1
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Chen C, Heng EYH, Lim AST, Lau LC, Lim TH, Wong GC, Tien SL. Chromosomal microarray analysis is superior in identifying cryptic aberrations in patients with acute lymphoblastic leukemia at diagnosis/relapse as a single assay. Int J Lab Hematol 2019; 41:561-571. [PMID: 31112375 DOI: 10.1111/ijlh.13052] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Revised: 04/23/2019] [Accepted: 04/27/2019] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Conventional cytogenetics (CC) is important in diagnosis, therapy, monitoring of post-transplant bone marrow, and prognosis assessment of acute lymphoblastic leukemia (ALL). However, due to the nature of ALL, CC often encounters difficulties of complex karyotype, poor chromosome morphology, low mitotic index, or normal cells dividing only. In contrast, chromosomal microarray analysis (CMA) showed a specificity >99% and a sensitivity of 100% in chronic lymphocytic leukemia (CLL) patients. Here, we report our experience with CMA on adult ALL patients. METHODS Thirty-three bone marrow/blood samples from ALL patients (aged 18-79 years, median 44) at diagnosis/relapse, analyzed by CC and/or fluorescence in situ hybridization (FISH), were recruited. Chromosomal microarray analysis results were compared with CC. Fluorescence in situ hybridization analysis, if available, was applied when there was a discrepancy. RESULTS Copy-neutral loss-of-heterozygosity (CN-LOH) was found in 8 cases (24.2%). Only CN-LOH at 9p was recurrent (3 cases, 9.1%). Copy number alterations (CNAs) were detected in 6 of 9 cases (66.7%) with normal karyotypes, in 3 of 5 cases (60.0%) with sole "balanced" translocations, and in 18 of 19 cases (94.7%) with complex karyotypes. Common CNAs involved CDKN2A/2B (30.3%), IKZF1 (27.3%), PAX5 (9.1%), RB1 (9.1%), BTG1 (6.7%), and ETV6 (6.7%), which regulate cell cycle, B lymphopoiesis, or act as tumor suppressors in ALL. Copy number alteration detection rate by CMA was 81.8% (27 of 33 cases) as compared to 57.6% (19 of 33 cases) by CC. CONCLUSION Incorporation of CMA as a routine clinical test at the time of diagnosis/relapse, in conjunction with CC and/or FISH, is highly recommended.
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Affiliation(s)
- Chuanfei Chen
- Cytogenetics Laboratory, Department of Molecular Pathology, Division of Pathology, Singapore General Hospital, Singapore, Singapore
| | - Evelyn Yee Hsieh Heng
- Cytogenetics Laboratory, Department of Molecular Pathology, Division of Pathology, Singapore General Hospital, Singapore, Singapore
| | - Alvin Soon Tiong Lim
- Cytogenetics Laboratory, Department of Molecular Pathology, Division of Pathology, Singapore General Hospital, Singapore, Singapore
| | - Lai Ching Lau
- Cytogenetics Laboratory, Department of Molecular Pathology, Division of Pathology, Singapore General Hospital, Singapore, Singapore
| | - Tse Hui Lim
- Cytogenetics Laboratory, Department of Molecular Pathology, Division of Pathology, Singapore General Hospital, Singapore, Singapore
| | - Gee Chuan Wong
- Department of Haematology, Singapore General Hospital, Singapore, Singapore
| | - Sim Leng Tien
- Cytogenetics Laboratory, Department of Molecular Pathology, Division of Pathology, Singapore General Hospital, Singapore, Singapore.,Department of Haematology, Singapore General Hospital, Singapore, Singapore
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2
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Tokar T, Pastrello C, Ramnarine VR, Zhu CQ, Craddock KJ, Pikor LA, Vucic EA, Vary S, Shepherd FA, Tsao MS, Lam WL, Jurisica I. Differentially expressed microRNAs in lung adenocarcinoma invert effects of copy number aberrations of prognostic genes. Oncotarget 2018; 9:9137-9155. [PMID: 29507679 PMCID: PMC5823624 DOI: 10.18632/oncotarget.24070] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 01/02/2018] [Indexed: 12/30/2022] Open
Abstract
In many cancers, significantly down- or upregulated genes are found within chromosomal regions with DNA copy number alteration opposite to the expression changes. Generally, this paradox has been overlooked as noise, but can potentially be a consequence of interference of epigenetic regulatory mechanisms, including microRNA-mediated control of mRNA levels. To explore potential associations between microRNAs and paradoxes in non-small-cell lung cancer (NSCLC) we curated and analyzed lung adenocarcinoma (LUAD) data, comprising gene expressions, copy number aberrations (CNAs) and microRNA expressions. We integrated data from 1,062 tumor samples and 241 normal lung samples, including newly-generated array comparative genomic hybridization (aCGH) data from 63 LUAD samples. We identified 85 “paradoxical” genes whose differential expression consistently contrasted with aberrations of their copy numbers. Paradoxical status of 70 out of 85 genes was validated on sample-wise basis using The Cancer Genome Atlas (TCGA) LUAD data. Of these, 41 genes are prognostic and form a clinically relevant signature, which we validated on three independent datasets. By meta-analysis of results from 9 LUAD microRNA expression studies we identified 24 consistently-deregulated microRNAs. Using TCGA-LUAD data we showed that deregulation of 19 of these microRNAs explains differential expression of the paradoxical genes. Our results show that deregulation of paradoxical genes is crucial in LUAD and their expression pattern is maintained epigenetically, defying gene copy number status.
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Affiliation(s)
- Tomas Tokar
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Chiara Pastrello
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Varune R Ramnarine
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada.,The Vancouver Prostate Centre, Vancouver General Hospital, Vancouver, Canada
| | - Chang-Qi Zhu
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Kenneth J Craddock
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Larrisa A Pikor
- Department of Integrative Oncology, British Columbia Cancer Research Centre, Vancouver, Canada
| | - Emily A Vucic
- Department of Integrative Oncology, British Columbia Cancer Research Centre, Vancouver, Canada
| | - Simon Vary
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada.,Mathematical Institute, University of Oxford, Oxford, United Kingdom.,Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava, Slovakia
| | - Frances A Shepherd
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Ming-Sound Tsao
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
| | - Wan L Lam
- Department of Integrative Oncology, British Columbia Cancer Research Centre, Vancouver, Canada
| | - Igor Jurisica
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Canada.,Department of Computer Science, University of Toronto, Toronto, Canada.,Institute of Neuroimmunology, Slovak Academy of Sciences, Bratislava, Slovakia
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Dixon-McIver A. Emerging technologies in paediatric leukaemia. Transl Pediatr 2015; 4:116-24. [PMID: 26835367 PMCID: PMC4729090 DOI: 10.3978/j.issn.2224-4336.2015.03.02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Genetic changes, in particular chromosomal aberrations, are a hallmark of acute lymphoblastic lymphoma (ALL) and accurate detection of them is important in ensuring assignment to the appropriate drug protocol. Our ability to detect these genetic changes has been somewhat limited in the past due to the necessity to analyse mitotically active cells by conventional G-banded metaphase analysis and by mutational analysis of individual genes. Advances in technology include high resolution, microarray-based techniques that permit examination of the whole genome. Here we will review the current available methodology and discuss how the technology is being integrated into the diagnostic setting.
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Towle R, Tsui IFL, Zhu Y, MacLellan S, Poh CF, Garnis C. Recurring DNA copy number gain at chromosome 9p13 plays a role in the activation of multiple candidate oncogenes in progressing oral premalignant lesions. Cancer Med 2014; 3:1170-84. [PMID: 25060540 PMCID: PMC4302668 DOI: 10.1002/cam4.307] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 05/26/2014] [Accepted: 06/19/2014] [Indexed: 12/11/2022] Open
Abstract
Genomic alteration at chromosome 9p has been previously reported as a frequent and critical event in oral premalignancy. While this alteration is typically reported as a loss driven by selection for CDKN2A deactivation (at 9p21.3), we detect a recurrent DNA copy number gain of ∼2.49 Mbp at chromosome 9p13 in oral premalignant lesions (OPLs) that later progressed to invasive lesions. This recurrent alteration event has been validated using fluorescence in situ hybridization in an independent set of OPLs. Analysis of publicly available gene expression datasets aided in identifying three oncogene candidates that may have driven selection for DNA copy number increases in this region (VCP, DCTN3, and STOML2). We performed in vitro silencing and activation experiments for each of these genes in oral cancer cell lines and found that each gene is independently capable of upregulating proliferation and anchorage-independent growth. We next analyzed the activity of each of these genes in biopsies of varying histological grades that were obtained from a diseased oral tissue field in a single patient, finding further molecular evidence of parallel activation of VCP, DCTN3, and STOML2 during progression from normal healthy tissue to invasive oral carcinoma. Our results support the conclusion that DNA gain at 9p13 is important to the earliest stages of oral tumorigenesis and that this alteration event likely contributes to the activation of multiple oncogene candidates capable of governing oral cancer phenotypes.
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Affiliation(s)
- Rebecca Towle
- Department of Integrative Oncology, British Columbia Cancer Research Centre, Vancouver, BC, Canada
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5
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Yenamandra A, Wheeler F, Hollis A, Barba L, Wang Y, Geng L. Detection of Genomic Imbalances Involved in Common Chromosomal Rearrangements of Acute Leukemia by Cytogenomic SNP Microarray Analysis. Cancer Genet 2014. [DOI: 10.1016/j.cancergen.2014.06.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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6
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Labbé DP, Nowak DG, Deblois G, Lessard L, Giguère V, Trotman LC, Tremblay ML. Prostate cancer genetic-susceptibility locus on chromosome 20q13 is amplified and coupled to androgen receptor-regulation in metastatic tumors. Mol Cancer Res 2013; 12:184-9. [PMID: 24379448 DOI: 10.1158/1541-7786.mcr-13-0477] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
UNLABELLED The 20q13 chromosomal region has been previously identified as the hereditary prostate cancer genetic-susceptibility locus on chromosome 20 (HPC20). In this study, the 20q13 region was shown to be frequently co-amplified with the androgen receptor (AR) in metastatic prostate cancer. Furthermore, the AR signaling axis, which plays an essential role in the pathogenesis of prostate cancer, was demonstrated to be central to the regulation of the 20q13 common amplified region (CAR). High-resolution mapping analyses revealed hot spots of AR recruitment to response elements in the vicinity of most genes located on the 20q13 CAR. Moreover, amplification of AR significantly co-occurred with CAR amplification on 20q13 and it was confirmed that the majority of AR-bound genes on the 20q13 CAR were indeed regulated by androgens. These data reveal that amplification of the AR is tightly linked to amplification of the AR-regulated CAR region on 20q13. These results suggest that the cross-talk between gene amplification and gene transcription is an important step in the development of castration-resistant metastatic disease. IMPLICATIONS These novel results are a noteworthy example of the cross-talk between gene amplification and gene transcription in the development of advanced prostate cancer.
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Affiliation(s)
- David P Labbé
- Goodman Cancer Research Centre, McGill University, 1160 Pine Avenue, Room 617, Montréal, QC, Canada H3A 1A3.
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Elevated expression of BIRC6 protein in non-small-cell lung cancers is associated with cancer recurrence and chemoresistance. J Thorac Oncol 2013; 8:161-70. [PMID: 23287853 DOI: 10.1097/jto.0b013e31827d5237] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
INTRODUCTION Non-small-cell lung cancer (NSCLC) is an aggressive, highly chemoresistant disease. Reliable prognostic assays and more effective treatments are critically required. BIRC6 (baculoviral inhibitors of apoptosis proteins repeat-containing 6) protein is a member of the inhibitors of apoptosis protein family thought to play an important role in the progression or chemoresistance of many cancers. In this study, we investigated whether BIRC6 expression can be used as a prognostic marker or potential therapeutic target for NSCLC. METHODS In a retrospective analysis, BIRC6 protein expression was determined for 78 resected primary NSCLCs and nine benign lung tissues. Twenty-nine chemoresistant or chemosensitive subrenal capsule NSCLC tissue xenografts were assessed for BIRC6 expression, using immunohistochemistry, and 13 of them for BIRC6 gene copy number, using array comparative genomic hybridization analysis. The effect of small interfering RNA-induced BIRC6 knockdown on the growth of human NSCLC cell cultures and apoptosis (in combination with cisplatin) was investigated. RESULTS Elevated BIRC6 protein expression in NSCLC tissues was associated with poor 3-year relapse-free patient survival, lymph node involvement, and advanced pathological tumor, node, metastasis stage. In patient-derived lung squamous cell carcinoma xenografts, chemoresistance was associated with elevated BIRC6 expression and increased gene copy number. Small interfering RNA-induced BIRC6 down-regulation inhibited growth of the NSCLC cells and sensitized the cells to cisplatin. CONCLUSIONS BIRC6 may play an important role in the malignant progression and chemoresistance of NSCLC. Elevated BIRC6 protein expression may serve as a predictive marker for chemoresistance of NSCLCs and a poor prognostic factor for NSCLC patients. Down-regulation of the BIRC6 gene as a therapeutic approach may be effective, especially in combination with conventional chemotherapeutics.
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Cooley LD, Lebo M, Li MM, Slovak ML, Wolff DJ. American College of Medical Genetics and Genomics technical standards and guidelines: microarray analysis for chromosome abnormalities in neoplastic disorders. Genet Med 2013; 15:484-94. [DOI: 10.1038/gim.2013.49] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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Characterisation of retinoblastomas without RB1 mutations: genomic, gene expression, and clinical studies. Lancet Oncol 2013; 14:327-34. [PMID: 23498719 DOI: 10.1016/s1470-2045(13)70045-7] [Citation(s) in RCA: 238] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Retinoblastoma is the childhood retinal cancer that defined tumour-suppressor genes. Previous work shows that mutation of both alleles of the RB1 retinoblastoma suppressor gene initiates disease. We aimed to characterise non-familial retinoblastoma tumours with no detectable RB1 mutations. METHODS Of 1068 unilateral non-familial retinoblastoma tumours, we compared those with no evidence of RB1 mutations (RB1(+/+)) with tumours carrying a mutation in both alleles (RB1(-/-)). We analysed genomic copy number, RB1 gene expression and protein function, retinal gene expression, histological features, and clinical data. FINDINGS No RB1 mutations (RB1(+/+)) were reported in 29 (2·7%) of 1068 unilateral retinoblastoma tumours. 15 of the 29 RB1(+/+) tumours had high-level MYCN oncogene amplification (28-121 copies; RB1(+/+)MYCN(A)), whereas none of 93 RB1(-/-) primary tumours tested showed MYCN amplification (p<0·0001). RB1(+/+)MYCN(A) tumours expressed functional RB1 protein, had fewer overall genomic copy-number changes in genes characteristic of retinoblastoma than did RB1(-/-) tumours, and showed distinct aggressive histological features. MYCN amplification was the sole copy-number change in one RB1(+/+)MYCN(A) retinoblastoma. One additional MYCN(A) tumour was discovered after the initial frequencies were determined, and this is included in further analyses. Median age at diagnosis of the 17 children with RB1(+/+)MYCN(A) tumours was 4·5 months (IQR 3·5-10), compared with 24 months (15-37) for 79 children with non-familial unilateral RB1(-/-) retinoblastoma. INTERPRETATION Amplification of the MYCN oncogene might initiate retinoblastoma in the presence of non-mutated RB1 genes. These unilateral RB1(+/+)MYCN(A) retinoblastomas are characterised by distinct histological features, only a few of the genomic copy-number changes that are characteristic of retinoblastoma, and very early age of diagnosis. FUNDING National Cancer Institute-National Institutes of Health, Canadian Institutes of Health Research, German Research Foundation, Canadian Retinoblastoma Society, Hyland Foundation, Toronto Netralaya and Doctors Lions Clubs, Ontario Ministry of Health and Long Term Care, UK-Essen, and Foundations Avanti-STR and KiKa.
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10
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Hao JJ, Shi ZZ, Zhao ZX, Zhang Y, Gong T, Li CX, Zhan T, Cai Y, Dong JT, Fu SB, Zhan QM, Wang MR. Characterization of genetic rearrangements in esophageal squamous carcinoma cell lines by a combination of M-FISH and array-CGH: further confirmation of some split genomic regions in primary tumors. BMC Cancer 2012; 12:367. [PMID: 22920630 PMCID: PMC3561653 DOI: 10.1186/1471-2407-12-367] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Accepted: 08/17/2012] [Indexed: 01/29/2023] Open
Abstract
Background Chromosomal and genomic aberrations are common features of human cancers. However, chromosomal numerical and structural aberrations, breakpoints and disrupted genes have yet to be identified in esophageal squamous cell carcinoma (ESCC). Methods Using multiplex-fluorescence in situ hybridization (M-FISH) and oligo array-based comparative hybridization (array-CGH), we identified aberrations and breakpoints in six ESCC cell lines. Furthermore, we detected recurrent breakpoints in primary tumors by dual-color FISH. Results M-FISH and array-CGH results revealed complex numerical and structural aberrations. Frequent gains occurred at 3q26.33-qter, 5p14.1-p11, 7pter-p12.3, 8q24.13-q24.21, 9q31.1-qter, 11p13-p11, 11q11-q13.4, 17q23.3-qter, 18pter-p11, 19 and 20q13.32-qter. Losses were frequent at 18q21.1-qter. Breakpoints that clustered within 1 or 2 Mb were identified, including 9p21.3, 11q13.3-q13.4, 15q25.3 and 3q28. By dual-color FISH, we observed that several recurrent breakpoint regions in cell lines were also present in ESCC tumors. In particular, breakpoints clustered at 11q13.3-q13.4 were identified in 43.3% (58/134) of ESCC tumors. Both 11q13.3-q13.4 splitting and amplification were significantly correlated with lymph node metastasis (LNM) (P = 0.004 and 0.022) and advanced stages (P = 0.004 and 0.039). Multivariate logistic regression analysis revealed that only 11q13.3-q13.4 splitting was an independent predictor for LNM (P = 0.026). Conclusions The combination of M-FISH and array-CGH helps produce more accurate karyotypes. Our data provide significant, detailed information for appropriate uses of these ESCC cell lines for cytogenetic and molecular biological studies. The aberrations and breakpoints detected in both the cell lines and primary tumors will contribute to identify affected genes involved in the development and progression of ESCC.
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Affiliation(s)
- Jia-Jie Hao
- State Key Laboratory of Molecular Oncology, Cancer Institute (Hospital), Peking Union Medical College and Chinese Academy of Medical Science, 17 Panjiayuan Nanli, Chaoyang District, Beijing, 100021, China
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Martinez VD, Becker-Santos DD, Vucic EA, Lam S, Lam WL. Induction of human squamous cell-type carcinomas by arsenic. J Skin Cancer 2011; 2011:454157. [PMID: 22175027 PMCID: PMC3235812 DOI: 10.1155/2011/454157] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 10/07/2011] [Indexed: 01/14/2023] Open
Abstract
Arsenic is a potent human carcinogen. Around one hundred million people worldwide have potentially been exposed to this metalloid at concentrations considered unsafe. Exposure occurs generally through drinking water from natural geological sources, making it difficult to control this contamination. Arsenic biotransformation is suspected to have a role in arsenic-related health effects ranging from acute toxicities to development of malignancies associated with chronic exposure. It has been demonstrated that arsenic exhibits preference for induction of squamous cell carcinomas in the human, especially skin and lung cancer. Interestingly, keratins emerge as a relevant factor in this arsenic-related squamous cell-type preference. Additionally, both genomic and epigenomic alterations have been associated with arsenic-driven neoplastic process. Some of these aberrations, as well as changes in other factors such as keratins, could explain the association between arsenic and squamous cell carcinomas in humans.
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Affiliation(s)
- Victor D. Martinez
- Department of Integrative Oncology, BC Cancer Research Centre, 675 West 10th Avenue, Vancouver, BC, Canada V5Z 1L3
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12
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Martinez VD, Vucic EA, Adonis M, Gil L, Lam WL. Arsenic biotransformation as a cancer promoting factor by inducing DNA damage and disruption of repair mechanisms. Mol Biol Int 2011. [PMID: 22091411 DOI: 10.4061/2011/718974]] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chronic exposure to arsenic in drinking water poses a major global health concern. Populations exposed to high concentrations of arsenic-contaminated drinking water suffer serious health consequences, including alarming cancer incidence and death rates. Arsenic is biotransformed through sequential addition of methyl groups, acquired from s-adenosylmethionine (SAM). Metabolism of arsenic generates a variety of genotoxic and cytotoxic species, damaging DNA directly and indirectly, through the generation of reactive oxidative species and induction of DNA adducts, strand breaks and cross links, and inhibition of the DNA repair process itself. Since SAM is the methyl group donor used by DNA methyltransferases to maintain normal epigenetic patterns in all human cells, arsenic is also postulated to affect maintenance of normal DNA methylation patterns, chromatin structure, and genomic stability. The biological processes underlying the cancer promoting factors of arsenic metabolism, related to DNA damage and repair, will be discussed here.
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Affiliation(s)
- Victor D Martinez
- Department of Integrative Oncology, BC Cancer Research Centre, 675 West 10th Avenue, Vancouver, BC, Canada V5Z 1L3
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Martinez VD, Vucic EA, Becker-Santos DD, Gil L, Lam WL. Arsenic exposure and the induction of human cancers. J Toxicol 2011; 2011:431287. [PMID: 22174709 PMCID: PMC3235889 DOI: 10.1155/2011/431287] [Citation(s) in RCA: 216] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2011] [Revised: 08/25/2011] [Accepted: 08/25/2011] [Indexed: 12/21/2022] Open
Abstract
Arsenic is a metalloid, that is, considered to be a human carcinogen. Millions of individuals worldwide are chronically exposed through drinking water, with consequences ranging from acute toxicities to development of malignancies, such as skin and lung cancer. Despite well-known arsenic-related health effects, the molecular mechanisms involved are not fully understood; however, the arsenic biotransformation process, which includes methylation changes, is thought to play a key role. This paper explores the relationship of arsenic exposure with cancer development and summarizes current knowledge of the potential mechanisms that may contribute to the neoplastic processes observed in arsenic exposed human populations.
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Affiliation(s)
- Victor D. Martinez
- Department of Integrative Oncology, British Columbia Cancer Research Centre, 675 West 10th Avenue, Vancouver, BC, Canada V5Z 1L3
- Biomedical Sciences Institute, Faculty of Medicine, University of Chile, Independencia 1027, 8380453 Santiago, Chile
| | - Emily A. Vucic
- Department of Integrative Oncology, British Columbia Cancer Research Centre, 675 West 10th Avenue, Vancouver, BC, Canada V5Z 1L3
| | - Daiana D. Becker-Santos
- Department of Integrative Oncology, British Columbia Cancer Research Centre, 675 West 10th Avenue, Vancouver, BC, Canada V5Z 1L3
| | - Lionel Gil
- Biomedical Sciences Institute, Faculty of Medicine, University of Chile, Independencia 1027, 8380453 Santiago, Chile
| | - Wan L. Lam
- Department of Integrative Oncology, British Columbia Cancer Research Centre, 675 West 10th Avenue, Vancouver, BC, Canada V5Z 1L3
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Martinez VD, Vucic EA, Adonis M, Gil L, Lam WL. Arsenic biotransformation as a cancer promoting factor by inducing DNA damage and disruption of repair mechanisms. Mol Biol Int 2011; 2011:718974. [PMID: 22091411 PMCID: PMC3200225 DOI: 10.4061/2011/718974] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Accepted: 06/06/2011] [Indexed: 11/20/2022] Open
Abstract
Chronic exposure to arsenic in drinking water poses a major global health concern. Populations exposed to high concentrations of arsenic-contaminated drinking water suffer serious health consequences, including alarming cancer incidence and death rates. Arsenic is biotransformed through sequential addition of methyl groups, acquired from s-adenosylmethionine (SAM). Metabolism of arsenic generates a variety of genotoxic and cytotoxic species, damaging DNA directly and indirectly, through the generation of reactive oxidative species and induction of DNA adducts, strand breaks and cross links, and inhibition of the DNA repair process itself. Since SAM is the methyl group donor used by DNA methyltransferases to maintain normal epigenetic patterns in all human cells, arsenic is also postulated to affect maintenance of normal DNA methylation patterns, chromatin structure, and genomic stability. The biological processes underlying the cancer promoting factors of arsenic metabolism, related to DNA damage and repair, will be discussed here.
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Affiliation(s)
- Victor D Martinez
- Department of Integrative Oncology, BC Cancer Research Centre, 675 West 10th Avenue, Vancouver, BC, Canada V5Z 1L3
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15
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Huang YT, Wu MH. Inference of chromosome-specific copy numbers using population haplotypes. BMC Bioinformatics 2011; 12:194. [PMID: 21605463 PMCID: PMC3128032 DOI: 10.1186/1471-2105-12-194] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2010] [Accepted: 05/24/2011] [Indexed: 12/28/2022] Open
Abstract
Background Using microarray and sequencing platforms, a large number of copy number variations (CNVs) have been identified in humans. In practice, because our human genome is a diploid, these platforms are limited to or more accurate for detecting total copy numbers rather than chromosome-specific copy numbers at each of the two homologous chromosomes. Nevertheless, the analysis of linkage disequilibrium (LD) between CNVs and SNPs indicates that distinct copy numbers often sit on their own background haplotypes. Results We propose new computational models for inferring chromosome-specific copy numbers by distinguishing background haplotypes of each copy number. The formulated problems are shown to be NP-hard and approximation/heuristic algorithms are developed. Simulation indicates that our method is accurate and outperforms the existing approach. By testing the program in 60 parent-offspring trios, the inferred chromosome-specific copy numbers are highly consistent with the law of Mendelian inheritance. The distributions of copy numbers at chromosomal level are provided for 270 individuals in three HapMap panels. Conclusions The estimation of chromosome-specific copy numbers using microarray or sequencing platforms was often confounded by a number of factors. This study showed that the integration of background haplotypes is able to improve the accuracies of copy number estimation at chromosome level, especially for the CNVs having strong LD with SNPs in proximity.
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Affiliation(s)
- Yao-Ting Huang
- Department of Computer Science and Information Engineering, National Chung Cheng University, Chia-Yi, Taiwan.
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Joshua AM, Shen E, Yoshimoto M, Marrano P, Zielenska M, Evans AJ, Van der Kwast T, Squire JA. Topographical analysis of telomere length and correlation with genomic instability in whole mount prostatectomies. Prostate 2011; 71:778-90. [PMID: 21031437 DOI: 10.1002/pros.21294] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Accepted: 09/26/2010] [Indexed: 11/06/2022]
Abstract
BACKGROUND Many critical events in prostatic carcinogenesis appear to relate to the emergence of genomic instability. Characteristic genomic abnormalities such as 8p loss, 8q gain, trisomy 7, and PTEN microdeletions may provide selective advantages to increase neoplastic transformation. Evidence suggests that telomere dysfunction is a plausible mechanism for some of these abnormalities on the basis of the break-fusion-bridge cycle that can lead to manifestations of genomic instability. METHODS In this study, we correlate telomere length measured by quantitative FISH in various prostatic histologies with markers of genomic instability and immunohistochemical measures of proliferation and oxidative stress. RESULTS We find that telomere shortening is correlated with abnormalities on chromosome 8, but not with trisomy 7 or abnormalities of the PTEN locus. There are associations with C-MYC aberrations in stroma with greater proximity to cancer and a correlation between telomere length in a number of prostatic histologies and the adjacent stroma, suggesting the importance of microenvironmental effects on telomere maintenance in the prostate. This finding was also supported by the finding of the correlation between telomere attrition and the levels of oxidative stress as measured by malondialdehyde staining in HPIN lesions close to cancer. CONCLUSIONS Telomere attrition in the prostate gland is associated with particular genomic aberrations that contribute to the genomic instability characteristic of prostatic carcinogenesis. Correlations between various histologies and adjacent stroma telomere length suggest it is also may reveal microenvironmental effects within the prostate gland. Oxidative stress may contribute to telomere attrition in HPIN close to cancer.
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Affiliation(s)
- A M Joshua
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
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Morrison C, Miecznikowski J, Darcy KM, Dolce JM, Kandel E, Erwin DO, Liu S, Shepherd L, Cohn D, McMeekin DS, Block AW, Nowak NJ, Maxwell L. A GOG 210 aCGH study of gain at 1q23 in endometrioid endometrial cancer in the context of racial disparity and outcome. Genes Chromosomes Cancer 2010; 49:791-802. [PMID: 20607851 DOI: 10.1002/gcc.20782] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The goal of this study was to identify recurrent regions of genomic gain or loss in endometrial cancer of the endometrioid type in the context of racial disparities in mortality for this disease. Array comparative genomic hybridization (aCGH) analysis was performed on 80 frozen primary tumors from the Gynecologic Oncology Group (GOG)-210 bank using the RPCI 19K BAC arrays. The 80 patients included 20 African American (AA) Stage I, 20 White (W) Stage I, 20 African American (AA) Stage IIIC/IV, and 20 White (W) Stage IIIC/IV. A separate subset of 220 endometrial cancers with outcome data was used for validation. A 1.6-Mbp region of gain at 1q23 was identified by aCGH in all AA patients and high grade W patients, but not W low grade patients. In the validation arm of 220 patients copy number gain at this region was validated using FISH and locus specific BACs. The number of AA patients in the validation arm was too small to confirm the aCGH association with racial disparity. Kaplan-Meier curves for survival showed a significant difference for gain at 1q23 versus no gain (log rank P = 0.0014). When subdivided into various groups of risk by stage and grade the survival curves showed a decreased survival for high grade and/or stage tumors, but not for low grade and/or stage endometrioid tumors. Univariate analyses for gain at 1q23 showed a significant association (P = 0.009) with survival. Multivariate analysis for gain at 1q23 did not show a significant association with survival (P = 0.14).
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Affiliation(s)
- Carl Morrison
- Division of Molecular Pathology, Department of Pathology, Roswell Park Cancer Institute, Buffalo, NY 14263, USA.
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18
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Abstract
Background: Lung squamous cell carcinomas (SqCCs) occur at higher rates following arsenic exposure. Somatic DNA copy-number alterations (CNAs) are understood to be critical drivers in several tumour types. We have assembled a rare panel of lung tumours from a population with chronic arsenic exposure, including SqCC tumours from patients with no smoking history. Methods: Fifty-two lung SqCCs were analysed by whole-genome tiling-set array comparative genomic hybridisation. Twenty-two were derived from arsenic-exposed patients from Northern Chile (10 never smokers and 12 smokers). Thirty additional cases were obtained for comparison from North American smokers without arsenic exposure. Twenty-two blood samples from healthy individuals from Northern Chile were examined to identify germline DNA copy-number variations (CNVs) that could be excluded from analysis. Results: We identified multiple CNAs associated with arsenic exposure. These alterations were not attributable to either smoking status or CNVs. DNA losses at chromosomes 1q21.1, 7p22.3, 9q12, and 19q13.31 represented the most recurrent events. An arsenic-associated gain at 19q13.33 contains genes previously identified as oncogene candidates. Conclusions: Our results provide a comprehensive approach to molecular characteristics of the arsenic-exposed lung cancer genome and the non-smoking lung SqCC genome. The distinct and recurrent arsenic-related alterations suggest that this group of tumours may be considered as a separate disease subclass.
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Shao L, Kang SHL, Li J, Hixson P, Taylor J, Yatsenko SA, Shaw CA, Milosavljevic A, Chang CC, Cheung SW, Patel A. Array comparative genomic hybridization detects chromosomal abnormalities in hematological cancers that are not detected by conventional cytogenetics. J Mol Diagn 2010; 12:670-9. [PMID: 20724749 DOI: 10.2353/jmoldx.2010.090192] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Application of array comparative genomic hybridization (aCGH) has allowed an unprecedented high-resolution analysis of cancer genomes. We developed a custom genome-wide oligonucleotide microarray interrogating 493 genes involved in hematological disorders. We analyzed 55 patients with hematological neoplasms by using this microarray. In 33 patients with apparent normal conventional cytogenetic analysis, aneuploidy or isochromosomes were detected in 12% (4 of 33) of the patients by aCGH. The chromosomal changes included trisomy of chromosomes 10, 14, and 15, tetrasomy 11, and isochromosome 17q. In 17 patients with chronic lymphocytic leukemia who were initially investigated by using a panel of standard fluorescence in situ hybridization probes, additional copy number changes that were not interrogated by the fluorescence in situ hybridization (FISH) panel were detected in 47% (8 of 17) of the patients by aCGH. Important copy number changes included gain on 2p16 involving REL and BCL11A genes, rearrangements of chromosomes 8 and 15, and trisomy of chromosomes 19 and 22. In five patients with known abnormal karyotypes, aCGH identified the origin of two marker chromosomes and detected microdeletions at five breakpoints involved in three apparent balanced translocations. Our results suggest that a subset of potentially significant genomic alterations is missed by the currently available cytogenetic techniques. This pilot study clearly demonstrates high sensitivity of oligonucleotide aCGH for potential use in diagnosis and follow-up in patients with hematological neoplasms.
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Affiliation(s)
- Lina Shao
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77021-2039, USA
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Integrative genomic analyses identify BRF2 as a novel lineage-specific oncogene in lung squamous cell carcinoma. PLoS Med 2010; 7:e1000315. [PMID: 20668658 PMCID: PMC2910599 DOI: 10.1371/journal.pmed.1000315] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Accepted: 06/17/2010] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Traditionally, non-small cell lung cancer is treated as a single disease entity in terms of systemic therapy. Emerging evidence suggests the major subtypes--adenocarcinoma (AC) and squamous cell carcinoma (SqCC)--respond differently to therapy. Identification of the molecular differences between these tumor types will have a significant impact in designing novel therapies that can improve the treatment outcome. METHODS AND FINDINGS We used an integrative genomics approach, combing high-resolution comparative genomic hybridization and gene expression microarray profiles, to compare AC and SqCC tumors in order to uncover alterations at the DNA level, with corresponding gene transcription changes, which are selected for during development of lung cancer subtypes. Through the analysis of multiple independent cohorts of clinical tumor samples (>330), normal lung tissues and bronchial epithelial cells obtained by bronchial brushing in smokers without lung cancer, we identified the overexpression of BRF2, a gene on Chromosome 8p12, which is specific for development of SqCC of lung. Genetic activation of BRF2, which encodes a RNA polymerase III (Pol III) transcription initiation factor, was found to be associated with increased expression of small nuclear RNAs (snRNAs) that are involved in processes essential for cell growth, such as RNA splicing. Ectopic expression of BRF2 in human bronchial epithelial cells induced a transformed phenotype and demonstrates downstream oncogenic effects, whereas RNA interference (RNAi)-mediated knockdown suppressed growth and colony formation of SqCC cells overexpressing BRF2, but not AC cells. Frequent activation of BRF2 in >35% preinvasive bronchial carcinoma in situ, as well as in dysplastic lesions, provides evidence that BRF2 expression is an early event in cancer development of this cell lineage. CONCLUSIONS This is the first study, to our knowledge, to show that the focal amplification of a gene in Chromosome 8p12, plays a key role in squamous cell lineage specificity of the disease. Our data suggest that genetic activation of BRF2 represents a unique mechanism of SqCC lung tumorigenesis through the increase of Pol III-mediated transcription. It can serve as a marker for lung SqCC and may provide a novel target for therapy. Please see later in the article for the Editors' Summary.
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Przybylski GK, Dittmann K, Grabarczyk P, Dölken G, Gesk S, Harder L, Landmann E, Siebert R, Schmidt CA. Molecular characterization of a novel chromosomal translocation t(12;14)(q23;q11.2) in T-lymphoblastic lymphoma between the T-cell receptor delta-deleting elements (TRDREC and TRAJ61) and the hypothetical gene C12orf42. Eur J Haematol 2010; 85:452-6. [DOI: 10.1111/j.1600-0609.2010.01508.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Chari R, Thu KL, Wilson IM, Lockwood WW, Lonergan KM, Coe BP, Malloff CA, Gazdar AF, Lam S, Garnis C, MacAulay CE, Alvarez CE, Lam WL. Integrating the multiple dimensions of genomic and epigenomic landscapes of cancer. Cancer Metastasis Rev 2010; 29:73-93. [PMID: 20108112 DOI: 10.1007/s10555-010-9199-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Advances in high-throughput, genome-wide profiling technologies have allowed for an unprecedented view of the cancer genome landscape. Specifically, high-density microarrays and sequencing-based strategies have been widely utilized to identify genetic (such as gene dosage, allelic status, and mutations in gene sequence) and epigenetic (such as DNA methylation, histone modification, and microRNA) aberrations in cancer. Although the application of these profiling technologies in unidimensional analyses has been instrumental in cancer gene discovery, genes affected by low-frequency events are often overlooked. The integrative approach of analyzing parallel dimensions has enabled the identification of (a) genes that are often disrupted by multiple mechanisms but at low frequencies by any one mechanism and (b) pathways that are often disrupted at multiple components but at low frequencies at individual components. These benefits of using an integrative approach illustrate the concept that the whole is greater than the sum of its parts. As efforts have now turned toward parallel and integrative multidimensional approaches for studying the cancer genome landscape in hopes of obtaining a more insightful understanding of the key genes and pathways driving cancer cells, this review describes key findings disseminating from such high-throughput, integrative analyses, including contributions to our understanding of causative genetic events in cancer cell biology.
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Affiliation(s)
- Raj Chari
- Genetics Unit - Department of Integrative Oncology, British Columbia Cancer Research Centre, Vancouver, BC, Canada.
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The identification of chromosomal translocation, t(4;6)(q22;q15), in prostate cancer. Prostate Cancer Prostatic Dis 2010; 13:117-25. [PMID: 20177423 DOI: 10.1038/pcan.2010.2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Our previous work identified a chromosomal translocation t(4;6) in prostate cancer cell lines and primary tumors. Using probes located on 4q22 and 6q15, the breakpoints identified in LNCaP cells, we performed fluorescence in situ hybridization analysis to detect this translocation in a large series of clinical localized prostate cancer samples treated conservatively. We found that t(4;6)(q22;q15) occurred in 78 of 667 cases (11.7%). The t(4;6)(q22;q15) was not independently associated with patient outcome. However, it occurs more frequently in high clinical T stage, high tumor volume specimens and in those with high baseline PSA (P=0.001, 0.001 and 0.01, respectively). The t(4;6)(q22;q15) occurred more frequently in samples with two or more TMPRSS2:ERG fusion genes caused by internal deletion than in samples without these genomic alterations, but this correlation is not statistically significant (P=0.0628). The potential role of this translocation in the development of human prostate cancer is discussed.
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Lonergan KM, Chari R, Coe BP, Wilson IM, Tsao MS, Ng RT, MacAulay C, Lam S, Lam WL. Transcriptome profiles of carcinoma-in-situ and invasive non-small cell lung cancer as revealed by SAGE. PLoS One 2010; 5:e9162. [PMID: 20161782 PMCID: PMC2820080 DOI: 10.1371/journal.pone.0009162] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2009] [Accepted: 01/07/2010] [Indexed: 12/29/2022] Open
Abstract
Background Non-small cell lung cancer (NSCLC) presents as a progressive disease spanning precancerous, preinvasive, locally invasive, and metastatic lesions. Identification of biological pathways reflective of these progressive stages, and aberrantly expressed genes associated with these pathways, would conceivably enhance therapeutic approaches to this devastating disease. Methodology/Principal Findings Through the construction and analysis of SAGE libraries, we have determined transcriptome profiles for preinvasive carcinoma-in-situ (CIS) and invasive squamous cell carcinoma (SCC) of the lung, and compared these with expression profiles generated from both bronchial epithelium, and precancerous metaplastic and dysplastic lesions using Ingenuity Pathway Analysis. Expression of genes associated with epidermal development, and loss of expression of genes associated with mucociliary biology, are predominant features of CIS, largely shared with precancerous lesions. Additionally, expression of genes associated with xenobiotic metabolism/detoxification is a notable feature of CIS, and is largely maintained in invasive cancer. Genes related to tissue fibrosis and acute phase immune response are characteristic of the invasive SCC phenotype. Moreover, the data presented here suggests that tissue remodeling/fibrosis is initiated at the early stages of CIS. Additionally, this study indicates that alteration in copy-number status represents a plausible mechanism for differential gene expression in CIS and invasive SCC. Conclusions/Significance This study is the first report of large-scale expression profiling of CIS of the lung. Unbiased expression profiling of these preinvasive and invasive lesions provides a platform for further investigations into the molecular genetic events relevant to early stages of squamous NSCLC development. Additionally, up-regulated genes detected at extreme differences between CIS and invasive cancer may have potential to serve as biomarkers for early detection.
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Affiliation(s)
- Kim M. Lonergan
- Genetics Unit, Integrative Oncology, British Columbia Cancer Research Centre, Vancouver, British Columbia, Canada
- * E-mail:
| | - Raj Chari
- Genetics Unit, Integrative Oncology, British Columbia Cancer Research Centre, Vancouver, British Columbia, Canada
| | - Bradley P. Coe
- Genetics Unit, Integrative Oncology, British Columbia Cancer Research Centre, Vancouver, British Columbia, Canada
| | - Ian M. Wilson
- Genetics Unit, Integrative Oncology, British Columbia Cancer Research Centre, Vancouver, British Columbia, Canada
| | - Ming-Sound Tsao
- Ontario Cancer Institute, Princess Margaret Hospital, Toronto, Ontario, Canada
| | - Raymond T. Ng
- Genetics Unit, Integrative Oncology, British Columbia Cancer Research Centre, Vancouver, British Columbia, Canada
- Computer Science, University of British Columbia, Vancouver, British Columbia, Canada
| | - Calum MacAulay
- Imaging Unit, Integrative Oncology, British Columbia Cancer Research Centre, Vancouver, British Columbia, Canada
| | - Stephen Lam
- Imaging Unit, Integrative Oncology, British Columbia Cancer Research Centre, Vancouver, British Columbia, Canada
| | - Wan L. Lam
- Genetics Unit, Integrative Oncology, British Columbia Cancer Research Centre, Vancouver, British Columbia, Canada
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Gulley ML, Shea TC, Fedoriw Y. Genetic tests to evaluate prognosis and predict therapeutic response in acute myeloid leukemia. J Mol Diagn 2009; 12:3-16. [PMID: 19959801 DOI: 10.2353/jmoldx.2010.090054] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Management of patients with acute myeloid leukemia relies on genetic tests that inform diagnosis and prognosis, predict response to therapy, and measure minimal residual disease. The value of genetics is reinforced in the revised 2008 World Health Organization acute myeloid leukemia classification scheme. The various analytic procedures-karyotype, fluorescence in situ hybridization, reverse transcription polymerase chain reaction, DNA sequencing, and microarray technology-each have advantages in certain clinical settings, and understanding their relative merits assists in specimen allocation and in effective utilization of health care resources. Karyotype and array technology represent genome-wide screens, whereas the other methods target specific prognostic features such as t(15;17) PML-RARA, t(8;21) RUNX1-RUNX1T1, inv(16) CBFB-MYH11, 11q23 MLL rearrangement, FLT3 internal tandem duplication, or NPM1 mutation. New biomarkers and pharmacogenetic tests are emerging. The pathologist's expertise is critical in 1) consulting with clinicians about test selection as well as specimen collection and handling; 2) allocating tissue for immediate testing and preserving the remaining specimen for any downstream testing that is indicated once morphology and other pertinent test results are known; 3) performing tests that maximize outcome based on the strengths and limitations of each assay in each available specimen type; and 4) interpreting and conveying results to the rest of the health care team in a format that facilitates clinical management. Acute myeloid leukemia leads the way for modern molecular medicine.
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Affiliation(s)
- Margaret L Gulley
- Department of Pathology and Laboratory Medicine, 913 Brinkhous-Bullitt Building, University of North Carolina, Chapel Hill, NC 27599-7525, USA.
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Elder PT, McMullin MF, Humphreys MW, Hamilton J, McGrattan P. The finding of a reciprocal whole-arm translocation t(X;12)(p10;p10) in association with atypical chronic myeloid leukaemia. Med Oncol 2009; 27:760-2. [PMID: 19657750 DOI: 10.1007/s12032-009-9282-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Accepted: 07/27/2009] [Indexed: 12/21/2022]
Abstract
Atypical chronic myeloid leukaemia (aCML) belongs to the myeloproliferative/myelodysplastic category of haematological disease. Main characteristics are marked dysgranulopoiesis, bone marrow dysfunction and the failure to demonstrate the presence of the Philadelphia chromosome or BCR/ABL fusion gene normally associated with CML t(9;22)(q34;q11). It carries a poor prognosis with limited therapeutic options available. Most cases of aCML have one or more karyotypic abnormalities. We highlight a clinical presentation of aCML associated with an acquired reciprocal whole-arm translocation (WAT), t(X;12)(p10;p10), which to our knowledge has not yet been described. We also discuss how such a translocation might lead to tumorigenesis.
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Affiliation(s)
- P T Elder
- Department of Haematology, Belfast City Hospital, Belfast Health and Social Care Trust, Belfast, BT9-7AB, UK.
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27
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Garnis C, Chari R, Buys TPH, Zhang L, Ng RT, Rosin MP, Lam WL. Genomic imbalances in precancerous tissues signal oral cancer risk. Mol Cancer 2009; 8:50. [PMID: 19627613 PMCID: PMC2726119 DOI: 10.1186/1476-4598-8-50] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Accepted: 07/23/2009] [Indexed: 10/29/2022] Open
Abstract
Oral cancer develops through a series of histopathological stages: through mild (low grade), moderate, and severe (high grade) dysplasia to carcinoma in situ and then invasive disease. Early detection of those oral premalignant lesions (OPLs) that will develop into invasive tumors is necessary to improve the poor prognosis of oral cancer. Because no tools exist for delineating progression risk in low grade oral lesions, we cannot determine which of these cases require aggressive intervention. We undertook whole genome analysis by tiling-path array comparative genomic hybridization for a rare panel of early and late stage OPLs (n = 62), all of which had extensive longitudinal follow up (>10 years). Genome profiles for oral squamous cell carcinomas (n = 24) were generated for comparison. Parallel analysis of genome alterations and clinical parameters was performed to identify features associated with disease progression. Genome alterations in low grade dysplasias progressing to invasive disease more closely resembled those observed for later stage disease than they did those observed for non-progressing low grade dysplasias. This was despite the histopathological similarity between progressing and non-progressing cases. Strikingly, unbiased computational analysis of genomic alteration data correctly classified nearly all progressing low grade dysplasia cases. Our data demonstrate that high resolution genomic analysis can be used to evaluate progression risk in low grade OPLs, a marked improvement over present histopathological approaches which cannot delineate progression risk. Taken together, our data suggest that whole genome technologies could be used in management strategies for patients presenting with precancerous oral lesions.
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Affiliation(s)
- Cathie Garnis
- Department of Cancer Genetics and Developmental Biology, British Columbia Cancer Research Centre, BC, Canada.
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28
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Ishkanian AS, Mallof CA, Ho J, Meng A, Albert M, Syed A, van der Kwast T, Milosevic M, Yoshimoto M, Squire JA, Lam WL, Bristow RG. High-resolution array CGH identifies novel regions of genomic alteration in intermediate-risk prostate cancer. Prostate 2009; 69:1091-100. [PMID: 19350549 DOI: 10.1002/pros.20959] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Approximately one-third of prostate cancer patients present with intermediate risk disease. Interestingly, while this risk group is clinically well defined, it demonstrates the most significant heterogeneity in PSA-based biochemical outcome. Further, the majority of candidate genes associated with prostate cancer progression have been identified using cell lines, xenograft models, and high-risk androgen-independent or metastatic patient samples. We used a global high-resolution array comparative genomic hybridization (CGH) assay to characterize copy number alterations (CNAs) in intermediate risk prostate cancer. Herein, we show this risk group contains a number of alterations previously associated with high-risk disease: (1) deletions at 21q22.2 (TMPRSS2:ERG), 16q22-24 (containing CDH1), 13q14.2 (RB1), 10q23.31 (PTEN), 8p21 (NKX3.1); and, (2) amplification at 8q21.3-24.3 (containing c-MYC). In addition, we identified six novel microdeletions at high frequency: 1q42.12-q42.3 (33.3%), 5q12.3-13.3 (21%), 20q13.32-13.33 (29.2%), 22q11.21 (25%), 22q12.1 (29.2%), and 22q13.31 (33.3%). Further, we show there is little concordance between CNAs from these clinical samples and those found in commonly used prostate cancer cell models. These unexpected findings suggest that the intermediate-risk category is a crucial cohort warranting further study to determine if a unique molecular fingerprint can predict aggressive versus indolent phenotypes.
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Affiliation(s)
- Adrian S Ishkanian
- Department of Radiation Oncology, University of Toronto and Radiation Medicine Program, Princess Margaret Hospital-University Health Network, Toronto, Ontario, Canada
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Watson SK, Woolcock BW, Fee JN, Bainbridge TC, Webber D, Kinahan TJ, Lam WL, Vielkind JR. Minimum altered regions in early prostate cancer progression identified by high resolution whole genome tiling path BAC array comparative hybridization. Prostate 2009; 69:961-75. [PMID: 19267368 DOI: 10.1002/pros.20949] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Carcinoma of the prostate (CaP) is a serious health problem. The altered molecular mechanisms that lead to this disease are poorly understood. METHODS Specimens from radical prostatectomies and blood were collected from 18 CaP surgery patients. For CGH studies, 20 CaP-related samples (16 Gleason grade 3, 3 higher grades, 1 BPH sample) and 18 samples of patient-matched normal epithelial cells were obtained by laser-assisted microdissection from frozen sections of the 18 prostatectomy specimens. High resolution SMRT aCGH was used to compare genomic profiles of prostatic samples to patient-matched blood and pooled female DNA. TMPRSS2-ERG fusion transcript analysis was performed by RT-PCR in relation to alterations detected at the TMPRSS2 locus. RESULTS Our comprehensive aCGH approach allowed us to define 35 regions of recurrent alterations while excluding germline copy number polymorphisms. Novel regions identified include 2q14.2, containing INHBB, and 17q21.31. The TMPRSS2 locus at 21q22.3 may be a hotspot for rearrangements with 75% of the alterations resulting in the expression of a TMPRSS2-ERG fusion transcript. Differences in fusion expression in different areas in an individual tumor focus and expression in adjacent normal epithelium supported intrafocal heterogeneity and field cancerization, respectively. Both features challenge our efforts to develop more objective markers for diagnosis and prediction of the severity of CaP. CONCLUSION The high-density array enabled precise mapping of genomic alterations and consequently definition of minimum altered regions smaller than previously reported thus facilitating identification of those genes that contribute to the cancer transformation process.
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Affiliation(s)
- Spencer K Watson
- Department of Cancer Genetics and Developmental Biology, Vancouver, British Columbia, Canada
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Defining genomic alteration boundaries for a combined small cell and non-small cell lung carcinoma. J Thorac Oncol 2009; 4:227-39. [PMID: 19179901 DOI: 10.1097/jto.0b013e3181952678] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In the rare case of a male patient presenting with a combined small cell lung carcinoma (SCLC), large cell neuroendocrine carcinoma and adenocarcinoma, we used whole genome analysis by tiling-path array comparative genomic hybridization to evaluate the clonal relationship between nodules. In two areas of SCLC distinguishable by divergent neuroendocrine marker expression (CD56 and chromogranin-A), the presence of identical genomic breakpoints and rearrangements indicated a common origin, with the presence of additional distinct genomic alterations in these two components indicating diverging clonal evolution. The absence of shared genome alteration features for the adenocarcinoma and large cell neuroendocrine carcinoma components suggested that these tumors evolved independently from the SCLC. Taken together, the array comparative genomic hybridization data demonstrate the development and evolution of three independent primary lung cancers in close proximity to each other to form a combined carcinoma. Application of whole genome analysis shows the potential utility of high resolution molecular tools in resolving the origin and delineating the clonal relationships of a tumor that contains heterogeneous histologic components leading to an ambiguous histogenesis.
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Campbell JM, Lockwood WW, Buys TPH, Chari R, Coe BP, Lam S, Lam WL. Integrative genomic and gene expression analysis of chromosome 7 identified novel oncogene loci in non-small cell lung cancer. Genome 2009; 51:1032-9. [PMID: 19088816 DOI: 10.1139/g08-086] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Lung cancer accounts for over a quarter of cancer deaths, with non-small cell lung cancer (NSCLC) accounting for approximately 80% of cases. Several genome studies have been undertaken in both cell models of NSCLC and clinical samples to identify alterations underlying disease behaviour, and many have identified recurring aberrations of chromosome 7. The presence of recurring chromosome 7 alterations that do not span the well-studied oncogenes EGFR (at 7p11.2) and MET (at 7q31.2) has raised the hypothesis of additional genes on this chromosome that contribute to tumourigenesis. In this study, we demonstrated that multiple loci on chromosome 7 are indeed amplified in NSCLC, and through integrative analysis of gene dosage alterations and parallel gene expression changes, we identified new lung cancer oncogene candidates, including FTSJ2, NUDT1, TAF6, and POLR2J. Activation of these key genes was confirmed in panels of clinical lung tumour tissue as compared with matched normal lung tissue. The detection of gene activation in multiple cohorts of samples strongly supports the presence of key genes involved in lung cancer that are distinct from the EGFR and MET loci on chromosome 7.
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Affiliation(s)
- Jennifer M Campbell
- Department of Cancer Genetics and Developmental Biology, British Columbia Cancer Research Centre, 675 West 10th Avenue, Vancouver, BC V5Z1L3 Canada
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Cancer gene discovery in mouse and man. Biochim Biophys Acta Rev Cancer 2009; 1796:140-61. [PMID: 19285540 PMCID: PMC2756404 DOI: 10.1016/j.bbcan.2009.03.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2009] [Revised: 03/03/2009] [Accepted: 03/05/2009] [Indexed: 12/31/2022]
Abstract
The elucidation of the human and mouse genome sequence and developments in high-throughput genome analysis, and in computational tools, have made it possible to profile entire cancer genomes. In parallel with these advances mouse models of cancer have evolved into a powerful tool for cancer gene discovery. Here we discuss the approaches that may be used for cancer gene identification in both human and mouse and discuss how a cross-species 'oncogenomics' approach to cancer gene discovery represents a powerful strategy for finding genes that drive tumourigenesis.
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Homozygous deletions and recurrent amplifications implicate new genes involved in prostate cancer. Neoplasia 2008; 10:897-907. [PMID: 18670647 DOI: 10.1593/neo.08428] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2008] [Revised: 05/21/2008] [Accepted: 05/24/2008] [Indexed: 12/13/2022] Open
Abstract
Prostate cancer cell lines provide ideal in vitro systems for the identification and analysis of prostate tumor suppressors and oncogenes. A detailed characterization of the architecture of prostate cancer cell line genomes would facilitate the study of precise roles of various genes in prostate tumorigenesis in general. To contribute to such a characterization, we used the GeneChip 500K single nucleotide polymorphic (SNP) array for analysis of genotypes and relative DNA copy number changes across the genome of 11 cell lines derived from both normal and cancerous prostate tissues. For comparison purposes, we also examined the alterations observed in the cell lines in tumor/normal pairs of clinical samples from 72 patients. Along with genome-wide maps of DNA copy number changes and loss of heterozygosity for these cell lines, we report previously unreported homozygous deletions and recurrent amplifications in prostate cancers in this study. The homozygous deletions affected a number of biologically important genes, including PPP2R2A and BNIP3L identified in this study and CDKN2A/CDKN2B reported previously. Although most amplified genomic regions tended to be large, amplifications at 8q24.21 were of particular interest because the affected regions are relatively small, are found in multiple cell lines, are located near MYC, an oncogene strongly implicated in prostate tumorigenesis, and are known to harbor SNPs that are associated with inherited susceptibility for prostate cancer. The genomic alterations revealed in this study provide an important catalog of positional information relevant to efforts aimed at deciphering the molecular genetic basis of prostate cancer.
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High-resolution whole genome tiling path array CGH analysis of CD34+ cells from patients with low-risk myelodysplastic syndromes reveals cryptic copy number alterations and predicts overall and leukemia-free survival. Blood 2008; 112:3412-24. [PMID: 18663149 DOI: 10.1182/blood-2007-11-122028] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Abstract
Myelodysplastic syndromes (MDSs) pose an important diagnostic and treatment challenge because of the genetic heterogeneity and poorly understood biology of the disease. To investigate initiating genomic alterations and the potential prognostic significance of cryptic genomic changes in low-risk MDS, we performed whole genome tiling path array comparative genomic hybridization (aCGH) on CD34+ cells from 44 patients with an International Prognostic Scoring System score less than or equal to 1.0. Clonal copy number differences were detected in cells from 36 of 44 patients. In contrast, cells from only 16 of the 44 patients displayed karyotypic abnormalities. Although most patients had normal karyotype, aCGH identified 21 recurring copy number alterations. Examples of frequent cryptic alterations included gains at 11q24.2-qter, 17q11.2, and 17q12 and losses at 2q33.1-q33.2, 5q13.1-q13.2, and 10q21.3. Maintenance of genomic integrity defined as less than 3 Mb total disruption of the genome correlated with better overall survival (P = .002) and was less frequently associated with transformation to acute myeloid leukemia (P = .033). This study suggests a potential role for the use of aCGH in the clinical workup of MDS patients.
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Kennett JY, Watson SK, Saprunoff H, Heryet C, Lam WL. Technical demonstration of whole genome array comparative genomic hybridization. J Vis Exp 2008:870. [PMID: 19066503 DOI: 10.3791/870] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Array comparative genomic hybridization (array CGH) is a method for detecting gains and losses of DNA segments or gene dosage in the genome. Recent advances in this technology have enabled high resolution comparison of whole genomes for the identification of genetic alterations in cancer and other genetic diseases. The Sub-Megabase Resolution Tiling-set array (or SMRT) array is comprised of a set of approximately thirty thousand overlapping bacterial artificial chromosome (BAC) clones that span the human genome in approximately 100 kilobase pair (kb) segments. These BAC targets are individually synthesized and spotted in duplicate on a single glass slide. Array CGH is based on the principle of competitive hybridization. Sample and reference DNA are differentially labeled with Cyanine-3 and Cyanine-5 fluorescent dyes, and co-hybridized to the array. After an incubation period the unbound samples are washed from the slide and the array is imaged. A freely available custom software package called SeeGH (www.flintbox.ca) is used to process the large volume of data collected--a single experiment generates 53,892 data points. SeeGH visualizes the log2 signal intensity ratio between the 2 samples at each BAC target which is vertically aligned with chromosomal position. The SMRT array can detect alterations as small as 50 kb in size. The SMRT array can detect a variety of DNA rearrangement events including DNA gains, losses, amplifications and homozygous deletions. A unique advantage of the SMRT array is that one can use DNA isolated from formalin fixed paraffin embedded samples. When combined with the low input requirements of unamplified DNA (25-100 ng) this allows profiling of precious samples such as those produced by microdissection. This is attributed to the large size of each BAC hybridization target that allows the binding of sufficient labeled samples to produce signals for detection. Another advantage of this platform is the tolerance of tissue heterogeneity, decreasing the need for tedious tissue microdissection. This video protocol is a step-by-step tutorial from labeling the input DNA through to signal acquisition for the whole genome tiling path SMRT array.
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Lockwood WW, Chari R, Coe BP, Girard L, Macaulay C, Lam S, Gazdar AF, Minna JD, Lam WL. DNA amplification is a ubiquitous mechanism of oncogene activation in lung and other cancers. Oncogene 2008; 27:4615-24. [PMID: 18391978 DOI: 10.1038/onc.2008.98] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Chromosomal translocation is the best-characterized genetic mechanism for oncogene activation. However, there are documented examples of activation by alternate mechanisms, for example gene dosage increase, though its prevalence is unclear. Here, we answered the fundamental question of the contribution of DNA amplification as a molecular mechanism driving oncogenesis. Comparing 104 cancer lines representing diverse tissue origins identified genes residing in amplification 'hotspots' and discovered an unexpected frequency of genes activated by this mechanism. The 3431 amplicons identified represent approximately 10 per hematological and approximately 36 per epithelial cancer genome. Many recurrently amplified oncogenes were previously known to be activated only by disease-specific translocations. The 135 hotspots identified contain 538 unique genes and are enriched for proliferation, apoptosis and linage-dependency genes, reflecting functions advantageous to tumor growth. Integrating gene dosage with expression data validated the downstream impact of the novel amplification events in both cell lines and clinical samples. For example, multiple downstream components of the EGFR-family-signaling pathway, including CDK5, AKT1 and SHC1, are overexpressed as a direct result of gene amplification in lung cancer. Our findings suggest that amplification is far more common a mechanism of oncogene activation than previously believed and that specific regions of the genome are hotspots of amplification.
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Affiliation(s)
- W W Lockwood
- Department of Cancer Genetics, British Columbia Cancer Research Centre, Vancouver, British Columbia, Canada.
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37
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Higgins AW, Alkuraya FS, Bosco AF, Brown KK, Bruns GA, Donovan DJ, Eisenman R, Fan Y, Farra CG, Ferguson HL, Gusella JF, Harris DJ, Herrick SR, Kelly C, Kim HG, Kishikawa S, Korf BR, Kulkarni S, Lally E, Leach NT, Lemyre E, Lewis J, Ligon AH, Lu W, Maas RL, MacDonald ME, Moore SD, Peters RE, Quade BJ, Quintero-Rivera F, Saadi I, Shen Y, Shendure J, Williamson RE, Morton CC. Characterization of apparently balanced chromosomal rearrangements from the developmental genome anatomy project. Am J Hum Genet 2008; 82:712-22. [PMID: 18319076 DOI: 10.1016/j.ajhg.2008.01.011] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2007] [Revised: 12/17/2007] [Accepted: 01/04/2008] [Indexed: 12/27/2022] Open
Abstract
Apparently balanced chromosomal rearrangements in individuals with major congenital anomalies represent natural experiments of gene disruption and dysregulation. These individuals can be studied to identify novel genes critical in human development and to annotate further the function of known genes. Identification and characterization of these genes is the goal of the Developmental Genome Anatomy Project (DGAP). DGAP is a multidisciplinary effort that leverages the recent advances resulting from the Human Genome Project to increase our understanding of birth defects and the process of human development. Clinically significant phenotypes of individuals enrolled in DGAP are varied and, in most cases, involve multiple organ systems. Study of these individuals' chromosomal rearrangements has resulted in the mapping of 77 breakpoints from 40 chromosomal rearrangements by FISH with BACs and fosmids, array CGH, Southern-blot hybridization, MLPA, RT-PCR, and suppression PCR. Eighteen chromosomal breakpoints have been cloned and sequenced. Unsuspected genomic imbalances and cryptic rearrangements were detected, but less frequently than has been reported previously. Chromosomal rearrangements, both balanced and unbalanced, in individuals with multiple congenital anomalies continue to be a valuable resource for gene discovery and annotation.
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Abstract
Genetic alterations are a key feature of cancer cells and typically target biological processes and pathways that contribute to cancer pathogenesis. Array-based comparative genomic hybridization (aCGH) has provided a wealth of new information on copy number changes in cancer on a genome-wide level and aCGH data have also been utilized in cancer classification. More importantly, aCGH analyses have allowed highly accurate localization of specific genetic alterations that, for example, are associated with tumor progression, therapy response, or patient outcome. The genes involved in these aberrations are likely to contribute to cancer pathogenesis, and the high-resolution mapping by aCGH greatly facilitates the subsequent identification of these cancer-associated genes.
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Affiliation(s)
- Anne Kallioniemi
- Laboratory of Cancer Genetics, Tampere University Hospital and Institute of Medical Technology, University of Tampere, Biokatu 6, Tampere FI-33014, Finland.
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Mao X, James SY, Yáñez-Muñoz RJ, Chaplin T, Molloy G, Oliver RTD, Young BD, Lu YJ. Rapid high-resolution karyotyping with precise identification of chromosome breakpoints. Genes Chromosomes Cancer 2007; 46:675-83. [PMID: 17431877 DOI: 10.1002/gcc.20452] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Many techniques have been developed in recent years for genome-wide analysis of genetic alterations, but no current approach is capable of rapidly identifying all chromosome rearrangements with precise definition of breakpoints. Combining multiple color fluorescent in situ hybridization and high-density single nucleotide polymorphism array analyses, we present here an approach for high resolution karyotyping and fast identification of chromosome breakpoints. We characterized all of the chromosome amplifications and deletions, and most of the chromosome translocation breakpoints of three prostate cancer cell lines at a resolution which can be further analyzed by sequence-based techniques. Genes at the breakpoints were readily determined and potentially fused genes identified. Using high-density exon arrays we simultaneously confirmed altered exon expression patterns in many of these breakpoint genes.
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Affiliation(s)
- Xueying Mao
- Medical Oncology Center, Cancer Institute, Barts and London School of Medicine and Dentistry, Queen Mary, University of London, London, UK
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Deleeuw RJ, Zettl A, Klinker E, Haralambieva E, Trottier M, Chari R, Ge Y, Gascoyne RD, Chott A, Müller-Hermelink HK, Lam WL. Whole-genome analysis and HLA genotyping of enteropathy-type T-cell lymphoma reveals 2 distinct lymphoma subtypes. Gastroenterology 2007; 132:1902-11. [PMID: 17484883 DOI: 10.1053/j.gastro.2007.03.036] [Citation(s) in RCA: 155] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2006] [Accepted: 01/31/2007] [Indexed: 12/17/2022]
Abstract
BACKGROUND & AIMS Enteropathy-type T-cell lymphoma (ETL) is an aggressive extranodal T-cell non-Hodgkin lymphoma assumed to arise in the setting of celiac disease. METHODS To precisely define the genetic alterations underlying the pathogenesis of ETL, 30 ETL samples were profiled for genetic copy number alterations using high-resolution whole-genome tiling path array comparative genomic hybridization. To investigate the potential association of genetic alterations in ETL with celiac disease, HLA-DQB1 genotyping was performed. RESULTS By array comparative genomic hybridization, 13 novel recurrent minimal regions of chromosomal alteration were identified on multiple chromosome arms. ETL is characterized by frequent complex gains of 9q31.3-qter (70% of cases), or by an almost mutually exclusive 2.5-megabase loss of 16q12.1 (23% of cases). Two distinct groups of ETL could be delineated morphologically and genetically: type 1 ETL is characterized by nonmonomorphic cytomorphology, CD56 negativity, and chromosomal gains of 1q and 5q. Type 1 ETL also appears to be linked pathogenetically to celiac disease, sharing genetic alterations and HLA-DQB1 genotype patterns with (refractory) celiac disease. Type 2 ETL shows monomorphic small- to medium-sized tumor cell morphology, frequently shows CD56 expression, MYC oncogene locus gain, and rare gains of chromosomes 1q and 5q. In contrast to type 1 ETL, type 2 ETL shows a HLA-DQB1 genotype pattern more resembling that of the normal Caucasian population. CONCLUSIONS Contrary to current clinical classification, ETL comprises 2 morphologically, clinically, and genetically distinct lymphoma entities. In addition, type 2 ETL may not be associated with celiac disease.
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MESH Headings
- Adult
- Aged
- Aged, 80 and over
- CD56 Antigen/genetics
- CD56 Antigen/metabolism
- CD8 Antigens/genetics
- CD8 Antigens/metabolism
- Celiac Disease/complications
- Celiac Disease/genetics
- Celiac Disease/physiopathology
- Chromosome Mapping
- Chromosomes, Human, Pair 1/genetics
- Chromosomes, Human, Pair 5/genetics
- DNA, Neoplasm/genetics
- Female
- Gene Expression Regulation, Neoplastic
- Genome, Human/genetics
- Genotype
- HLA-DQ Antigens/genetics
- HLA-DQ Antigens/metabolism
- HLA-DQ beta-Chains
- Humans
- Lymphoma, T-Cell/classification
- Lymphoma, T-Cell/etiology
- Lymphoma, T-Cell/genetics
- Male
- Middle Aged
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Affiliation(s)
- Ronald J Deleeuw
- Department of Cancer Genetics, British Columbia Cancer Research Centre, Vancouver, British Columbia, Canada.
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