Orientador: Mariângela Esther Alencar Marques / Banca: Gilberto Uemura / Banca: Sérgio Vicente Serrano / Banca: José Roberto Figaro Caldeira / Banca: Cleverson Teixeira Soares / Resumo: O câncer de mama (CM) representa um importante problema de saúde pública no mundo, com aproximadamente 1.400.000 casos diagnosticados e 460.000 mortes por ano. É considerada uma doença heterogênea, com alterações em diversas vias de sinalização molecular. Tanto os marcadores prognósticos quanto os preditivos são de grande importância para a tomada de decisões terapêuticas. No caso do CM operado, os marcadores prognósticos ajudam a determinar se a paciente necessita de tratamento adicional e os marcadores preditivos auxiliam o clínico a decidir qual tratamento a ser utilizado. Desta forma, o melhor conhecimento dos marcadores prognósticos e preditivos conhecidos e a identificação de novos marcadores, poderão auxiliar o tratamento de pacientes com CM de forma mais adequada. Dois marcadores tumorais com possíveis implicações clínicas são o TGF-β1 e o seu receptor TGF-βRII. Em relação ao impacto preditor de resposta a quimioterapia, os referidos marcadores ainda não foram devidamente estudados. Quanto ao papel prognóstico, os estudos em literatura são contraditórios. Acredita-se que o TGF-β atue de forma diferente em função do tipo celular e do contexto biológico envolvido. Assim, é supressor tumoral nos estágios iniciais da carcinogenese e promotor tumoral nos estágios tardios. O momento da troca de papéis não está estabelecido, porém, sabe-se que, em um mesmo tumor, o TGF-β pode atuar tanto como supressor quanto como promotor tumoral simultaneamente. Em face da complexidade biológica do TGF-β, optou-se por estudar um grupo homogêneo de mulheres com CM em estádio TNM III, com longo período de seguimento clínico, submetidas à quimioterapia neoadjuvante (QtNeo) baseada em doxorrubicina e também à quimioterapia adjuvante. Desta forma, o objetivo deste... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Breast cancer (BC) represents an important public heatlh problem worldwide, with approximately 1.4 million new cases and 460,000 deaths per year. It is considered a heterogeneous disease with changes in several molecular signalling pathways. Both the predictive and prognostic markers are important for making therapeutic decisions. In the case of operated BC, prognostic markers help to determine if the patient needs additional treatment and predictive markers help the clinician to decide which treatment to use. Thus, a better knowledge of known predictive and prognostic markers and the identification of new markers, may improve the treatment of BC patients. Two tumor markers with potential clinical implications are TGF-β1 and its receptor TGF-βRII. Regarding the prediction of response to cancer chemotherapy, these markers have not been adequately studied. Considering its prognostic value, published studies are contradictory. It is believed that the TGF-β acts differently depending on the cell type and the biological context involved. Thus, it acts as a tumor suppressor in the early stages of carcinogenesis and as a tumor promoter in later stages. The moment of role switch is not established, however, it is known that in the same tumor, TGF-β can act as both tumor suppressor and promoter simultaneously. Given the biological complexity of TGF-β, we chose to study a homogeneous group of women with TNM stage III BCs comprising tumors with long follow-up period, submitted to doxorubicinbased neoadjuvant chemotherapy (NAC) and adjuvant chemotherapy as well. Thus, the aim of this study was to evaluate the protein expression of TGF-β1 and TGF-βRII in a sample of BCs and to correlate it with clinical and pathological response rates, occurrence of distant metastasis, and survival analysis. To this end... (Complete abstract click electronic access below) / Doutor

Mammographic density (MD), created predominantly by increased stromal tissue, is a major breast cancer risk factor, though little is known about the biological mechanisms mediating it. Tamoxifen prevents breast cancer in a subset of high risk women via mechanisms that appear dependent on reduction of MD. Animal models suggest tamoxifen remodels the mammary stroma to a tumour-inhibitory phenotype. This study aims to analyse the effect of tamoxifen on human breast fibroblast function and identify pro-tumourigenic pathways contributing to density-associated risk. Methods Primary human breast fibroblasts from normal, high risk or breast cancer patients were treated with hydroxytamoxifen (100nM-5μM). Fibroblast function was analysed by measuring: proliferation, expression of stromal proteins fibronectin and collagen 1; effects on TGF-β signalling and up-regulation of myofibroblast marker SMA. Genome wide analysis was performed using RNA-Seq. Significantly deregulated pathways were validated by PCR, western blotting and mass spectrometry. Results Fibroblasts from 23 patients were treated with hydroxytamoxifen. All patients showed reduced proliferation with treatment. 62% of patients showed reduced fibronectin expression. TGF- β-mediated up-regulation of SMA and fibronectin were consistently inhibited by tamoxifen. RNA-Seq analysis revealed down-regulation of Wnt signalling, an established profibrogenic and pro-tumourigenic pathway. In addition, there was significant modulation of many metabolic pathways, including components of the microsomal anti-oestrogen binding site (AEBS). Binding of tamoxifen to the AEBS inhibits cholesterol epoxide hydrolase (ChEH) enzyme activity, promoting an anti-tumourigenic phenotype. The effects of tamoxifen on fibroblasts could be partly replicated using tesmilifene, a commercially available 5 inhibitor of ChEH. Mass spectrometry analysis confirmed an altered cholesterol metabolite profile in tamoxifen treated fibroblasts. Conclusion These data indicate that tamoxifen can directly remodel the mammary stromal microenvironment, generating a less 'reactive' stroma. Thus, tamoxifen impacts on multiple pathways, many independent of the oestrogen receptor, to create a tumourinhibitory microenvironment. This offers exciting potential for patient monitoring and alternative breast cancer prevention strategies.

Metastasis is the leading cause of poor prognosis for individuals diagnosed with cancer. Breast cancer is particularly prevalent with 1 in 10 women receiving a breast cancer diagnosis in her lifetime. There are various types of breast cancers that are distinguished by molecular subtype as defined by specific biomarker expression profiles: estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). The subtypes defined by the varying expression of these receptors respond differently to cancer treatments. For example, luminal A ([ER/PR+] HER2- KI67-) responds well to endocrine therapy and patients generally have a good prognosis, whereas triple negative breast cancer (TNBC) ([ER/PR-] HER2- basal marker+) has no specific targeted treatment available and the prognosis is usually poor. Patients with the HER2 subtype often develop resistance to the treatment specific to the breast cancer molecular subtype. Since 90% of all cancer-related deaths are due to metastatic disease, effectively treating all of these types of breast cancers before metastasis is an important factor in achieving a more positive outcome, In order for metastasis to occur, a tumor cell must have the ability to mobilize, intravasate into the vasculature, and then extravasate and proliferate into a tumor at a distant site. Numerous biological and environmental factors must facilitate each of these steps in order for metastasis to occur. One biomarker of metastasis is a tumor microenvironment of metastasis (TMEM). A TMEM is the physical apposition of a Mena-expressing tumor cell, a macrophage (a type of white blood cell), and an endothelial cell (a blood vessel cell). Each TMEM component plays a key role in breast cancer biology. The automated clinical assay MetaSite BreastTM was developed by MetaStat, Inc. to quantify TMEMs. The MetaSiteTM score directly correlates with risk of developing metastasis. The Mena protein is involved in cell motility and expressed isoforms can either promote metastasis (for example, MenaINV), or protect and prevent metastasis (for example, Mena11a). These isoforms are not expressed in a binary manner and studies have shown that the ratio of MenaINV to Mena11a can give insight into the pro-metastatic/anti-metastatic biology of the cell. To indirectly measure the amount of MenaINV, the Z-score of Mena11a is subtracted from the Z-score of pan-Mena (all Mena isoforms), yielding a theoretical maximum amount of MenaINV, called Menacalc. This process is performed by quantitative analysis of multiplexed immunofluorescence staining through the MenaCalcTM assay developed by MetaStat, Inc. The results of this study demonstrated that MenaCalcTM is a high-performing, high-throughput assay that was clinically validated under CLIA-approved protocol in January 2016. The assay surpassed all benchmark goals for precision and performance. For both day-to-day and run-to-run operations, precision and reproducibility were analyzed using Pearson’s R and slope. The day-to-day reproducibility yielded Pearson’s R values of 0.879 and 0.853 comparing Day 1 vs. Day 2 and Day 2 vs. Day 3, respectively. The slopes for the same comparisons were 0.985 and 0.982, respectively. The analysis of run-to-run precision had Pearson’s R values of 0.999 and 0.994 comparing Day 1 vs. Day 2 and Day 2 vs. Day 3, respectively. The slopes were 0.999 for both comparisons. The development of such an assay brings new elements of precision and reproducibility to the current market of breast cancer biomarker tests. Statistical analysis revealed a wide range of MenaCalcTM scores that were independent of total Mena expression. Individual images showed a range of MenaCalcTM values from a low of only 2.9% of cells with a high MenaCalcTM score to a high of 97.4% of cells with a high MenaCalcTM score. Regions of high MenaCalcTM scores correlated with areas of invasive tumor. Preliminary data assessing the synergistic use of both the MetaSite BreastTM and the MenaCalcTM assays were promising. These data suggests that both physical MetaSiteTM structures and protein expression levels can be used to more thoroughly understand the biology of breast cancer and the path to metastasis. Three clusters of combined MetaSiteTM/MenaCalcTM scores were observed: MetaSiteTM low/MenaCalcTM low, MetaSiteTM low/MenaCalcTM high, MetaSiteTM high/MenaCalcTM high. Because a MetaSiteTM High/MenaCalcTM Low score combination was not observed, a high MenaCalcTM score may be necessary for TMEM formation. Studies are ongoing to further evaluate the synergy of the MetaSite BreastTM and the MenaCalcTM in order to bring more power to the assessment of metastatic risk. / 2016-12-16T00:00:00Z

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Physics, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Bibliography: leaves 190-193. / by Bruce Robert Rosen. / M.S.

Worldwide, more than 1,000,000 women develop breast cancer each year, and more than 400,000 die because of it. Basal-like breast cancers, which account for 8% to 20% of all breast cancer cases, represent the most aggressive of breast cancers with the majority resistant to existing targeted therapies. Accumulating lines of evidence implicate the Notch pathway in the aetiology of these basal-like breast cancers; while current work in our lab supports the notion that signalling through the Ectodermal Dysplasin Receptor (EDAR) pathway is also important. Notch signalling functions in normal development to control cell fate decisions and is mediated primarily, although not exclusively, through the CBF1 / RBP-Jĸ transcription factor. Aberrant Notch signalling leads to mammary tumourigenesis in mice; however at the outset of this work it was unclear whether signalling through RBP-Jĸ and / or through alternative pathways is required. This thesis presents novel data showing that elevated Notch signalling through the RBP-Jĸ-dependent pathway alone in murine mammary glands causes a number of developmental defects, including reduced ductal outgrowth, increased ductal side branching at puberty and, most significantly, is sufficient to induce mammary tumourigenesis. The data presented also provide supporting evidence that Notch signalling through RBP-Jĸ likely contributes to tumourigenesis, at least in part, via the suppression of apoptosis. At the outset of this thesis far less was known regarding the role(s) of the EDAR pathway within the mammary gland. Despite its recognised function in the development of ectodermal appendages it has been predominantly studied in the context of hair and tooth development. We show here that elevated Edar signalling affects the morphology of numerous ectodermally-derived glands, including the mammary gland, where in general, it results in glands that are enlarged or more elaborately branched. Most significantly, we show that elevated Edar signalling causes mammary tumourigenesis in mice, and provide data to support the hypothesis that elevated EDAR signalling might also be important in a subset of basal-like breast cancers in humans. The murine mammary gland phenotypes seen in response to elevated Edar signalling, including the squamous metaplasia within Edar-induced tumours, are very similar to those observed when Wnt signalling is increased. We provide data to support a positive correlation between activation of the EDAR and Wnt pathways in murine mammary tumourigenesis and provide data to support a comparable interaction in the aetiology of basal-like breast cancer showing squamous differentiation in humans. In summary, this thesis identifies the EDAR pathway as a novel potential therapeutic target in the treatment of a subset of basal-like breast cancers, and provides evidence that signalling through the RBP-Jĸ-dependent Notch pathway is sufficient to induce mammary tumourigenesis, most likely through the suppression of apoptosis.

Lee Mei Lan May. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 48-56). / Abstracts in English and Chinese. / ABSTRACT --- p.I / 中文摘要 --- p.III / ACKNOWLEDGEMENTS --- p.IV / PUBLICATION --- p.V / LIST OF FIGURES --- p.VI / LIST OF TABLES --- p.VII / ABBREVIATION --- p.VIII / CONTENTS --- p.IX / Chapter CHAPTER ONE: --- INTRODUCTION AND LITERATURE / Chapter 1.1 --- THYROID CANCER AND ITS EPIDEMIOLOGY --- p.1 / Chapter 1.1.1 --- Histology --- p.1 / Chapter 1.1.2 --- Gender comparison --- p.3 / Chapter 1.1.3 --- Female hormone 一 risk factor --- p.6 / Chapter 1.2 --- BIOLOGICAL BACKGROUND OF HORMONE´-´ؤؤ --- p.7 / Chapter 1.2.1 --- Estrogen --- p.8 / Chapter 1.2.2 --- Estrogen antagonist --- p.9 / Chapter 1.2.3 --- Estrogen receptors --- p.10 / Chapter 1.2.4 --- Estrogen receptor and thyroid cancer --- p.12 / Chapter 1.3 --- THE ROLE OF APOPTOSIS --- p.13 / Chapter 1.3.1 --- Bcl-family protein --- p.13 / Chapter 1.3.2 --- Bcl-family protein and cancer --- p.14 / Chapter 1.3.3 --- Estrogen and Bcl-family protein --- p.15 / Chapter 1.4 --- Objectives --- p.16 / Chapter CHAPTER TWO: --- GENERAL MATERIALS AND METHODS / Chapter 2.1 --- MATERIALS --- p.17 / Chapter 2.1.1 --- Culture media and treatment reagents --- p.17 / Chapter 2.1.2 --- Reagents for Western blot assay --- p.18 / Chapter 2.1.3 --- Antibodies --- p.19 / Chapter 2.1.4 --- Materials for RT-PCR --- p.19 / Chapter 2.1.5 --- Kits --- p.20 / Chapter 2.1.6 --- Instrumentations --- p.20 / Chapter 2.2 --- Methods --- p.21 / Chapter 2.2.1 --- Cell culture and treatment --- p.21 / Chapter 2.2.2 --- MTT assay --- p.22 / Chapter 2.2.3 --- Western blot analysis --- p.23 / Chapter 2.2.3.1 --- Protein extraction --- p.23 / Chapter 2.2.3.2 --- SDS-PAGE and protein transfer --- p.23 / Chapter 2.2.3.3 --- Immunoblotting analysis --- p.24 / Chapter 2.2.4 --- RNA extraction and RT-PCR --- p.25 / Chapter 2.2.4.1 --- RNA extraction --- p.25 / Chapter 2.2.4.2 --- cDNA synthesis --- p.26 / Chapter 2.2.4.3 --- Polymerase Chain Reaction (PCR) --- p.27 / Chapter 2.2.5 --- Statistical analysis --- p.28 / Chapter CHAPTER THREE: --- RESULTS / Chapter 3.1 --- Effect of E2 and tamoxifen on proliferation --- p.29 / Chapter 3.2 --- Comparison of effects of E and testosterone on Proliferation --- p.31 / Chapter 3.3 --- Differential Bcl-xL expression in response to E2 and testosterone stimulation --- p.33 / Chapter 3.4 --- Expression of ERα and ERβ in response to E2 stimulation --- p.35 / Chapter 3.5 --- Bcl-xL and Bax protein expression in response to E2 stimulation --- p.36 / Chapter 3.6 --- Expression of Bcl-xL and Bax mRNA in response to E2 stimulation --- p.39 / Chapter CHAPTER FOUR: --- DISCUSSION --- p.41 / Chapter CHAPTER FIVE: --- CONCLUSION --- p.47 / REFERENCES --- p.48

Breast cancer (BC) survivors are at increased risk of cancer recurrence, a second cancer, and non-cancer comorbidities. Previous studies suggest that many women adopt a spontaneous change in lifestyle after a BC diagnosis in hope of achieving a better survival outcome. While this observation has led to the suggestion that a BC diagnosis is a “teachable moment” for improving health behaviors, other conflicting studies report that BC survivors do not make positive changes in health behaviors following a breast cancer diagnosis. Although previous studies suggest that receipt of cancer chemotherapy and hormonal therapy is associated with weight loss or weight gain, the association between post-diagnosis weight change with changes in lifestyle has not been studied in detail. The majority of prior studies of post-diagnosis changes in behavior and weight have examined the mean change between two time points, and therefore may over simplify the trajectory of change over time due to lack of more granular data. New methods are needed to examine the distribution and correlates of behavior/weight trajectories following the BC diagnosis. In my dissertation, a systematic literature review was conducted to evaluate the evidence regarding the frequency, magnitude and pattern of post-diagnosis changes in diet [fruit/vegetable (F/V), dietary fat], physical activity [moderate to vigorous physical activity (MVPA) and sedentary behaviors], alcohol intake, and body weight among BC survivors. A total of 66 studies were included in the systematic review. These studies suggest that after a breast cancer diagnosis, women are less likely to engage in MVPA and more likely to reduce alcohol intake. Previous studies suggested that women may experience weight change after a BC diagnosis, although there were strong evidence showing both weight gain and weight loss were common. The reports of changes in diet and sedentary behavior following a BC diagnosis are limited and inconclusive about the direction of change. The results of the review suggested that there is wide variation in post-diagnosis lifestyle changes among BC survivors. However, very few studies have investigated the variability in multiple behavior trajectories following a BC diagnosis. In this dissertation, I made use of a population of 4,505 women newly diagnosed with a BC and enrolled in the Kaiser Permanente Northern California Pathways Study. I used a combination of statistical methods, including a semi-parametric, group-based trajectory modeling and a non-parametric K-means for longitudinal data analysis, to identify latent trajectories groups that are unobserved clusters of individuals following similar trajectories of a behavior. These analyses tested the hypotheses that in the 24 months following a breast cancer diagnosis, women follow a mixture of lifestyle (F/V, dietary fat, MVPA, sedentary behavior, alcohol) and body mass index (BMI) trajectories, which can be stable, temporarily increase or temporarily decrease. My analysis identified multiple distinct trajectories of lifestyle behaviors and BMI during the first 24 months after a BC diagnosis. The trajectory analysis results suggest that the large majority of women maintained their lifestyles following a BC diagnosis. Socioeconomic status, dispositional optimism, perceived social support, and the severity of CIPN during active treatment were associated with the post-diagnosis trajectories of. Furthermore, the BMI trajectories were stable over the first 24 months following a BC diagnosis. The BMI trajectories were associated with trajectories of F/V, dietary fat intake, MVPA, sedentary behavior and alcohol intake over the same period, independent of demographic characteristics, tumor characteristics and cancer treatment received. In summary, previous studies suggest that women may spent fewer time on MVPA and drink less alcohol after a BC diagnosis, while both weight gain and loss are common post diagnosis. In a trajectory analysis of 4505 BC survivors enrolled in the Pathways Study, I did not observe any latent trajectory of meaningful change in health behavior or BMI in the first 24 months after a BC diagnosis in the Pathways Study. Instead, my analysis suggests that most women maintained their body weight following a BC diagnosis. The BMI trajectories were strongly associated with trajectory of F/V, dietary fat intake, MVPA, sedentary behavior, and alcohol intake over the same period, independent of demographic characteristics, tumor characteristics and receipt of cancer therapies. These results suggest that there is an absence of spontaneous changes in lifestyle behaviors after BC diagnosis and the importance of maintaining a healthy lifestyle in weight management after a BC diagnosis. Future studies should examine the associations of these health behaviors and BMI trajectories and BC prognosis to better understand the effect of post-diagnosis changes in lifestyle and weight on BC-specific and all-cause mortality.

Submitted by Rosivalda Pereira (mrs.pereira@ufma.br) on 2017-05-17T18:21:50Z No. of bitstreams: 1 MaraPimentel.pdf: 993761 bytes, checksum: b5eab957349c798d9e42282f3a9a67d1 (MD5) / Made available in DSpace on 2017-05-17T18:21:50Z (GMT). No. of bitstreams: 1 MaraPimentel.pdf: 993761 bytes, checksum: b5eab957349c798d9e42282f3a9a67d1 (MD5) Previous issue date: 2014-11-11 / Breast cancer still affects thousands of women each year worldwide. The aim of this study was to characterize the profile of women diagnosed with breast cancer treated at a referral hospital in oncology in São Luís - MA. This is a descriptive, cross-sectional study with 157 women diagnosed with breast cancer. Including women aged 30 and 70 years of age. Sociodemographic and clinical variables such as were studied: age, marital status, education, origin, family income, and risk factors such as skin color, physical activity, early menarche, menopause, parity, age at first birth, breastfeeding, use of oral contraceptives, hormone replacement therapy, alcohol use, smoking, knowledge and realization of self-examination of breasts. The type of treatment, time to search for professional help and psychological support were recorded respectively (demographic and clinical). The results showed that the majority of women in the age group ranges from 41 to 50 and 51 to 60 years old (32.5%), respectively; married (48.4%); with high school education (41.4%) respectively of the others; coming from the municipalities of the state (51.6%); income of one to two minimum wages (56.7%); dark brown skin (66.9%). Highest percentage is recorded that physical inactivity (54.1%) did not consume alcohol (58.0%) and nonsmokers (74.5%). Other indications found: menarche from the age of twelve (81.9%); menopause before age 50 (59.2%); age at 1st calving (90.0%) and breastfeeding (96.5%). This sample, deny use of oral contraceptives (53.5%) and hormone replacement therapy (86%); performed breast self-examination (73.25%) and had knowledge about self-examination (88.54%). As treatment, evaluated underwent chemotherapy (30.6%) followed by surgery combined with chemotherapy (26.8%). The search time for professional help prevailed within one month (67.3%) and did not receive psychological support (56.7%). It is considered breast cancer neoplasia easily preventable through the adoption of lifestyle changes and undergoing the monitoring, and diagnostic methods, thereby contributing to the reduction of some risk factors. / O câncer de mama ainda acomete milhares de mulheres a cada ano em todo o mundo. O objetivo deste estudo foi caracterizar o perfil de mulheres diagnosticadas com câncer de mama, atendidas em um hospital de referência em oncologia no município de São Luís - MA. Trata-se de um estudo descritivo, transversal com 157 mulheres diagnosticadas com câncer de mama. Incluindo mulheres na faixa etária de 30 e 70 anos de idade. Foram estudadas as variáveis sociodemográficas e clínicas tais como: idade, estado civil, escolaridade, procedência, renda familiar e os fatores de risco, como a cor da pele, prática de atividade física, menarca precoce, menopausa, paridade, idade do primeiro parto, amamentação, utilização de anticoncepcional oral, terapia de reposição hormonal, uso de bebida alcoólica, tabagismo, conhecimento e realização do autoexame das mamas. Foram registrados respectivamente (demográficos e clínicos) o tipo de tratamento, o tempo de busca por ajuda profissional e o apoio psicológico. Os resultados mostraram que a maioria das mulheres na faixa etária nos intervalos entre 41 a 50 e 51 a 60 anos de idade (32,5%), respectivamente; casadas (48,4%); com ensino médio completo (41,4%) respectivamente das demais; procedentes dos municípios do Estado (51,6%); renda de um a dois salários mínimos (56,7%); cor da pele parda (66,9%). Registra-se percentual maior que não praticavam atividade física (54,1%), não consumiram bebidas alcoólicas (58,0%) e não tabagistas (74,5%). Outros indicativos encontrados: menarca a partir dos doze anos de idade (81,9%); menopausa antes dos 50 anos (59,2%); idade do 1º parto (90,0%) e aleitamento materno (96,5%). Desta amostra, negam uso de anticoncepcional oral (53,5%) e terapia de reposição hormonal (86%); realizavam o autoexame das mamas (73,25%) e tinham conhecimento sobre o autoexame (88,54%). Como tratamento, as avaliadas submeteram-se à quimioterapia (30,6%) seguida da cirurgia associada à quimioterapia (26,8%). O tempo de procura por ajuda profissional prevaleceu em até um mês (67,3%) e não obtiveram apoio psicológico (56,7%). Considera-se o câncer de mama uma neoplasia de fácil prevenção, mediante a adoção em mudanças de hábitos de vida e submetendo-se ao monitoramento, métodos e diagnósticos, contribuindo, dessa forma, para a redução de alguns fatores de risco.

Background and objectives: Despite an abundance of research in the field of psycho-oncology, there is little that has come from the discipline of counselling psychology placing importance on social justice-oriented work of 'giving voice' (by providing a space for storytelling) and 'consciousness raising'. This study explores the experience of breast cancer by generating and analysing individual stories of women with breast cancer. The wider objective of this research is to enhance psychological support offered to women with breast cancer through embracing the process of meaning-making. Method and analysis: Adopting a narrative framework, an unstructured narrative encounter took place with four women at varying stages of breast cancer. The transcribed oral stories told by each woman were then restoried into a prose account. The final restoried version was then analysed using a narrative analysis. This approach allowed me to critically investigate and interpret the construction of meaning within each story, using language to bring light to unique aspects of the experience of breast cancer. Analysis: By examining the narratives of four women, the diversity of experience was made apparent. The transformations that took place were varied and non-linear, with the stories oscillating between different 'narrative types' (Frank, 1995). Analysis focused on how metaphor was used to express contradictory meanings and concepts that might otherwise be difficult to express. In conjunction with the analysis, I reflexively analysed my own theoretical and philosophical standpoint, making transparent the context in which I carried out the research. Conclusion: The insights gained from this research have the potential to extend our understanding of what counselling psychology could offer the field of psycho-oncology. The stories highlight the importance for practitioners to encourage encountering of suffering, and offer a space in which existential questions that have no answer can be explored. There needs to be sensitivity to the complex meanings that are made when forming a coherent story, and adjusting to the appearance of breast cancer.

Thesis (M.Sc.(Biochemistry)) -- University of Limpopo, 2019. / Retinoblastoma binding protein 6 (RBBP6) is the protein encoded by the Retinoblastoma Binding Protein 6 (RBBP6) gene that is located in chromosome 16p12.2. There is a growing list of newly discovered RBBP6 hypothetical splice variants but there are only three RBBP6 splice variants that are well documented. RBBP6 has been previously implicated in the regulation of cell cycle and apoptosis but little is known about the expression and regulation of the human RBBP6 splice variants during cell cycle progression and breast cancer development. This study was aimed at determining the expression pattern of RBBP6 alternatively spliced variants during arsenic trioxide-induced cell cycle arrest and apoptosis in breast cancer MCF-7 cells. It was also aimed at determining RBBP6 specific microRNAs and how they are regulated in MCF-7 breast cancer cells. MCF-7 cells were maintained and subjected to arsenic trioxide-induced cell cycle arrest and apoptosis. The MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) and the Muse™ Count & Viability assays were used to evaluate the effect of arsenic trioxide on the viability of MCF-7 cells. Cell cycle arrest using 11 μM arsenic trioxide and apoptosis using 32 μM arsenic trioxide were analysed using the MUSE® Cell Analyzer, light and fluorescence microscopy. Arsenic triode-induced apoptosis was analysed using the Muse™ Annexin V & Dead Cell Kit, MultiCaspase and MitoPotential assays using the Muse™ MultiCaspase Kit and Muse™ MitoPotential Kit. Arsenic trioxide-induced cell cycle arrest was analysed using the Muse™ Cell Cycle Kit. Semi-quantitative analysis of RBBP6 variants was carried out using the conventional Polymerase Chain Reaction (PCR), while the quantitative analysis was done using the Real-Time Quantitative PCR. The localization of RBBP6 isoforms was done using Immunocytochemistry (ICC). Web based Bioinformatics tools were used to identify RBBP6-specific microRNAs. The MTT results showed that arsenic trioxide decreased the viability of the MCF-7 cells in a dose-dependent manner. The Muse™ Cell Cycle analysis showed that 11 μM of arsenic trioxide induced G2/M cell cycle arrest in MCF-7 cells, while the Muse™ Annexin V & Dead Cell assay showed that 32 μM of arsenic trioxide induced the extrinsic apoptotic pathway in MCF-7 breast cancer cells. Using the conventional PCR, the MCF-7 cells were found to express the RBBP6 variant 1 transcript but lacks the expression of variant 2 and 3 transcripts, contrary to the kidney embryonic Hek 293 cells that exhibited the expression of RBBP6 variant 1, 2 and 3. Additionally, arsenic trioxide downregulated RBBP6 variant 1 in breast cancer cells during cell cycle arrest and apoptosis. The Real-Time PCR confirmed that MCF-7 cells lowly express RBBP6 variant 3. On the other hand, the ICC analysis showed that RBBP6 isoform 1 is localized and highly expressed in MCF-7 breast cancer cells. The Web based Bioinformatics tools showed that RBBP6 variant 1 specific microRNAs are down regulated in MCF-7 breast cancer cells. These results together showed that As2O3 is effective against MCF-7 cells and also regulated the expression of RBBP6 variants, especially, variant 1. This study showed that there are RBBP6 variants that are involved in breast cancer progression and there are those that may be involved in breast cancer suppression. Targeting these RBBP6 variants for therapeutic development is a promising strategy. In conjunction with RBBP6 expression, arsenic trioxide should be further explored as a breast cancer drug.