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Toprani SM. DNA damage and repair scenario in ameloblastoma. Oral Oncol 2020; 108:104804. [PMID: 32474390 DOI: 10.1016/j.oraloncology.2020.104804] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 05/12/2020] [Indexed: 12/14/2022]
Abstract
Ameloblastoma is a rare human disease of benign neoplasm odontogenic tumor with a lower prevalence but higher recurrence rate. Etiology of ameloblastoma is not fully understood thus lacks implementation of curative treatments. One of the proposed models of evolution of ameloblastoma is related to alteration in DNA damage and repair effects. Growing body of literature has associated defect in DNA damage and repair mechanisms with cancer risk and various adverse health outcomes in humans. Persistent defect of repair and escape of these genomic unstable cells from cell death mechanisms can contribute towards accumulation of oncogene driver or tumor suppressor mutations selective for malignant transformations. In addition, growth, progression and survival of tumor depends upon its DNA repair mechanisms too, thus identifying a DNA repair biomarker can be of advantageous to eliminate the tumor. Understanding the interconnection of oral lesion and role of various DNA repair mechanisms in context to ameloblastoma will assist to build up a platform for translational based research. This study is a literature review of research work published up to date in the field of ameloblastoma in regard to DNA damage and repair effects.
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Affiliation(s)
- Sneh M Toprani
- John B Little Center for Radiation Sciences, Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
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Santos HBDP, Morais EFD, Cavalcante RB, Nogueira RLM, Nonaka CFW, Souza LBD, Freitas RDA. Immunoexpression of DNA base excision repair and nucleotide excision repair proteins in ameloblastomas, syndromic and non-syndromic odontogenic keratocysts and dentigerous cysts. Arch Oral Biol 2019; 110:104627. [PMID: 31862643 DOI: 10.1016/j.archoralbio.2019.104627] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 12/01/2019] [Accepted: 12/02/2019] [Indexed: 12/22/2022]
Abstract
OBJECTIVE To evaluate the immunoexpression of DNA base excision repair (BER) [apurinic/apyrimidinic endonuclease 1 (APE-1), X-ray repair cross complementing 1 (XRCC-1)] and nucleotide excision repair (NER) [xeroderma pigmentosum complementation group (XPF)] proteins in benign epithelial odontogenic lesions with different biological behaviors. DESIGN Thirty solid ameloblastomas, 30 non-syndromic odontogenic keratocysts (NSOKCs), 29 syndromic odontogenic keratocysts (SKOCs), 30 dentigerous cysts (DCs) and 20 dental follicles (DFs) were evaluated quantitatively for APE-1, XRCC-1 and XPF through immunohistochemistry. RESULTS Nuclear expression of APE-1 was significantly higher in NSOKCs, SOKCs, and ameloblastomas in comparison to DCs (p < 0.001). Nuclear expression of XRCC-1 was higher in NSOKCs and SOKCs than in DCs (p < 0.05). At the nuclear level, XPF expression was higher in NSOKCs and SOKCs than in DCs and ameloblastomas (p < 0.05). A statistically significant higher expression of APE-1 (nuclear), XRCC-1 (nuclear), and XPF (nuclear and cytoplasmic) was found in all odontogenic lesion samples as compared to DFs (p < 0.05). For all lesions, there was a positive correlation between nuclear expression of APE-1 and XRCC-1 or XPF (p < 0.05). CONCLUSIONS Our results suggest a potential involvement of APE-1, XRCC-1 and XPF proteins in the pathogenesis of benign epithelial odontogenic lesions, especially in those with more aggressive biological behavior, such as ameloblastomas, NSOKCs, and SOKCs. We also showed that the expression of APE-1 was positively correlated with the nuclear expression of XRCC-1 and XPF, which may suggest an interaction between the BER and NER pathways in all odontogenic lesions studied herein.
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Bologna-Molina R, Pereira-Prado V, Sánchez-Romero C, Tapia-Repetto G, Soria S, Hernandez M, Gónzalez-Gónzalez R, Molina-Frechero M, Mikami T. Expression of hMLH1 and hMSH2 proteins in ameloblastomas and tooth germs. Med Oral Patol Oral Cir Bucal 2018; 23:e126-e131. [PMID: 29476681 PMCID: PMC5911352 DOI: 10.4317/medoral.22210] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 12/09/2017] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Mismatch repair proteins (MMRPs) are a group of nuclear enzymes that participate in the repair of base mismatches that occur during DNA replication in all proliferating cells. The most studied MMRPs are hMSH2 and hMLH1, which are known to be highly expressed in normal tissues. A loss of MMRPs leads to the accumulation of DNA replication errors in proliferating cells. Ki-67 is a biomarker regarded to be the gold-standard tool for determining cell proliferation by immunohistochemical methods. The aim of this study was to investigate the immunohistochemical expression of hMLH1, hMSH2 and Ki-67 proteins in ameloblastomas and tooth germs, to contribute to the understanding of the development of this odontogenic neoplasm. MATERIAL AND METHODS Immunohistochemical assays to determine the presence of proteins hMSH2, hMLH1 and Ki-67 were performed in 80 ameloblastomas (40 solid and 40 unicystic) and five tooth germs. RESULTS Unicystic ameloblastomas showed higher MMRP expression (hMLH1: 62.5 ± 43.4; hMSH2: 83.3 ± 47.8) than did solid ameloblastomas (hMLH1: 59.4 ± 13.5; hMSH2: 75.8 ± 40.2). Additionally, the cell proliferation index assessed by Ki-67 was inversely proportional to the expression of MMRP. Comparison between tooth germs and ameloblastoma revealed significantly higher expression of hMLH1, hMSH2 and Ki-67 in tooth germs (p=0.02). CONCLUSIONS The differences of MMRP and Ki-67 immunoexpression between ameloblastomas and tooth germ suggest that alterations in the MMRP mechanisms could participate in the biological behavior of ameloblastomas.
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Affiliation(s)
- R Bologna-Molina
- School of Dentistry, Molecular Pathology Area, Universidad de la República, Las Heras 1925, Montevideo, Uruguay,
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Amaral-Silva GKD, Sánchez-Romero C, Wagner VP, Martins MD, Pontes HAR, Fregnani ER, Soares FA, Almeida OPD, Rocha AC, Santos-Silva AR, Fonseca FP, Vargas PA. Prognostic significance of hMSH2, hMSH3, and hMSH6 expression in ameloblastoma. Oral Surg Oral Med Oral Pathol Oral Radiol 2017; 124:286-295. [DOI: 10.1016/j.oooo.2017.05.511] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Revised: 05/23/2017] [Accepted: 05/30/2017] [Indexed: 01/18/2023]
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Guerra E, Cimadamore A, Simeone P, Vacca G, Lattanzio R, Botti G, Gatta V, D'Aurora M, Simionati B, Piantelli M, Alberti S. p53, cathepsin D, Bcl-2 are joint prognostic indicators of breast cancer metastatic spreading. BMC Cancer 2016; 16:649. [PMID: 27538498 PMCID: PMC4991058 DOI: 10.1186/s12885-016-2713-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 08/11/2016] [Indexed: 02/04/2023] Open
Abstract
Background Traditional prognostic indicators of breast cancer, i.e. lymph node diffusion, tumor size, grading and estrogen receptor expression, are inadequate predictors of metastatic relapse. Thus, additional prognostic parameters appear urgently needed. Individual oncogenic determinants have largely failed in this endeavour. Only a few individual tumor growth drivers, e.g. mutated p53, Her-2, E-cadherin, Trops, did reach some prognostic/predictive power in clinical settings. As multiple factors are required to drive solid tumor progression, clusters of such determinants were expected to become stronger indicators of tumor aggressiveness and malignant progression than individual parameters. To identify such prognostic clusters, we went on to coordinately analyse molecular and histopathological determinants of tumor progression of post-menopausal breast cancers in the framework of a multi-institutional case series/case-control study. Methods A multi-institutional series of 217 breast cancer cases was analyzed. Twenty six cases (12 %) showed disease relapse during follow-up. Relapsed cases were matched with a set of control patients by tumor diameter, pathological stage, tumor histotype, age, hormone receptors and grading. Histopathological and molecular determinants of tumor development and aggressiveness were then analyzed in relapsed versus non-relapsed cases. Stepwise analyses and model structure fitness assessments were carried out to identify clusters of molecular alterations with differential impact on metastatic relapse. Results p53, Bcl-2 and cathepsin D were shown to be coordinately associated with unique levels of relative risk for disease relapse. As many Ras downstream targets, among them matrix metalloproteases, are synergistically upregulated by mutated p53, whole-exon sequence analyses were performed for TP53, Ki-RAS and Ha-RAS, and findings were correlated with clinical phenotypes. Notably, TP53 insertion/deletion mutations were only detected in relapsed cases. Correspondingly, Ha-RAS missense oncogenic mutations were only found in a subgroup of relapsing tumors. Conclusions We have identified clusters of specific molecular alterations that greatly improve prognostic assessment with respect to singularly-analysed indicators. The combined analysis of these multiple tumor-relapse risk factors promises to become a powerful approach to identify patients subgroups with unfavourable disease outcome. Electronic supplementary material The online version of this article (doi:10.1186/s12885-016-2713-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Emanuela Guerra
- Unit of Cancer Pathology, CeSI-MeT, University of Chieti, Chieti, Italy
| | | | - Pasquale Simeone
- Unit of Cancer Pathology, CeSI-MeT, University of Chieti, Chieti, Italy
| | - Giovanna Vacca
- Unit of Cancer Pathology, CeSI-MeT, University of Chieti, Chieti, Italy
| | - Rossano Lattanzio
- Unit of Cancer Pathology, CeSI-MeT, University of Chieti, Chieti, Italy.,Department of Medical, Oral and Biotechnological Sciences, University 'G. D'Annunzio', Chieti, Italy
| | - Gerardo Botti
- Department of Pathology "Foundation G.Pascale", National Cancer Institute, Naples, Italy
| | - Valentina Gatta
- Department of Psychological, Health ad Territorial Sciences, School of Medicine and Life Sciences, University 'G. D'Annunzio', Chieti, Italy
| | - Marco D'Aurora
- Department of Psychological, Health ad Territorial Sciences, School of Medicine and Life Sciences, University 'G. D'Annunzio', Chieti, Italy
| | | | - Mauro Piantelli
- Unit of Cancer Pathology, CeSI-MeT, University of Chieti, Chieti, Italy.,Department of Medical, Oral and Biotechnological Sciences, University 'G. D'Annunzio', Chieti, Italy
| | - Saverio Alberti
- Unit of Cancer Pathology, CeSI-MeT, University of Chieti, Chieti, Italy. .,Department of Neurosciences, Imaging and Clinical Sciences, University 'G. D'Annunzio', Chieti, Italy.
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Amaral-Silva GKD, Martins MD, Pontes HAR, Fregnani ER, Lopes MA, Fonseca FP, Vargas PA. Mismatch repair system proteins in oral benign and malignant lesions. J Oral Pathol Med 2016; 46:241-245. [PMID: 27509575 DOI: 10.1111/jop.12484] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/20/2016] [Indexed: 12/15/2022]
Abstract
Different environmental agents may cause DNA mutations by disrupting its double-strand structure; however, even normal DNA polymerase function may synthesize mismatch nucleotide bases, occasionally demonstrating failure in its proofreading activity. To overcome this issue, mismatch repair (MMR) system, a group of proteins specialized in finding mispairing bases and small loops of insertion or deletion, works to avoid the occurrence of mutations that could ultimately lead to innumerous human diseases. In the last decades, the role of MMR proteins in oral carcinogenesis and in the development of other oral cavity neoplasms has grown, but their importance in the pathogenesis and their prognostic potential for patients affected by oral malignancies, especially oral squamous cell carcinoma (OSCC), remain unclear. Therefore, in this manuscript we aimed to review and critically discuss the currently available data on MMR proteins expression in oral potentially malignant lesions, in OSCC, and in other oral neoplasms to better understand their relevance in these lesions.
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Affiliation(s)
| | - Manoela Domingues Martins
- Department of Pathology, School of Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Hélder Antônio Rebelo Pontes
- Service of Buccal Pathology, João de Barros Barreto University Hospital, Federal University of Pará, Belém, Brazil
| | | | - Márcio Ajudarte Lopes
- Department of Oral Diagnosis, Piracicaba Dental School, University of Campinas, Piracicaba, Brazil
| | - Felipe Paiva Fonseca
- Department of Oral Diagnosis, Piracicaba Dental School, University of Campinas, Piracicaba, Brazil
| | - Pablo Agustin Vargas
- Department of Oral Diagnosis, Piracicaba Dental School, University of Campinas, Piracicaba, Brazil
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Li Y, Melnikov AA, Levenson V, Guerra E, Simeone P, Alberti S, Deng Y. A seven-gene CpG-island methylation panel predicts breast cancer progression. BMC Cancer 2015; 15:417. [PMID: 25986046 PMCID: PMC4438505 DOI: 10.1186/s12885-015-1412-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 05/01/2015] [Indexed: 12/31/2022] Open
Abstract
Background DNA methylation regulates gene expression, through the inhibition/activation of gene transcription of methylated/unmethylated genes. Hence, DNA methylation profiling can capture pivotal features of gene expression in cancer tissues from patients at the time of diagnosis. In this work, we analyzed a breast cancer case series, to identify DNA methylation determinants of metastatic versus non-metastatic tumors. Methods CpG-island methylation was evaluated on a 56-gene cancer-specific biomarker microarray in metastatic versus non-metastatic breast cancers in a multi-institutional case series of 123 breast cancer patients. Global statistical modeling and unsupervised hierarchical clustering were applied to identify a multi-gene binary classifier with high sensitivity and specificity. Network analysis was utilized to quantify the connectivity of the identified genes. Results Seven genes (BRCA1, DAPK1, MSH2, CDKN2A, PGR, PRKCDBP, RANKL) were found informative for prognosis of metastatic diffusion and were used to calculate classifier accuracy versus the entire data-set. Individual-gene performances showed sensitivities of 63–79 %, 53–84 % specificities, positive predictive values of 59–83 % and negative predictive values of 63–80 %. When modelled together, these seven genes reached a sensitivity of 93 %, 100 % specificity, a positive predictive value of 100 % and a negative predictive value of 93 %, with high statistical power. Unsupervised hierarchical clustering independently confirmed these findings, in close agreement with the accuracy measurements. Network analyses indicated tight interrelationship between the identified genes, suggesting this to be a functionally-coordinated module, linked to breast cancer progression. Conclusions Our findings identify CpG-island methylation profiles with deep impact on clinical outcome, paving the way for use as novel prognostic assays in clinical settings. Electronic supplementary material The online version of this article (doi:10.1186/s12885-015-1412-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yan Li
- Rush University Medical Center, 653 W Congress Pkwy, Chicago, IL, 60612, USA.
| | | | - Victor Levenson
- US Biomarkers, Inc, 29 Buckingham Ln., Buffalo Grove, IL, 60089, USA. .,Currently at Center for Translational Research, Catholic Health Initiatives, Englewood, USA.
| | - Emanuela Guerra
- Unit of Cancer Pathology, CeSI, 'G. d'Annunzio' University Foundation, Via L. Polacchi 11, 66100, Chieti, Italy.
| | - Pasquale Simeone
- Unit of Cancer Pathology, CeSI, 'G. d'Annunzio' University Foundation, Via L. Polacchi 11, 66100, Chieti, Italy.
| | - Saverio Alberti
- Unit of Cancer Pathology, CeSI, 'G. d'Annunzio' University Foundation, Via L. Polacchi 11, 66100, Chieti, Italy. .,Department of Neuroscience, Imaging and Clinical Sciences, Unit of Physiology and Physiopathology, 'G. d'Annunzio' University, Via dei Vestini, 66100, Chieti, Italy.
| | - Youping Deng
- Rush University Medical Center, 653 W Congress Pkwy, Chicago, IL, 60612, USA.
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de Brito Monteiro BV, Cavalcante RB, Maia Nogueira RL, da Costa Miguel MC, Weege Nonaka CF, da Silveira ÉJD. Participation of hMLH1, p63, and MDM2 proteins in the pathogenesis of syndromic and nonsyndromic keratocystic odontogenic tumors. Oral Surg Oral Med Oral Pathol Oral Radiol 2015; 120:52-7. [PMID: 25957541 DOI: 10.1016/j.oooo.2015.03.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 03/10/2015] [Accepted: 03/12/2015] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To evaluate the expression of hMLH1, p63, and MDM2 in Gorlin syndrome-associated keratocystic odontogenic tumors (SKOTs) and nonsyndromic keratocystic odontogenic tumors (NSKOTs). STUDY DESIGN Seventeen primary NSKOTs, 17 SKOTs, and 8 recurrent NSKOTs were analyzed by using immunohistochemistry. RESULTS No significant differences in the hMLH1, p63, or MDM2 labeling indices were observed between groups (P = .398; P = .232; P = .426, respectively). Higher hMLH1 immunoexpression was found in the basal layer of primary NSKOTs. Most KOTs exhibited p63 immunoexpression in the upper layers of the epithelium. MDM2 immunoexpression was observed in the upper epithelial layers of SKOTs and recurrent NSKOTs. CONCLUSION It was not possible to correlate the immunoexpression of hMLH1, p63, and MDM2 in SKOTs and primary and recurrent NSKOTs, suggesting that these proteins exert independent effects on the development of these groups of tumors.
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Affiliation(s)
- Bárbara Vanessa de Brito Monteiro
- Postgraduate Program of Oral Pathology, Department of Oral Pathology, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | | | | | - Márcia Cristina da Costa Miguel
- Postgraduate Program of Oral Pathology, Department of Oral Pathology, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | | | - Éricka Janine Dantas da Silveira
- Postgraduate Program of Oral Pathology, Department of Oral Pathology, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil.
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Bologna-Molina R, Salazar-Rodríguez S, Bedoya-Borella AM, Carreón-Burciaga RG, Tapia-Repetto G, Molina-Frechero N. A histopathological and immunohistochemical analysis of ameloblastic fibrodentinoma. Case Rep Pathol 2013; 2013:604560. [PMID: 23476862 PMCID: PMC3580908 DOI: 10.1155/2013/604560] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 01/07/2013] [Indexed: 02/07/2023] Open
Abstract
Ameloblastic fibrodentinoma (AFD) is considered a mixed odontogenic tumor that is characterized by conserved epithelial and ectomesenchymal neoplastic components. AFD is composed of long narrow cords and islands of odontogenic epithelium; the epithelial strands lie in a myxoid cell-rich ectomesenchymal tissue with stellate-shaped fibroblasts that exhibit long slender cytoplasmic extensions that resemble dental papilla. The lesions show the presence of dysplastic dentin. Although AFD is a rare entity and its very existence is not completely accepted, based on the extent of histodifferentiation, it is considered to represent a stage between ameloblastic fibroma and ameloblastic fibroodontoma. This study aimed to provide a histopathological and immunohistochemical characterization of this infrequent tumor. A large panel of antibodies including amelogenin, Ck 19, calretinin, syndecan-1, E-cadherin, MSH2, histone H3, and Ki-67 was used to illustrate the nature of the tumor.
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Affiliation(s)
- Ronell Bologna-Molina
- 1Oral Pathology, Research Department, School of Dentistry, Universidad Juárez del Estado de Durango (UJED), 34000 Durango, DGO, Mexico
- 2School of Dentistry, Universidad de la República (UDELAR), 19200 Montevideo, Uruguay
- *Ronell Bologna-Molina:
| | - Sirced Salazar-Rodríguez
- 3Pathology Department, Instituto Nacional de Oncología y Radiobiología (INOR), 10400 Havana, Cuba
| | | | - Ramón Gil Carreón-Burciaga
- 1Oral Pathology, Research Department, School of Dentistry, Universidad Juárez del Estado de Durango (UJED), 34000 Durango, DGO, Mexico
| | - Gabriel Tapia-Repetto
- 2School of Dentistry, Universidad de la República (UDELAR), 19200 Montevideo, Uruguay
| | - Nelly Molina-Frechero
- 5Health Care Department, Universidad Autónoma Metropolitana, Xochimilco, 04960 Mexico City, DF, Mexico
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Migaldi M, Sartori G, Rossi G, Cittadini A, Sgambato A. Tumor cell proliferation and microsatellite alterations in human ameloblastoma. Oral Oncol 2008; 44:50-60. [PMID: 17307020 DOI: 10.1016/j.oraloncology.2006.12.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2006] [Revised: 12/06/2006] [Accepted: 12/06/2006] [Indexed: 10/23/2022]
Abstract
Ameloblastoma is the most common odontogenic tumor. It can exhibit a variety of histological patterns, a great infiltrative potential and a high recurrence rate. Mutations in microsatellite sequences are a hallmark of neoplastic transformation but little is known about their role in ameloblastoma development. In this study DNA was extracted from laser-microdissected samples of 24 ameloblastomas and was analyzed for the status of 22 microsatellite loci. The occurrence and the pattern of microsatellite alterations, in form of loss or length variation, was evaluated and correlated with the Ki67 labeling index and with other clinicopathologic parameters. The prognostic significance of these alterations was also evaluated. High Ki67 expression was significantly associated with a shorter disease-free survival (p=0.003 by log-rank test). Alterations of at least one of the selected loci was observed in all (100%) the ameloblastomas analyzed with a mean of 4 altered microsatellites for each tumor. The microsatellites most frequently altered were D9S747 and D11S488 (42%). All the other loci analyzed were altered in less than 40% of cases and some of them (D3S1312, D3S1300, IFNA, D9S164, D13S176 and TP53) did not show alterations in any of the ameloblastomas analyzed. No relationship was observed between the occurrence of microsatellite alterations and other parameters, such as patients age and gender, tumor size, localization and histotype. The occurrence of microsatellite alterations was more frequent in tumors displaying a high Ki67 labeling index (p=0.03) and in a univariate analysis was predictor of an increased risk of disease recurrence (p=0.039 by log-rank test). These findings demonstrate that microsatellite alterations are frequent event in ameloblastomas. They also suggest that evaluation of tumor cells proliferative activity and microsatellite alterations may be helpful to stratify ameloblastomas prognostically and to predict the clinical behavior of these tumors.
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Affiliation(s)
- M Migaldi
- Dipartimento Misto di Anatomia Patologica e di Medicina Legale, Sezione di Anatomia Patologica, University of Modena and Reggio Emilia, Modena, Italy
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Hou Y, Gao F, Wang Q, Zhao J, Flagg T, Zhang Y, Deng X. Bcl2 Impedes DNA Mismatch Repair by Directly Regulating the hMSH2-hMSH6 Heterodimeric Complex. J Biol Chem 2007; 282:9279-87. [PMID: 17259174 DOI: 10.1074/jbc.m608523200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Bcl2 has been reported to suppress DNA mismatch repair (MMR) with promotion of mutagenesis, but the mechanism(s) is not fully understood. MutSalpha is the hMSH2-hMSH6 heterodimer that primarily functions to correct mutations that escape the proofreading activity of DNA polymerase. Here we have discovered that Bcl2 potently suppresses MMR in association with decreased MutSalpha activity and increased mutagenesis. Exposure of cells to nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone results in accumulation of Bcl2 in the nucleus, which interacts with hMSH6 but not hMSH2 via its BH4 domain. Deletion of the BH4 domain from Bcl2 abrogates the ability of Bcl2 to interact with hMSH6 and is associated with enhanced MMR efficiency and decreased mutation frequency. Overexpression of Bcl2 reduces formation of the hMSH2-hMSH6 complex in cells, and purified Bcl2 protein directly disrupts the hMSH2-hMSH6 complex and suppresses MMR in vitro. Importantly, depletion of endogenous Bcl2 by RNA interference enhances formation of the hMSH2-hMSH6 complex in association with increased MMR and decreased mutagenesis. Thus, Bcl2 suppression of MMR may occur in a novel mechanism by directly regulating the heterodimeric hMSH2-hMSH6 complex, which potentially contributes to genetic instability and carcinogenesis.
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Affiliation(s)
- Yongzhong Hou
- Department of Medicine, Shands Cancer Center, University of Florida, Gainesville, Florida 32610-3633, USA
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Abstract
Odontogenic tumors are lesions derived from the elements of the tooth-forming apparatus and are found exclusively within the jawbones. This review represents a contemporary outline of our current understanding of the molecular and genetic alterations associated with the development and progression of odontogenic tumors, including oncogenes, tumor-suppressor genes, oncoviruses, growth factors, telomerase, cell cycle regulators, apoptosis-related factors, regulators of tooth development, hard tissue-related proteins, cell adhesion molecules, matrix-degrading proteinases, angiogenic factors, and osteolytic cytokines. It is hoped that better understanding of related molecular mechanisms will help to predict the course of odontogenic tumors and lead to the development of new therapeutic concepts for their management.
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Affiliation(s)
- H Kumamoto
- Division of Oral Pathology, Department of Oral Medicine and Surgery, Tohoku University Graduate School of Dentistry, Sendai, Japan
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Brieger A, Plotz G, Raedle J, Weber N, Baum W, Caspary WF, Zeuzem S, Trojan J. Characterization of the nuclear import of human MutLalpha. Mol Carcinog 2005; 43:51-8. [PMID: 15754314 DOI: 10.1002/mc.20081] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
DNA mismatch repair (MMR) is essential for the maintenance of replication fidelity. Its major task is to recognize mismatches as well as insertion/deletion loops of newly synthesized DNA strands. Although different players of human MMR have been identified, the regulation of essential steps of MMR is poorly understood. Because MMR is initiated in the nucleus, nuclear import might be a mechanism to regulate MMR. Nuclear targeting is accomplished by conserved signal sequences called nuclear localization signals (NLS), which represent clusters of positively charged amino acids (aa). hMLH1 contains two clusters of positively charged amino acids, which are candidate NLS sequences (aa 469-472 and 496-499), while hPMS2 contains one (aa 574-580). To study the effect of these clusters on nuclear import, NLS mutants of hMLH1 and hPMS2 were generated and expressed in 293T cells. The subcellular localization of the mutant constructs was monitored by confocal laser microscopy. We demonstrated that missense mutations of two signal sequences, one in hMLH1 and one in hPMS2, lead to impaired nuclear import, which was especially prominent for mutants of the hMLH1 residues K471 and R472; and hPMS2 residues K577 and R578.
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Affiliation(s)
- A Brieger
- Medizinische Klinik I, Klinikum der Johann Wolfgang Goethe-Universität, Frankfurt a.M., Germany
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Nodit L, Barnes L, Childers E, Finkelstein S, Swalsky P, Hunt J. Allelic loss of tumor suppressor genes in ameloblastic tumors. Mod Pathol 2004; 17:1062-7. [PMID: 15133474 DOI: 10.1038/modpathol.3800147] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Ameloblastoma is an odontogenic tumor with a variety of histologic appearances and an unpredictable biologic behavior. Little is known about allelic losses of tumor suppressor genes in ameloblastomas. This study surveyed DNA damage in ameloblastomas and correlated this with histologic sub-type and clinical outcome. There were 12 ameloblastomas (two peripheral, eight solid, and two unicystic) and three ameloblastic carcinoma studied for loss of heterozygosity of tumor suppressor genes on chromosomes 1p, 3p, 9p,10q, and 17p (L-myc, hOGG1, p16, pten, and p53). The frequency of allelic loss and the intratumoral heterogeneity were calculated. L-myc (71% frequency of allelic loss) and pten (62% frequency of allelic loss) had the most frequent allelic losses. Overall frequency of allelic loss and intratumoral heterogeneity were higher in mandibular and in unicystic tumors and lower in tumors that recurred/metastasized. The rate of allelic loss in the three carcinomas was similar to that seen in benign tumors. The frequency of allelic loss and intratumoral heterogeneity did not correlate with age, gender, histologic subtype, or prognosis. Since tumors that behaved aggressively did not harbor more allelic losses, it is likely that DNA damage in ameloblastomas and ameloblastic carcinomas is sporadic and cumulative. We conclude that other genetic or epigenetic mechanisms may be responsible for malignant behavior in ameloblastic carcinomas.
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Affiliation(s)
- Laurentia Nodit
- Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
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