infection is considered the main driving factor to gastric cancer development. Thus, in this review, we summarize the current knowledge of the role of H. pylori infection on the epigenetic regulation of DNA repair machinery in gastric carcinogenesis.
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Sekal M, Ameurtesse H, Chbani L, Ouldim K, Bennis S, Abkari M, Boulouz A, Benajah DA, Benjelloun B, Ousadden A, Ait Taleb K, Ait Laalim S, Toghrai I, Mazaz K, Arifi S, Mellas N, El Rhazi K, Harmouch T, Ibrahimi SA, Amarti Riffi A. Epigenetics could explain some Moroccan population colorectal cancers peculiarities: microsatellite instability pathway exploration. Diagn Pathol 2015; 10:77. [PMID: 26104511 PMCID: PMC4477595 DOI: 10.1186/s13000-015-0326-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 06/12/2015] [Indexed: 12/12/2022] Open
Abstract
Background Colorectal Cancers (CRC) are one of the most common malignancies in the world. Their incidence in Morocco, between 2005 and 2007, was 5.6 for 100000 inhabitants, which is very low compared to what found in developed countries. In addition, CRCs show a high frequency of rectal localizations, and occurs in a younger population in Morocco compared to what found in developed countries. The purpose of this study is to confirm these CRC peculiarities in Morocco and try to explain them by exploring the microsatellite instability molecular pathway. Methods This is a prospective observational study conducted since January 2010, including 385 patients admitted in Hassan II University Hospital of Fez. We collected clinical, radiological and pathological data. We investigated the expression of mismatch repair (MMR) proteins in 214 patients and BRAF gene mutations in 159 patients. Results Mean age was 55.08 +/− 15.16 years. 36.5 % of patients were less than 50 years old and 49.3 % of tumors were localized in the rectum. Loss of MMR protein expression was observed in 11.2 % of cases. It was independently associated with individual or family history of cancer belonging to Hereditary Non-Polyposis Colorectal Cancer (HNPCC) spectrum (p = 0.01) and proximal localization (p = 0.02). No BRAF mutation was detected in all cases. Conclusions These results confirm the high occurrence of CRCs to young patients and the high frequency of rectal localizations in Moroccan population. They mostly show an absence of BRAF mutation, supposing a rarity of MLH1 promoter hypermethylation pathway, which may even partially explain the CRC peculiarities in our context. Virtual Slides The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/5868184711716884
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Affiliation(s)
- Mohammed Sekal
- Department of pathology, University hospital Hassan II of Fez, Fez, Morocco.
| | - Hassania Ameurtesse
- Department of pathology, University hospital Hassan II of Fez, Fez, Morocco.
| | - Laila Chbani
- Department of pathology, University hospital Hassan II of Fez, Fez, Morocco.
| | - Karim Ouldim
- Department of molecular genetics, University hospital Hassan II of Fez, Fez, Morocco.
| | - Sanae Bennis
- Department of molecular genetics, University hospital Hassan II of Fez, Fez, Morocco.
| | - Mohammed Abkari
- Department of gastroenterology, University hospital Hassan II of Fez, Fez, Morocco.
| | - Amal Boulouz
- Department of molecular genetics, University hospital Hassan II of Fez, Fez, Morocco.
| | - Dafr Allah Benajah
- Department of gastroenterology, University hospital Hassan II of Fez, Fez, Morocco.
| | - Basher Benjelloun
- Department of visceral surgery, University hospital Hassan II of Fez, Fez, Morocco.
| | - Abdelmalek Ousadden
- Department of visceral surgery, University hospital Hassan II of Fez, Fez, Morocco.
| | - Khalid Ait Taleb
- Department of visceral surgery, University hospital Hassan II of Fez, Fez, Morocco.
| | - Said Ait Laalim
- Department of visceral surgery, University hospital Hassan II of Fez, Fez, Morocco.
| | - Imane Toghrai
- Department of visceral surgery, University hospital Hassan II of Fez, Fez, Morocco.
| | - Khalid Mazaz
- Department of visceral surgery, University hospital Hassan II of Fez, Fez, Morocco.
| | - Samia Arifi
- Department of oncology, University hospital Hassan II of Fez, Fez, Morocco.
| | - Nawfel Mellas
- Department of oncology, University hospital Hassan II of Fez, Fez, Morocco.
| | - Karima El Rhazi
- Department of epidemiology, University hospital Hassan II of Fez, Fez, Morocco.
| | - Taoufiq Harmouch
- Department of pathology, University hospital Hassan II of Fez, Fez, Morocco.
| | - Sidi Adil Ibrahimi
- Department of gastroenterology, University hospital Hassan II of Fez, Fez, Morocco.
| | - Afaf Amarti Riffi
- Department of pathology, University hospital Hassan II of Fez, Fez, Morocco.
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Berg M, Nordgaard O, Kørner H, Oltedal S, Smaaland R, Søreide JA, Søreide K. Molecular subtypes in stage II-III colon cancer defined by genomic instability: early recurrence-risk associated with a high copy-number variation and loss of RUNX3 and CDKN2A. PLoS One 2015; 10:e0122391. [PMID: 25879218 PMCID: PMC4399912 DOI: 10.1371/journal.pone.0122391] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 02/20/2015] [Indexed: 01/02/2023] Open
Abstract
Objective We sought to investigate various molecular subtypes defined by genomic instability that may be related to early death and recurrence in colon cancer. Methods We sought to investigate various molecular subtypes defined by instability at microsatellites (MSI), changes in methylation patterns (CpG island methylator phenotype, CIMP) or copy number variation (CNV) in 8 genes. Stage II-III colon cancers (n = 64) were investigated by methylation-specific multiplex ligated probe amplification (MS-MLPA). Correlation of CNV, CIMP and MSI, with mutations in KRAS and BRAFV600E were assessed for overlap in molecular subtypes and early recurrence risk by uni- and multivariate regression. Results The CIMP phenotype occurred in 34% (22/64) and MSI in 27% (16/60) of the tumors, with noted CIMP/MSI overlap. Among the molecular subtypes, a high CNV phenotype had an associated odds ratio (OR) for recurrence of 3.2 (95% CI 1.1-9.3; P = 0.026). Losses of CACNA1G (OR of 2.9, 95% CI 1.4-6.0; P = 0.001), IGF2 (OR of 4.3, 95% CI 1.1-15.8; P = 0.007), CDKN2A (p16) (OR of 2.0, 95% CI 1.1-3.6; P = 0.024), and RUNX3 (OR of 3.4, 95% CI 1.3-8.7; P = 0.002) were associated with early recurrence, while MSI, CIMP, KRAS or BRAF V600E mutations were not. The CNV was significantly higher in deceased patients (CNV in 6 of 8) compared to survivors (CNV in 3 of 8). Only stage and loss of RUNX3 and CDKN2A were significant in the multivariable risk-model for early recurrence. Conclusions A high copy number variation phenotype is a strong predictor of early recurrence and death, and may indicate a dose-dependent relationship between genetic instability and outcome. Loss of tumor suppressors RUNX3 and CDKN2A were related to recurrence-risk and warrants further investigation.
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Affiliation(s)
- Marianne Berg
- Centre of Organelle Research (CORE), University of Stavanger, Stavanger, Norway
- Department of Gastrointestinal Surgery, Stavanger University Hospital, Stavanger, Norway
| | - Oddmund Nordgaard
- Department of Hematology and Oncology, Stavanger University Hospital, Stavanger, Norway
| | - Hartwig Kørner
- Department of Gastrointestinal Surgery, Stavanger University Hospital, Stavanger, Norway
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Satu Oltedal
- Department of Hematology and Oncology, Stavanger University Hospital, Stavanger, Norway
| | - Rune Smaaland
- Department of Hematology and Oncology, Stavanger University Hospital, Stavanger, Norway
| | - Jon Arne Søreide
- Department of Gastrointestinal Surgery, Stavanger University Hospital, Stavanger, Norway
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Kjetil Søreide
- Department of Gastrointestinal Surgery, Stavanger University Hospital, Stavanger, Norway
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- * E-mail:
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Veganzones S, Maestro ML, Rafael S, de la Orden V, Vidaurreta M, Mediero B, Espantaleón M, Cerdán J, Díaz-Rubio E. Combined methylation of p16 and hMLH1 (CMETH2) discriminates a subpopulation with better prognosis in colorectal cancer patients with microsatellite instability tumors. Tumour Biol 2015; 36:3853-61. [DOI: 10.1007/s13277-014-3027-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 12/26/2014] [Indexed: 12/26/2022] Open
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Epigenetic alterations in a gastric leiomyoma. Case Rep Gastrointest Med 2014; 2014:371638. [PMID: 25544907 PMCID: PMC4273588 DOI: 10.1155/2014/371638] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 11/17/2014] [Accepted: 11/17/2014] [Indexed: 01/17/2023] Open
Abstract
Leiomyomas constitute 2.5% of all resected neoplasms of the stomach. They are usually asymptomatic, but may present mucosal ulceration. Aberrant DNA methylation is a well-defined epigenetic change in human neoplasms; however, gene-acquired methylation may not necessarily be related with a malignant phenotype. In this report we analyzed in a gastric leiomyoma, the methylation status of 84 CpGI in tumor suppressor and DNA repair genes. We analyzed the tumor center (TC) and tumor periphery (TP) separately. We found aberrant methylation in 2/84 CpGI in the TC portion, that is, MLH1 and MSH3, and 5/84 CpGI in the TP, that is, MLH1, MSH3, APC, MSH6, and MGMT. The gene with the highest methylation percentage in the TC and TP was MLH1. Given that MLH1 methylation has been associated with microsatellite instability, we analyzed the status of the microsatellite Bat-26. We found that neither the TC nor the TP presented instability. The methylation of MLH1, MGMT, and APC has been described in GISTs, but to the best of our knowledge this is the first time that the methylation of these genes has been associated with gastric leiomyoma. Further research should be conducted to identify reliable molecular markers that could differentiate between GISTs and gastric leiomyomas.
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Funck A, Santos JC, Silva-Fernandes IJL, Rabenhorst SHB, Martinez CAR, Ribeiro ML. Effect of MLH1 -93G>A on gene expression in patients with colorectal cancer. Med Oncol 2014; 31:160. [PMID: 25115745 DOI: 10.1007/s12032-014-0160-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 08/01/2014] [Indexed: 11/27/2022]
Abstract
The DNA repair machinery plays a key role in maintaining genomic stability by preventing the emergence of mutations. Furthermore, the -93G>A polymorphism in the MLH1 gene has been associated with an increased risk of developing colorectal cancer. Therefore, the aim of this study was to examine the expression pattern and effect of this polymorphism in normal and tumour samples from patients with colorectal cancer. The MLH1 -93G>A (rs1800734) polymorphism was detected by PCR-RFLP in 49 cases of colorectal cancer. MLH1 expression was investigated using real-time quantitative PCR. The results indicate a significant decrease in MLH1 expression in tumour samples compared to their normal counterparts. The MLH1 gene was also significantly repressed in samples from patients who had some degree of tumour invasion into other organs. Similarly, those patients who were in a more advanced tumour stage (TNM III and IV) exhibited a significant reduction in MLH1 gene expression. Finally, the mutant genotype AA of MLH1 was associated with a significant decrease in the expression of this gene. This finding suggests that this polymorphism could increase the risk of developing colorectal cancer by a defective mismatch repair system, particularly through the loss of MLH1 expression in an allele-specific manner.
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Affiliation(s)
- Alexandre Funck
- Unidade Integrada de Farmacologia e Gastroenterologia, Laboratory of Microbiology and Molecular Biology, Sao Francisco University Medical School, Av. São Francisco de Assis, 218. Jd. São José, Bragança Paulista, SP, Brazil
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Barrow TM, Michels KB. Epigenetic epidemiology of cancer. Biochem Biophys Res Commun 2014; 455:70-83. [PMID: 25124661 DOI: 10.1016/j.bbrc.2014.08.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2014] [Revised: 07/15/2014] [Accepted: 08/01/2014] [Indexed: 02/06/2023]
Abstract
Epigenetic epidemiology includes the study of variation in epigenetic traits and the risk of disease in populations. Its application to the field of cancer has provided insight into how lifestyle and environmental factors influence the epigenome and how epigenetic events may be involved in carcinogenesis. Furthermore, it has the potential to bring benefit to patients through the identification of diagnostic markers that enable the early detection of disease and prognostic markers that can inform upon appropriate treatment strategies. However, there are a number of challenges associated with the conduct of such studies, and with the identification of biomarkers that can be applied to the clinical setting. In this review, we delineate the challenges faced in the design of epigenetic epidemiology studies in cancer, including the suitability of blood as a surrogate tissue and the capture of genome-wide DNA methylation. We describe how epigenetic epidemiology has brought insight into risk factors associated with lung, breast, colorectal and bladder cancer and review relevant research. We discuss recent findings on the identification of epigenetic diagnostic and prognostic biomarkers for these cancers.
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Affiliation(s)
- Timothy M Barrow
- Institute for Prevention and Tumor Epidemiology, Freiburg Medical Center, University of Freiburg, 79106, Germany; German Consortium for Translational Cancer Research (DKTK), Heidelberg, Germany; German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Karin B Michels
- Institute for Prevention and Tumor Epidemiology, Freiburg Medical Center, University of Freiburg, 79106, Germany; Obstetrics and Gynecology Epidemiology Center, Department of Obstetrics, Gynecology and Reproductive Biology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA.
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64
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Joost P, Veurink N, Holck S, Klarskov L, Bojesen A, Harbo M, Baldetorp B, Rambech E, Nilbert M. Heterogenous mismatch-repair status in colorectal cancer. Diagn Pathol 2014; 9:126. [PMID: 24968821 PMCID: PMC4074838 DOI: 10.1186/1746-1596-9-126] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2014] [Accepted: 06/22/2014] [Indexed: 01/28/2023] Open
Abstract
Abstract Virtual Slides The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1771940323126788
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Affiliation(s)
- Patrick Joost
- Department of Oncology and Pathology, Institute of Clinical Sciences, Lund University, SE-22381, Lund, Sweden.
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65
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Bishehsari F, Mahdavinia M, Vacca M, Malekzadeh R, Mariani-Costantini R. Epidemiological transition of colorectal cancer in developing countries: Environmental factors, molecular pathways, and opportunities for prevention. World J Gastroenterol 2014; 20:6055-6072. [PMID: 24876728 PMCID: PMC4033445 DOI: 10.3748/wjg.v20.i20.6055] [Citation(s) in RCA: 183] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Revised: 01/14/2014] [Accepted: 04/16/2014] [Indexed: 02/06/2023] Open
Abstract
Colorectal cancer (CRC) is one of the leading causes of cancer and cancer-related mortality worldwide. The disease has been traditionally a major health problem in industrial countries, however the CRC rates are increasing in the developing countries that are undergoing economic growth. Several environmental risk factors, mainly changes in diet and life style, have been suggested to underlie the rise of CRC in these populations. Diet and lifestyle impinge on nuclear receptors, on the intestinal microbiota and on crucial molecular pathways that are implicated in intestinal carcinogenesis. In this respect, the epidemiological transition in several regions of the world offers a unique opportunity to better understand CRC carcinogenesis by studying the disease phenotypes and their environmental and molecular associations in different populations. The data from these studies may have important implications for the global prevention and treatment of CRC.
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66
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Yang W, Wang X, Li X, Wang M, Chen X, Wu X, Wang Y, Fan Y, Jin H. The specific methylation characteristics of cancer related genes in Chinese colorectal cancer patients. Tumour Biol 2014; 35:8267-79. [PMID: 24852431 DOI: 10.1007/s13277-014-2100-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2014] [Accepted: 05/13/2014] [Indexed: 02/07/2023] Open
Abstract
Aberrant DNA methylation at CpG islands has been implicated as a critical player in colorectal cancer (CRC). However, its biological role and clinical significance in carcinogenesis have not been clearly clarified in Chinese CRC patients. In order to examine the methylation status of cancer-related genes in CRC progression, 184 tumor tissues were collected from Chinese patients diagnosed with CRC during 2008-2011. Promoter methylation was assessed by combined bisulphite-restriction analysis, methylation-specific PCR, and bisulphite sequencing PCR . The relationship between the gene promoter methylation status and clinicopathological factors/CRC mortality was examined by using the chi-square test/Cox-proportional hazards models. Promoter hypermethylation of MLH1, p16, SFRP2, PHD3, KLOTHO, and IGFBP7 was observed in 1.6, 10.9, 97.3, 44.0, 59.8, and 88.6 % of CRC samples, respectively. KLOTHO promoter methylation reduced with age (P = 0.018) whereas p16 promoter methylation increased with age (P = 0.044) and was more frequent among males (P = 0.017). Tumor tissues (73.9 %) had concurrent methylation of two or more genes, with the most frequent combination as KLOTHO and IGFBP7 (53.8 %). Concurrent methylation of KLOTHO and IGFBP7 occurred more frequently among patients less than 70 years old (P = 0.035) and those with poor differentiation (P = 0.024). CRC-specific mortality was not associated with promoter methylation and clinicopathological features except for age (P = 0.038; risk ratio (RR), 1.96; 95 % confidence interval (CI), 1.04-3.70) and TNM stage (P = 0.034; RR, 3.47; 95 % CI, 1.10-10.92). Methylation frequencies of MLH1, p16, PHD3, KLOTHO, and IGFBP7 in CRC tissues were significantly higher than that in the paired normal tissues, while promoter hypermethylation of SFRP2 was widespread in normal tissues. In conclusion, we suggest that methylation of some genes (MLH1, PHD3, KLOTHO, p16, and IGFBP7) is important in CRC progression whereas SFRP2 methylation is unlikely to contribute to CRC development in Chinese patients. Besides, by identifying the characteristics of concordant methylation, we confirm the multifactorial nature of tumor progression.
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Affiliation(s)
- WenJie Yang
- Department of Medical Genetics, Medical School, Nanjing University, Nanjing, 210093, China
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67
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McNally B, Linder M, Valdes R. Epigenetic primer for diagnostic applications: a window into personalized medicine. Per Med 2014; 11:323-337. [DOI: 10.2217/pme.14.21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Epigenetic testing, primarily in the form of DNA methylation analysis, is currently being used in healthcare settings to help identify and manage disease conditions and to develop and select drugs that specifically target epigenetic machinery. Yet, the clinical application of epigenetic analysis is still in its infancy. With a number of large-scale national and international epigenomic consortia projects in progress to identify tissue-specific epigenomes in normal and disease conditions, we are now poised for a new era of understanding disease processes based upon genetic changes that do not involve alterations to the DNA sequence. The developing epigenetic knowledge base will significantly advance the practice of personalized medicine and precision therapeutics. In this article, we provide a primer on the fundamentals of epigenetics with an emphasis on DNA methylation and review the prospective uses of epigenetic testing in advancing healthcare.
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Affiliation(s)
| | - Mark Linder
- PGXL Laboratories, Louisville, KY 40202, USA
- Department of Pathology & Laboratory Medicine, University of Louisville School of Medicine, MDR Building, 511 S Flloyd Street, Room 222, Louisville KY 40292, USA
| | - Roland Valdes
- PGXL Laboratories, Louisville, KY 40202, USA
- Department of Pathology & Laboratory Medicine, University of Louisville School of Medicine, MDR Building, 511 S Flloyd Street, Room 222, Louisville KY 40292, USA
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68
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Strickertsson JAB, Desler C, Rasmussen LJ. Impact of bacterial infections on aging and cancer: impairment of DNA repair and mitochondrial function of host cells. Exp Gerontol 2014; 56:164-74. [PMID: 24704713 DOI: 10.1016/j.exger.2014.03.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 03/19/2014] [Accepted: 03/26/2014] [Indexed: 02/06/2023]
Abstract
The commensal floras that inhabit the gastrointestinal tract play critical roles in immune responses, energy metabolism, and even cancer prevention. Pathogenic and out of place commensal bacteria, can however have detrimental effects on the host, by introducing genomic instability and mitochondrial dysfunction, which are hallmarks of both aging and cancer. Helicobacter pylori and Enterococcus faecalis are bacteria of the gastrointestinal tract that have been demonstrated to affect these two hallmarks. These, and other bacteria, have been shown to decrease the transcription and translation of essential DNA repair subunits of major DNA repair pathways and increase production of reactive oxygen species (ROS). Defects in DNA repair cause mutations and genomic instability and are found in several cancers as well as in progeroid syndromes. This review describes our contemporary view on how bacterial infections impact DNA repair and damage, and the consequence on the mitochondrial and nuclear genomes. We argue that in the gastrointestinal tract, these mechanisms can contribute to tumorigenesis as well as cellular aging of the digestive system.
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Affiliation(s)
- Jesper A B Strickertsson
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Claus Desler
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Lene Juel Rasmussen
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, DK-2200 Copenhagen, Denmark.
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Mitchell SM, Ross JP, Drew HR, Ho T, Brown GS, Saunders NFW, Duesing KR, Buckley MJ, Dunne R, Beetson I, Rand KN, McEvoy A, Thomas ML, Baker RT, Wattchow DA, Young GP, Lockett TJ, Pedersen SK, LaPointe LC, Molloy PL. A panel of genes methylated with high frequency in colorectal cancer. BMC Cancer 2014; 14:54. [PMID: 24485021 PMCID: PMC3924905 DOI: 10.1186/1471-2407-14-54] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 01/20/2014] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND The development of colorectal cancer (CRC) is accompanied by extensive epigenetic changes, including frequent regional hypermethylation particularly of gene promoter regions. Specific genes, including SEPT9, VIM1 and TMEFF2 become methylated in a high fraction of cancers and diagnostic assays for detection of cancer-derived methylated DNA sequences in blood and/or fecal samples are being developed. There is considerable potential for the development of new DNA methylation biomarkers or panels to improve the sensitivity and specificity of current cancer detection tests. METHODS Combined epigenomic methods - activation of gene expression in CRC cell lines following DNA demethylating treatment, and two novel methods of genome-wide methylation assessment - were used to identify candidate genes methylated in a high fraction of CRCs. Multiplexed amplicon sequencing of PCR products from bisulfite-treated DNA of matched CRC and non-neoplastic tissue as well as healthy donor peripheral blood was performed using Roche 454 sequencing. Levels of DNA methylation in colorectal tissues and blood were determined by quantitative methylation specific PCR (qMSP). RESULTS Combined analyses identified 42 candidate genes for evaluation as DNA methylation biomarkers. DNA methylation profiles of 24 of these genes were characterised by multiplexed bisulfite-sequencing in ten matched tumor/normal tissue samples; differential methylation in CRC was confirmed for 23 of these genes. qMSP assays were developed for 32 genes, including 15 of the sequenced genes, and used to quantify methylation in tumor, adenoma and non-neoplastic colorectal tissue and from healthy donor peripheral blood. 24 of the 32 genes were methylated in >50% of neoplastic samples, including 11 genes that were methylated in 80% or more CRCs and a similar fraction of adenomas. CONCLUSIONS This study has characterised a panel of 23 genes that show elevated DNA methylation in >50% of CRC tissue relative to non-neoplastic tissue. Six of these genes (SOX21, SLC6A15, NPY, GRASP, ST8SIA1 and ZSCAN18) show very low methylation in non-neoplastic colorectal tissue and are candidate biomarkers for stool-based assays, while 11 genes (BCAT1, COL4A2, DLX5, FGF5, FOXF1, FOXI2, GRASP, IKZF1, IRF4, SDC2 and SOX21) have very low methylation in peripheral blood DNA and are suitable for further evaluation as blood-based diagnostic markers.
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Affiliation(s)
- Susan M Mitchell
- CSIRO Animal, Food & Health Sciences, Preventative Health Flagship, North Ryde, NSW, Australia
| | - Jason P Ross
- CSIRO Animal, Food & Health Sciences, Preventative Health Flagship, North Ryde, NSW, Australia
| | - Horace R Drew
- CSIRO Animal, Food & Health Sciences, Preventative Health Flagship, North Ryde, NSW, Australia
| | - Thu Ho
- CSIRO Animal, Food & Health Sciences, Preventative Health Flagship, North Ryde, NSW, Australia
| | - Glenn S Brown
- CSIRO Animal, Food & Health Sciences, Preventative Health Flagship, North Ryde, NSW, Australia
| | - Neil FW Saunders
- CSIRO Computational Informatics, Preventative Health Flagship, North Ryde, NSW, Australia
| | - Konsta R Duesing
- CSIRO Animal, Food & Health Sciences, Preventative Health Flagship, North Ryde, NSW, Australia
| | - Michael J Buckley
- CSIRO Computational Informatics, Preventative Health Flagship, North Ryde, NSW, Australia
| | - Rob Dunne
- CSIRO Computational Informatics, Preventative Health Flagship, North Ryde, NSW, Australia
| | - Iain Beetson
- Clinical Genomics Pty Ltd, North Ryde, NSW, Australia
| | - Keith N Rand
- CSIRO Animal, Food & Health Sciences, Preventative Health Flagship, North Ryde, NSW, Australia
| | - Aidan McEvoy
- Clinical Genomics Pty Ltd, North Ryde, NSW, Australia
| | | | - Rohan T Baker
- Clinical Genomics Pty Ltd, North Ryde, NSW, Australia
| | - David A Wattchow
- Flinders Centre for Innovation in Cancer, Flinders University (FMC), Adelaide, SA, Australia
| | - Graeme P Young
- Flinders Centre for Innovation in Cancer, Flinders University (FMC), Adelaide, SA, Australia
| | - Trevor J Lockett
- CSIRO Animal, Food & Health Sciences, Preventative Health Flagship, North Ryde, NSW, Australia
| | | | | | - Peter L Molloy
- CSIRO Animal, Food & Health Sciences, Preventative Health Flagship, North Ryde, NSW, Australia
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Leclerc D, Lévesque N, Cao Y, Deng L, Wu Q, Powell J, Sapienza C, Rozen R. Genes with aberrant expression in murine preneoplastic intestine show epigenetic and expression changes in normal mucosa of colon cancer patients. Cancer Prev Res (Phila) 2013; 6:1171-81. [PMID: 24169962 DOI: 10.1158/1940-6207.capr-13-0198] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
An understanding of early genetic/epigenetic changes in colorectal cancer would aid in diagnosis and prognosis. To identify these changes in human preneoplastic tissue, we first studied our mouse model in which Mthfr⁺/⁻ BALB/c mice fed folate-deficient diets develop intestinal tumors in contrast to Mthfr⁺/⁺ BALB/c mice fed control diets. Transcriptome profiling was performed in normal intestine from mice with low or high tumor susceptibility. We identified 12 upregulated and 51 downregulated genes in tumor-prone mice. Affected pathways included retinoid acid synthesis, lipid and glucose metabolism, apoptosis and inflammation. We compared murine candidates from this microarray analysis, and murine candidates from an earlier strain-based comparison, with a set of human genes that we had identified in previous methylome profiling of normal human colonic mucosa, from colorectal cancer patients and controls. From the extensive list of human methylome candidates, our approach uncovered five orthologous genes that had shown changes in murine expression profiles (PDK4, SPRR1A, SPRR2A, NR1H4, and PYCARD). The human orthologs were assayed by bisulfite-pyrosequencing for methylation at 14 CpGs. All CpGs exhibited significant methylation differences in normal mucosa between colorectal cancer patients and controls; expression differences for these genes were also observed. PYCARD and NR1H4 methylation differences showed promise as markers for presence of polyps in controls. We conclude that common pathways are disturbed in preneoplastic intestine in our animal model and morphologically normal mucosa of patients with colorectal cancer, and present an initial version of a DNA methylation-based signature for human preneoplastic colon.
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Affiliation(s)
- Daniel Leclerc
- Montreal Children's Hospital Research Institute, 4060 Ste-Catherine West, Room 200, Montreal, Canada H3Z 2Z3.
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Gyparaki MT, Basdra EK, Papavassiliou AG. DNA methylation biomarkers as diagnostic and prognostic tools in colorectal cancer. J Mol Med (Berl) 2013; 91:1249-56. [PMID: 24057814 DOI: 10.1007/s00109-013-1088-z] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 09/05/2013] [Accepted: 09/10/2013] [Indexed: 02/07/2023]
Abstract
Colorectal cancer (CRC) is the third most common type of cancer and is responsible for 9 % of cancer deaths in both men and women in the USA for 2013. It is a heterogenous disease, and its three classification types are microsatellite instability, chromosomal instability, and CpG island methylator phenotype. Biomarkers are molecules, which can be used as indicators of cancer. They have the potential to achieve great sensitivities and specificities in diagnosis and prognosis of CRC. DNA methylation biomarkers are epigenetic markers, more specifically genes that become silenced after aberrant methylation of their promoter in CRC. Some methylation biomarkers like SEPT9 (ColoVantage®) and vimentin (ColoSure(TM)) are already commercially available. Other blood and fecal-based biomarkers are currently under investigation and clinical studies so that they can be used in the near future. Biomarker panels are also currently being studied since they show great potential in diagnosis as they can combine robust biomarkers to achieve even greater sensitivities than single markers. Finally, methylation-sensitive microRNAs (miRNAs) are very promising markers, and their investigation as biomarkers, is only at primitive stage.
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Affiliation(s)
- Melina-Theoni Gyparaki
- Department of Biological Chemistry, University of Athens Medical School, 11527, Athens, Greece
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