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Vizcaino MA, Giannini C, Vaubel RA, Nguyen AT, Trejo-Lopez JA, Raghunathan A, Jenkins SM, Jenkins RB, Zepeda Mendoza CJ. Comparing loss of p16 and MTAP expression in detecting CDKN2A homozygous deletion in pleomorphic xanthoastrocytoma. J Neuropathol Exp Neurol 2024:nlae076. [PMID: 39042515 DOI: 10.1093/jnen/nlae076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2024] Open
Abstract
Pleomorphic xanthoastrocytomas (PXAs) harbor CDKN2A homozygous deletion in >90% of cases, resulting in loss of p16 expression by immunohistochemistry. Considering the proximity of MTAP to CDKN2A and their frequent concurrent deletions, loss of MTAP expression may be a surrogate for CDKN2A homozygous deletion. We evaluated p16 and MTAP expression in 38 patient PXAs (CNS WHO grade 2: n = 23, 60.5%; grade 3: n = 15, 39.5%) with available chromosomal microarray data to determine whether MTAP can be utilized independently or in combination with p16 to predict CDKN2A status. CDKN2A, CDKN2B, and MTAP homozygous deletion were present in 37 (97.4%), 36 (94.7%), and 25 (65.8%) cases, respectively. Expression of p16 was lost in 35 (92.1%) cases, equivocal in one (2.6%), and failed in 2 (5.3%), while MTAP expression was lost in 27 (71.1%) cases, retained in 10 (26.3%), and equivocal in one (2.6%). This yielded a sensitivity of 94.6% for p16 and 73.0% for MTAP in detecting CDKN2A homozygous deletion through immunohistochemistry. MTAP expression was lost in the 2 cases with failed p16 staining (combined sensitivity of 100%). Our findings demonstrate that combined p16 and MTAP immunostains correctly detect CDKN2A homozygous deletion in PXA, while MTAP expression alone shows reduced sensitivity.
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Affiliation(s)
- M Adelita Vizcaino
- Department of Laboratory of Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Caterina Giannini
- Department of Laboratory of Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Rachael A Vaubel
- Department of Laboratory of Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Aivi T Nguyen
- Department of Laboratory of Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Jorge A Trejo-Lopez
- Department of Laboratory of Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Aditya Raghunathan
- Department of Laboratory of Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Sarah M Jenkins
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, United States
| | - Robert B Jenkins
- Department of Laboratory of Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
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The Role of Epigenetics in Brain and Spinal Cord Tumors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1394:119-136. [PMID: 36587385 DOI: 10.1007/978-3-031-14732-6_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Identification of distinct genetic and epigenetic profiles in various neuroepithelial tumors has improved the classification and uncovered novel diagnostic, prognostic, and predictive molecular biomarkers for improved prediction of treatment response and outcome. Especially, in pediatric high-grade brain tumors, such as diffuse midline glioma, H3K27M-altered and posterior fossa group A-ependymoma, epigenetic changes predominate, along with changes in expression of known oncogenes and tumor suppressor genes induced by histone modifications and DNA methylation. The precise role of epigenetic abnormalities is important for understanding tumorigenesis and the establishment of brain tumor treatment strategies. Using powerful epigenetic-based therapies for cancer cells, the aberrantly regulated epigenome can be restored to a more normal state through epigenetic reprogramming. Combinations of agents targeting DNA methylation and/or other epigenetic modifications may be a promising cancer treatment. Therefore, the integration of multi-omics data including epigenomics is now important for classifying primary brain tumors and predicting their biological behavior. Recent advances in molecular genetics and epigenetic integrated diagnostics of brain tumors influence new strategies for targeted therapy.
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Tian Y, Zhou J, Qiao J, Liu Z, Gu L, Zhang B, Lu Y, Xing R, Deng D. Detection of somatic copy number deletion of the CDKN2A gene by quantitative multiplex PCR for clinical practice. Front Oncol 2022; 12:1038380. [DOI: 10.3389/fonc.2022.1038380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 11/17/2022] [Indexed: 12/05/2022] Open
Abstract
BackgroundA feasible method to detect somatic copy number deletion (SCND) of genes is still absent to date.MethodsInterstitial base-resolution deletion/fusion coordinates for CDKN2A were extracted from published articles and our whole genome sequencing (WGS) datasets. The copy number of the CDKN2A gene was measured with a quantitative multiplex PCR assay P16-Light and confirmed with whole genome sequencing (WGS).ResultsEstimated common deletion regions (CDRs) were observed in many tumor suppressor genes, such as ATM, CDKN2A, FAT1, miR31HG, PTEN, and RB1, in the SNP array-based COSMIC datasets. A 5.1 kb base-resolution CDR could be identified in >90% of cancer samples with CDKN2A deletion by sequencing. The CDKN2A CDR covers exon-2, which is essential for P16INK4A and P14ARF synthesis. Using the true CDKN2A CDR as a PCR target, a quantitative multiplex PCR assay P16-Light was programmed to detect CDKN2A gene copy number. P16-Light was further confirmed with WGS as the gold standard among cancer tissue samples from 139 patients.ConclusionThe 5.1 kb CDKN2A CDR was found in >90% of cancers containing CDKN2A deletion. The CDKN2A CDR was used as a potential target for developing the P16-Light assay to detect CDKN2A SCND and amplification for routine clinical practices.
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Hain C, Stadler R, Kalinowski J. Unraveling the Structural Variations of Early-Stage Mycosis Fungoides-CD3 Based Purification and Third Generation Sequencing as Novel Tools for the Genomic Landscape in CTCL. Cancers (Basel) 2022; 14:4466. [PMID: 36139626 PMCID: PMC9497107 DOI: 10.3390/cancers14184466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/08/2022] [Accepted: 09/12/2022] [Indexed: 11/16/2022] Open
Abstract
Mycosis fungoides (MF) is the most common cutaneous T-cell lymphoma (CTCL). At present, knowledge of genetic changes in early-stage MF is insufficient. Additionally, low tumor cell fraction renders calling of copy-number variations as the predominant mutations in MF challenging, thereby impeding further investigations. We show that enrichment of T cells from a biopsy of a stage I MF patient greatly increases tumor fraction. This improvement enables accurate calling of recurrent MF copy-number variants such as ARID1A and CDKN2A deletion and STAT5 amplification, undetected in the unprocessed biopsy. Furthermore, we demonstrate that application of long-read nanopore sequencing is especially useful for the structural variant rich CTCL. We detect the structural variants underlying recurrent MF copy-number variants and show phasing of multiple breakpoints into complex structural variant haplotypes. Additionally, we record multiple occurrences of templated insertion structural variants in this sample. Taken together, this study suggests a workflow to make the early stages of MF accessible for genetic analysis, and indicates long-read sequencing as a major tool for genetic analysis for MF.
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Affiliation(s)
- Carsten Hain
- Center for Biotechnology (CeBiTec), Bielefeld University, 33615 Bielefeld, Germany
| | - Rudolf Stadler
- University Clinic for Dermatology, Johannes Wesling Medical Centre, UKRUB, University of Bochum, 32429 Minden, Germany
| | - Jörn Kalinowski
- Center for Biotechnology (CeBiTec), Bielefeld University, 33615 Bielefeld, Germany
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Mirzaei G, Petreaca RC. Distribution of copy number variations and rearrangement endpoints in human cancers with a review of literature. Mutat Res 2022; 824:111773. [PMID: 35091282 PMCID: PMC11301607 DOI: 10.1016/j.mrfmmm.2021.111773] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 12/08/2021] [Accepted: 12/10/2021] [Indexed: 12/13/2022]
Abstract
Copy number variations (CNVs) which include deletions, duplications, inversions, translocations, and other forms of chromosomal re-arrangements are common to human cancers. In this report we investigated the pattern of these variations with the goal of understanding whether there exist specific cancer signatures. We used re-arrangement endpoint data deposited on the Catalogue of Somatic Mutations in Cancers (COSMIC) for our analysis. Indeed, we find that human cancers are characterized by specific patterns of chromosome rearrangements endpoints which in turn result in cancer specific CNVs. A review of the literature reveals tissue specific mutations which either drive these CNVs or appear as a consequence of CNVs because they confer an advantage to the cancer cell. We also identify several rearrangement endpoints hotspots that were not previously reported. Our analysis suggests that in addition to local chromosomal architecture, CNVs are driven by the internal cellular or nuclear physiology of each cancer tissue.
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Affiliation(s)
- Golrokh Mirzaei
- Department of Computer Science and Engineering, The Ohio State University at Marion, Marion, OH, 43302, USA
| | - Ruben C Petreaca
- Department of Molecular Genetics, The Ohio State University at Marion, Marion, OH, 43302, USA; Cancer Biology Program, The Ohio State University James Comprehensive Cancer Center, Columbus, OH, 43210, USA.
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NTRK Fusions in Sarcomas: Diagnostic Challenges and Clinical Aspects. Diagnostics (Basel) 2021; 11:diagnostics11030478. [PMID: 33803146 PMCID: PMC8000177 DOI: 10.3390/diagnostics11030478] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 03/04/2021] [Accepted: 03/05/2021] [Indexed: 02/06/2023] Open
Abstract
Tropomyosin receptor kinase (TK) is encoded by the neurotrophic tyrosine receptor kinase genes (NTRK) 1, 2, and 3, whose activation plays an important role in cell cycle proliferation and survival. Fusions of one of these genes can lead to constitutive activation of TRK, which can potentially be oncogenic. NTRK fusions are commonly present in rare histologic tumor types. Among sarcomas, infantile fibrosarcoma shows NTRK fusion in more than 90% of the cases. Many other sarcoma types are also investigated for NTRK fusions. These fusions are druggable alteration of the agnostic type, meaning that all NTRK fused tumors can be treated with NTRK-inhibitors regardless of tumor type or tissue of origin. TRK-inhibitors have shown good response rates, with durable effects and limited side effects. Resistance to therapy will eventually occur in some cases, wherefore the next-generation TRK-inhibitors are introduced. The diagnosis of NTRK fused tumors, among them sarcomas, remains an issue, as many algorithms but no guidelines exist to date. Given the importance of this diagnosis, in this paper we aim to (1) analyze the histopathological features of sarcomas that correlate more often with NTRK fusions, (2) give an overview of the TRK-inhibitors and the problems that arise from resistance to the therapy, and (3) discuss the diagnostic algorithms of NTRK fused tumors with emphasis on sarcomas.
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González-Gil C, Ribera J, Ribera JM, Genescà E. The Yin and Yang-Like Clinical Implications of the CDKN2A/ARF/CDKN2B Gene Cluster in Acute Lymphoblastic Leukemia. Genes (Basel) 2021; 12:genes12010079. [PMID: 33435487 PMCID: PMC7827355 DOI: 10.3390/genes12010079] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 01/04/2021] [Accepted: 01/05/2021] [Indexed: 12/13/2022] Open
Abstract
Acute lymphoblastic leukemia (ALL) is a malignant clonal expansion of lymphoid hematopoietic precursors that exhibit developmental arrest at varying stages of differentiation. Similar to what occurs in solid cancers, transformation of normal hematopoietic precursors is governed by a multistep oncogenic process that drives initiation, clonal expansion and metastasis. In this process, alterations in genes encoding proteins that govern processes such as cell proliferation, differentiation, and growth provide us with some of the clearest mechanistic insights into how and why cancer arises. In such a scenario, deletions in the 9p21.3 cluster involving CDKN2A/ARF/CDKN2B genes arise as one of the oncogenic hallmarks of ALL. Deletions in this region are the most frequent structural alteration in T-cell acute lymphoblastic leukemia (T-ALL) and account for roughly 30% of copy number alterations found in B-cell-precursor acute lymphoblastic leukemia (BCP-ALL). Here, we review the literature concerning the involvement of the CDKN2A/B genes as a prognosis marker of good or bad response in the two ALL subtypes (BCP-ALL and T-ALL). We compare frequencies observed in studies performed on several ALL cohorts (adult and child), which mainly consider genetic data produced by genomic techniques. We also summarize what we have learned from mouse models designed to evaluate the functional involvement of the gene cluster in ALL development and in relapse/resistance to treatment. Finally, we examine the range of possibilities for targeting the abnormal function of the protein-coding genes of this cluster and their potential to act as anti-leukemic agents in patients.
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Affiliation(s)
- Celia González-Gil
- Josep Carreras Leukaemia Research Institute (IJC), Campus ICO-Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona (UAB), 08916 Badalona, Spain; (C.G.-G.); (J.R.); (J.M.R.)
| | - Jordi Ribera
- Josep Carreras Leukaemia Research Institute (IJC), Campus ICO-Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona (UAB), 08916 Badalona, Spain; (C.G.-G.); (J.R.); (J.M.R.)
| | - Josep Maria Ribera
- Josep Carreras Leukaemia Research Institute (IJC), Campus ICO-Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona (UAB), 08916 Badalona, Spain; (C.G.-G.); (J.R.); (J.M.R.)
- Clinical Hematology Department, ICO-Hospital Germans Trias i Pujol, 08916 Badalona, Spain
| | - Eulàlia Genescà
- Josep Carreras Leukaemia Research Institute (IJC), Campus ICO-Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona (UAB), 08916 Badalona, Spain; (C.G.-G.); (J.R.); (J.M.R.)
- Correspondence: ; Tel.: +34-93-557-28-08
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Park JW, Kang J, Lim KY, Kim H, Kim SI, Won JK, Park CK, Park SH. The prognostic significance of p16 expression pattern in diffuse gliomas. J Pathol Transl Med 2020; 55:102-111. [PMID: 33348944 PMCID: PMC7987518 DOI: 10.4132/jptm.2020.10.22] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 10/22/2019] [Indexed: 12/13/2022] Open
Abstract
Background CDKN2A is a tumor suppressor gene that encodes the cell cycle inhibitor protein p16. Homozygous deletion of the CDK-N2A gene has been associated with shortened survival in isocitrate dehydrogenase (IDH)–mutant gliomas. This study aimed to analyze the prognostic value of p16 and to evaluate whether p16 immunohistochemical staining could be used as a prognostic marker to replace CDKN2A genotyping in diffuse gliomas. Methods p16 immunohistochemistry was performed on tissue microarrays of 326 diffuse gliomas with diagnoses that reflected IDH-mutations and 1p/19q codeletion status. The results were divided into three groups (negative, focal expression, overexpression) according to the presence and degree of p16 expression. Survival analysis was performed to assess the prognostic value of p16 expression. Results A loss of p16 expression predicted a significantly worse outcome in all glioma patients (n = 326, p < .001), in the IDH-mutant glioma patients (n = 103, p = .010), and in the IDH-mutant astrocytoma patients (n = 73, p = .032). However, loss of p16 expression did not predict the outcome in the IDH-wildtype glioma patients (n = 223, p = .121) or in the oligodendroglial tumor patients with the IDH-mutation and 1p/19q codeletion (n = 30, p = .457). Multivariate analysis showed the association was still significant in the IDH-mutant glioma patients (p = .008; hazard ratio [HR], 2.637; 95% confidence interval [CI], 1.295 to 5.372) and in the IDH-mutant astrocytoma patients (p = .001; HR, 3.586; 95% CI, 1.649 to 7.801). Interestingly, patients who presented with tumors with p16 overexpression also had shorter survival times than did patients with tumors with p16 focal expression in the whole glioma (p < .001) and in IDH-mutant glioma groups. (p = .046). Conclusions This study suggests that detection of p16 expression by immunohistochemistry can be used as a useful surrogate test to predict prognosis, especially in IDH-mutant astrocytoma patients.
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Affiliation(s)
- Jin Woo Park
- Department of Pathology, Seoul National University Hospital, Seoul, Korea
| | - Jeongwan Kang
- Department of Pathology, Seoul National University Hospital, Seoul, Korea
| | - Ka Young Lim
- Department of Pathology, Seoul National University Hospital, Seoul, Korea
| | - Hyunhee Kim
- Department of Pathology, Seoul National University Hospital, Seoul, Korea
| | - Seong-Ik Kim
- Department of Pathology, Seoul National University Hospital, Seoul, Korea
| | - Jae Kyung Won
- Department of Pathology, Seoul National University Hospital, Seoul, Korea
| | - Chul-Kee Park
- Department of Neurosurgery, Seoul National University Hospital, Seoul, Korea
| | - Sung-Hye Park
- Department of Pathology, Seoul National University Hospital, Seoul, Korea.,Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, Korea
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Thomson DW, Shahrin NH, Wang PPS, Wadham C, Shanmuganathan N, Scott HS, Dinger ME, Hughes TP, Schreiber AW, Branford S. Aberrant RAG-mediated recombination contributes to multiple structural rearrangements in lymphoid blast crisis of chronic myeloid leukemia. Leukemia 2020; 34:2051-2063. [PMID: 32076119 DOI: 10.1038/s41375-020-0751-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 01/08/2020] [Accepted: 02/06/2020] [Indexed: 11/10/2022]
Abstract
Blast crisis of chronic myeloid leukemia is associated with poor survival and the accumulation of genomic lesions. Using whole-exome and/or RNA sequencing of patients at chronic phase (CP, n = 49), myeloid blast crisis (MBC, n = 19), and lymphoid blast crisis (LBC, n = 20), we found 25 focal gene deletions and 14 fusions in 24 patients in BC. Deletions predominated in LBC (83% of structural variants). Transcriptional analysis identified the upregulation of genes involved in V(D)J recombination, including RAG1/2 and DNTT in LBC. RAG recombination is a reported mediator of IKZF1 deletion. We investigated the extent of RAG-mediated genomic lesions in BC. Molecular hallmarks of RAG activity; DNTT-mediated nucleotide insertions and a RAG-binding motif at structural variants were exclusively found in patients with high RAG expression. Structural variants in 65% of patients in LBC displayed these hallmarks compared with only 5% in MBC. RAG-mediated events included focal deletion and novel fusion of genes associated with hematologic cancer: IKZF1, RUNX1, CDKN2A/B, and RB1. Importantly, 8/8 patients with elevated DNTT at CP diagnosis progressed to LBC by 12 months, potentially enabling early prediction of LBC. This work confirms the central mutagenic role of RAG in LBC and describes potential clinical utility in CML management.
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Affiliation(s)
- Daniel W Thomson
- Department of Genetics and Molecular Pathology, Centre for Cancer Biology, SA Pathology, Adelaide, SA, Australia
- School of Pharmacy and Medical Science, Division of Health Sciences, University of South Australia, Adelaide, SA, Australia
| | - Nur Hezrin Shahrin
- Department of Genetics and Molecular Pathology, Centre for Cancer Biology, SA Pathology, Adelaide, SA, Australia
- School of Pharmacy and Medical Science, Division of Health Sciences, University of South Australia, Adelaide, SA, Australia
| | - Paul P S Wang
- School of Pharmacy and Medical Science, Division of Health Sciences, University of South Australia, Adelaide, SA, Australia
- Australian Cancer Research Foundation Genomics Facility, Centre for Cancer Biology, SA Pathology, Adelaide, SA, Australia
| | - Carol Wadham
- Department of Genetics and Molecular Pathology, Centre for Cancer Biology, SA Pathology, Adelaide, SA, Australia
- School of Pharmacy and Medical Science, Division of Health Sciences, University of South Australia, Adelaide, SA, Australia
| | - Naranie Shanmuganathan
- Department of Genetics and Molecular Pathology, Centre for Cancer Biology, SA Pathology, Adelaide, SA, Australia
- School of Pharmacy and Medical Science, Division of Health Sciences, University of South Australia, Adelaide, SA, Australia
- School of Medicine, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA, Australia
- South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Hamish S Scott
- Department of Genetics and Molecular Pathology, Centre for Cancer Biology, SA Pathology, Adelaide, SA, Australia
- School of Pharmacy and Medical Science, Division of Health Sciences, University of South Australia, Adelaide, SA, Australia
- Australian Cancer Research Foundation Genomics Facility, Centre for Cancer Biology, SA Pathology, Adelaide, SA, Australia
- School of Medicine, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Marcel E Dinger
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington Campus, Sydney, NSW, Australia
| | - Timothy P Hughes
- School of Medicine, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA, Australia
- South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Andreas W Schreiber
- School of Pharmacy and Medical Science, Division of Health Sciences, University of South Australia, Adelaide, SA, Australia
- Australian Cancer Research Foundation Genomics Facility, Centre for Cancer Biology, SA Pathology, Adelaide, SA, Australia
- School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Susan Branford
- Department of Genetics and Molecular Pathology, Centre for Cancer Biology, SA Pathology, Adelaide, SA, Australia.
- School of Pharmacy and Medical Science, Division of Health Sciences, University of South Australia, Adelaide, SA, Australia.
- School of Medicine, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA, Australia.
- School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia.
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Evidence-based review of genomic aberrations in B-lymphoblastic leukemia/lymphoma: Report from the cancer genomics consortium working group for lymphoblastic leukemia. Cancer Genet 2020; 243:52-72. [PMID: 32302940 DOI: 10.1016/j.cancergen.2020.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Revised: 03/04/2020] [Accepted: 03/17/2020] [Indexed: 12/19/2022]
Abstract
Clinical management and risk stratification of B-lymphoblastic leukemia/ lymphoma (B-ALL/LBL) depend largely on identification of chromosomal abnormalities obtained using conventional cytogenetics and Fluorescence In Situ Hybridization (FISH) testing. In the last few decades, testing algorithms have been implemented to support an optimal risk-oriented therapy, leading to a large improvement in overall survival. In addition, large scale genomic studies have identified multiple aberrations of prognostic significance that are not routinely tested by existing modalities. However, as chromosomal microarray analysis (CMA) and next-generation sequencing (NGS) technologies are increasingly used in clinical management of hematologic malignancies, these abnormalities may be more readily detected. In this article, we have compiled a comprehensive, evidence-based review of the current B-ALL literature, focusing on known and published subtypes described to date. More specifically, we describe the role of various testing modalities in the diagnosis, prognosis, and therapeutic relevance. In addition, we propose a testing algorithm aimed at assisting laboratories in the most effective detection of the underlying genomic abnormalities.
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11
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Han X, Tan Q, Yang S, Li J, Xu J, Hao X, Hu X, Xing P, Liu Y, Lin L, Gui L, Qin Y, Yang J, Liu P, Wang X, Dai W, Lin D, Lin H, Shi Y. Comprehensive Profiling of Gene Copy Number Alterations Predicts Patient Prognosis in Resected Stages I-III Lung Adenocarcinoma. Front Oncol 2019; 9:556. [PMID: 31448219 PMCID: PMC6691340 DOI: 10.3389/fonc.2019.00556] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 06/07/2019] [Indexed: 12/21/2022] Open
Abstract
Background: Lung adenocarcinoma (LUAD) possesses a poor prognosis with a low 5-year survival rate even for stages I-III resected patients, it is thus critical to understand the determinants that affect the survival and discover new potentially prognostic biomarkers. Somatic copy number alterations (CNAs) are major source of genomic variations driving tumor evolution, CNAs screening may identify prognostic biomarkers. Methods: Oncoscan MIP array was used to analyze the patterns of CNAs on formalin fixed paraffin embedded(FFPE) tumor specimens from 163 consecutive stage I-III resected LUAD patients, 145 out of which received platinum-based adjuvant chemotherapy. Results: Of the 163 patients, 91(55.8%) were recurred within 3 years after surgery. The most common aberrations in our cohort were 1q, 5p, 5q, 7p, 8q, 14p, 16p, 17q, 20q for copy number gains and 8p, 9p, 13p, 16q, 18q for losses. The GISTIC2 analysis produced 45 amplification peaks and 40 deletion peaks, involving some reported genes TERT, EGFR, MYC, CCND1, CDK4, MDM2, ERBB2, NKX2-1, CCNE1, and CDKN2A, most of which were consistent with TCGA database. The amplifications of 12p12.1 (CMAS, GOLT1B, YS2, LDHB, RECQL, ETNK1, IAPP, PYROXD1, KRAS) and KDM5A were correlated with worse prognosis in our cohort, this result was further validated in 506 LUAD patients from TCGA. In addition, 163 patients could be well-classified into five groups, and the clinical outcomes were significantly different based on threshold copy number at reoccurring alteration peaks. Among the 145 patients who received adjuvant chemotherapy, focal amplification of ERBB2 and deletion of 4q34.3 were found to be specific in relapsed patients, this result was validated in an independent group of Imielinski et al., demonstrating these two CNAs may contribute to resected LUAD recurrence after adjuvant chemotherapy. Conclusion: This study suggests that CNAs profiling may be a potential prognostic classifier in resected LAUD patients. Amplifications of 12p12.1 and KDM5A might be prognostic biomarkers for LUAD, and amplification of ERBB2 and deletion of 4q34.3 predicted early relapse after adjuvant chemotherapy. These novel findings may provide implication for better implementation of precision therapy for lung cancer patients.
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Affiliation(s)
- Xiaohong Han
- Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing Key Laboratory of Clinical Study on Anticancer Molecular Targeted Drugs, Beijing, China
- Department of Clinical Laboratory, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Qiaoyun Tan
- Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing Key Laboratory of Clinical Study on Anticancer Molecular Targeted Drugs, Beijing, China
| | - Sheng Yang
- Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing Key Laboratory of Clinical Study on Anticancer Molecular Targeted Drugs, Beijing, China
| | - Junling Li
- Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing Key Laboratory of Clinical Study on Anticancer Molecular Targeted Drugs, Beijing, China
| | - Jianping Xu
- Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing Key Laboratory of Clinical Study on Anticancer Molecular Targeted Drugs, Beijing, China
| | - Xuezhi Hao
- Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing Key Laboratory of Clinical Study on Anticancer Molecular Targeted Drugs, Beijing, China
| | - Xingsheng Hu
- Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing Key Laboratory of Clinical Study on Anticancer Molecular Targeted Drugs, Beijing, China
| | - Puyuan Xing
- Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing Key Laboratory of Clinical Study on Anticancer Molecular Targeted Drugs, Beijing, China
| | - Yutao Liu
- Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing Key Laboratory of Clinical Study on Anticancer Molecular Targeted Drugs, Beijing, China
| | - Lin Lin
- Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing Key Laboratory of Clinical Study on Anticancer Molecular Targeted Drugs, Beijing, China
| | - Lin Gui
- Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing Key Laboratory of Clinical Study on Anticancer Molecular Targeted Drugs, Beijing, China
| | - Yan Qin
- Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing Key Laboratory of Clinical Study on Anticancer Molecular Targeted Drugs, Beijing, China
| | - Jianliang Yang
- Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing Key Laboratory of Clinical Study on Anticancer Molecular Targeted Drugs, Beijing, China
| | - Peng Liu
- Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing Key Laboratory of Clinical Study on Anticancer Molecular Targeted Drugs, Beijing, China
| | - Xingyuan Wang
- Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing Key Laboratory of Clinical Study on Anticancer Molecular Targeted Drugs, Beijing, China
| | - Wumin Dai
- Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing Key Laboratory of Clinical Study on Anticancer Molecular Targeted Drugs, Beijing, China
| | - Dongmei Lin
- Department of Pathology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Hua Lin
- Department of Medical Record, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Yuankai Shi
- Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing Key Laboratory of Clinical Study on Anticancer Molecular Targeted Drugs, Beijing, China
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12
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Hamid A, Petreaca B, Petreaca R. Frequent homozygous deletions of the CDKN2A locus in somatic cancer tissues. Mutat Res 2019; 815:30-40. [PMID: 31096160 DOI: 10.1016/j.mrfmmm.2019.04.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 04/09/2019] [Accepted: 04/10/2019] [Indexed: 02/07/2023]
Abstract
Here we present and describe data on homozygous deletions (HD) of human CDKN2 A and neighboring regions on the p arm of Chromosome 9 from cancer genome sequences deposited on the online Catalogue of Somatic Mutations in Cancer (COSMIC) database. Although CDKN2 A HDs have been previously described in many cancers, this is a pan-cancer report of these aberrations with the aim to map the distribution of the breakpoints. We find that HDs of this locus have a median range of 1,255,650bps. When the deletion breakpoints were mapped on both the telomere and centromere proximal sides of CDKN2A, most of the telomere proximal breakpoints concentrate to a narrow region of the chromosome which includes the gene MTAP.. The centromere proximal breakpoints of the deletions are distributed over a wider chromosomal region. Furthermore, gene expression analysis shows that the deletions that include the CDKN2A region also include the MTAP region and this observation is tissue independent. We propose a model that may explain the origin of the telomere proximal CDKN2A breakpoints Finally, we find that HD distributions for at least three other loci, RB1, SMAD4 and PTEN are also not random.
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Affiliation(s)
- Abdulaziz Hamid
- The Ohio State University, MSE110A, 1464 Mount Vernon Ave, Marion, OH 43302, United States
| | - Beniamin Petreaca
- The Ohio State University, MSE110A, 1464 Mount Vernon Ave, Marion, OH 43302, United States
| | - Ruben Petreaca
- The Ohio State University, MSE110A, 1464 Mount Vernon Ave, Marion, OH 43302, United States.
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13
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Sundaresh A, Williams O. Mechanism of ETV6-RUNX1 Leukemia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 962:201-216. [PMID: 28299659 DOI: 10.1007/978-981-10-3233-2_13] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The t(12;21)(p13;q22) translocation is the most frequently occurring single genetic abnormality in pediatric leukemia. This translocation results in the fusion of the ETV6 and RUNX1 genes. Since its discovery in the 1990s, the function of the ETV6-RUNX1 fusion gene has attracted intense interest. In this chapter, we will summarize current knowledge on the clinical significance of ETV6-RUNX1, the experimental models used to unravel its function in leukemogenesis, the identification of co-operating mutations and the mechanisms responsible for their acquisition, the function of the encoded transcription factor and finally, the future therapeutic approaches available to mitigate the associated disease.
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Affiliation(s)
- Aishwarya Sundaresh
- Cancer section, Developmental Biology and Cancer Programme, UCL Institute of Child Health, London, UK
| | - Owen Williams
- Cancer section, Developmental Biology and Cancer Programme, UCL Institute of Child Health, London, UK.
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14
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Karrman K, Johansson B. Pediatric T-cell acute lymphoblastic leukemia. Genes Chromosomes Cancer 2016; 56:89-116. [PMID: 27636224 DOI: 10.1002/gcc.22416] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 09/06/2016] [Indexed: 12/29/2022] Open
Abstract
The most common pediatric malignancy is acute lymphoblastic leukemia (ALL), of which T-cell ALL (T-ALL) comprises 10-15% of cases. T-ALL arises in the thymus from an immature thymocyte as a consequence of a stepwise accumulation of genetic and epigenetic aberrations. Crucial biological processes, such as differentiation, self-renewal capacity, proliferation, and apoptosis, are targeted and deranged by several types of neoplasia-associated genetic alteration, for example, translocations, deletions, and mutations of genes that code for proteins involved in signaling transduction, epigenetic regulation, and transcription. Epigenetically, T-ALL is characterized by gene expression changes caused by hypermethylation of tumor suppressor genes, histone modifications, and miRNA and lncRNA abnormalities. Although some genetic and gene expression patterns have been associated with certain clinical features, such as immunophenotypic subtype and outcome, none has of yet generally been implemented in clinical routine for treatment decisions. The recent advent of massive parallel sequencing technologies has dramatically increased our knowledge of the genetic blueprint of T-ALL, revealing numerous fusion genes as well as novel gene mutations. The challenges now are to integrate all genetic and epigenetic data into a coherent understanding of the pathogenesis of T-ALL and to translate the wealth of information gained in the last few years into clinical use in the form of improved risk stratification and targeted therapies. Here, we provide an overview of pediatric T-ALL with an emphasis on the acquired genetic alterations that result in this disease. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Kristina Karrman
- Department of Clinical Genetics, Office for Medical Services, Division of Laboratory Medicine, Lund, Sweden.,Division of Clinical Genetics, Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Bertil Johansson
- Department of Clinical Genetics, Office for Medical Services, Division of Laboratory Medicine, Lund, Sweden.,Division of Clinical Genetics, Department of Laboratory Medicine, Lund University, Lund, Sweden
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15
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Braun M, Pastorczak A, Fendler W, Madzio J, Tomasik B, Taha J, Bielska M, Sedek L, Szczepanski T, Matysiak M, Derwich K, Lejman M, Kowalczyk J, Kazanowska B, Badowska W, Styczynski J, Irga-Jaworska N, Trelinska J, Zalewska-Szewczyk B, Pierlejewski F, Wlodarska I, Młynarski W. Biallelic loss of CDKN2A is associated with poor response to treatment in pediatric acute lymphoblastic leukemia. Leuk Lymphoma 2016; 58:1162-1171. [PMID: 27756164 DOI: 10.1080/10428194.2016.1228925] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The inactivation of tumor suppressor genes located within 9p21 locus (CDKN2A, CDKN2B) occurs in up to 30% of children with B-cell precursor acute lymphoblastic leukemia (BCP-ALL), but its independent prognostic significance remains controversial. In order to investigate the prognostic impact of deletions and promoter methylation within 9p21, 641 children with newly diagnosed BCP-ALL using methylation specific multiplex ligation-dependent probe amplification (MS-MLPA) were investigated. A total of 169 (26.4%) microdeletions in 9p21 were detected, of which 71 were homozygous. Patients with CDKN2A homozygous deletions were older at diagnosis (p < .001), more frequently steroid resistant (p = .049), had higher WBC count (p < .001), higher MRD at Day 15 (p = .013) and lower relapse-free survival [p = .028, hazard ratio: 2.28 (95% confidence interval: 1.09-4.76)] than patients without these alterations. CDKN2A homozygous deletions coexisted with IKZF1 and PAX5 deletions (p < .001). In conclusion, CDKN2A homozygous deletions, but not promoter methylation, are associated with poor response to treatment and increased relapse risk of pediatric BCP-ALL.
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Affiliation(s)
- Marcin Braun
- a Department of Pediatrics, Oncology, Hematology and Diabetology , Medical University of Lodz , Lodz , Poland.,b Department of Pathology , Medical University of Lodz , Lodz , Poland.,c Postgraduate School of Molecular Medicine , Medical University of Warsaw , Warsaw , Poland
| | - Agata Pastorczak
- a Department of Pediatrics, Oncology, Hematology and Diabetology , Medical University of Lodz , Lodz , Poland
| | - Wojciech Fendler
- d Department of Biostatistics and Translational Medicine , Medical University of Lodz , Lodz , Poland
| | - Joanna Madzio
- a Department of Pediatrics, Oncology, Hematology and Diabetology , Medical University of Lodz , Lodz , Poland.,c Postgraduate School of Molecular Medicine , Medical University of Warsaw , Warsaw , Poland
| | - Bartlomiej Tomasik
- d Department of Biostatistics and Translational Medicine , Medical University of Lodz , Lodz , Poland
| | - Joanna Taha
- a Department of Pediatrics, Oncology, Hematology and Diabetology , Medical University of Lodz , Lodz , Poland
| | - Marta Bielska
- a Department of Pediatrics, Oncology, Hematology and Diabetology , Medical University of Lodz , Lodz , Poland
| | - Lukasz Sedek
- e Department of Pediatric Hematology and Oncology , Medical University of Silesia , Zabrze , Poland
| | - Tomasz Szczepanski
- e Department of Pediatric Hematology and Oncology , Medical University of Silesia , Zabrze , Poland
| | - Michal Matysiak
- f Department of Pediatric Hematology and Oncology , Medical University of Warsaw , Warsaw , Poland
| | - Katarzyna Derwich
- g Department of Pediatric Hematology , Oncology and Transplantology, University of Medical Sciences , Poznan , Poland
| | - Monika Lejman
- h Department of Pediatric Hematology and Oncology , Medical University of Lublin , Lublin , Poland
| | - Jerzy Kowalczyk
- h Department of Pediatric Hematology and Oncology , Medical University of Lublin , Lublin , Poland
| | - Bernarda Kazanowska
- i Department of Pediatric Hematology , Oncology and Transplantology, Medical University of Wroclaw , Wroclaw , Poland
| | - Wanda Badowska
- j Department of Pediatric Hematology and Oncology , Olsztyn , Poland
| | - Jan Styczynski
- k Department of Pediatric Hematology and Oncology, Collegium Medicum , Nicolaus Copernicus University , Bydgoszcz , Poland
| | - Nina Irga-Jaworska
- l Department of Pediatric Hematology , Gdansk Medical University , Gdansk , Poland
| | - Joanna Trelinska
- a Department of Pediatrics, Oncology, Hematology and Diabetology , Medical University of Lodz , Lodz , Poland
| | - Beata Zalewska-Szewczyk
- a Department of Pediatrics, Oncology, Hematology and Diabetology , Medical University of Lodz , Lodz , Poland
| | - Filip Pierlejewski
- a Department of Pediatrics, Oncology, Hematology and Diabetology , Medical University of Lodz , Lodz , Poland
| | | | - Wojciech Młynarski
- a Department of Pediatrics, Oncology, Hematology and Diabetology , Medical University of Lodz , Lodz , Poland
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16
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Norris AL, Kamiyama H, Makohon-Moore A, Pallavajjala A, Morsberger LA, Lee K, Batista D, Iacobuzio-Donahue CA, Lin MT, Klein AP, Hruban RH, Wheelan SJ, Eshleman JR. Transflip mutations produce deletions in pancreatic cancer. Genes Chromosomes Cancer 2015; 54:472-481. [PMID: 26031834 DOI: 10.1002/gcc.22258] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 03/18/2015] [Accepted: 03/24/2015] [Indexed: 12/30/2022] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC) is driven by the inactivation of the tumor suppressor genes (TSGs), CDKN2A (P16) and SMAD4 (DPC4), commonly by homozygous deletions (HDs). Using a combination of high density single-nucleotide polymorphism (SNP) microarray and whole genome sequencing (WGS), we fine-mapped novel breakpoints surrounding deletions of CDKN2A and SMAD4 and characterized them by their underlying structural variants (SVs). Only one third of CDKN2A and SMAD4 deletions (6 of 18) were simple interstitial deletions, rather, the majority of deletions were caused by complex rearrangements, specifically, a translocation on one side of the TSG in combination with an inversion on the other side. We designate these as "TransFlip" mutations. Characteristics of TransFlip mutations are: (1) a propensity to target the TSGs CDKN2A and SMAD4 (P < 0.005), (2) not present in the germline of the examined samples, (3) non-recurrent breakpoints, (4) relatively small (47 bp to 3.4 kb) inversions, (5) inversions can be either telomeric or centromeric to the TSG, and (6) non-reciprocal, and non-recurrent translocations. TransFlip mutations are novel complex genomic rearrangements with unique breakpoint signatures in pancreatic cancer. We hypothesize that they are a common but poorly understood mechanism of TSG inactivation in human cancer. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Alexis L Norris
- Department of Pathology, The Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins School of Medicine, Baltimore, MD, 21231
| | - Hirohiko Kamiyama
- Department of Pathology, The Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins School of Medicine, Baltimore, MD, 21231
| | - Alvin Makohon-Moore
- Department of Pathology, The Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins School of Medicine, Baltimore, MD, 21231
| | - Aparna Pallavajjala
- Department of Pathology, The Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins School of Medicine, Baltimore, MD, 21231.,Department of Oncology, The Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins School of Medicine, Baltimore, MD, 21231
| | - Laura A Morsberger
- Department of Pathology, The Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins School of Medicine, Baltimore, MD, 21231
| | - Kurt Lee
- Department of Pathology, The Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins School of Medicine, Baltimore, MD, 21231
| | - Denise Batista
- Department of Pathology, The Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins School of Medicine, Baltimore, MD, 21231
| | - Christine A Iacobuzio-Donahue
- Department of Pathology, The Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins School of Medicine, Baltimore, MD, 21231.,Department of Oncology, The Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins School of Medicine, Baltimore, MD, 21231
| | - Ming-Tseh Lin
- Department of Pathology, The Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins School of Medicine, Baltimore, MD, 21231
| | - Alison P Klein
- Department of Pathology, The Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins School of Medicine, Baltimore, MD, 21231.,Department of Oncology, The Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins School of Medicine, Baltimore, MD, 21231
| | - Ralph H Hruban
- Department of Pathology, The Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins School of Medicine, Baltimore, MD, 21231.,Department of Oncology, The Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins School of Medicine, Baltimore, MD, 21231
| | - Sarah J Wheelan
- Department of Oncology, The Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins School of Medicine, Baltimore, MD, 21231
| | - James R Eshleman
- Department of Pathology, The Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins School of Medicine, Baltimore, MD, 21231.,Department of Oncology, The Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins School of Medicine, Baltimore, MD, 21231
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17
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PTEN microdeletions in T-cell acute lymphoblastic leukemia are caused by illegitimate RAG-mediated recombination events. Blood 2014; 124:567-78. [PMID: 24904117 DOI: 10.1182/blood-2014-03-562751] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Phosphatase and tensin homolog (PTEN)-inactivating mutations and/or deletions are an independent risk factor for relapse of T-cell acute lymphoblastic leukemia (T-ALL) patients treated on Dutch Childhood Oncology Group or German Cooperative Study Group for Childhood Acute Lymphoblastic Leukemia protocols. Some monoallelic mutated or PTEN wild-type patients lack PTEN protein, implying that additional PTEN inactivation mechanisms exist. We show that PTEN is inactivated by small deletions affecting a few exons in 8% of pediatric T-ALL patients. These microdeletions were clonal in 3% and subclonal in 5% of patients. Conserved deletion breakpoints are flanked by cryptic recombination signal sequences (cRSSs) and frequently have non-template-derived nucleotides inserted in between breakpoints, pointing to an illegitimate RAG recombination-driven activity. Identified cRSSs drive RAG-dependent recombination in a reporter system as efficiently as bona fide RSSs that flank gene segments of the T-cell receptor locus. Remarkably, equivalent microdeletions were detected in thymocytes of healthy individuals. Microdeletions strongly associate with the TALLMO subtype characterized by TAL1 or LMO2 rearrangements. Primary and secondary xenotransplantation of TAL1-rearranged leukemia allowed development of leukemic subclones with newly acquired PTEN microdeletions. Ongoing RAG activity may therefore actively contribute to the acquisition of preleukemic hits, clonal diversification, and disease progression.
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18
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Papaemmanuil E, Rapado I, Li Y, Potter NE, Wedge DC, Tubio J, Alexandrov LB, Van Loo P, Cooke SL, Marshall J, Martincorena I, Hinton J, Gundem G, van Delft FW, Nik-Zainal S, Jones DR, Ramakrishna M, Titley I, Stebbings L, Leroy C, Menzies A, Gamble J, Robinson B, Mudie L, Raine K, O’Meara S, Teague JW, Butler AP, Cazzaniga G, Biondi A, Zuna J, Kempski H, Muschen M, Ford AM, Stratton MR, Greaves M, Campbell PJ. RAG-mediated recombination is the predominant driver of oncogenic rearrangement in ETV6-RUNX1 acute lymphoblastic leukemia. Nat Genet 2014; 46:116-25. [PMID: 24413735 PMCID: PMC3960636 DOI: 10.1038/ng.2874] [Citation(s) in RCA: 266] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 12/13/2013] [Indexed: 12/16/2022]
Abstract
The ETV6-RUNX1 fusion gene, found in 25% of childhood acute lymphoblastic leukemia (ALL) cases, is acquired in utero but requires additional somatic mutations for overt leukemia. We used exome and low-coverage whole-genome sequencing to characterize secondary events associated with leukemic transformation. RAG-mediated deletions emerge as the dominant mutational process, characterized by recombination signal sequence motifs near breakpoints, incorporation of non-templated sequence at junctions, ∼30-fold enrichment at promoters and enhancers of genes actively transcribed in B cell development and an unexpectedly high ratio of recurrent to non-recurrent structural variants. Single-cell tracking shows that this mechanism is active throughout leukemic evolution, with evidence of localized clustering and reiterated deletions. Integration of data on point mutations and rearrangements identifies ATF7IP and MGA as two new tumor-suppressor genes in ALL. Thus, a remarkably parsimonious mutational process transforms ETV6-RUNX1-positive lymphoblasts, targeting the promoters, enhancers and first exons of genes that normally regulate B cell differentiation.
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Affiliation(s)
| | | | - Yilong Li
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, UK
| | | | - David C Wedge
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, UK
| | - Jose Tubio
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, UK
| | | | - Peter Van Loo
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, UK
- Department of Human Genetics, VIB and University of Leuven, Leuven, Belgium
| | - Susanna L Cooke
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, UK
| | - John Marshall
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, UK
| | | | - Jonathan Hinton
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, UK
| | - Gunes Gundem
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, UK
| | - Frederik W van Delft
- Institute for Cancer Research, Sutton, London, UK
- Northern Institute for Cancer Research, University of Newcastle, Newcastle upon Tyne, UK
| | | | - David R Jones
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, UK
| | | | - Ian Titley
- Institute for Cancer Research, Sutton, London, UK
| | - Lucy Stebbings
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, UK
| | - Catherine Leroy
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, UK
| | - Andrew Menzies
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, UK
| | - John Gamble
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, UK
| | - Ben Robinson
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, UK
| | - Laura Mudie
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, UK
| | - Keiran Raine
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, UK
| | - Sarah O’Meara
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, UK
| | - Jon W Teague
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, UK
| | - Adam P Butler
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, UK
| | - Giovanni Cazzaniga
- Centro Ricerca Tettamanti, Hospital San Gerardo, Via Pergolesi, 33, 20052 Monza (Mi), Italy
| | - Andrea Biondi
- Centro Ricerca Tettamanti, Hospital San Gerardo, Via Pergolesi, 33, 20052 Monza (Mi), Italy
| | - Jan Zuna
- CLIP, Department of Paediatric Haematology and Oncology, 2nd Faculty of Medicine, Charles University Prague and University Hospital Motol, Prague, Czech Republic
| | - Helena Kempski
- Paediatric Malignancy Unit, CBL Level 2, Molecular Haematology & Cancer Biology Unit, Camelia Botnar Laboratories, Level 2, Great Ormond Street Hospital for Children & UCL Institute of Child Health, Great Ormond Street, London WC1N 3JH
| | - Markus Muschen
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, CA
| | | | | | - Mel Greaves
- Institute for Cancer Research, Sutton, London, UK
| | - Peter J Campbell
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, UK
- Addenbrooke’s NHS Foundation Trust, Cambridge, UK
- University of Cambridge, Cambridge, UK
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19
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Abstract
Genomic aberrations affecting genes in B cell differentiation are hallmarks of B-precursor acute lymphoblastic leukemia (ALL). A new whole-genome sequencing study of ETV6-RUNX1-positive ALL has now identified RAG-mediated recombination, which specifically targets genes and regulatory elements active during B cell differentiation, as the underlying mechanism.
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20
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Rajaram M, Zhang J, Wang T, Li J, Kuscu C, Qi H, Kato M, Grubor V, Weil RJ, Helland A, Borrenson-Dale AL, Cho KR, Levine DA, Houghton AN, Wolchok JD, Myeroff L, Markowitz SD, Lowe SW, Zhang M, Krasnitz A, Lucito R, Mu D, Powers RS. Two Distinct Categories of Focal Deletions in Cancer Genomes. PLoS One 2013; 8:e66264. [PMID: 23805207 PMCID: PMC3689739 DOI: 10.1371/journal.pone.0066264] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Accepted: 05/03/2013] [Indexed: 01/07/2023] Open
Abstract
One of the key questions about genomic alterations in cancer is whether they are functional in the sense of contributing to the selective advantage of tumor cells. The frequency with which an alteration occurs might reflect its ability to increase cancer cell growth, or alternatively, enhanced instability of a locus may increase the frequency with which it is found to be aberrant in tumors, regardless of oncogenic impact. Here we’ve addressed this on a genome-wide scale for cancer-associated focal deletions, which are known to pinpoint both tumor suppressor genes (tumor suppressors) and unstable loci. Based on DNA copy number analysis of over one-thousand human cancers representing ten different tumor types, we observed five loci with focal deletion frequencies above 5%, including the A2BP1 gene at 16p13.3 and the MACROD2 gene at 20p12.1. However, neither RNA expression nor functional studies support a tumor suppressor role for either gene. Further analyses suggest instead that these are sites of increased genomic instability and that they resemble common fragile sites (CFS). Genome-wide analysis revealed properties of CFS-like recurrent deletions that distinguish them from deletions affecting tumor suppressor genes, including their isolation at specific loci away from other genomic deletion sites, a considerably smaller deletion size, and dispersal throughout the affected locus rather than assembly at a common site of overlap. Additionally, CFS-like deletions have less impact on gene expression and are enriched in cell lines compared to primary tumors. We show that loci affected by CFS-like deletions are often distinct from known common fragile sites. Indeed, we find that each tumor tissue type has its own spectrum of CFS-like deletions, and that colon cancers have many more CFS-like deletions than other tumor types. We present simple rules that can pinpoint focal deletions that are not CFS-like and more likely to affect functional tumor suppressors.
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Affiliation(s)
- Megha Rajaram
- Cancer Genome Center, Cold Spring Harbor Laboratory, Woodbury, New York, United States of America
| | - Jianping Zhang
- Cancer Genome Center, Cold Spring Harbor Laboratory, Woodbury, New York, United States of America
| | - Tim Wang
- Cancer Genome Center, Cold Spring Harbor Laboratory, Woodbury, New York, United States of America
| | - Jinyu Li
- Cancer Genome Center, Cold Spring Harbor Laboratory, Woodbury, New York, United States of America
| | - Cem Kuscu
- Cancer Genome Center, Cold Spring Harbor Laboratory, Woodbury, New York, United States of America
| | - Huan Qi
- Cancer Genome Center, Cold Spring Harbor Laboratory, Woodbury, New York, United States of America
| | - Mamoru Kato
- Cancer Genome Center, Cold Spring Harbor Laboratory, Woodbury, New York, United States of America
| | - Vladimir Grubor
- Cancer Genome Center, Cold Spring Harbor Laboratory, Woodbury, New York, United States of America
| | - Robert J. Weil
- Department of Neurosurgery, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Aslaug Helland
- Department of Genetics, The Norwegian Radium Hospital, Oslo, Norway
| | | | - Kathleen R. Cho
- Departments of Internal Medicine and Pathology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Douglas A. Levine
- Departments of Medicine and Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Alan N. Houghton
- Departments of Medicine and Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Jedd D. Wolchok
- Departments of Medicine and Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Lois Myeroff
- Department of Medicine and Ireland Cancer Center, Case Western Reserve University and University Hospitals of Cleveland, Cleveland, Ohio, United States of America
| | - Sanford D. Markowitz
- Department of Medicine and Ireland Cancer Center, Case Western Reserve University and University Hospitals of Cleveland, Cleveland, Ohio, United States of America
| | - Scott W. Lowe
- Cancer Genome Center, Cold Spring Harbor Laboratory, Woodbury, New York, United States of America
| | - Michael Zhang
- Cancer Genome Center, Cold Spring Harbor Laboratory, Woodbury, New York, United States of America
| | - Alex Krasnitz
- Cancer Genome Center, Cold Spring Harbor Laboratory, Woodbury, New York, United States of America
| | - Robert Lucito
- Cancer Genome Center, Cold Spring Harbor Laboratory, Woodbury, New York, United States of America
| | - David Mu
- Cancer Genome Center, Cold Spring Harbor Laboratory, Woodbury, New York, United States of America
| | - R. Scott Powers
- Cancer Genome Center, Cold Spring Harbor Laboratory, Woodbury, New York, United States of America
- * E-mail:
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Yasaei H, Gilham E, Pickles JC, Roberts TP, O'Donovan M, Newbold RF. Carcinogen-specific mutational and epigenetic alterations in INK4A, INK4B and p53 tumour-suppressor genes drive induced senescence bypass in normal diploid mammalian cells. Oncogene 2012; 32:171-9. [DOI: 10.1038/onc.2012.45] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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22
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Waanders E, Scheijen B, van der Meer LT, van Reijmersdal SV, van Emst L, Kroeze Y, Sonneveld E, Hoogerbrugge PM, van Kessel AG, van Leeuwen FN, Kuiper RP. The origin and nature of tightly clustered BTG1 deletions in precursor B-cell acute lymphoblastic leukemia support a model of multiclonal evolution. PLoS Genet 2012; 8:e1002533. [PMID: 22359517 PMCID: PMC3280973 DOI: 10.1371/journal.pgen.1002533] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 12/23/2011] [Indexed: 11/18/2022] Open
Abstract
Recurrent submicroscopic deletions in genes affecting key cellular pathways are a hallmark of pediatric acute lymphoblastic leukemia (ALL). To gain more insight into the mechanism underlying these deletions, we have studied the occurrence and nature of abnormalities in one of these genes, the B-cell translocation gene 1 (BTG1), in a large cohort of pediatric ALL cases. BTG1 was found to be exclusively affected by genomic deletions, which were detected in 65 out of 722 B-cell precursor ALL (BCP-ALL) patient samples (9%), but not in 109 T-ALL cases. Eight different deletion sizes were identified, which all clustered at the telomeric site in a hotspot region within the second (and last) exon of the BTG1 gene, resulting in the expression of truncated BTG1 read-through transcripts. The presence of V(D)J recombination signal sequences at both sites of virtually all deletions strongly suggests illegitimate RAG1/RAG2-mediated recombination as the responsible mechanism. Moreover, high levels of histone H3 lysine 4 trimethylation (H3K4me3), which is known to tether the RAG enzyme complex to DNA, were found within the BTG1 gene body in BCP-ALL cells, but not T-ALL cells. BTG1 deletions were rarely found in hyperdiploid BCP-ALLs, but were predominant in other cytogenetic subgroups, including the ETV6-RUNX1 and BCR-ABL1 positive BCP-ALL subgroups. Through sensitive PCR-based screening, we identified multiple additional BTG1 deletions at the subclonal level in BCP-ALL, with equal cytogenetic distribution which, in some cases, grew out into the major clone at relapse. Taken together, our results indicate that BTG1 deletions may act as “drivers” of leukemogenesis in specific BCP-ALL subgroups, in which they can arise independently in multiple subclones at sites that are prone to aberrant RAG1/RAG2-mediated recombination events. These findings provide further evidence for a complex and multiclonal evolution of ALL. Recent studies have alluded to the existence of a complex clonal cellular architecture in acute lymphoblastic leukemia (ALL), where multiple subclones contribute to leukemogenesis. Here, we show that in pediatric B-cell precursor ALL (BCP-ALL) monoallelic deletions in the tumor suppressor BTG1 locus, which were found to occur in 9% of the patients studied, result in truncations of the gene rather than in complete allelic losses. Using both genetic and epigenetic approaches, we show that these deletions most likely originate from illegitimate RAG recombination. Sensitive backtracking using deletion-spanning PCRs revealed that these BTG1 deletions occur in specific BCP-ALL subtypes, with frequencies higher than previously anticipated, often in one minor subclone or in multiple independent subclones within individual patients. Subclones that carry a BTG1 deletion at diagnosis can evolve into the major clone at relapse. These findings link a mechanism of tumor suppressor gene deletion to the multiclonal evolution of ALL.
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Affiliation(s)
- Esmé Waanders
- Department of Human Genetics, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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Iacobucci I, Ferrari A, Lonetti A, Papayannidis C, Paoloni F, Trino S, Storlazzi CT, Ottaviani E, Cattina F, Impera L, Abbenante MC, Vignetti M, Vitale A, Potenza L, Paolini S, Soverini S, Pane F, Luppi M, Foà R, Baccarani M, Martinelli G. CDKN2A/B Alterations Impair Prognosis in Adult BCR-ABL1–Positive Acute Lymphoblastic Leukemia Patients. Clin Cancer Res 2011; 17:7413-23. [DOI: 10.1158/1078-0432.ccr-11-1227] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Microarray detection of multiple recurring submicroscopic chromosomal aberrations in pediatric T-cell acute lymphoblastic leukemia. Leukemia 2011; 25:1042-6. [PMID: 21383747 DOI: 10.1038/leu.2011.33] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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25
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Niller HH, Wolf H, Minarovits J. Viral hit and run-oncogenesis: genetic and epigenetic scenarios. Cancer Lett 2010; 305:200-17. [PMID: 20813452 DOI: 10.1016/j.canlet.2010.08.007] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Revised: 07/29/2010] [Accepted: 08/09/2010] [Indexed: 12/31/2022]
Abstract
It is well documented that viral genomes either inserted into the cellular DNA or co-replicating with it in episomal form can be lost from neoplastic cells. Therefore, "hit and run"-mechanisms have been a topic of longstanding interest in tumor virology. The basic idea is that the transient acquisition of a complete or incomplete viral genome may be sufficient to induce malignant conversion of host cells in vivo, resulting in neoplastic development. After eliciting a heritable change in the gene expression pattern of the host cell (initiation), the genomes of tumor viruses may be completely lost, i.e. in a hit and run-scenario they are not necessary for the maintenance of the malignant state. The expression of viral oncoproteins and RNAs may interfere not only with regulators of cell proliferation, but also with DNA repair mechanisms. DNA recombinogenic activities induced by tumor viruses or activated by other mechanisms may contribute to the secondary loss of viral genomes from neoplastic cells. Viral oncoproteins can also cause epigenetic dysregulation, thereby reprogramming cellular gene expression in a heritable manner. Thus, we expect that epigenetic scenarios of viral hit and run-tumorigenesis may facilitate new, innovative experiments and clinical studies in spite of the fact that the regular presence of a suspected human tumor virus in an early phase of neoplastic development and its subsequent regular loss have not been demonstrated yet. We propose that virus-specific "epigenetic signatures", i.e. alterations of the host cell epigenome, especially altered DNA methylation patterns, may help to identify viral hit and run-oncogenic events, even after the complete loss of tumor viruses from neoplastic cells.
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Affiliation(s)
- Hans Helmut Niller
- Institute for Medical Microbiology and Hygiene of the University of Regensburg, Franz-Josef-Strauss-Allee 11, Regensburg, Germany.
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Abstract
Retrotransposons like L1 are silenced in somatic cells by a
variety of mechanisms acting at different levels. Protective
mechanisms include DNA methylation and packaging into inactive
chromatin to suppress transcription and prevent recombination,
potentially supported by cytidine deaminase editing of RNA.
Furthermore, DNA strand breaks arising during attempted
retrotranspositions ought to activate cellular checkpoints, and L1
activation outside immunoprivileged sites may elicit immune
responses. A number of observations indicate that L1 sequences
nevertheless become reactivated in human cancer. Prominently,
methylation of L1 sequences is diminished in many cancer types and
full-length L1 RNAs become detectable, although strong expression
is restricted to germ cell cancers. L1 elements have been found to
be enriched at sites of illegitimate recombination in many
cancers. In theory, lack of L1 repression in cancer might cause
transcriptional deregulation, insertional mutations, DNA breaks,
and an increased frequency of recombinations, contributing to
genome disorganization, expression changes, and chromosomal
instability. There is however little evidence that such effects
occur at a gross scale in human cancers. Rather, as a rule, L1
repression is only partly alleviated. Unfortunately, many
techniques commonly used to investigate genetic and epigenetic
alterations in cancer cells are not well suited to detect subtle
effects elicited by partial reactivation of retroelements like L1
which are present as abundant, but heterogeneous copies.
Therefore, effects of L1 sequences exerted on the local chromatin
structure, on the transcriptional regulation of individual genes,
and on chromosome fragility need to be more closely investigated
in normal and cancer cells.
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Affiliation(s)
- Wolfgang A. Schulz
- Department of Urology, Heinrich Heine University, Mooreustrasse 5, 40225 Düsseldorf, Germany
- *Wolfgang A. Schulz:
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27
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Senff NJ, Zoutman WH, Vermeer MH, Assaf C, Berti E, Cerroni L, Espinet B, de Misa Cabrera RF, Geerts ML, Kempf W, Mitchell TJ, Paulli M, Petrella T, Pimpinelli N, Santucci M, Whittaker SJ, Willemze R, Tensen CP. Fine-Mapping Chromosomal Loss at 9p21: Correlation with Prognosis in Primary Cutaneous Diffuse Large B-Cell Lymphoma, Leg Type. J Invest Dermatol 2009; 129:1149-55. [DOI: 10.1038/jid.2008.357] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Bentley J, L'Hôte C, Platt F, Hurst CD, Lowery J, Taylor C, Sak SC, Harnden P, Knowles MA, Kiltie AE. Papillary and muscle invasive bladder tumors with distinct genomic stability profiles have different DNA repair fidelity and KU DNA-binding activities. Genes Chromosomes Cancer 2009; 48:310-21. [PMID: 19105236 DOI: 10.1002/gcc.20641] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Low-grade noninvasive papillary bladder tumors are genetically stable whereas muscle invasive bladder tumors display high levels of chromosomal aberrations. As cells deficient for nonhomologous end-joining (NHEJ) pathway components display increased genomic instability, we sought to determine the NHEJ repair characteristics of bladder tumors and correlate this with tumor stage and grade. A panel of 13 human bladder tumors of defined stage and grade were investigated for chromosomal aberrations by comparative genomic hybridization and for NHEJ repair fidelity and function. Repair assays were conducted with extracts made directly from bladder tumor specimens to avoid culture-induced phenotypic alterations and selection bias as only a minority of bladder tumors grow in culture. Four noninvasive bladder tumors (pTaG2), which were genetically stable, repaired a partially incompatible double-strand break (DSB) by NHEJ-dependent annealing of termini and fill-in of overhangs with minimal loss of nucleotides. In contrast, four muscle invasive bladder cancers (pT2-3G3), which displayed gross chromosomal rearrangements, repaired DSBs in an error-prone manner involving extensive resection and microhomology association. Four minimally invasive bladder cancers (pT1G3) had characteristics of both repair types. Error-prone repair in bladder tumors correlated with reduced KU DNA-binding and loss of TP53 function. In conclusion, there were distinct differences in DSB repair between noninvasive papillary tumors and higher stage/grade invasive cancers. End-joining fidelity correlated with stage and was increasingly error-prone as tumors became more invasive and KU binding activity reduced; these changes may underlie the different genomic profiles of these tumors.
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Affiliation(s)
- Johanne Bentley
- Cancer Research UK Clinical Centre, Section of Experimental Oncology, Leeds Institute of Molecular Medicine, St James's University Hospital, Leeds, UK
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Adamovic T, Hamta A, Roshani L, Lü X, Röhme D, Helou K, Klinga-Levan K, Levan G. Rearrangement and allelic imbalance on chromosome 5 leads to homozygous deletions in the CDKN2A/2B tumor suppressor gene region in rat endometrial cancer. ACTA ACUST UNITED AC 2008; 184:9-21. [PMID: 18558284 DOI: 10.1016/j.cancergencyto.2008.02.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2007] [Revised: 02/22/2008] [Accepted: 02/25/2008] [Indexed: 11/16/2022]
Abstract
The inbred BDII rat is a valuable experimental model for the genetic analysis of hormone-dependent endometrial adenocarcinoma (EAC). One common aberration detected previously by comparative genomic hybridization in rat EAC is loss affecting mostly the middle part of rat chromosome 5 (RNO5). First, we applied an RNO5-specific painting probe and four region-specific gene probes onto tumor cell metaphases from 21 EACs, and found that rearrangements involving RNO5 were common. The copy numbers of loci situated on RNO5 were found to be reduced, particularly for the CDKN2A/2B locus. Second, polymerase chain reaction analysis was performed with 22 genes and markers and homozygous deletions of the CDKN2A exon 1beta and CDKN2B genes were detected in 13 EACs (62%) and of CDKN2A exon 1alpha in 12 EACs (57%) Third, the occurrence of allelic imbalance in RNO5 was analyzed using 39 microsatellite markers covering the entire chromosome and frequent loss of heterozygosity was detected. Even more intriguing was the repeated finding of allele switching in a narrow region of 7 Mb across the CDKN2A/2B locus. We conclude that genetic events affecting the middle part of RNO5 (including bands 5q31 approximately q33 and the CDKN2A locus) contribute to the development of EAC in rat, with the CDKN2A locus having a primary role.
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Affiliation(s)
- Tatjana Adamovic
- Human and Molecular Genetics Center, Medical College of Wisconsin, HRC-5th Floor, 8701 Watertown Plank Road, Milwaukee, WI 53226-0509, USA.
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30
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Hoffmann TK, Sonkoly E, Hauser U, van Lierop A, Whiteside TL, Klussmann JP, Hafner D, Schuler P, Friebe-Hoffmann U, Scheckenbach K, Erjala K, Grénman R, Schipper J, Bier H, Balz V. Alterations in the p53 pathway and their association with radio- and chemosensitivity in head and neck squamous cell carcinoma. Oral Oncol 2008; 44:1100-9. [PMID: 18487078 DOI: 10.1016/j.oraloncology.2008.02.006] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2008] [Revised: 02/14/2008] [Accepted: 02/15/2008] [Indexed: 11/30/2022]
Abstract
Chemotherapy and/or radiotherapy are established measures in treatment protocols of head and neck squamous cell carcinoma (HNSCC). However, we still lack reliable predictive markers for the response to radio- and chemotherapy. The p53 pathway is involved in stress response and thus might influence chemo-/radiosensitivity. Using 29 HNSCC cell lines previously characterized for p53 mutations, we simultaneously analyzed several key players in the p53 pathway by RT-PCR, transcript sequencing and immunohistochemistry, and investigated their association with chemosensitivity and radiosensitivity. Cell lines with p53 mutations were slightly more sensitive to cisplatin than those with wild-type p53. The type of mutation did not influence radio- or chemosensitivity. p14(ARF), an activator of p53, was lost or mutated in all cell lines. Three cell lines showed overexpression of HDM-2, a major negative regulator of p53; however, HDM-2 levels did not correlate with radio- or chemosensitivity. HPV-16 oncoproteins were detected in one highly chemoresistant cell line. Our findings suggest that molecular events resulting in the inactivation of the p53 pathway occur in all HNSCC cell lines. However, single alterations in the p53 pathway are not reliable predictors for the response to radio- or chemotherapy in HNSCC.
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Affiliation(s)
- Thomas K Hoffmann
- Department of Otorhinolaryngology, Heinrich-Heine-University Düsseldorf, Moorenstrasse 5, D-40225 Düsseldorf, Germany.
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31
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Chromosomal instability in bladder cancer. Arch Toxicol 2008; 82:173-82. [PMID: 18253719 DOI: 10.1007/s00204-008-0280-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Accepted: 01/09/2008] [Indexed: 01/10/2023]
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32
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Distinctive differences in DNA double-strand break repair between normal urothelial and urothelial carcinoma cells. Mutat Res 2007; 638:56-65. [PMID: 17928011 DOI: 10.1016/j.mrfmmm.2007.08.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2007] [Revised: 08/24/2007] [Accepted: 08/29/2007] [Indexed: 01/10/2023]
Abstract
Several lines of evidence suggest that defective repair of DNA double-strand breaks (DSB) contributes to genomic instability in human cancers, including urothelial carcinoma. In particular, extracts from urothelial cancers have been reported to repair DSBs preferentially by microhomology-mediated end-joining (MMEJ), considered as more error-prone than canonical non-homologous end-joining (NHEJ) predominating in normal urothelial cell extracts. However, it is not clear whether such differences are relevant to intact cells. We therefore transfected plasmids digested with different restriction enzymes to yield incompatible ends (blunt, 5'-protruding or 3'-protruding) into urothelial carcinoma cell lines or normal urothelial cells and characterized the recovered circular plasmids. All cells competently repaired DSBs in a standard cloning vector plasmid, processing 5'- as well as 3'-protruding ends. No significant differences in the extent of processing were detected and the junctions presented short microhomologies indicative of canonical NHEJ. However, dramatic and distinctive differences between normal and cancerous urothelial cells were seen in two different experiments. First, cancer cell lines processed a significantly higher fraction of plasmids cut with a single restriction enzyme that could have been repaired by direct ligation than normal cells. Secondly, for the repair of a large plasmid with incompatible ends containing a large fragment of human genomic DNA, normal cells used almost exclusively MMEJ exploiting a microhomology with the 3'-end of the break, whereas cancer cell lines often processed DNA despite suitable microhomologies. DNA repair of the small or large plasmid was almost abolished by siRNA knockdown of Ku70. These findings strongly suggest that urothelial carcinoma cells lack control mechanisms preventing overprocessing during NHEJ repair. This may account for previous findings that urothelial cancers contain unusually large chromosomal deletions. Moreover, in contrast to prevailing interpretations, our observations suggest that MMEJ, despite its error-proneness, in some instances may act as a failsafe mechanism against overprocessing during NHEJ.
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Bashir A, Liu YT, Raphael BJ, Carson D, Bafna V. Optimization of primer design for the detection of variable genomic lesions in cancer. ACTA ACUST UNITED AC 2007; 23:2807-15. [PMID: 17766270 DOI: 10.1093/bioinformatics/btm390] [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: 01/22/2023]
Abstract
Primer approximation multiplex PCR (PAMP) is a new experimental protocol for efficiently assaying structural variation in genomes. PAMP is particularly suited to cancer genomes where the precise breakpoints of alterations such as deletions or translocations vary between patients. The design of PCR primer sets for PAMP is challenging because a large number of primer pairs are required to detect alterations in the hundreds of kilobases range that can occur in cancer. These sets of primers must achieve high coverage of the region of interest, while avoiding primer dimers and satisfying the physico-chemical constraints of good PCR primers. We describe a natural formulation of these constraints as a combinatorial optimization problem. We show that the PAMP primer design problem is NP-hard, and design algorithms based on simulated annealing and integer programming, that provide good solutions to this problem in practice. The algorithms are applied to a test region around the known CDKN2A deletion, which show excellent results even in a 1:49 mixture of mutated:wild-type cells. We use these test results to help set design parameters for larger problems. We can achieve near-optimal designs for regions close to 1 Mb.
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Affiliation(s)
- Ali Bashir
- Bioinformatics Program, University of California, San Diego, CA, USA.
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Liu YT, Carson DA. A novel approach for determining cancer genomic breakpoints in the presence of normal DNA. PLoS One 2007; 2:e380. [PMID: 17440616 PMCID: PMC1847701 DOI: 10.1371/journal.pone.0000380] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Accepted: 03/27/2007] [Indexed: 01/03/2023] Open
Abstract
CDKN2A (encodes p16(INK4A) and p14(ARF)) deletion, which results in both Rb and p53 inactivation, is the most common chromosomal anomaly in human cancers. To precisely map the deletion breakpoints is important to understanding the molecular mechanism of genomic rearrangement and may also be useful for clinical applications. However, current methods for determining the breakpoint are either of low resolution or require the isolation of relatively pure cancer cells, which can be difficult for clinical samples that are typically contaminated with various amounts of normal host cells. To overcome this hurdle, we have developed a novel approach, designated Primer Approximation Multiplex PCR (PAMP), for enriching breakpoint sequences followed by genomic tiling array hybridization to locate the breakpoints. In a series of proof-of-concept experiments, we were able to identify cancer-derived CDKN2A genomic breakpoints when more than 99.9% of wild type genome was present in a model system. This design can be scaled up with bioinformatics support and can be applied to validate other candidate cancer-associated loci that are revealed by other more systemic but lower throughput assays.
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Affiliation(s)
- Yu-Tsueng Liu
- Moores UCSD Cancer Center, University of California San Diego, La Jolla, California, United States of America.
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35
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Taniguchi T, Karnan S, Fukui T, Yokoyama T, Tagawa H, Yokoi K, Ueda Y, Mitsudomi T, Horio Y, Hida T, Yatabe Y, Seto M, Sekido Y. Genomic profiling of malignant pleural mesothelioma with array-based comparative genomic hybridization shows frequent non-random chromosomal alteration regions including JUN amplification on 1p32. Cancer Sci 2007; 98:438-46. [PMID: 17270034 PMCID: PMC11158069 DOI: 10.1111/j.1349-7006.2006.00386.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Genome-wide array-based comparative genomic hybridization analysis of malignant pleural mesotheliomas (MPM) was carried out to identify regions that display DNA copy number alterations. Seventeen primary tumors and nine cell lines derived from 22 individuals were studied, some of them originating from the same patients. Regions of genomic aberrations observed in >20% of individuals were 1q, 5p, 7p, 8q24 and 20p with gains, and 1p36.33, 1p36.1, 1p21.3, 3p21.3, 4q22, 4q34-qter, 6q25, 9p21.3, 10p, 13q33.2, 14q32.13, 18q and 22q with losses. Two regions at 1p32.1 and 11q22 showed a high copy gain. The 1p32.1 region contained a protooncogene, JUN, and we further demonstrated overexpression of JUN with real-time polymerase chain reaction analysis. As MPM cell lines did not overexpress JUN, our findings suggested that induction of JUN expression was involved in the development of MPM cells in vivo, which also might result in gene amplification in a subset of MPM. Meanwhile, the most frequent alteration was the 9p21.3 deletion, which includes the p16(INK4a)/p14(ARF) locus. With polymerase chain reaction analysis, we determined the extent of the homozygous deletion regions of the p16(INK4a)/p14(ARF) locus in MPM cell lines, which indicated that the deletion regions varied among cell lines. Our results with array comparative genomic hybridization analysis provide new insights into the genetic background of MPM, and also give some clues to develop a new molecular target therapy for MPM.
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Affiliation(s)
- Tetsuo Taniguchi
- Division of Molecular Oncology, Aichi Cancer Center Research Institute, 1-1 Kanokoden, Chikusa-ku, Nagoya, Japan
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36
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Schulz WA, Steinhoff C, Florl AR. Methylation of endogenous human retroelements in health and disease. Curr Top Microbiol Immunol 2006; 310:211-50. [PMID: 16909913 DOI: 10.1007/3-540-31181-5_11] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Retroelements constitute approximately 45% of the human genome. Long interspersed nuclear element (LINE) autonomous retrotransposons are predominantly represented by LINE-1, nonautonomous small interspersed nuclear elements (SINEs) are primarily represented by ALUs, and LTR retrotransposons by several families of human endogenous retroviruses (HERVs). The vast majority of LINE and HERV elements are densely methylated in normal somatic cells and contained in inactive chromatin. Methylation and chromatin structure together ensure a stable equilibrium between retroelements and their host. Hypomethylation and expression in developing germ cells opens a "window of opportunity" for retrotransposition and recombination that contribute to human evolution, but also inherited disease. In somatic cells, the presence of retroelements may be exploited to organize the genome into active and inactive regions, to separate domains and functional regions within one chromatin domain, to suppress transcriptional noise, and to regulate transcript stability. Retroelements, particularly ALUs, may also fulfill physiological roles during responses to stress and infections. Reactivation and hypomethylation of LINEs and HERVs may be important in the pathophysiology of cancer and various autoimmune diseases, contributing to chromosomal instability and chronically aberrant immune responses. The emerging insights into the pathophysiological importance of endogenous retroelements accentuate the gaps in our knowledge of how these elements are controlled in normal developing and mature cells.
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Affiliation(s)
- W A Schulz
- Urologische Klinik, Heinrich Heine Universität, Düsseldorf, Germany.
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37
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Kohno T, Yokota J. Molecular processes of chromosome 9p21 deletions causing inactivation of the p16 tumor suppressor gene in human cancer: deduction from structural analysis of breakpoints for deletions. DNA Repair (Amst) 2006; 5:1273-81. [PMID: 16931177 DOI: 10.1016/j.dnarep.2006.05.021] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Chromosome interstitial deletion (i.e., deletion of a chromosome segment in a chromosome arm) is a critical genetic event for the inactivation of tumor suppressor genes and activation of oncogenes leading to the carcinogenic conversion of human cells. The deletion at chromosome 9p21 removing the p16 tumor suppressor gene is a genetic alteration frequently observed in a variety of human cancers. Thus, structural analyses of breakpoints for p16 deletions in several kinds of human cancers have been performed to elucidate the molecular process of chromosome interstitial deletion consisting of formation of DNA double strand breaks (DSBs) and subsequent joining of DNA ends in human cells. The results indicated that DSBs triggering deletions in lymphoid leukemia are formed at a few defined sites by illegitimate action of the RAG protein complex, while DSBs in solid tumors are formed at unspecific sites by factors unidentified yet. In both types of tumors, the intra-nuclear architecture of chromatin was considered to affect the susceptibility of genomic segments of the p16 locus to DSBs. Broken DNA ends were joined by non-homologous end joining (NHEJ) repair in both types of tumors, however, microhomologies of DNA ends were preferentially utilized in the joining in solid tumors but not in lymphoid leukemia. The configuration of broken DNA ends as well as NHEJ activity in cells was thought to underlie the features of joining. Further structural analysis of other hot spots of chromosomal DNA breaks as well as the evaluation of the activity and specificity of NHEJ in human cells will elucidate the mechanisms of chromosome interstitial deletions in human cells.
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Affiliation(s)
- Takashi Kohno
- Biology Division, National Cancer Center Research Institute, Tokyo, Japan.
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38
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Indraccolo S, Tisato V, Agata S, Moserle L, Ferrari S, Callegaro M, Persano L, Palma MD, Scaini MC, Esposito G, Fassina A, Nicoletto O, Plebani M, Chieco-Bianchi L, Amadori A, D'Andrea E, Montagna M. Establishment and characterization of xenografts and cancer cell cultures derived from BRCA1 -/- epithelial ovarian cancers. Eur J Cancer 2006; 42:1475-83. [PMID: 16759848 DOI: 10.1016/j.ejca.2006.01.057] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2005] [Revised: 01/20/2006] [Accepted: 01/20/2006] [Indexed: 11/24/2022]
Abstract
The BRCA1 gene is responsible for a high number of hereditary breast and ovarian cancers that cluster in families with a strong genetic predisposition. Despite intense investigation, the accumulating findings on BRCA1 biological functions have not yet been translated into specific therapeutic approaches, also due to the lack of suitable experimental models. The purpose of this study was to establish and characterize cell cultures and xenografts from patients with BRCA1 -/- ovarian cancers. We derived two ovarian cancer cell lines, termed PD-OVCA1 and PD-OVCA2, both from patients previously treated with chemotherapy, that propagate in SCID mice as well as in vitro for a limited number of passages. Both cell lines expressed cytokeratins and the CA125 tumour marker. A detailed molecular characterization highlighted both constitutive and somatic genetic events that abrogate BRCA1 gene function. Both cell lines were shown to lose the wild type BRCA1 allele; intriguingly, these deletions were apparently accompanied by gain of one or more copies of the mutant alleles. Finally, a genomic profile of major chromosomal aberrations was obtained by the Multiplex Ligation-dependent Probe Amplification (MLPA) technique, which disclosed chromosomal imbalances targeting specific genes in each cell line. The PD-OVCA1 and PD-OVCA2 ovarian cancer cell lines will provide a valuable tool for new experimental models for the study of BRCA1-associated tumour biology.
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Dijkman R, Tensen CP, Jordanova ES, Knijnenburg J, Hoefnagel JJ, Mulder AA, Rosenberg C, Raap AK, Willemze R, Szuhai K, Vermeer MH. Array-based comparative genomic hybridization analysis reveals recurrent chromosomal alterations and prognostic parameters in primary cutaneous large B-cell lymphoma. J Clin Oncol 2005; 24:296-305. [PMID: 16330669 DOI: 10.1200/jco.2005.02.0842] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PURPOSE To evaluate the clinical relevance of genomic aberrations in primary cutaneous large B-cell lymphoma (PCLBCL). PATIENTS AND METHODS Skin biopsy samples of 31 patients with a PCLBCL classified as either primary cutaneous follicle center lymphoma (PCFCL; n = 19) or PCLBCL, leg type (n = 12), according to the WHO-European Organisation for Research and Treatment of Cancer (EORTC) classification, were investigated using array-based comparative genomic hybridization, fluorescence in situ hybridization (FISH), and examination of promoter hypermethylation. RESULTS The most recurrent alterations in PCFCL were high-level DNA amplifications at 2p16.1 (63%) and deletion of chromosome 14q32.33 (68%). FISH analysis confirmed c-REL amplification in patients with gains at 2p16.1. In PCLBCL, leg type, most prominent aberrations were a high-level DNA amplification of 18q21.31-q21.33 (67%), including the BCL-2 and MALT1 genes as confirmed by FISH, and deletions of a small region within 9p21.3 containing the CDKN2A, CDKN2B, and NSG-x genes. Homozygous deletion of 9p21.3 was detected in five of 12 patients with PCLBCL, leg type, but in zero of 19 patients with PCFCL. Complete methylation of the promoter region of the CDKN2A gene was demonstrated in one PCLBCL, leg type, patient with hemizygous deletion, in one patient without deletion, but in zero of 19 patients with PCFCL. Seven of seven PCLBCL, leg type, patients with deletion of 9p21.3 and/or complete methylation of CDKN2A died as a result of their lymphoma. CONCLUSION Our results demonstrate prominent differences in chromosomal alterations between PCFCL and PCLBCL, leg type, that support their classification as separate entities within the WHO-EORTC scheme. Inactivation of CDKN2A by either deletion or methylation of its promoter could be an important prognostic parameter for the group of PCLBCL, leg type.
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Affiliation(s)
- Remco Dijkman
- Department of Dermatology, Leiden University Medical Center, Leiden, The Netherlands
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Hoffmann MJ, Schulz WA. Causes and consequences of DNA hypomethylation in human cancer. Biochem Cell Biol 2005; 83:296-321. [PMID: 15959557 DOI: 10.1139/o05-036] [Citation(s) in RCA: 172] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
While specific genes are hypermethylated in the genome of cancer cells, overall methylcytosine content is often decreased as a consequence of hypomethylation affecting many repetitive sequences. Hypomethylation is also observed at a number of single-copy genes. While global hypomethylation is highly prevalent across all cancer types, it often displays considerable specificity with regard to tumor type, tumor stage, and sequences affected. Following an overview of hypomethylation alterations in various cancers, this review focuses on 3 hypotheses. First, hypomethylation at a single-copy gene may occur as a 2-step process, in which selection for gene function follows upon random hypo methylation. In this fashion, hypomethylation facilitates the adaptation of cancer cells to the ever-changing tumor tissue microenvironment, particularly during metastasis. Second, the development of global hypomethylation is intimately linked to chromatin restructuring and nuclear disorganization in cancer cells, reflected in a large number of changes in histone-modifying enzymes and other chromatin regulators. Third, DNA hypomethylation may occur at least partly as a consequence of cell cycle deregulation disturbing the coordination between DNA replication and activity of DNA methyltransferases. Finally, because of their relation to tumor progression and metastasis, DNA hypomethylation markers may be particularly useful to classify cancer and predict their clinical course.
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Sato M, Sasaki H, Kazui T, Yokota J, Kohno T. Probing the chromosome 9p21 region susceptible to DNA double-strand breaks in human cells in vivo by restriction enzyme transfer. Oncogene 2005; 24:6108-18. [PMID: 16007206 DOI: 10.1038/sj.onc.1208750] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
A restriction enzyme, MspI, was introduced into cultured human cells as a probe to detect genomic regions susceptible to DNA double-strand breaks (DSBs). A 2 h exposure to MspI at a concentration of 8 U/mul produced DSBs at MspI sites in more than 80% of HeLa cells. The sensitivity to digestion was examined on chromosomal DNAs for the region containing the p16 tumor suppressor gene and two other related genes, p14ARF and p15, by Southern blot hybridization analysis and linker-mediated capture of DNA fragments digested in vivo. DNAs for the promoter regions of the three genes, respectively, were sensitive to MspI digestion in HeLa cells, while DNA for the p16 promoter region was less sensitive in lung cancer cells with hypermethylation of the region. Breakpoints for interstitial 9p21 deletions removing the p16/p14ARF/p15 locus in a variety of human cancers were significantly over-represented in the three sensitive regions. The results suggest that the MspI sensitivity in vivo of each genomic region reflects its susceptibility to DSBs that trigger chromosome aberrations in human cells. This method could help us understand the pathogenic significance of differential susceptibility to DSBs among genomic regions in human carcinogenesis.
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Affiliation(s)
- Masanori Sato
- Biology Division, National Cancer Center Research Institute, Tokyo 1040045, Japan
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Tsuji T, Ikeda H, Tsuchikawa T, Kikuchi K, Baba T, Ishizu A, Yoshiki T. Malignant transformation of thymoma in recipient rats by heterotopic thymus transplantation from HTLV-I transgenic rats. J Transl Med 2005; 85:851-61. [PMID: 15924152 DOI: 10.1038/labinvest.3700292] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Transgenic rats expressing the pX gene of human T lymphocyte virus type-I (HTLV-I) under control of the rat lymphocyte-specific protein tyrosine kinase type-I promoter (lck-pX rats) developed benign epithelial thymomas. When the thymuses of newborn lck-pX rats were transplanted into the subcapsular space of the kidney in other thymectomized lck-pX rats, similar tumors developed in the transplanted thymuses. Following the tumor growth, dissemination in the abdominal cavity and distant metastasis occurred. The tumors were histopathologically similar to the original thymomas, but prominent nuclear atypia and high mitotic activity were present. The Ki-67 index was twice as high as that in the originals. The tumors were transplantable into the subcutis of lck-pX rats, although transplantation of the originals never succeeded. All evidence indicated that malignant transformation of thymoma was induced by the heterotopic transplantation. Expression of the pX transgene in the transformed tumors were significantly reduced. Among host genes, the expression of p16ink4a/ARF, which was significantly upregulated in the originals, was never detected in the transformed tumors. Genomic Southern blots and PCR suggest that homozygous deletion of the p16ink4a/ARF gene may play important roles in malignant transformation in this model. Our model described here is a useful unique model for in vivo malignant transformation.
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Affiliation(s)
- Takahiro Tsuji
- Department of Pathology/Pathophysiology, Division of Pathophysiological Science, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan
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