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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Molecular and Biological Characteristics of Stroma and Tumor Cells in Colorectal Cancer

Gao, Jingfang January 2008 (has links)
Carcinogenesis is a progressive process involving multiple genetic alterations in tumor cells and complex interactions in the tumor-host microenvironment. To better understand the contribution of molecular alterations in tumor cells and stromal variables to the development of colorectal cancer (CRC) and identify prognostic factors, in this study we examined the clinicopathological and biological significance of stromal variables, including particularly interesting new cysteine-histidine rich protein (PINCH), inflammatory infiltration, angiogenesis and lymphangiogenesis, as well as hRAD50/hMRE11/hNBS1 proteins and hRAD50 mutation in tumor cell in CRC. PINCH protein expression in the stroma was increased from normal mucosa to primary tumors and further to lymph node metastases. In particular, PINCH expression was most intense at the tumor invasive margin, which was related to low inflammatory infiltration and independently related to an unfavorable prognosis. Low inflammatory infiltration at the tumor invasive margin was related to advanced tumor stage, worse differentiation and microsatellite instability (MSI). Further, it was independently related to an unfavorable prognosis. Increased blood and lymphatic vessel density was observed in the primary tumors compared with the corresponding normal mucosa. However, neither angiogenesis nor lymphangiogenesis was associated with tumor stage and patients’ survival. Moreover, PINCH was present in a proportion of endothelial cells of the tumor vasculature, and PINCH expression in tumor-associated stroma was positively related to blood vessel density. In primary tumor cells of CRC, strong expression of hRAD50, hMRE11 or hNBS1 was related to microsatellite stability (MSS). A high percentage of hMRE11 expression was associated with less local recurrence and high apoptotic activity. Further, we observed that the expression of hRAD50, hMRE11 or hNBS1 among normal mucosa, primary tumors and metastases in MSS CRC differed from that in MSI CRC. In MSS CRC, the expression intensity of hRAD50, hMRE11 and hNBS1 was consistently increased with respect to normal mucosa, but there was no difference between the primary tumors and metastases. In the primary MSS tumors, the expression of individual or combination of hRAD50/hMRE11/hNBS1 was associated with a favorable prognosis in the same series of the CRCs. Moreover, strong/high hRAD50 in MSS primary tumors was related to earlier tumor stage, better differentiation and high inflammatory infiltration, whereas strong hNBS1 expression tended to be independently related to a favorable prognosis in MSS CRC with earlier tumor stage. However, in MSI CRC, there were neither differences in the expression of hRAD50/hMRE11/hNBS1 among normal mucosa, primary tumors and metastases, nor any association of the protein expressions with clinicopathological variables. On the other hand, frameshift mutations of (A)9 at coding region of hRAD50 were only found in MSI CRC. Our study indicates that 1) PINCH is likely a regulator of angiogenesis, and PINCH expression at the tumor invasive margin is an independent prognostic indicator in CRC. 2) Inflammatory infiltration at the tumor invasive margin is also an independent prognostic indicator in CRC. The lack of association between high inflammatory infiltration and MSI may help to explain the non-association of MSI with survival in CRC patients. 3) Angiogenesis and lymphangiogenesis occur in the early stage of CRC development, but do not associate with CRC progression and patients’ prognosis. 4) hRAD50/hMRE11/hNBS1 may act dependently and independently, playing different roles in MSS and MSI CRC development. In MSS CRC, the strong expression of the three proteins, associated with a favorable prognosis, may present the cellular response against tumor progression. Expression of hNBS1 may be a prognostic indicator for MSS CRC patients in the earlier tumor stage. In MSI CRC, the frameshift mutations at the coding region of hRAD50 may contribute to tumor development.
2

Inactivation et activation de régions chromosomiques par des modifications épigénétiques. Mécanismes impliqués et rôle dans la progression tumorale dans les cancers de la vessie / Inactivation and activation of chromosomal regions by epigenetic modifications.Mechanisms involved and role in tumor progression in bladder cancer.

Wong, Jennifer 27 November 2018 (has links)
Dans les cancers, la transcription des gènes peut être altérée par des mécanismes génétiques ou épigénétiques. En 2011, mon laboratoire a montré que la progression des cancers de la vessie pouvait être liée à un mécanisme épigénétique appelé MRES (« Mutiple Regional Epigenetic Silencing »). Les tumeurs possédant ce phénotype présentent une inactivation simultanée de gènes voisins dans 7 régions du génome. A l’aide d’une nouvelle approche bio-informatique : « SegCorr », nous avons identifié plus de 400 régions du génome dont l’expression des gènes est corrélée indépendamment du nombre de copie du gène. Ces régions se répartissent en 7 groupes et sont associées à 6 phénotypes de cancer de la vessie. De plus, l’extinction de l’expression des gènes d’une faible proportion de régions est associée à la méthylation de l’ADN et/ou une perte sur les histones de de marques d’activation de la transcription : H3K9ac et H3K4me3 ou des gains de marques de répression de la transcription : H3K27me3 et H3K9me3. Grâce au nouvel algorithme « Musette », J’ai montré que le phénotype MRES n’était probablement pas dû à des altérations génétiques. Enfin, pour comprendre à quel stade de la progression tumorale du cancer de la vessie le phénotype MRES pourrait apparaître, j’ai montré que les tumeurs de cancer de vessie induites chez les souris par ingestion d’un carcinogène (N-butyl-N-(4-hydroxybutyl)nitrosamine) pouvait être un bon modèle d’étude. / In cancers, gene transcription can be altered by genetic or epigenetic mechanisms. In 2011, my laboratory showed that the progression of bladder cancer could be linked to an epigenetic mechanism called MRES ("Mutiple Regional Epigenetic Silencing"). Tumors with this phenotype exhibit simultaneous inactivation of neighboring genes in 7 regions of the genome. Using a new bioinformatics approach: "SegCorr", we have identified more than 400 genomic regions in which gene expression is correlated. These regions fall into 7 groups and are associated with 6 phenotypes of bladder cancer. In addition, the extinction of gene expression from a small proportion of regions is associated with DNA methylation and / or loss of histone marks associated with active transcription: H3K9ac and H3K4me3 or gains of histone marks associated with transcription repression: H3K27me3 and H3K9me3. Using a new algorithm “Musette”, I have shown that the MRES phenotype is probably not due to genetic alterations. Finally, to understand at which stage of tumor progression of bladder cancer the MRES phenotype might appear, I have shown that bladder cancer tumors induced in mice by ingestion of a carcinogen (N-butyl-N-(4-hydroxybutyl) nitrosamine) could be a good model.
3

Estudo de alterações gênicas em amostras de sarcomas e carcinossarcomas uterinos: identificação de mercadores para  diagnóstico diferencial e tratamento / Study of gene alterations in uterine sarcomas and carcinosarcoma samples

Costa, Leonardo Tomiatti da 29 March 2018 (has links)
Os sarcomas uterinos são tumores mesodérmicos raros que compreendem cerca de 3% de todos os cânceres nesse órgão. Apresentam diversidade histológica, comportamento agressivo, disseminação precoce e altas taxas mortalidade. Recentemente, os carcinossarcomas (CS) foram reclassificados histologicamente como carcinomas. Neste trabalho, os CS foram incluídos na casuística tanto para fins de comparação de seu componente mesenquimal, como por ainda fazerem parte da maioria dos estudos sobre sarcomas de corpo uterino e também da última classificação da WHO (Word Health Organization). Devido à sua diversidade e raridade, não há consenso relacionado aos fatores de risco para pior prognóstico e tratamento adequados para esses tumores. Informações sobre seus perfis gênicos e proteicos poderiam contribuir na caracterização de marcadores moleculares que auxiliassem no diagnóstico e prognóstico desses tumores, bem como no entendimento de sua biologia e comportamento clínico. Assim, nos propusemos a avaliar a presença de alterações gênicas nesses tumores, utilizando um painel de 409 genes, oncogenes e supressores de tumor, frequentemente mutados em tumores sólidos. Para isso, foram selecionadas 66 amostras, das quais 14 foram sequenciadas, incluindo, 5 carcinossarcomas (CCS), 4 leiomiossarcomas (LMS), 4 sarcomas de estroma endometrial (SEE) e 1 adenossarcoma (ADS). As reações foram realizadas utilizando a plataforma Ion Proton System (ThermoFisher) de Sequenciamento de Nova Geração. Nas 14 amostras encontramos 27 LoF e 40 mutações missenses, numa média de 39 inserções e 52 deleções por amostra, totalizando 70 mutações. Dessas, 25 encontram-se no banco de dados COSMIC. Os genes mais comumente mutados em nossa amostragem foram: TP53 (50%), KMT2D (36%), ATM (29%), DICER1 (21%), PIK3CA (21%), TRRAP (21%). Nosso objetivo principal era encontrar mutações específicas para cada subtipo histológico, porém apenas os SEEs (PDE4DIP) e os CCS (ERBB4 e PIK3CA) tiveram mutações especificas. Em outra análise, observamos que todos os subtipos histológicos compartilham o gene KMT2D. Embora não tenha sido possível estabelecer um perfil mutacional para cada subtipo histológico avaliado, nossos resultados abrem perspectivas para uma nova linha de pesquisa nos sarcomas de corpo do útero e certamente contribuem para um melhor entendimento dessas neoplasias / Uterine sarcomas are rare mesodermal tumors that comprise about 3% of all cancers in this organ. They present histological diversity, aggressive behavior, early dissemination and high mortality rates. Recently, carcinosarcomas (CCS) were histological reclassified as carcinomas. Here, we have included them in our series for purposes of comparison of the mesenchymal component and also because these tumors still form part of both the majority of studies and the WHO\'s latest classification for uterine sarcomas (Word Health Organization). Because of their diversity and rarity, there is no consensus regarding the risk factors for poor prognosis and appropriate treatment for these tumors. Thus, information about their gene and protein profiles can help in the diagnosis and prognosis of these tumors, as well as in the understanding of their biology and clinical behavior. We performed the New Generation Sequencing of 14 samples of uterine sarcomas (5 CCS, 4 LMS, 4 SEE and 1 ADS, using the Ion Proton System platform (ThermoFisher).) Among the 14 samples, we found 27 LoF (loss of gene function) and 40 missense mutations, with a mean of 39 insertions and 52 deletions per sample, totaling 70 mutations, 25 described in the COSMIC database. The most commonly mutated genes in our sample were TP53 (50%), KMT2D (36%), ATM (29%), DICER1 (21%), PIK3CA (21%), TRRAP (21%).Our main objective was to find specific mutations for each histological subtype, but only SEEs (PDE4DIP) and CCS (ERBB4 and PIK3CA) had specific mutations. In another analysis, we observed that all the histological subtypes share the KMT2D gene, which will be studied in future analyzes. Others analyzes, using a custom panel, are necessary to understand these mutations and its biological implication in uterine carcinosarcoma and sarcomas
4

Estudo de alterações gênicas em amostras de sarcomas e carcinossarcomas uterinos: identificação de mercadores para  diagnóstico diferencial e tratamento / Study of gene alterations in uterine sarcomas and carcinosarcoma samples

Leonardo Tomiatti da Costa 29 March 2018 (has links)
Os sarcomas uterinos são tumores mesodérmicos raros que compreendem cerca de 3% de todos os cânceres nesse órgão. Apresentam diversidade histológica, comportamento agressivo, disseminação precoce e altas taxas mortalidade. Recentemente, os carcinossarcomas (CS) foram reclassificados histologicamente como carcinomas. Neste trabalho, os CS foram incluídos na casuística tanto para fins de comparação de seu componente mesenquimal, como por ainda fazerem parte da maioria dos estudos sobre sarcomas de corpo uterino e também da última classificação da WHO (Word Health Organization). Devido à sua diversidade e raridade, não há consenso relacionado aos fatores de risco para pior prognóstico e tratamento adequados para esses tumores. Informações sobre seus perfis gênicos e proteicos poderiam contribuir na caracterização de marcadores moleculares que auxiliassem no diagnóstico e prognóstico desses tumores, bem como no entendimento de sua biologia e comportamento clínico. Assim, nos propusemos a avaliar a presença de alterações gênicas nesses tumores, utilizando um painel de 409 genes, oncogenes e supressores de tumor, frequentemente mutados em tumores sólidos. Para isso, foram selecionadas 66 amostras, das quais 14 foram sequenciadas, incluindo, 5 carcinossarcomas (CCS), 4 leiomiossarcomas (LMS), 4 sarcomas de estroma endometrial (SEE) e 1 adenossarcoma (ADS). As reações foram realizadas utilizando a plataforma Ion Proton System (ThermoFisher) de Sequenciamento de Nova Geração. Nas 14 amostras encontramos 27 LoF e 40 mutações missenses, numa média de 39 inserções e 52 deleções por amostra, totalizando 70 mutações. Dessas, 25 encontram-se no banco de dados COSMIC. Os genes mais comumente mutados em nossa amostragem foram: TP53 (50%), KMT2D (36%), ATM (29%), DICER1 (21%), PIK3CA (21%), TRRAP (21%). Nosso objetivo principal era encontrar mutações específicas para cada subtipo histológico, porém apenas os SEEs (PDE4DIP) e os CCS (ERBB4 e PIK3CA) tiveram mutações especificas. Em outra análise, observamos que todos os subtipos histológicos compartilham o gene KMT2D. Embora não tenha sido possível estabelecer um perfil mutacional para cada subtipo histológico avaliado, nossos resultados abrem perspectivas para uma nova linha de pesquisa nos sarcomas de corpo do útero e certamente contribuem para um melhor entendimento dessas neoplasias / Uterine sarcomas are rare mesodermal tumors that comprise about 3% of all cancers in this organ. They present histological diversity, aggressive behavior, early dissemination and high mortality rates. Recently, carcinosarcomas (CCS) were histological reclassified as carcinomas. Here, we have included them in our series for purposes of comparison of the mesenchymal component and also because these tumors still form part of both the majority of studies and the WHO\'s latest classification for uterine sarcomas (Word Health Organization). Because of their diversity and rarity, there is no consensus regarding the risk factors for poor prognosis and appropriate treatment for these tumors. Thus, information about their gene and protein profiles can help in the diagnosis and prognosis of these tumors, as well as in the understanding of their biology and clinical behavior. We performed the New Generation Sequencing of 14 samples of uterine sarcomas (5 CCS, 4 LMS, 4 SEE and 1 ADS, using the Ion Proton System platform (ThermoFisher).) Among the 14 samples, we found 27 LoF (loss of gene function) and 40 missense mutations, with a mean of 39 insertions and 52 deletions per sample, totaling 70 mutations, 25 described in the COSMIC database. The most commonly mutated genes in our sample were TP53 (50%), KMT2D (36%), ATM (29%), DICER1 (21%), PIK3CA (21%), TRRAP (21%).Our main objective was to find specific mutations for each histological subtype, but only SEEs (PDE4DIP) and CCS (ERBB4 and PIK3CA) had specific mutations. In another analysis, we observed that all the histological subtypes share the KMT2D gene, which will be studied in future analyzes. Others analyzes, using a custom panel, are necessary to understand these mutations and its biological implication in uterine carcinosarcoma and sarcomas

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