Small Cell Lung Cancer (SCLC) is a very aggressive neuroendocrine tumour of the lung, which demonstrates a 5 year survival of only 10% for extensive stage disease (20-30% for limited stage), with only modest improvement over the last few decades. Identification of new molecular diagnostic and therapeutic targets is thus imperative. Previous efforts in identifying molecular changes in SCLC by gene expression profiling using microarrays have facilitated disease classification but yielded very limited information on SCLC biology. Previous DNA studies have been successful in identifying several loci important to SCLC. However the low resolution of conventional chromosomal Comparative Genomic Hybridization (CGH) has limited the findings to large chromosomal regions with only a few specific candidate genes discovered to date. Thus, to further understand the biological behaviour of SCLC, better methods for studying the genomic alterations in SCLC are necessary. This thesis highlights the development of array CGH technology for the high resolution dissection of aneuploidy in cancer genomes and the application of this new technology to the study of SCLC. I present the development of the first whole genome CGH array which offered unprecedented resolution in the profiling of cancer genomes allowing fine mapping of genes in a single experiment. Through application of DNA based analysis in conjunction with integrated expression analysis and comparison of SCLC to less aggressive non-small cell lung tumours I have identified novel patterns of pathway disruption specific to SCLC. This included alteration to Wnt pathway members and striking patterns of cell cycle activation through predominantly downstream disruption of signalling pathways including direct activation of the E2F transcription factors, which are normally repressed by the Rb gene. Analysis of targets of the E2F/Rb pathway identified EZH2 as being specifically hyper-activated in SCLC, compared to NSCLC. EZH2 is a polycomb group gene involved in the control of many cellular functions including targeted DNA methylation and escape from senescence in hematopoietic stem cells. Taken together these results suggest that in SCLC, downstream disruption may replace multiple upstream alterations leading to activation independent of a specific mitogenic pathway, and that EZH2 represents a potentially important therapeutic target.

Small Cell Lung Cancer (SCLC) is a very aggressive neuroendocrine tumour of the lung, which demonstrates a 5 year survival of only 10% for extensive stage disease (20-30% for limited stage), with only modest improvement over the last few decades. Identification of new molecular diagnostic and therapeutic targets is thus imperative. Previous efforts in identifying molecular changes in SCLC by gene expression profiling using microarrays have facilitated disease classification but yielded very limited information on SCLC biology. Previous DNA studies have been successful in identifying several loci important to SCLC. However the low resolution of conventional chromosomal Comparative Genomic Hybridization (CGH) has limited the findings to large chromosomal regions with only a few specific candidate genes discovered to date. Thus, to further understand the biological behaviour of SCLC, better methods for studying the genomic alterations in SCLC are necessary. This thesis highlights the development of array CGH technology for the high resolution dissection of aneuploidy in cancer genomes and the application of this new technology to the study of SCLC. I present the development of the first whole genome CGH array which offered unprecedented resolution in the profiling of cancer genomes allowing fine mapping of genes in a single experiment. Through application of DNA based analysis in conjunction with integrated expression analysis and comparison of SCLC to less aggressive non-small cell lung tumours I have identified novel patterns of pathway disruption specific to SCLC. This included alteration to Wnt pathway members and striking patterns of cell cycle activation through predominantly downstream disruption of signalling pathways including direct activation of the E2F transcription factors, which are normally repressed by the Rb gene. Analysis of targets of the E2F/Rb pathway identified EZH2 as being specifically hyper-activated in SCLC, compared to NSCLC. EZH2 is a polycomb group gene involved in the control of many cellular functions including targeted DNA methylation and escape from senescence in hematopoietic stem cells. Taken together these results suggest that in SCLC, downstream disruption may replace multiple upstream alterations leading to activation independent of a specific mitogenic pathway, and that EZH2 represents a potentially important therapeutic target.

Orientador: Patrícia Pintor dos Reis / Resumo: Introdução: o Edema de Reinke (ER) é uma lesão laríngea considerada benigna relacionada ao tabagismo. Dados em literatura relatam associações entre o ER e a detecção de diferentes graus de displasia e carcinoma in situ, bem como alterações na imunoexpressão de proteínas tumorais como a p53. Alguns autores classificam o ER entre as lesões pré-malignas, com risco de transformação e progressão para carcinoma de laringe. Não havendo consenso na literatura, torna-se necessária a realização de estudos moleculares. Objetivos: caracterizar o perfil genômico global de alterações no número de cópias do DNA em amostras de pacientes com ER. Métodos: oito amostras removidas por microcirurgia foram submetidas à extração do DNA. Os perfis de alteração no número de cópias genômicas e os genes candidatos associados foram analisados pela metodologia da hibridação genômica comparativa (CGH array), utilizando-se a plataforma de 4x180K (Agilent Technologies). Os dados de microarranjos foram analisados utilizando o programa CytoGenomics v4.0.2.21 (Agilent Technologies). As alterações no número de cópias (CNAs) obtidas foram comparadas com o banco de dados Database of Genomic Variants (DGV). A classificação dos genes selecionados para análise foi realizada baseada em dados descritos no National Center for Biotechnology Information (NCBI). Resultados: Foram encontrados perdas, ganhos ou deleções em 54 genes, um RNA não codificador longo intergênico (lincRNA), seis sequências hipotéticas e 10 microRN... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

DNA copy number alterations (CNAs) are genetic changes that can produce adverse effects in numerous human diseases, including cancer. CNAs are segments of DNA that have been deleted or amplified and can range in size from one kilobases to whole chromosome arms. Development of array comparative genomic hybridization (aCGH) technology enables CNAs to be measured at sub-megabase resolution using tens of thousands of probes. However, aCGH data are noisy and result in continuous valued measurements of the discrete CNAs. Consequently, the data must be processed through algorithmic and statistical techniques in order to derive meaningful biological insights. We introduce model-based approaches to analysis of aCGH data and develop state-of-the-art solutions to three distinct analytical problems. In the simplest scenario, the task is to infer CNAs from a single aCGH experiment. We apply a hidden Markov model (HMM) to accurately identify CNAs from aCGH data. We show that borrowing statistical strength across chromosomes and explicitly modeling outliers in the data, improves on baseline models. In the second scenario, we wish to identify recurrent CNAs in a set of aCGH data derived from a patient cohort. These are locations in the genome altered in many patients, providing evidence for CNAs that may be playing important molecular roles in the disease. We develop a novel hierarchical HMM profiling method that explicitly models both statistical and biological noise in the data and is capable of producing a representative profile for a set of aCGH experiments. We demonstrate that our method is more accurate than simpler baselines on synthetic data, and show our model produces output that is more interpretable than other methods. Finally, we develop a model based clustering framework to stratify a patient cohort, expected to be composed of a fixed set of molecular subtypes. We introduce a model that jointly infers CNAs, assigns patients to subgroups and infers the profiles that represent each subgroup. We show our model to be more accurate on synthetic data, and show in two patient cohorts how the model discovers putative novel subtypes and clinically relevant subgroups. / Science, Faculty of / Computer Science, Department of / Graduate

Small Cell Lung Cancer (SCLC) is a very aggressive neuroendocrine tumour of the lung, which demonstrates a 5 year survival of only 10% for extensive stage disease (20-30% for limited stage), with only modest improvement over the last few decades. Identification of new molecular diagnostic and therapeutic targets is thus imperative. Previous efforts in identifying molecular changes in SCLC by gene expression profiling using microarrays have facilitated disease classification but yielded very limited information on SCLC biology. Previous DNA studies have been successful in identifying several loci important to SCLC. However the low resolution of conventional chromosomal Comparative Genomic Hybridization (CGH) has limited the findings to large chromosomal regions with only a few specific candidate genes discovered to date. Thus, to further understand the biological behaviour of SCLC, better methods for studying the genomic alterations in SCLC are necessary. This thesis highlights the development of array CGH technology for the high resolution dissection of aneuploidy in cancer genomes and the application of this new technology to the study of SCLC. I present the development of the first whole genome CGH array which offered unprecedented resolution in the profiling of cancer genomes allowing fine mapping of genes in a single experiment. Through application of DNA based analysis in conjunction with integrated expression analysis and comparison of SCLC to less aggressive non-small cell lung tumours I have identified novel patterns of pathway disruption specific to SCLC. This included alteration to Wnt pathway members and striking patterns of cell cycle activation through predominantly downstream disruption of signalling pathways including direct activation of the E2F transcription factors, which are normally repressed by the Rb gene. Analysis of targets of the E2F/Rb pathway identified EZH2 as being specifically hyper-activated in SCLC, compared to NSCLC. EZH2 is a polycomb group gene involved in the control of many cellular functions including targeted DNA methylation and escape from senescence in hematopoietic stem cells. Taken together these results suggest that in SCLC, downstream disruption may replace multiple upstream alterations leading to activation independent of a specific mitogenic pathway, and that EZH2 represents a potentially important therapeutic target. / Medicine, Faculty of / Pathology and Laboratory Medicine, Department of / Graduate

Array comparative genomic hybridization (aCGH) is a technique for identifying duplications and deletions of DNA at specific locations across a genome. Potential objectives of aCGH analysis are the identification of (1) altered regions for a given subject, (2) altered regions across a set of individuals, and (3) clinically relevant clusters of hybridizations. aCGH analysis can be particularly useful when it identifies previously unknown clusters with clinical relevance. This project focuses on the assessment of existing aCGH clustering methodologies. Three methodologies are considered: hierarchical clustering, weighted clustering of called aCGH data, and clustering based on probabilistic recurrent regions of alteration within subsets of individuals. Assessment is conducted first through the analysis of aCGH data obtained from patients with ovarian cancer and then through simulations. Performance assessment for the data analysis is based on cluster assignment correlation with clinical outcomes (e.g., survival). For each method, 1,000 simulations are summarized with Cohen's kappa coefficient, interpreted as the proportion of correct cluster assignments beyond random chance. Both the data analysis and the simulation results suggest that hierarchical clustering tends to find more clinically relevant clusters when compared to the other methods. Additionally, these clusters are composed of more patients who belong in the clusters to which they are assigned.

No description available.

Les carcinomes urothéliaux représentent la 4ème cause de cancer chez l'homme après les cancers de la prostate, du colon et du poumon. Leur incidence est en augmentation de plus de 50% depuis 25 ans. Ce cancer présente principalement deux formes, une superficielle (70% des cas) de bon pronostic et une invasive (30%) de mauvais pronostic. Les formes superficielles nécessitent une surveillance active rapprochée afin d'identifier les récidives fréquentes et l'évolution vers un stade invasif. Cette surveillance fait principalement appel à la cystoscopie et engendre morbidité et cout importants. Une alternative à la cystoscopie est possible à l'aide de tests de détection urinaire des cellules cancéreuses, mais leur sensibilité jusqu'à présent n'est pas suffisante pour une utilisation en pratique courante. Notre but a été de développer un outil de détection urinaire des tumeurs urothéliales.Matériel, Méthode et RésultatsLes tumeurs urothéliales étant très instables sur le plan génétique, le travail a initialement consisté à faire la synthèse des anomalies cytogénétiques retrouvées dans la littérature. Les anomalies les plus pertinentes ont été sélectionnées et une puce de CGH en a été développée comprenant 341 clones (BAC) répartis sur l'ensemble des chromosomes. Cette puce intitulée BCA-1 a été développée en collaboration avec la société ArrayGenomics (Voisins Le Bretonneux, France). La validité de ce test a été confirmée sur 10 lignées cellulaires tumorales et bénignes.Notre travail a ensuite consisté à étudier la valeur ajoutée de cette puce en pratique clinique. Pour ce faire, une cohorte de 163 patients porteurs de tumeurs urothéliales et de témoins a été constituée. Les urines ont été prélevées et analysées en utilisant la puce BCA-1. Un logiciel a été développé sous filemaker pro afin de permettre une saisie uniforme et détaillée des données cliniques et de prendre en considération le caractère complexe de la prise en charge de ces tumeurs.Le test urinaire utilisant la puce de CGH a montré une excellente performance diagnostique avec une sensibilité de 96% et une spécificité de 98% dans les tumeurs vésicale, et une sensibilité de 100% tumeurs du haut appareil urinaire.Enfin, le test a aussi permit de caractériser le caractère agressif ou non agressif des tumeurs sur le plan cytogénétique. Cette caractérisation est fortement corrélée avec le stade anatomopathologique et un troisième aspect de notre travail a montré que la détermination cytogénétique de l'agressivité des tumeurs prédisait l'évolution défavorable des tumeurs du haut appareil urinaire. Notre travail a permis le développement et l'analyse d'un nouveau test de dépistage urinaire des tumeurs urothéliales permettant le diagnostic urinaire de ces tumeurs et la caractérisation de leur caractère agressif éventuel, ainsi que le développement d'un logiciel de saisie et d'analyse des données cliniques. / Urothelial carcinomas are the 4th cause of cancer in men, following prostate, colon and lung cancer. An increase of 50% in its incidence was observed on the last 25 years. This cancer presents two types, a superficial type (70% of the cases) of good prognosis and an invasive type (30% of the cases) of bad prognosis. Superficial type require an active monitoring to identify recurrences and evolution to an invasive stage. This follow up is performed using cystoscopy and leads to some level of morbidity and a high cost. An alternative to cystoscopy is possible using urine test to detect cancer cells, but they are lacking of sensitivity to be used instead of cystoscopy in clinical practice. Our goal was to develop a urine detection tool of urothélial carcinomas.Material and MethodsUrothelial carcinoma usually present with a high level of genetic instability. We first analyse literature so to identify most relevant cytogenetic abnormalities that occur in urothélial carcinomas. A CGH array chip was designed using 341 clones (BAC) that were selected according to initial analysis. This chip called BCA-1 covers the whole genome and was developed in collaboration with ArrayGenomics (Voisins Le Bretonneux, France).ResultsThis test has shown a good efficacy on a preliminary study of cytogenetic analysis on 10 cancerous and benign bladder cell lines. The Chip was then assessed in clinical practice on a series of 163 patients diagnosed with or without urothelial cancer. Urines were collected and analysed using the BCA-1 chip. A software was designed to favour homogeneous and detailed clinical data collection and take into consideration the complex management of the tumours.The test using the CGH chip as shown an excellent diagnosis performance with a sensitivity of 96% and a specificity of 98% for bladder cancer detection, and a sensitivity of 100% on upper urinary tract detection.Finaly, the test was able to define the grade of the tumour according to cytogenetic loci affected. This grade was strongly correlated with the pathology score and could be used to predict outcomes in upper urinary tract carcinomas. Our work lead to the developpement and the analysis of a new urothélial carcinoma urinary detection test, to the identification of the agressivity of the tumour, and to the development of an analysis and data entry software for clinical details.

A translocação recíproca é o rearranjo equilibrado mais comum em humanos. Frequentemente, indivíduos com rearranjos equilibrados não apresentam manifestações clínicas, entretanto, na meiose, o pareamento entre cromossomos translocados forma uma figura quadrivalente em forma de cruz que torna a disjunção cromossômica incerta e dependendo do rearranjo, o individuo pode vir a ser infértil, apresentar um risco aumentado de abortamento espontâneo e/ou da prole apresentar alterações fenotípicas. Neste projeto, investigamos duas famílias de pacientes inférteis, portadores de translocações cromossômicas. O objetivo foi caracterizar as alterações citogenéticas e citogenômicas relacionadas à infertilidade masculina em pacientes portadores de rearranjos aparentemente equilibrados, associando técnicas de citogenética clássica (bandeamento GTG), citogenética molecular (FISH) e citogenômica (array-CGH). Foram estudados sete indivíduos da família 1, sendo diagnosticados três portadores da translocação (X;22), sendo um deles azoospérmico. Nesta família foram ainda detectados dois casos de mosaicismo para síndrome de Turner. A família 2 foi composta por dois irmãos oligozoospérmicos, portadores de translocação (8;13). Com a aplicação da técnica de FISH, definimos o cariótipo final dos portadores dos rearranjos como 46,XX ou 46,XY,t(X;22)(p22.3;q11.2) para a família 1 e 46,XY,t(8;13)(q13;q14)para a família 2. A técnica de array-CGH (plataforma 2x400K, Agilent) detectou alterações no número de cópias de alguns genes candidatos relacionados ao fenótipo de infertilidade, sendo a sequência 132 de piRNAs, os genes DDX11, Jagged 2 e ADAM18 na família 1 e os genes candidatos ADAM18 e POTE nos pacientes da família 2. / Reciprocal translocations are the most common balanced rearrangement in humans. Often individuals with balanced rearrangements show no clinical findings. However, in meiosis, the pairing between translocated chromosomes forms a quadrivalent cross-shaped figure which has the effect of making chromosome disjunction uncertain and, depending on the rearrangement, and on the segregation of the unbalanced chromosomes, the individual can be infertile, can present with an increased risk of spontaneous abortions or can have an offspring with abnormal phenotype. We have studied two families of infertile patients, who were carriers of chromosomal translocations. The objective was to characterize the cytogenetic and cytogenomic alterations related to male infertility in patients with apparently balanced rearrangements using classical cytogenetic techniques (GTG banding), molecular cytogenetics (FISH) and cytogenomics (array-CGH). Seven subjects of the family 1 were studied, including three carriers of translocation (X;22), one azoospermic. Two cases of mosaicism for Turner syndrome were detected in this family. The second family consisted of two oligozoospermic brothers with translocation (8;13). FISH was used to characterize the karyotypes as 46, XX or 46,XY, t(X;22)(p22.3;q11.2) for the members of the family 1 and 46,XY,t(8;13)(q13;q14) for family 2. Array-CGH was also performed using the Agilent platform 2x400K, to detect associated copy number variations of some of the candidate genes that could be related to infertility. In the family 1 the candidate genes were 132 piRNAs sequences and DDX11,Jagged 2 and ADAM18 genes. The candidate genes for the family 2 were ADAM18 and POT.

No description available.