Apie 5–10 proc. visų krūties navikų atvejų sudaro paveldimas vėžys. BRCA1 ir BRCA2 genai yra patys svarbiausi polinkį susirgti krūties vėžiu sąlygojantys genai. Kiti reikšmingai su padidėjusia krūties navikų išsivystymo rizika susiję – CHEK2 ir NBS1 genai. Šiame darbe ištirtos paveldimos dažniausiai Europos regione nustatomos šių genų mutacijos. Nustatytas BRCA1 ir CHEK2 genų mutacijų dažnis tarp jaunų krūties vėžiu susirgusių moterų, ištyrinėtos jų sąsajos su pacientės amžiumi, naviko klinikinėmis ir morfologinėmis savybėmis. Išanalizuota šeiminės anamnezės prognozinė vertė nustatant paveldimus BRCA1 ir CHEK2 genų pokyčius. Pirmą kartą Lietuvoje įsisavintas CHEK2 bei NBS1 genų tyrimas, nustatyta, kokios CHEK2 geno mutacijos dažniausios. Nors NBS1 geno mutacijų nerasta, bet įsisavinta metodika, kuri bus panaudota ateities tyrimams. Sukurtas kompleksinis BRCA1 bei CHEK2 genų mutacijų radimo prognozavimo modelis. Šiandien klinikinėje praktikoje panašūs modeliai naudojami įvertinti BRCA1/2 genų mutacijų tikimybę. Jų pritaikomumas ir specifiškumas skirtingose etninėse grupėse gali skirtis. Naudojant tirtų pacienčių charakteristikas, įtraukiant ne tik šeiminę anamnezę, pacientės ypatybes, bet ir klinikinius bei molekulinius navikų požymius, sukurti mūsų regionui pritaikyti modeliai bei nustatyti kriterijai, kurie padės atrinkti pacientes genetiniam konsultavimui dėl BRCA1 bei CHEK2 genų mutacijų. Šis naujas požiūris turi didžiulę praktinę naudą. / Approximately 5–10% of all breast cancer cases are considered to be hereditary. BRCA1 and BRCA2 genes are the most important breast cancer predisposing genes. Other genes significantly linked with an increased risk of breast tumors are CHEK2 and NBS1 gene. In this scientific work were studied the most prevalent in European region mutations of these genes. The rate of BRCA1 and CHEK2 gene mutations in young women with breast cancer was evaluated and the relationships between these mutations and patient's age, clinical and morphological tumor features are examined. The prognostic value of family history was analyzed when forecasting hereditary BRCA1 and CHEK2 gene mutations. For the first time in Lithuania the CHEK2, NBS1 genes tests were applied and the evaluation of which CHEK2 gene mutations are most prevalent was obtained. Although NBS1 gene mutations were not found, but applied test technique will be used in future research. There was created a prognostic model for determination of BRCA1 and CHEK2 gene mutations. In today's clinical practice similar models are used to assess the likelihood of the BRCA1/2 mutation. Their applicability and specificity in different ethnic groups may vary. Applying the studied data there was created a model adapted to our region. Testing patients, there were considered not only family medical history and personal characteristics, but also the clinical and molecular features of tumors. The criteria have been found which will help in selecting... [to full text]

INTRODUÇÃO: O câncer constitui-se na principal causa de mortalidade entre indivíduos de 45 a 84 anos, configurando-se em um dos principais problemas de saúde pública dos países em desenvolvimento. As reações de hipersensibilidade aos quimioterápicos têm aumentado, impedindo muitas vezes a utilização de terapias de primeira linha no tratamento de neoplasias primárias ou recidivantes. O procedimento de dessensibilização é uma abordagem alternativa, por meio do qual o paciente passa a tolerar a medicação que antes desencadeava reações potencialmente letais. Quimioterápicos do grupo das platinas são exemplos de drogas passíveis de readministração por meio do processo de dessensibilização, no entanto faltam biomarcadores preditivos de reações durante o procedimento. OBJETIVOS: O objetivo principal do estudo foi avaliar o papel do teste de ativação de basófilos (BAT) como biomarcador para reações de hipersensibilidade ocorridas durante a dessensibilização em pacientes alérgicas às platinas. Como objetivo secundário, avaliou-se a prevalência e o impacto da mutação dos genes BRCA 1 e 2 em pacientes com hipersensibilidade imediata à carboplatina submetidas à dessensibilização. MÉTODOS: Padronizou-se o BAT, com análise da expressão de CD63 e CD203c na superfície de basófilos de pacientes com hipersensibilidade imediata às platinas submetidas à dessensibilização. Foram realizados BATs em 15 pacientes portadoras de neoplasias malignas submetidas a 27 dessensibilizações devido à anafilaxia a quimioterápico do grupo das platinas e em 12 indivíduos de dois grupos controle (Grupo 1: seis pacientes tolerantes às platinas e Grupo 2: seis voluntários sadios que nunca foram expostos às platinas). Os resultados dos BATs foram comparados entre os três grupos. Correlacionou-se o BAT com a ocorrência ou não de reação durante a dessensibilização e com os níveis de triptase sérica. Para análise da prevalência e impacto da mutação dos genes BRCA 1 e 2 nas dessensibilizações, realizou-se análise retrospectiva de prontuários de 138 portadoras de neoplasias malignas ginecológicas submetidas à dessensibilização à carboplatina. RESULTADOS: O BAT foi positivo em 11 das 15 pacientes alérgicas (n= 11; 73,3%), com aumento de expressão de CD203c e CD63 em 11 (73,3%) e 6 (40%) pacientes, respectivamente. Todos os participantes dos grupos controles apresentaram testes negativos. Maior expressão de CD63 foi observada em pacientes com reações iniciais mais graves. O BAT foi positivo em 92,3% das reações ocorridas durante as dessensibilizações (n=12/13), sendo positivo em todas as reações que apresentaram aumento concomitante de triptase sérica (n=5). Com relação à mutação dos genes BRCA 1 e 2, sua prevalência foi de 34% nas pacientes com hipersensibilidade às platinas (n=47/138), sendo que 51% das portadoras reagiram durante a dessensibilização. CONCLUSÕES: O BAT positivo, com aumento da expressão de CD63 e/ou CD203c na superfície do basófilo, identificou pacientes alérgicos às platinas com especificidade de 100% e sensibilidade de 73,3%. O BAT e a mutação dos genes BRCA 1 e 2 identificaram pacientes mais propensos a reagir durante o procedimento de dessensibilização. A utilização de biomarcadores preditores de reações durante a dessensibilização aos quimioterápicos do grupo das platinas pode aumentar a segurança do procedimento e auxiliar na manutenção do esquema quimioterápico de primeira linha do paciente / INTRODUCTION: Cancer is the leading cause of death in the age group of 45 to 84 years, and one of the main public health issues in developing nations. Hypersensitivity reactions to chemotherapeutic agents have been increasing, sometimes hindering the use of first-line therapies in the treatment of primary or relapsed tumors. Rapid drug desensitization (RDD) is an alternative approach, through which a patient becomes tolerant to the medication that once triggered a potentially lethal hypersensitivity reaction. Platinum-based compounds are examples of drugs that can be readministered through the desensitization procedure, but currently there are no known biomarkers that could help predict reactions during RDD. OBJECTIVES: The main goal of our study was to assess the basophil activation test (BAT) as a biomarker of breakthrough reactions occurred during RDD in patients allergic to platinum-based agents. As a secondary goal, we evaluated the prevalence and impact of the BRCA 1/2 mutation in carboplatin-allergic patients undergoing RDD. METHODS: We standardized the BAT by evaluating CD63 and CD203c expressions on the basophils of patients with immediate hypersensitivity reactions to platinum-based agents undergoing RDD. We analyzed BATs of 15 patients with malignant neoplasms who had undergone 27 RDD procedures due to anaphylaxis to platinum-based agents, and of 12 control subjects (Group 1: six patients tolerant to platinum-based agents, and Group 2: six healthy volunteers who had never been exposed to platinum-based agents). BAT results were compared among the three groups. We correlated BAT results with the occurrence of breakthrough reactions during RDD and with serum tryptase levels. To conduct the analysis of the BRCA 1/2 mutation prevalence and its impact on RDD, a retrospective review of 138 medical records of patients with gynecological malignancies who underwent RDD to carboplatin was performed. RESULTS: BAT was positive in 11/15 allergic patients (73.3%), with increased expression of CD203c and CD63 in 11 (73.3%) and 6 (40%) patients, respectively. All control subjects presented negative BATs. A higher CD63 expression was observed in patients with severe initial reactions. BAT was positive in 92.3% of the breakthrough reactions occurred during RDD (n=12/13), and in all reactions with concomitant increased tryptase levels (n=5). Regarding the BRCA1/2 mutation, its prevalence was 34% in patients allergic to platinum-based agents (n=47/138), and 51% of the mutation carriers had breakthrough reactions during RDD. CONCLUSIONS: A positive BAT, with an increased expression of CD63 and/or CD203c, identified patients allergic to platinum-based agents with a specificity of 100% and a sensitivity of 73.3%. The BAT and the BRCA 1/2 mutation helped identify patients at risk of breakthrough reactions during RDD. The use of predictive biomarkers of breakthrough reactions during RDD to platinum-based agents might enhance RDD safety and help maintain a patient`s first-line treatment

INTRODUÇÃO: Diversas sociedades profissionais recomendam a realização de testes genéticos para mulheres que desenvolveram câncer de ovário, a fim de identificar portadores de mutação germinativa em genes BRCA1/2 e oferecer terapia redutora de risco. OBJETIVO: O objetivo deste estudo foi realizar análise de custo-efetividade de programa para diagnóstico de mutação germinativa em genes BRCA1/2 e de estratégias preventivas para pacientes com o diagnóstico de câncer de ovário e seus familiares de primeiro grau. METODOLOGIA: O estudo realizou análise de custo-efetividade mediante desenvolvimento de modelo de decisão de Markov e perspectiva do Sistema Único de Saúde. As estratégias comparadas refletiram a adoção de teste genético e estratégias preventivas para pacientes e familiares ou o acompanhamento proposto atualmente. A razão de custo-efetividade incremental foi expressa em termos de custo por caso evitado de neoplasia maligna. A análise de sensibilidade foi realizada de forma determinística univariada. RESULTADOS: Demonstrou-se incremento em efetividade e em custos com a realização de testes genéticos e a adoção de medidas profiláticas para pacientes e familiares. A razão de custo-efetividade incremental foi calculada em R$ 14.224,40 e em R$ 908,58, respectivamente, por caso evitado em pacientes com o diagnóstico prévio de câncer de ovário e em seus familiares de primeiro grau. Estes valores foram considerados inferiores ao limiar de custo-efetividade selecionado no estudo (de R$ 7.543,50 a R$ 23.786,70). DISCUSSÃO: O programa analisado pode ser considerado como estratégia custo-efetiva para a realidade nacional, sobretudo no que tange aos familiares de primeiro grau de pacientes com o diagnóstico de câncer de ovário. Outras publicações demonstraram conclusões similares para o tema em diversos países. CONCLUSÃO: Um possível desdobramento deste trabalho poderia ser representado pela realização de uma análise de impacto orçamentário da incorporação do programa como política de saúde no país / INTRODUCTION: Several professional societies recommend performing genetic tests for women who have developed ovarian cancer in order to identify BRCA1/2 germline-mutation carriers and offer risk-reducing therapy. OBJECTIVE: The objective of this study was to perform a cost-effectiveness analysis of a BRCA1/2 germline mutation diagnosis program and preventive strategies for patients diagnosed with ovarian cancer and their first degree relatives. METHODS: The study performed a cost-effectiveness analysis through the development of a Markov decision model and the perspective of the Unified Health System. The compared strategies reflected the adoption of genetic testing and preventive strategies for patients and their relatives or the usual follow-up. The incremental cost-effectiveness ratio was expressed in terms of cost per avoided case of cancer. Sensitivity analysis was performed in a univariate and deterministic manner. RESULTS: There has been an increase in effectiveness and in costs with genetic testing and the adoption of prophylactic measures for patients and their relatives. The incremental cost-effectiveness ratio was calculated at R$ 14,224.40 and R$ 908.58, respectively, for avoided cases in patients with prior diagnosis of ovarian cancer and their first-degree relatives. These values were considered lower than the cost-effectiveness threshold selected in the study (from R$ 7,543.50 to R$ 23,786.70). DISCUSSION: The analyzed program can be considered as a cost-effective strategy for the national reality, especially in relation to the first-degree relatives of patients with ovarian cancer. Other publications have shown similar conclusions for the subject in several countries. CONCLUSION: A possible development of this work could be represented by a budget impact analysis of the incorporation of the program as health policy in Brazil

The progression of replication forks can be slowed down or paused by various external and internal factors during DNA replication. This phenomenon is referred to as replication stress and substantially contributes to genomic instability that is a hallmark of cancer. Transcription complex belongs to the internal replication-interfering factors and represents a barrier for progression of the replication complex. The replication forks are slowed down or paused while passing through the transcriptionally active regions of the genome that can lead to subsequent collapse of stalled forks and formation of DNA double-strand breaks, especially under conditions of increased replication stress. DNA helicase RECQ5 is significantly involved in maintenance of genomic stability during replication stress, but the mechanisms of its action are not clear. In this diploma theses, we have shown that RECQ5 helicase, in collaboration with BRCA1 protein, participates in the resolution of collisions between replication and transcription complexes. BRCA1 protein is a key factor in the homologous recombination process, which is essential for the restart of stalled replication forks. Furthermore, we have shown that RECQ5 helicase is involved in ubiquitination of PCNA protein at stalled replication forks. Key words DNA...

Background: Prophylactic mastectomies in carriers of mutations in BRCA1 or BRCA2 are becoming increasingly more accepted. We investigated the outcome after prophylactic mastectomy, especially regarding satisfaction with the procedure, in a monocenter study. Methods: BRCA1/2 mutation carriers and non-carriers with elevated pedigree-based cancer risk were followed prospectively in a structured surveillance program between 2000 and 2017. A retrospective telephone survey was conducted among all patients with documented prophylactic mastectomy. Complications and satisfaction with the decision for prophylactic mastectomy were recorded. Results: 39 patients who opted for a prophylactic mastectomy (38 BRCA1/2 mutation carriers and 1 noncarrier) were interviewed. Mostly nipple-sparing mastectomy with reconstruction was performed (87%). Half of the patients (22/39; 56.4%) had a history of unilateral breast cancer. The median time since prophylactic mastectomy was 5.6 years. While 61.5% did not report any complications, flap loss was seen in 15% (3/20) and moderate limitations in everyday life were present in 20% (7/35). An improvement in quality of life was noticed by 82% after prophylactic mastectomy and no patient expressed regret with regard to the decision. Conclusions: Prophylactic mastectomy is a procedure with risk for long-term complications in some cases. Our results confirm high satisfaction with the decision and improved quality of life.

L’ubiquitination est une modification post-traductionnelle qui joue un rôle majeur dans la régulation d’une multitude de processus cellulaires. Dans cette thèse, je discuterai de la caractérisation de deux protéines, BRCA1 et BAP1, soit deux suppresseurs de tumeurs fonctionnellement reliés. BRCA1, une ubiquitine ligase qui catalyse la liaison de l’ubiquitine à une protéine cible, est mutée dans les cancers du sein et de l'ovaire. Il est bien établi que cette protéine aide à maintenir la stabilité génomique suite à un bris double brin de l’ADN (BDB), et ce, à l’aide d’un mécanisme de réparation bien caractérisé appelé recombinaison homologue. Cependant, les mécanismes de régulation de BRCA1 suite à des stresses génotoxiques n’impliquant pas directement un BDB ne sont pas pleinement élucidés. Nous avons démontré que BRCA1 est régulée par dégradation protéasomale suite à une exposition des cellules à deux agents génotoxiques reconnus pour ne pas directement générer des BDBs, soit les rayons UV, qui provoquent la distorsion de l’hélice d’ADN, et le méthyle méthanesulfonate (MMS), qui entraîne l’alkylation de l’ADN. La dégradation de BRCA1 est réversible et indépendante des kinases associées à la voie des PI3 kinase, soit ATM, ATR et DNA-PK, protéines qui sont rapidement activées par les dommages à l’ADN. Nous proposons que la dégradation de BRCA1 prévienne son recrutement intempestif, ainsi que celui des facteurs qui lui sont associés, à des sites de dommages d’ADN qui ne sont pas des BDBs, et que cette régulation coordonne la réparation de l’ADN. L’enzyme de déubiquitination BAP1 a initialement été identifiée comme une protéine capable d’interagir avec BRCA1 et de réguler sa fonction. Elle est également connue pour sa capacité à se lier avec les protéines du groupe Polycomb, ASXL1 et ASXL2. Cependant, l’importance de ces interactions n’a toujours pas été établie. Nous avons démontré que BAP1 forme deux complexes protéiques mutuellement exclusifs avec ASXL1 et ASXL2. Ces interactions sont critiques pour la liaison de BAP1 à l’ubiquitine ainsi que pour la stimulation de son activité enzymatique envers l’histone H2A. Nous avons également identifié des mutations de BAP1 dérivées de cancers qui empêchent à la fois son interaction avec ASXL1 et AXSL2, et son activité de déubiquitinase, ce qui fournit un lien mécanistique direct entre la déubiquitination de H2A et la tumorigenèse. Élucider les mécanismes de régulation de BRCA1 et BAP1 menera à une meilleure compréhension de leurs rôles de suppresseurs de tumeurs, permettant ainsi d’établir de nouvelles stratégies de diagnostic et traitement du cancer. / Ubiquitination is a post-translational modification that plays major roles in regulating a plethora of cellular processes. In this thesis, I will discuss the biochemical and functional characterization of two functionally related proteins, BRCA1 and BAP1, both of which are important tumor suppressors. BRCA1, an ubiquitin ligase that catalyzes the attachment of ubiquitin to target proteins, is mutated in breast and ovarian cancers. BRCA1 roles in maintaining genomic stability following DNA double strand breaks (DSBs) by promoting the homologous recombination repair pathway is well established. However, how BRCA1 is regulated following genotoxic stress that does not directly involve DSBs is still not fully elucidated. We showed that BRCA1 is downregulated, through proteasomal degradation, following exposure of the cells to the DNA helix distorting agent UV or the DNA alkylating agent Methyl Methanesulfonate (MMS), two DNA damaging agents that do not directly generate DSBs. BRCA1 downregulation is reversible and is independent of the PI3 kinase related kinases, ATM, ATR or DNA-PK which constitute primary responders that are rapidly activated by DNA damage. We proposed that BRCA1 downregulation prevents the untimely recruitment of BRCA1 and associated factors to DNA damage sites that are not DSBs, thus coordinating the DNA damage/repair response. The deubiquitinating enzyme BAP1 was initially identified as an interacting protein that regulates the function of BRCA1. BAP1 is also known to interact with the Polycomb group proteins ASXL1 and ASXL2. However, the importance of this interaction was not fully understood. We showed that BAP1 forms two mutually exclusive complexes with ASXL1 and ASXL2. These interactions are critical for BAP1 binding to ubiquitin and stimulation of its deubiquitinase activity towards histone H2A. We also identified cancer-derived mutations of BAP1 that abrogate its interaction with ASXL1 and ASXL2 and deubiquitinase activity, which provide a direct mechanistic link between H2A deubiquitination and tumorigenesis. Elucidating how BRCA1 and BAP1 are regulated will lead to a better understanding of their roles as tumor suppressors and this will in turn help establishing improved diagnostic and therapeutic strategies to treat cancer.

Submitted by Franciele Moreira (francielemoreyra@gmail.com) on 2019-01-31T13:01:42Z No. of bitstreams: 2 Dissertação - Juliana Fracalossi Paes - 2018.pdf: 3499755 bytes, checksum: 913f34f36a97b5b7412e4eec7b1af1c1 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2019-02-01T10:04:10Z (GMT) No. of bitstreams: 2 Dissertação - Juliana Fracalossi Paes - 2018.pdf: 3499755 bytes, checksum: 913f34f36a97b5b7412e4eec7b1af1c1 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2019-02-01T10:04:10Z (GMT). No. of bitstreams: 2 Dissertação - Juliana Fracalossi Paes - 2018.pdf: 3499755 bytes, checksum: 913f34f36a97b5b7412e4eec7b1af1c1 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-09-27 / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / Introduction: MicroRNAs are small molecules of single-stranded non-coding RNAs that regulate gene expression in the post-transcriptional phase and are being evaluated as prognostic and predictive markers in breast cancer. Objective: The aim of this study was to evaluate the expression of hsa-miR-205ab and hsa-miR-218a microRNAs and BRCA1 protein in breast cancer samples and their associations with the pathological and prognostic clinical aspects of tumors. Method: A group of 92 breast cancer cases was evaluated for clinical-pathological aspects, five-year survival, expression of BRCA1, hsa-miR-205ab and hsa-miR-218a. BRCA1 expression was assessed by immunohistochemistry and the quantification of the miRNAs by quantitative PCR in real time. The clinical-pathological aspects were compared in relation to the expression of BRCA1, hsa-miR- 205ab and hsa-miR-218a using the Mann-Whitney test. Survival curves were generated by the Kaplan-Meyer method and compared by the long-rank method. Results: The group of tumors comprised 56 cases of non-triple-negative breast carcinomas and 36 tumors with triple-negative phenotype. Hypoexpression of hsa-miR-205ab and hsa-miR-218a was associated with larger tumors (> 2 cm), presence of lymph node metastasis and distant metastasis, the highest histological grade, triple negative phenotype, absence of expression of BRCA1 and lower survival. (P = 0.044), more advanced stages (p = 0.005), lymph node involvement (p = 0.038), presence of distant metastasis (p = 0, 0008) and absence of BRCA1 expression (p = 0.039). Conclusion: The hypoexpression of hsa-miR-205ab and hsa-miR-218a was associated with factors of poor prognosis, absence of BRCA1 expression and the lowest survival rate in breast cancer patients evaluated in this study. / Introdução: Os microRNAs são pequenas moléculas de RNAs não-codificantes de cadeia simples, que regulam a expressão gênica na fase pós-transcricional e vem sendo avaliados como marcadores prognósticos e preditivos no câncer de mama. Objetivo: O objetivo deste estudo foi avaliar a expressão dos microRNAs hsa-miR-205ab e hsa-miR-218a e da proteína BRCA1 em amostras de câncer de mama e suas associações com os aspectos clínico patológicos e prognósticos dos tumores. Método: Um grupo de 92 casos de câncer de mama foi avaliado quanto aos aspectos clínico-patológicos, a sobrevida em cinco anos, a expressão de BRCA1, hsa-miR-205ab e hsa-miR-218a. A expressão de BRCA1 foi avaliada por imuno- histoquímica e a quantificação dos miRNAs por PCR quantitativa em tempo real. Os aspectos clínicos-patológicos foram comparados em relação à expressão de BRCA1, hsa-miR-205ab e hsa-miR-218a, utilizando o teste de Mann-Whitney. As curvas de sobrevida foram geradas pelo método de Kaplan-Meyer e comparadas pelo método de long-rank. Resultados: O grupo de tumores compreendeu 56 casos de carcinomas de mama não triplo-negativos e 36 tumores com fenótipo triplo-negativo. A hipoexpressão de hsa-miR-205ab e hsa-miR-218a foi associada aos tumores maiores (> 2 cm), à presença de metástase linfonodal e de metástase a distância, ao grau histológico mais elevado, fenótipo triplo negativo, ausência de expressão de BRCA1 e menor sobrevida. A sobrevida das pacientes em função das características clínico patológicas foi influenciada pelo fenótipo triplo-negativo (p=0,044), estádios mais avançados (p=0,005), acometimento linfonodal (p=0,038), presença de metástase à distância (p=0,0008) e ausência da expressão de BRCA1 (p=0,039). Conclusão: A hipoexpressão de hsa-miR-205ab e hsa-miR-218a foi associada aos fatores de pior prognóstico, ausência de expressão de BRCA1 e à menor sobrevida nas pacientes com câncer de mama avaliadas neste estudo.

Studies of prophylactic salpingectomy specimens from BRCA1/2 mutation carriers, at risk for tubal and ovarian high-grade serous carcinoma (SerCa), have consistently revealed occult carcinomas and putative histological cancer precursors in the distal fallopian tube epithelium (FTE), supporting the FTE as the source of SerCa. In this thesis I molecularly characterized and compared non-malignant FTE from mutation carriers (FTEb) and control patients (FTEn) to identify alterations that may predispose to malignant transformation. Gene expression profiling of laser capture microdissected FTEn, FTEb and SerCa indicated that SerCa have similar molecular profiles whether of presumed ovarian or tubal origin, supporting the notion they share a common cell of origin within the FTE. Furthermore, FTEb samples obtained during the post-ovulatory luteal phase showed gene expression profiles closely resembling SerCa samples, suggesting that the luteal phase milieu may contribute to serous carcinogenesis. An initial hypothesis was that FTEb may respond differently to luteal progesterone compared to FTEn, via differential expression of progesterone receptor (PR) isoforms. However, similar relative isoform expression in FTEn and FTEb samples suggested that a luteal phase-associated factor other than progesterone directs gene expression changes in FTEb. The possibility that FTEb respond differently to ovulation-associated inflammatory cytokines that are locally elevated during the luteal phase was next investigated. Importantly, FTEb specimens previously found to cluster with SerCa based on their global gene expression profiles showed evidence of increased nuclear factor-κB (NFκB)-dependent (pro-inflammatory) signalling and diminished glucocorticoid receptor (GR)-dependent (anti-inflammatory) signalling. Furthermore, I demonstrate that disabled homolog 2 (DAB2), an adaptor molecule decreased in SerCa and FTE luteal samples, enhances both GR-mediated transactivation and suppression of NFκB signalling, implicating DAB2 as a crucial determinant of inflammatory signalling and ovarian cancer risk. Altogether, this thesis identifies gene expression changes in FTE from BRCA mutation carriers during the post-ovulatory luteal phase that parallel those detected in SerCa. The data support a proposed novel testable model for predisposing events contributing to SerCa that centres on an altered ability to quickly resolve the pro-inflammatory environment created by the ovulatory event.

Studies of prophylactic salpingectomy specimens from BRCA1/2 mutation carriers, at risk for tubal and ovarian high-grade serous carcinoma (SerCa), have consistently revealed occult carcinomas and putative histological cancer precursors in the distal fallopian tube epithelium (FTE), supporting the FTE as the source of SerCa. In this thesis I molecularly characterized and compared non-malignant FTE from mutation carriers (FTEb) and control patients (FTEn) to identify alterations that may predispose to malignant transformation. Gene expression profiling of laser capture microdissected FTEn, FTEb and SerCa indicated that SerCa have similar molecular profiles whether of presumed ovarian or tubal origin, supporting the notion they share a common cell of origin within the FTE. Furthermore, FTEb samples obtained during the post-ovulatory luteal phase showed gene expression profiles closely resembling SerCa samples, suggesting that the luteal phase milieu may contribute to serous carcinogenesis. An initial hypothesis was that FTEb may respond differently to luteal progesterone compared to FTEn, via differential expression of progesterone receptor (PR) isoforms. However, similar relative isoform expression in FTEn and FTEb samples suggested that a luteal phase-associated factor other than progesterone directs gene expression changes in FTEb. The possibility that FTEb respond differently to ovulation-associated inflammatory cytokines that are locally elevated during the luteal phase was next investigated. Importantly, FTEb specimens previously found to cluster with SerCa based on their global gene expression profiles showed evidence of increased nuclear factor-κB (NFκB)-dependent (pro-inflammatory) signalling and diminished glucocorticoid receptor (GR)-dependent (anti-inflammatory) signalling. Furthermore, I demonstrate that disabled homolog 2 (DAB2), an adaptor molecule decreased in SerCa and FTE luteal samples, enhances both GR-mediated transactivation and suppression of NFκB signalling, implicating DAB2 as a crucial determinant of inflammatory signalling and ovarian cancer risk. Altogether, this thesis identifies gene expression changes in FTE from BRCA mutation carriers during the post-ovulatory luteal phase that parallel those detected in SerCa. The data support a proposed novel testable model for predisposing events contributing to SerCa that centres on an altered ability to quickly resolve the pro-inflammatory environment created by the ovulatory event.

MCM7, une des sous unités de l'ADN hélicase MCM, est poly-ubiquitinylée quand elle est sur la chromatine en réplication ou en réparation. Pendant la réplication, l'ubiquitinylation dégradative de MCM7 provoque son départ de la chromatine. La proto-oncoprotéine Int6 interagit avec les formes ubiquitinylées de MCM7 pour les protéger de la dégradation. Son absence entraîne la déstabilisation de MCM7 et l'apparition de lésions à l'ADN. La capacité d'Int6 à réguler la dégradation de MCM7 et peut-être d'autres facteurs semble donc primordiale pour la stabilité génomique. Suite à une irradiation causant des cassures de l'ADN, l'ubiquitinylation de MCM7 la stabilise et est stimulée par BRCA1, un suppresseur de tumeur doté d'une activité ubiquitine ligase. Cette stabilisation participerait au rôle de MCM7 dans le signalement des lésions de l'ADN. Ces travaux ajoutent MCM7 à la liste des protéines dont l'ubiquitinylation régule le métabolisme de l'ADN pour maintenir l'intégrité génomique.