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The genomic and transcriptional landscape of primary central nervous system lymphoma. Nat Commun 2022; 13:2558. [PMID: 35538064 PMCID: PMC9091224 DOI: 10.1038/s41467-022-30050-y] [Citation(s) in RCA: 49] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 04/12/2022] [Indexed: 02/07/2023] Open
Abstract
Primary lymphomas of the central nervous system (PCNSL) are mainly diffuse large B-cell lymphomas (DLBCLs) confined to the central nervous system (CNS). Molecular drivers of PCNSL have not been fully elucidated. Here, we profile and compare the whole-genome and transcriptome landscape of 51 CNS lymphomas (CNSL) to 39 follicular lymphoma and 36 DLBCL cases outside the CNS. We find recurrent mutations in JAK-STAT, NFkB, and B-cell receptor signaling pathways, including hallmark mutations in MYD88 L265P (67%) and CD79B (63%), and CDKN2A deletions (83%). PCNSLs exhibit significantly more focal deletions of HLA-D (6p21) locus as a potential mechanism of immune evasion. Mutational signatures correlating with DNA replication and mitosis are significantly enriched in PCNSL. TERT gene expression is significantly higher in PCNSL compared to activated B-cell (ABC)-DLBCL. Transcriptome analysis clearly distinguishes PCNSL and systemic DLBCL into distinct molecular subtypes. Epstein-Barr virus (EBV)+ CNSL cases lack recurrent mutational hotspots apart from IG and HLA-DRB loci. We show that PCNSL can be clearly distinguished from DLBCL, having distinct expression profiles, IG expression and translocation patterns, as well as specific combinations of genetic alterations.
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2
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Dlamini Z, Hull R, Mbatha SZ, Alaouna M, Qiao YL, Yu H, Chatziioannou A. Prognostic Alternative Splicing Signatures in Esophageal Carcinoma. Cancer Manag Res 2021; 13:4509-4527. [PMID: 34113176 PMCID: PMC8186946 DOI: 10.2147/cmar.s305464] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 04/06/2021] [Indexed: 01/10/2023] Open
Abstract
Alternative splicing (AS) is a method of increasing the number of proteins that the genome is capable of coding for, by altering the pre-mRNA during its maturation. This process provides the ability of a broad range of proteins to arise from a single gene. AS events are known to occur in up to 94% of human genes. Cumulative data have shown that aberrant AS functionality is a major factor in human diseases. This review focuses on the contribution made by aberrant AS functionality in the development and progression of esophageal cancer. The changes in the pattern of expression of alternately spliced isoforms in esophageal cancer can be used as diagnostic or prognostic biomarkers. Additionally, these can be used as targets for the development of new treatments for esophageal cancer.
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Affiliation(s)
- Zodwa Dlamini
- SAMRC Precision Prevention & Novel Drug Targets for HIV-Associated Cancers Extramural Unit, Pan African Cancer Research Institute, University of Pretoria, Pretoria, South Africa
| | - Rodney Hull
- SAMRC Precision Prevention & Novel Drug Targets for HIV-Associated Cancers Extramural Unit, Pan African Cancer Research Institute, University of Pretoria, Pretoria, South Africa
| | - Sikhumbuzo Z Mbatha
- Department of Surgery, Steve Biko Academic Hospital, University of Pretoria, Pretoria, South Africa
| | - Mohammed Alaouna
- SAMRC Precision Prevention & Novel Drug Targets for HIV-Associated Cancers Extramural Unit, Pan African Cancer Research Institute, University of Pretoria, Pretoria, South Africa.,Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - You-Lin Qiao
- SAMRC Precision Prevention & Novel Drug Targets for HIV-Associated Cancers Extramural Unit, Pan African Cancer Research Institute, University of Pretoria, Pretoria, South Africa.,Cancer Institute/Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, People's Republic of China
| | - Herbert Yu
- SAMRC Precision Prevention & Novel Drug Targets for HIV-Associated Cancers Extramural Unit, Pan African Cancer Research Institute, University of Pretoria, Pretoria, South Africa.,University of Hawaii Cancer Center, Honolulu, HI, USA
| | - Aristotelis Chatziioannou
- SAMRC Precision Prevention & Novel Drug Targets for HIV-Associated Cancers Extramural Unit, Pan African Cancer Research Institute, University of Pretoria, Pretoria, South Africa.,Center of Systems Biology, Biomedical Research Foundation Academy of Athens, Athens, Greece.,e-NIOS Applications PC, Kallithea, Athens, 17676, Greece
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3
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hTERT gene amplification and clinical significance in pleural effusions of patients with lung cancer. Clin Lung Cancer 2012; 13:494-9. [PMID: 22464057 DOI: 10.1016/j.cllc.2012.01.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 01/16/2012] [Accepted: 01/23/2012] [Indexed: 11/22/2022]
Abstract
PATIENTS AND METHODS Human telomerase reverse transcriptase (hTERT) gene amplification was detected in pleural effusions of patients with lung cancer (n = 69) and in patients with benign lung disease (n = 46) when using a quantitative polymerase chain reaction (qPCR) technique. RESULTS hTERT gene relative copy numbers were significantly higher in effusions from patients with malignant, adenocarcinoma and small-cell lung cancer than in effusions from patients with benign lung disease (P < .01). By using a threshold value of 1.39, hTERT gene amplification was significantly more frequent in malignant effusions compared with benign effusions and more likely to be positive for malignant effusions, compared with cytology (P < .01). The diagnostic performance of qPCR of hTERT gene amplification was significantly higher than that of cytology, in terms of sensitivity (91.3% vs. 56.5%), negative predictive value (87.8% vs. 60.5%), and accuracy (92.2% vs. 73.9%). CONCLUSIONS Detecting hTERT gene amplification by qPCR appears suitable for distinguishing carcinoma cells from reactive mesothelial cells in pleural effusions. hTERT gene amplification was more sensitive than cytology and may be useful for diagnosing pleural micrometastases.
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4
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Abstract
Observations in human tumours, as well as mouse models, have indicated that telomere dysfunction may be a key event driving genomic instability and disease progression in many solid tumour types. In this scenario, telomere shortening ultimately results in telomere dysfunction, fusion and genomic instability, creating the large-scale rearrangements that are characteristic of these tumours. It is now becoming apparent that this paradigm may also apply to haematological malignancies; indeed these conditions have provided some of the most convincing evidence of telomere dysfunction in any malignancy. Telomere length has been shown in several malignancies to provide clinically useful prognostic information, implicating telomere dysfunction in disease progression. In these malignancies extreme telomere shortening, telomere dysfunction and fusion have all been documented and correlate with the emergence of increased genomic complexity. Telomeres may therefore represent both a clinically useful prognostic tool and a potential target for therapeutic intervention.
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Affiliation(s)
- Ceri H Jones
- Department of Haematology,School of Medicine, Cardiff University, Cardiff, UK
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5
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Hiyama E, Hiyama K. Telomerase detection in the diagnosis and prognosis of cancer. Cytotechnology 2011; 45:61-74. [PMID: 19003244 DOI: 10.1007/s10616-004-5126-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2004] [Accepted: 09/21/2004] [Indexed: 01/27/2023] Open
Abstract
Telomerase, a critical enzyme responsible 'for cellular immortality, is usually repressed in somatic cells except for lymphocytes and self-renewal cells, but is activated in approximately 85% of human cancer tissues. The human telomerase reverse transcriptase (hTERT) is the catalytic component of human telomerase. In cancers in which telomerase activation occurs at the early stages of the disease, telomerase activity and hTERT expression are useful markers for the detection of cancer cells. In other cancers in which telomerase becomes upregulated upon tumor progression, they are useful as prognostic indicators. However, careful attention should be paid to false-negative results caused by the instability of telomerase and of the hTERT mRNA and the presence of PCR inhibitors, as well as to false-positive results caused by the presence of alternatively spliced hTERT mRNA and normal cells with telomerase activity. Recently, methods for the in situ detection of the hTERT mRNA and protein have been developed. These methods should facilitate the unequivocal detection of cancer cells, even in tissues containing a background of normal telomerase-positive cells.
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Affiliation(s)
- Eiso Hiyama
- Natural Science Center for Basic Research and Development, RIRBM, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan,
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6
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Li X, Qu Y, Mao M, Yu F, Li Q, Hua Y, Mu D. Expression of human telomerase reverse transcriptase in bone marrow CD34+ cells from patients with beta-thalassemia major. Transfusion 2008; 48:1627-33. [PMID: 18466174 DOI: 10.1111/j.1537-2995.2008.01724.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Normal stem cells usually express a low level of telomerase activity that serves to stabilize the chromosomes during cell division and helps prevent cell senescence. Human telomerase reverse transcriptase (hTERT) is a rate-limiting enzyme that dictates the activity of human telomerase and thus decides the life span of cells. The expression of hTERT and its roles in beta-thalassemia major are unclear, however. STUDY DESIGN AND METHODS hTERT mRNA expression in bone marrow (BM) CD34+ cells from 25 children with beta-thalassemia major and 15 control subjects was investigated using real-time reverse transcription polymerase chain reaction (RT-PCR) analysis. The serum erythropoietin (sEPO) and hemoglobin (Hb) levels in peripheral blood were also determined. The relationship between hTERT and sEPO as well as Hb was then examined. RESULTS It was found that hTERT mRNA expression was significantly up regulated in BM CD34+ cells from patients with beta-thalassemia major. Furthermore, a significantly positive correlation was found between hTERT mRNA and sEPO (r = 0.771, p < 0.001). A significantly inverse correlation, however, was found between hTERT mRNA and Hb concentration (r = -0.929, p < 0.001). CONCLUSION Our findings suggest that severe anemia with low Hb concentration might up regulate hTERT expression of BM CD34+ cells and sEPO levels in patients with beta-thalassemia major.
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Affiliation(s)
- Xihong Li
- Department of Pediatrics, West China Second University Hospital, Sichuan University, Sichuan, China
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7
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Yamano T, Kaneda Y, Hiramatsu SH, Huang S, Tran AN, Giuliano AE, Hoon DSB. Immunity against breast cancer by TERT DNA vaccine primed with chemokine CCL21. Cancer Gene Ther 2007; 14:451-9. [PMID: 17318199 DOI: 10.1038/sj.cgt.7701035] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Human telomerase reverse transcriptase (TERT) has been considered a potential tumor-associated antigen for active-specific immunotherapy. However, effective specific tumor antigen-specific immunity has been difficult to induce consistently by various TERT vaccine formulations. New adjuvant strategies have been employed, such as utilizing chemokines to attract T cells and antigen-presenting cells. Chemokine adjuvant strategies may enhance tumor antigen-specific immunity induced by vaccines. Therefore, we utilized chemokine ligand 21 (CCL21) as an adjuvant with a xenogeneic TERT DNA vaccine to induce tumor antigen-specific immunity against TERT-expressing breast cancer. The TERT DNA vaccine consisted of a plasmid containing the COOH terminal end of the TERT (cTERT) gene, encapsulated in multilayered liposomes with hemagglutinating virus of Japan coating. We demonstrated that CCL21 treatment before cTERT DNA vaccine, given intramuscularly, induced significantly higher anti-TERT specific cell-mediated immunity compared to cTERT DNA vaccine alone. Effective tumor antigen-specific immunity was shown both in prophylactic and therapeutic regimens against TS/A murine breast cancer. The study demonstrated that CCL21 administration before cTERT DNA vaccination significantly augmented tumor antigen-specific immunity against breast cancer.
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Affiliation(s)
- T Yamano
- Department of Molecular Oncology, John Wayne Cancer Institute, Saint John's Health Center, Santa Monica, CA 90404, USA
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8
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Zhu CQ, Cutz JC, Liu N, Lau D, Shepherd FA, Squire JA, Tsao MS. Amplification of telomerase (hTERT) gene is a poor prognostic marker in non-small-cell lung cancer. Br J Cancer 2006; 94:1452-9. [PMID: 16641908 PMCID: PMC2361293 DOI: 10.1038/sj.bjc.6603110] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Telomerase reactivation is a hallmark of human carcinogenesis. Increased telomerase activity may result from gene amplification and/or overexpression. This study evaluates the prognostic value of hTERT gene amplification and mRNA overexpression in 144 resectable non-small-cell lung cancer (NSCLC) specimens. The hTERT gene copy number was assessed by quantitative polymerase chain reaction (qPCR) on laser-capture microdissected tumour cells of 81 tumours, and by fluorescence in situ hybridisation (FISH) on a subset of 59 tumours. hTERT mRNA level was determined by reverse transcription (RT)-qPCR in 130 tumours. In total, 57% of (46 out of 81) primary NSCLC specimens demonstrated hTERT amplification, which was significantly more common (P<0.001) in adenocarcinoma (30 out of 40) than in squamous cell carcinoma (13 out of 37). The hTERT mRNA overexpression was noted in 74% (94 out of 130) of tumours; it was more frequent in squamous cell than in adenocarcinoma (87 vs 68%, P=0.03). Overexpression was significantly associated with amplification (P=0.03), especially in adenocarcinoma. The hTERT gene amplification was prognostic for shorter recurrence-free survival (hazard ratio=2.16, P=0.03). These data indicate that gene amplification is an important mechanism for hTERT overexpression in lung adenocarcinoma and is an independent poor prognostic marker for disease-free survival in NSCLC.
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MESH Headings
- Adult
- Aged
- Aged, 80 and over
- Biomarkers, Tumor/genetics
- Biomarkers, Tumor/metabolism
- Carcinoma, Non-Small-Cell Lung/diagnosis
- Carcinoma, Non-Small-Cell Lung/genetics
- Carcinoma, Non-Small-Cell Lung/metabolism
- DNA, Neoplasm/genetics
- DNA-Binding Proteins/genetics
- Disease Progression
- Female
- Gene Amplification
- Gene Expression Regulation, Neoplastic
- Humans
- In Situ Hybridization, Fluorescence
- Lung Neoplasms/diagnosis
- Lung Neoplasms/genetics
- Lung Neoplasms/metabolism
- Male
- Middle Aged
- Prognosis
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Telomerase/genetics
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Affiliation(s)
- C-Q Zhu
- Division of Applied Molecular Oncology, Ontario Cancer Institute, Ontario, Toranto, Canada
| | - J-C Cutz
- Department of Pathology, Princess Margaret Hospital, University Health Network, Toronto, Ontario, Canada
| | - N Liu
- Division of Applied Molecular Oncology, Ontario Cancer Institute, Ontario, Toranto, Canada
| | - D Lau
- Division of Applied Molecular Oncology, Ontario Cancer Institute, Ontario, Toranto, Canada
| | - F A Shepherd
- Division of Hematology and Medical Oncology, Princess Margaret Hospital, University Health Network, Toronto, Ontario, Canada
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada M5G 2M9
| | - J A Squire
- Division of Applied Molecular Oncology, Ontario Cancer Institute, Ontario, Toranto, Canada
- Department of Pathology, Princess Margaret Hospital, University Health Network, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada M5G 2M9
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada M5G 2M9
| | - M-S Tsao
- Division of Applied Molecular Oncology, Ontario Cancer Institute, Ontario, Toranto, Canada
- Department of Pathology, Princess Margaret Hospital, University Health Network, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada M5G 2M9
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada M5G 2M9
- Princess Margaret Hospital, 610 University Avenue, Toronto, Ontario, Canada M5G 2M9. E-mail:
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9
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Abstract
Telomerase adds telomeric repeats to the ends of telomeres to compensate for their progressive loss. A favorable prognosis is associated with low or no telomerase in some tumors. The authors investigated whether telomerase activity is associated with survival of patients with brain tumors. Sixty-two consecutive patients with brain tumors underwent surgery, and their surgical specimens were investigated. The patients were pathologically categorized as group I (aggressive group) and group II (non-aggressive group). Telomerase activity was examined by the telomeric repeat amplification protocol (TRAP) assay. The median time was calculated in association with overall survival and progression-free survival in each group. The significant difference was noted in telomerase activity between high-grade gliomas and lowgrade gliomas (p=0.022). Telomerase activity was significantly associated with the median overall survival and progression-free survival in all tumors of the aggressive group. On the other hand, the median overall survival in the non-aggressive group was not dependent on telomerase activity, while the median progression-free survival was. Our data suggests that telomerase is an important prognostic indicator of survival in patients with brain tumors.
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Affiliation(s)
- Choong Hyun Kim
- Department of Neurosurgery, Hanyang University College of Medicine, Seoul, Korea.
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10
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Barclay JY, Morris A, Nwokolo CU. Telomerase, hTERT and splice variants in Barrett's oesophagus and oesophageal adenocarcinoma. Eur J Gastroenterol Hepatol 2005; 17:221-7. [PMID: 15674101 DOI: 10.1097/00042737-200502000-00014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND AND OBJECTIVES The enzyme telomerase is re-activated in most cancers but its mechanism of regulation in oesophageal carcinogenesis is unclear. The aim of this study was to determine the roles of human telomerase reverse transcriptase (hTERT) mRNA expression and hTERT mRNA splicing in the regulation of telomerase enzyme activity in Barrett's oesophagus and oesophageal adenocarcinoma. METHODS Paired samples from oesophageal adenocarcinoma (n=21) and adjacent macroscopically normal mucosa, and paired samples from Barrett's oesophagus (n=16) and adjacent cardia mucosa were obtained. Telomerase activity was measured by the telomeric repeat amplification protocol assay. hTERT mRNA was quantified using real-time reverse transcriptase polymerase chain reaction (RT-PCR). Splice variants within the hTERT reverse transcriptase domain (alpha, beta, alpha beta) were detected by RT-PCR. RESULTS In oesophageal adenocarcinoma, compared to adjacent mucosa, median telomerase activity increased significantly (from 5 to 229 total product generated (tpg), P=0.0002), but median hTERT mRNA levels were not significantly different. Similarly, median telomerase activity was significantly higher in oesophageal adenocarcinoma compared to Barrett's oesophagus (229 vs 20 tpg, P=0.001), but hTERT mRNA levels were not significantly different. There was no significant difference in telomerase activity and hTERT mRNA levels between Barrett's oesophagus and adjacent cardia. The frequency of detection of all variants increased from cardia to Barrett's oesophagus to oesophageal adenocarcinoma (P<0.05). CONCLUSIONS A major increase in telomerase activity occurs after the Barrett's oesophagus stage in oesophageal carcinogenesis. Levels of hTERT mRNA and hTERT mRNA splicing patterns did not correlate with telomerase activity and do not appear to regulate enzyme activity. In this cancer, an important clinical diagnostic role for the transcripts of the telomerase gene is improbable.
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Affiliation(s)
- Jill Y Barclay
- University Hospitals, Coventry and Warwickshire NHS Trust, Coventry, UK
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11
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Tchirkov A, Chaleteix C, Magnac C, Vasconcelos Y, Davi F, Michel A, Kwiatkowski F, Tournilhac O, Dighiero G, Travade P. hTERT expression and prognosis in B-chronic lymphocytic leukemia. Ann Oncol 2004; 15:1476-80. [PMID: 15367406 DOI: 10.1093/annonc/mdh389] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND In B-chronic lymphocytic leukemia (B-CLL), there is a need for molecular markers to predict the evolution of this heterogeneous disease in individual patients. The level of expression of the human telomerase reverse transcriptase (hTERT) gene has been associated with disease aggressiveness in human cancers. The purpose of the present study was to examine the prognostic significance of hTERT expression in B-CLL. PATIENTS AND METHODS We used real-time reverse transcription-PCR to quantitate the amount of hTERT transcripts in mononuclear blood cells from 90 B-CLL patients. In addition, samples were analyzed for somatic mutations in the immunoglobulin V (IgV) genes. RESULTS The expression of hTERT gene was detected in 59% of patients. The level of expression increased with advancing B-CLL stage (P=0.0064). Patients expressing hTERT showed significantly shorter survival than hTERT-negative patients (P=0.000034), irrespective of the disease stage. On average, the level hTERT mRNA expression was seven-fold higher in the poor-prognosis B-CLL group with unmutated IgV than in the Ig-mutated group (P<10(-7)). The level of hTERT expression discriminated the Ig-unmutated from Ig-mutated B-CLL in 89% of cases. CONCLUSION Our data indicate that hTERT expression in B-CLL may serve as a molecular prognostic marker.
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Affiliation(s)
- A Tchirkov
- Service d'Hématologie Clinique, CHU, Clermont-Ferrand.
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12
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Abstract
Telomere shortening limits the proliferative capacity of primary human cells and restrains the regenerative capacity of organ systems during chronic diseases and aging. Telomere shortening apparently has a dual role in tumor development and progression. On the one hand, it induces chromosomal instability and the initiation of cancer; on the other hand, tumor progression requires stabilization of telomeres. The predominant mechanism of telomere stabilization in tumor cells is the activation of the telomere-synthesizing enzyme telomerase. The potential use of telomerase activators for the treatment of regenerative disorders will ultimately depend on their effects on tumorigenesis. This review focuses on the role of telomere shortening and telomerase in carcinogenesis with a special focus on hepatocellular carcinoma.
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Affiliation(s)
- Ande Satyanarayana
- Department of Gastroenterology, Hepatology and Endocrinology, Medical School of Hannover, Hannover, Germany
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13
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Abstract
Telomerase, a critical enzyme responsible for continuous cell growth, is repressed in most somatic cells except proliferating progenitor cells and activated lymphocytes, and activated in approximately 85% of human cancer tissues. Telomerase activity is a useful cancer-cell detecting marker in some types of cancers in which almost all cases show telomerase activation. In other types in which telomerase becomes upregulated according to tumor progression, it is a useful prognostic indicator. Detection of human telomerase reverse transcriptase (hTERT) mRNA or protein in various clinical samples is also applicable. However, careful attention should be paid to the false negative results due to the instability of this enzyme or hTERT mRNA and the existence of polymerase chain reaction inhibitors as well as the false-positive results due to the contamination by normal cells with telomerase activity. If these pitfalls are avoided, in situ detection of hTERT mRNA or protein will facilitate the reliability of telomerase as a tumor marker.
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14
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Schrader M, Burger AM, Müller M, Krause H, Straub B, Schostak M, Schulze W, Lauke H, Miller K. The differentiation status of primary gonadal germ cell tumors correlates inversely with telomerase activity and the expression level of the gene encoding the catalytic subunit of telomerase. BMC Cancer 2002; 2:32. [PMID: 12459049 PMCID: PMC139987 DOI: 10.1186/1471-2407-2-32] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2002] [Accepted: 11/29/2002] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND The activity of the ribonucleoprotein enzyme telomerase is detectable in germ, stem and tumor cells. One major component of telomerase is human telomerase reverse transcriptase (hTERT), which encodes the catalytic subunit of telomerase. Here we investigate the correlation of telomerase activity and hTERT gene expression and the differentiation status of primary testicular germ cell tumors (TGCT). METHODS Telomerase activity (TA) was detected by a quantitative telomerase PCR ELISA, and hTERT mRNA expression was quantified by online RT-PCR in 42 primary testicular germ cell tumors. The control group consisted of benign testicular biopsies from infertile patients. RESULTS High levels of telomerase activity and hTERT expression were detected in all examined undifferentiated TGCTs and in the benign testicular tissue specimens with germ cell content. In contrast, differentiated teratomas and testicular control tissue without germ cells (Sertoli-cell-only syndrome) showed no telomerase activity and only minimal hTERT expression. CONCLUSIONS These findings demonstrate an inverse relationship between the level of telomerase activity and hTERT mRNA expression and the differentiation state of germ cell tumors. Quantification of telomerase activity and hTERT mRNA expression enables a new molecular-diagnostic subclassification of germ cell tumors that describes their proliferation potential and differentiation status.
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Affiliation(s)
- Mark Schrader
- Department of Urology, Universitätsklinikum Benjamin Franklin, Freie Universität Berlin, Hindenburgdamm 30, 12200 Berlin, Germany
| | - Angelika M Burger
- Tumor Biology Center, University of Freiburg, Breisacher Str. 117, 79106 Freiburg, Germany
| | - Markus Müller
- Department of Urology, Universitätsklinikum Benjamin Franklin, Freie Universität Berlin, Hindenburgdamm 30, 12200 Berlin, Germany
| | - Hans Krause
- Department of Urology, Universitätsklinikum Benjamin Franklin, Freie Universität Berlin, Hindenburgdamm 30, 12200 Berlin, Germany
| | - Bernd Straub
- Department of Urology, Universitätsklinikum Benjamin Franklin, Freie Universität Berlin, Hindenburgdamm 30, 12200 Berlin, Germany
| | - Martin Schostak
- Department of Urology, Universitätsklinikum Benjamin Franklin, Freie Universität Berlin, Hindenburgdamm 30, 12200 Berlin, Germany
| | - Wolfgang Schulze
- Department of Andrology, University of Hamburg, Martinistraβe 52, 20246 Hamburg, Germany
| | - Heidrun Lauke
- Department of Anatomy, University of Hamburg, Martinistraβe 52, 20246 Hamburg, Germany
| | - Kurt Miller
- Department of Urology, Universitätsklinikum Benjamin Franklin, Freie Universität Berlin, Hindenburgdamm 30, 12200 Berlin, Germany
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15
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Basso U, Brandes AA. Diagnostic advances and new trends for the treatment of primary central nervous system lymphoma. Eur J Cancer 2002; 38:1298-312. [PMID: 12091059 DOI: 10.1016/s0959-8049(02)00031-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Primary central nervous system lymphoma (PCNSL) is a rare non-Hodgkin's lymphoma arising in the brain. Recent increase in its incidence has been noted both in immunocompetent individuals and patients with immunodeficiency. This review will focus on the epidemiology, pathogenesis, diagnosis and treatment of this aggressive extranodal lymphoma in immunocompetent patients. Stereotactic biopsy is usually required for diagnosis, while molecular biology and/or cytofluorimetric analysis may confirm the presence of clonal proliferation in the cerebrospinal fluid (CSF). Methotrexate-based chemotherapy plus whole-brain radiotherapy are the standard treatment for PCNSL and achieve a high rate of complete remissions (CR), but long-term neurotoxicity may heavily compromise the patient's quality of life. The metabolic rate of controversial gadolinium-enhancing lesions on magnetic resonance (MR) scans may be assessed with positron emission tomography (PET), which discriminates radiation necrosis from true recurrence. Withholding radiotherapy in patients achieving CR after first-line chemotherapy is a new and interesting treatment option, while the role of high-dose chemotherapy with stem cell rescue is still uncertain.
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Affiliation(s)
- U Basso
- Department of Medical Oncology, Azienda Ospedale-Università, Via Giustiniani 2, 35100 Padova, Italy
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16
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Abstract
Normal hematopoietic cells express telomerase activity, however the presence of telomerase does not necessarily imply stable and thus unchanging telomere length. Gradual telomere loss with aging and rapid cycling of hematopoietic stem cells might contribute to immunosenescence, exhausted hematopoiesis, and increased likelihood of malignant transformation. In leukemias and lymphomas, telomere length may reflect the cellular proliferative history, prior to immortalization. The level of telomerase activity is generally influenced by the fraction of cells in the proliferative pool. Shortened telomeres and high telomerase activity almost always correlates with disease severity in hematologic neoplasias such as relapsed leukemia and high-grade lymphomas, indicating that measurement of telomere length and telomerase activity might be useful to monitor disease condition. Since the mode of action of telomerase inhibitors may require telomeric shortening before induction of apoptosis, anti-telomerase therapy might be helpful for adjuvant therapy following conventional chemotherapy, in vitro purging of neoplastic cells in stem cell transplantation, and treating minimal residual disease. Some promising areas of tissue engineering include rejuvenation of hematopoietic stem cells for improving stem cell transplants or enhancing general immunity for older patients.
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Affiliation(s)
- Junko H Ohyashiki
- Department of Virology, Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Japan.
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17
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Abstract
In 1994 a sensitive method for the detection of telomerase was described. This assay, which was based on the polymerase chain reaction, suggested that telomerase activity was associated with immortal and cancer cells. Since then more than a thousand studies have documented the expression and activity of the enzyme in diseased tissues, primarily tumours. This review gives an overview of the biological significance of telomerase expression and methods for detecting its activity. This is followed by an organ system-based discussion of expression in normal tissues and disease states. We finish with speculation as to the future role of telomerase detection in diagnostic histopathology.
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Affiliation(s)
- P Matthews
- Department of Pathology, University of Wales College of Medicine, Cardiff, UK.
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Harada K, Kurisu K, Tahara H, Tahara E, Ide T, Tahara E. Telomerase activity in primary and secondary glioblastomas multiforme as a novel molecular tumor marker. J Neurosurg 2000; 93:618-25. [PMID: 11014540 DOI: 10.3171/jns.2000.93.4.0618] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Telomerase activity is responsible for cell immortality. To examine the role of telomerase in the carcinogenesis of human glioblastomas multiforme (GBMs), the authors studied telomerase activity, telomerase component expression, and telomere lengths in 42 GBM samples. METHODS In all samples, EGFR and MDM2 amplifications and overexpressions were examined using Southern and Northern blot analyses. The p53 mutation was analyzed using polymerase chain reaction-single strand conformational polymorphism and by direct sequence analysis. Specimens of tissues were immunostained with p53, EGFR, and MDM2 antibodies. Allelic loss on chromosomes 17p and 10 was assessed by loss of heterozygosity (LOH) assays. Telomerase activity, expression of its components (human telomerase reverse transcriptase [hTERT], human telomerase RNA component [hTERC], and telomerase-associated protein [TEP1]), and telomere lengths were analyzed using the telomeric repeat amplification protocol (TRAP)-hybridization protection assay, reverse transcription-polymerase chain reaction, and Southern blot analysis. According to the results of assessments of EGFR and MDM2 amplifications, p53 mutation, LOHs in chromosomes 17p and 10, and the clinical course of the disease, the 42 samples were classified into 22 primary and 20 secondary glioblastomas. Twenty-six (61.9%) of all 42 samples demonstrated detectable telomerase activity during the TRAP assay. Secondary GBMs displayed significantly higher levels of telomerase activity and hTERT expression than primary GBMs. Tumors with a p53 gene mutation demonstrated significantly higher telomerase activity than those without a p53 mutation. Four samples with a codon 175 mutation demonstrated an exceptionally high amount of telomerase activity. In secondary GBMs, the increase in telomerase activity and the hTERT expression level correlated with the increased frequency of p53 mutations. There was no significant difference in telomere length between primary and secondary GBMs. CONCLUSIONS These results suggest that telomerase activity and p53 mutations both play important roles in the multistep carcinogenesis of GBMs. Telomerase activity and hTERT expression may be considered as novel distinctive factors in human GBMs.
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Affiliation(s)
- K Harada
- Department of Neurosurgery, Kanbara Hospital, Hiroshima, Fukuyama-City, Japan.
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