Thesis (PhD (Pathology. Anatomical Pathology))--University of Stellenbosch, 2006. / Patients with chronic gastro-oesophageal reflux disease are predisposed to Barrett’s metaplasia and oesophageal adenocarcinoma. The availability of molecular markers that can objectively identify patients with Barrett’s oesophagus at increased risk of carcinoma is highly desirable. A literature search was conducted to identify potentially useful biomarkers for genotype-phenotype correlation studies in South African patients with Barrett’s oesophagus. The COX-2, c-myb and c-myc genes selected for mRNA expression analysis were analysed in 26 patients with Barrett’s metaplasia (BM) without dysplasia; 14 with Barrett’s oesophagus and dysplasia (BD); 2 patients with Barrett’s adenocarcinoma (BAC); 19 with erosive oesophagitis (ERD); 25 with non-erosive oesophagitis (NERD) and 19 control individuals with a normal gastroscopy and no gastro-oesophageal reflux disease (GORD) symptoms. In the BD/BAC group, 69% (11/16) showed increased c-myb mRNA expression compared with 35% (9/26) in the BM group (p = 0.03). A statistically significant difference (p = 0.002) in c-myb expression was also observed between Barrett’s patients (20/42, 48%) and the control groups (9/63, 14%). In the BD patients, 21% (3/14) had increased c-myc mRNA expression compared with none in those with BM (p < 0.05) and BAC. No significant differences in mRNA expression levels were observed between ethnic groups for the genes analysed. In an attempt to determine whether the low expression level of c-myc in the study cohort may be related to possible gene-gene interaction, DNA samples of 199 individuals were subjected to genotyping of the functional GT-repeat polymorphism in the promoter region of the NRAMP1/SLC11A1 gene. Both these genes are involved in iron metabolism and c-myc is known to repress NRAMP1/SLC11A1. Genotype and allele frequencies were similar in all the groups studied with the 3/3 genotype being the most common. However, none of the three above-mentioned BD patients with increased c-myc mRNA expression had the 3/3 genotype. Therefore, although small in number, c-myc-NRAMP1/SLC11A1 interaction may be of adverse significance in patients with allele 2. TP53 mutation analysis was performed on 68 Barrett’s patients, and TP53 immuno-staining on oesophageal biopsy specimens of 55 subjects. Sporadic TP53 mutations were not identified in any of the patients with BM or dysplasia without BAC. Immuno-histochemistry staining of 2+ and 3+ intensity was similar in patients with metaplasia and dysplasia (58%). The low mutation frequency and relative non-specificity of TP53 immunostaining observed in Barrett’s patients seem to preclude its widespread use as a screening tool. TP53 mutation detection may however be useful for risk stratification once dysplasia has been diagnosed, as mutations G245R and D281Y were identified in two patients with BAC. Of the genes studied in the South African population, c-myb represents the most useful marker for early detection of an increased cancer risk in Barrett’s patients. In future, patients with Barrett’s oesophagus may benefit from genetic assessment to complement existing cancer surveillance and treatment strategies.

Wang, Yajun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 118-126). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgements --- p.v / Table of Contents --- p.vi / List of Figures --- p.xi / List of Tables --- p.xii / Abbreviations and Symbols --- p.xiii / List of Publications and Sequence Submissions during the Study --- p.xv / Chapter Chapter One: --- General Introduction --- p.1 / Chapter Chapter Two: --- Literature Review --- p.8 / Chapter 2.1 --- DNA methylation --- p.8 / Chapter 2.1.1 --- Epigenetic changes --- p.8 / Chapter 2.1.2 --- Differential methylation pattern in normal and tumor cells --- p.10 / Chapter 2.2 --- TSGs --- p.13 / Chapter 2.2.1 --- "Cancer initiation, progression and cancer genes" --- p.13 / Chapter 2.2.2 --- TSGs could be inactivated through promoter hypermethylation --- p.14 / Chapter 2.3 --- NPC --- p.17 / Chapter 2.3.1 --- Epidemiology ofNPC --- p.18 / Chapter 2.3.2 --- Molecular genetic and epigenetic studies ofNPC --- p.19 / Chapter 2.3.3 --- NPC and chromosome 11q --- p.21 / Chapter 2.4 --- ESCC --- p.21 / Chapter 2.4.1 --- Epidemiology of ESCC --- p.22 / Chapter 2.4.2 --- Genetic and epigenetic studies of ESCC --- p.23 / Chapter 2.4.3 --- ESCC and chromosome 11q --- p.24 / Chapter 2.5 --- Chromosome 11q and other carcinomas --- p.24 / Chapter 2.5.1 --- Breast cancer --- p.24 / Chapter 2.5.2 --- Ovarian cancer --- p.25 / Chapter 2.5.3 --- Neuroblastoma --- p.26 / Chapter 2.5.4 --- Melanoma --- p.27 / Chapter 2.5.5 --- Multiple myeloma --- p.27 / Chapter 2.5.6 --- Lung Cancer --- p.27 / Chapter 2.6 --- Important candidate genes located at the project study 1 lq region --- p.28 / Chapter 2.6.1 --- ETS1 --- p.28 / Chapter 2.6.2 --- FLI1 --- p.29 / Chapter 2.6.3 --- P53AIP1 --- p.30 / Chapter 2.6.4 --- RICS --- p.30 / Chapter 2.6.5 --- BARX2 --- p.30 / Chapter 2.6.6 --- ST14 --- p.32 / Chapter 2.6.7 --- ADAMTS8 --- p.33 / Chapter 2.6.8 --- ADAMTS15 --- p.35 / Chapter 2.6.9 --- HNT --- p.36 / Chapter 2.6.10 --- OPCML --- p.36 / Chapter Chapter Three: --- Materials and Methods --- p.37 / Chapter 3.1 --- Cell lines and primary tumor samples --- p.37 / Chapter 3.2 --- Cell line demethylation treatment --- p.38 / Chapter 3.3 --- DNA and RNA extraction from cell lines and tissues --- p.39 / Chapter 3.4 --- Semiquantitative RT-PCR --- p.41 / Chapter 3.5 --- DNA bisulfite treatment --- p.42 / Chapter 3.6 --- Promoter analysis and identification of 5' CpG islands of target genes --- p.45 / Chapter 3.7 --- Methylation-Specific PCR (MSP) --- p.45 / Chapter 3.8 --- Bisulfite Genomic Sequencing (BGS) --- p.46 / Chapter 3.8.1 --- BGS PCR reaction --- p.46 / Chapter 3.8.2 --- TA cloning of the PCR products into the sequencing vector --- p.47 / Chapter 3.8.3 --- Plasmid mini-preparation on 96-well plate --- p.48 / Chapter 3.8.4 --- Plasmid sequencing --- p.49 / Chapter 3.9 --- Homozygous deletion detection --- p.50 / Chapter 3.10 --- Construction of expression plasmids --- p.51 / Chapter 3.10.1 --- The strategy of full length cDNA cloning --- p.51 / Chapter 3.10.2 --- Obtaining of full length covered cDNA by cloning PCR --- p.53 / Chapter 3.10.3 --- Ligation and transformation --- p.54 / Chapter 3.10.4 --- Mini preparation of plasmid in Eppendorf tubes --- p.54 / Chapter 3.10.5 --- Verification of correct inserts in the plasmid --- p.55 / Chapter 3.10.6 --- Subcloning --- p.55 / Chapter 3.10.7 --- Bacteria storage --- p.57 / Chapter 3.11 --- Colony formation assays (CFA) --- p.57 / Chapter 3.11.1 --- Midiprep of the transfection grade plasmid --- p.57 / Chapter 3.11.2 --- Transfection --- p.58 / Chapter 3.11.3 --- Selection of the transfected cells with G418 --- p.59 / Chapter 3.11.4 --- Colony staining --- p.60 / Chapter 3.12 --- Statistical analysis --- p.60 / Chapter Chapter Four: --- Results --- p.61 / Chapter 4.1 --- Narrow down the candidate genes for further study --- p.61 / Chapter 4.1.1 --- Define the study chromosome region --- p.61 / Chapter 4.1.2 --- Database search of all candidate genes --- p.61 / Chapter 4.1.3 --- Transcriptional expression analysis of the candidate genes --- p.63 / Chapter 4.1.4 --- Selection of the genes with tumor specific expression downregulation for further intensive study --- p.64 / Chapter 4.2 --- Further characterization of ADAMTS8 --- p.69 / Chapter 4.2.1 --- Tissue transcriptional expression panel --- p.69 / Chapter 4.2.2 --- Semiquantitative RT-PCR results in tumor cell lines --- p.70 / Chapter 4.2.3 --- Promoter CpG island identification and promoter methylation study --- p.70 / Chapter 4.2.4 --- Transcription reactivation by demethylation treatment --- p.72 / Chapter 4.2.5 --- High resolution promoter methylation analysis by BGS --- p.72 / Chapter 4.2.6 --- Detection of homozygous deletion --- p.73 / Chapter 4.2.7 --- Analysis of ADAMTS8 promoter methylation in clinical samples --- p.74 / Chapter 4.2.8 --- ADAMTS8 full length cDNA cloning --- p.74 / Chapter 4.2.9 --- Colony formation assay --- p.75 / Chapter 4.3 --- Further characterization of HNT --- p.80 / Chapter 4.3.1 --- Tissue transcriptional expression panel --- p.80 / Chapter 4.3.2 --- Semiquantitative RT-PCR results in tumor cell lines --- p.80 / Chapter 4.3.3 --- Promoter CpG island identification and promoter methylation study --- p.81 / Chapter 4.3.4 --- Transcription reactivation by demethylation treatment --- p.82 / Chapter 4.3.5 --- HNT full length cDNA cloning --- p.82 / Chapter 4.4 --- Further characterization of BARX2 --- p.87 / Chapter 4.4.1 --- Tissue transcriptional expression panel --- p.87 / Chapter 4.4.2 --- Semiquantitative RT-PCR results in tumor cell lines --- p.87 / Chapter 4.4.3 --- Promoter CpG island identification and promoter methylation study --- p.88 / Chapter 4.4.4 --- Transcription reactivation by demethylation treatment --- p.89 / Chapter 4.4.5 --- BARX2 full length cDNA cloning --- p.89 / Chapter 4.5 --- Further study of other downregulated genes --- p.92 / Chapter 4.5.1 --- FLII --- p.92 / Chapter 4.5.2 --- ADAMTS15 --- p.94 / Chapter 4.5.3 --- P53AIP1 --- p.97 / Chapter Chapter Five: --- Discussion --- p.100 / Reference List --- p.118 / Appendix I: Reagents Preparation Recipe --- p.127 / Appendix II: PCR Primers for cDNA Cloning --- p.129

Yu, Le. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 171-198). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese.

In brief, mRNA expression profiling of candidate genes in each locus was performed using semi-quantitative RT-PCR in a panel of ESCC and NPC cell lines, normal tissues and immortalized epithelial cell lines. Genes downregulated in cancer cells but with high expression in normal tissues and immortalized epithelial cells were subjected to promoter methylation analysis using methylation-specific PCR (MSP), bisulfite genomic sequencing (BGS) and pharmacological demethylation treatment. Genes with tumor-specific downregulation and methylation were further selected as candidates and their tumor suppressive roles were verified via functional studies. / In conclusion, RAB39 and WDRX, epigenetically silenced in multiple cancer cell lines, were identified as novel TSG candidates in this study. Meanwhile, the tumor suppressive functions of ADAMTS8 were further validated, proving the efficiency of this integrative approach. Further study on these novel TSG candidates may help to elucidate the detailed molecular mechanisms for ESCC and NPC, and provide novel therapeutic targets and biomarkers. / In this study, RAB39 and WDRX were identified as candidate TSGs in 11q22.3 and 15q21.3, respectively. Both genes were broadly expressed in normal tissues and immortalized epithelial cell lines, but significantly downregulated and methylated in multiple cancer cell lines. Demethylation treatment with 5-Aza-2'-deoxycytidine restored their mRNA expression, indicating that CpG methylation directly contributed to their transcriptional inactivation. Methylation of RAB39 and WDRX was detected in primary ESCC and NPC, but rarely observed in normal tissues, implicating that their tumor-specific methylation might be used as biomarkers. Ectopic expression of both genes significantly inhibited the clonogenicity of multiple cancer cell lines, supporting their potential roles as functional TSGs. Moreover, WDRX repressed WNT/beta-catenin signaling, underscoring a possible anti-tumorigenic mechanism for it. In addition, ADAMTS8 was revealed to inhibit clonogenicity of NPC and ESCC cell lines, acting as a negative modulator for ERK pathway and a potential pro-apoptotic metalloprotease. / Inactivation of tumor suppressor genes (TSGs) contributes to the genesis of cancers including esophageal squamous cell carcinoma (ESCC) and nasopharyngeal carcinoma (NPC), two prevalent causes of death in Hong Kong. Apart from genetic abnormalities, epigenetic disruptions including CpG methylation represent another major mechanism for TSG inactivation. Promoter methylation of multiple TSGs was detected in different cancer types, suggesting that it could be utilized as therapeutic target or biomarker for disease diagnosis and prognosis. / TSGs are often located at frequently deleted chromosomal regions and subjected to tumor-specific methylation, making it possible to use an integrative epigenetic and genomic approach combining array comparative genomic hybridization (aCGH) with epigenetic profiling to screen for novel TSGs. Previous aCGH revealed that several loci in 11822.3, 15q14, 15q21.1 and 15q21.3 underwent frequent copy number loss in ESCC cell lines. Loss of heterozygosity (LOH) of these regions was also reported in other cancers, indicating that TSGs might reside within them. The aim of this study was thus to identify the candidate TSGs in these loci and study their anti-tumorigenic roles. In addition, the tumor suppressive function of ADAMTS8, a silenced 11q25 candidate TSG previously identified in our lab via this approach, was also studied. / Li, Jisheng. / Adviser: Qian Tao. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 136-159). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Thesis (MSc (Genetics))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: Oesophageal cancer (OC) is the sixth leading cause of cancer related deaths in the world with approximately 300 000 new cases reported each year. OC may be characterized into two forms with 90% of cases presenting as squamous-cell carcinoma (SCC) and the remaining 10% as adenocarcinoma (ADC). Several factors have been attributed to the development of OC, including oesphageal injury and/or irritation, chronic inflammation and excess iron associated with enhanced tumour growth. The HAMP gene codes for a 25 amino-acid protein found to be primarily expressed in the liver and crucial to regulation of bodily iron status. Defects occurring in the HAMP gene could therefore lead to the dysregulation of the gene, resulting in an iron overload status. Iron overload is a previously described risk factor in the development of various cancers, including OC, and therefore the aim of this study was to investigate whether dysregulation of the HAMP gene may be involved in the cancer phenotype exhibition. The study cohort comprised of 48 unrelated patients presenting with SCC and a control group of 51 healthy, unrelated population-matched individuals. Mutation detection techniques included polymerase chain reaction (PCR) amplification, heteroduplex single-stranded conformation polymorphism (HEX-SSCP) analysis and bi-directional semi-automated DNA sequencing analysis. Screening of the 5’ regulatory region (5’UTR) of the HAMP gene revealed one known (-582A/G) and two novel (-188C/T and -429G/T) variants with the -429G/T variant showing statistically significant reduction in expression in patients relative to controls. Iron parameters were correlated between patient and control cohorts, as well as for variant presence and absence within individuals. Luciferase reporter constructs were used to investigate the functional implications of the presence of a variant on HAMP gene expression, and how these results correlated to the iron parameter statistics obtained. Luciferase reporter assay results indicated the -188C/T and -429G/T variants to result in under-, and the -582A/G variant to result in over-expression at the basal level, relative to the respective wild-type sequence constructs. Correlation of the luciferase data with the iron parameter statistics, indicate the -429G/T variant to be coupled to significantly higher levels of ferritin and C-reactive protein (CRP) and significantly lower levels of serum-iron and transferrin when compared to individuals without the variant. Considering only the patient group, the presence of the -188C/T and -429G/T variants were coupled to significantly lower levels of transferrin in patients with either variant, compared to patients without. The variants found within the HAMP promoter region are therefore able to alter gene regulation to an extent where iron parameters deviate between healthy and OC afflicted individuals, and also between patients with and without a variant. This dysregulation in iron homeostasis may play a role in the development and/ or progression of OC. Characterisation of the 5’ UTR of the HAMP gene may contribute to linking iron regulation to the establishment of an effective screening program, facilitating the early detection of OC. / AFRIKAANSE OPSOMMING: Slukdermkanker (SK) is die sesde grootste oorsaak van kanker-verwante sterftes in die wêreld, met sowat 300 000 nuwe gevalle wat aangemeld word elke jaar. SK kan geklassifiseer word in twee vorme, waar 90% van die gevalle plaveisel-selkarsinoom (SSC) vorm en die oorblywende 10%, adenokarsinoom (ADC). Verskeie faktore word toegeskryf aan die ontwikkeling van SK, insluitend slukderm beserings en/ of irritasie, chroniese inflammasie en oormatige ystervlakke wat geassosieer word met verhoogde gewasgroei. Die HAMP geen kodeer vir 'n 25 aminosuur proteïen wat hoofsaaklik in die lewer uitgedruk word en noodsaaklik is vir die regulering van ystervlakke in die liggaam. Defekte wat in die HAMP geen voorkom kan dus die onreëlmatige regulering van die geen tot gevolg hê, wat lei tot yster-oorlading. Yster-oorlading is voorheen beskryf as ‘n risiko faktor in die ontwikkeling van verskillende vorme van kanker, insluitend SK en gevolglik was die doel van hierdie studie om te bepaal of die wanregulering van die HAMP geen betrokke mag wees by die uitdrukking van die kanker fenotipe. Die studiepopulasie het bestaan uit 48 onverwante pasiënte met SSC en ‘n kontrole-groep van 51 gesonde, onverwante soortgelyke individue. Die mutasie opsporingstegnieke wat gebruik is, het polimerase kettingreaksie (PKR) amplifisering, heterodupleks enkelstring-konformasie polimorfisme (HEX-SSCP) analise en bidireksionele semi-outomatiese DNS volgordebepaling-analise van die geïdentifiseerde variante ingesluit. Sifting van die 5’ regulerende area (5'UTR) van die HAMP geen het een bekende (-582A/G) en twee nuwe (-188C/T en -429G/T) variante opgelewer, met die -429G/T variant wat statisties beduidend onderdruk is in pasiënt uitdrukkings vlakke relatief tot 'n gesonde kontole-groep. Yster-parameters van alle pasiënt en kontole individue is gekorreleerd tussen pasiënt en kontrole groepe, sowel as vir teenwoordigheid of afwesigheid van variante in elke individu. Luciferase verklikker konstrukte is gebruik om die funksionele implikasies van die teenwoordigheid van ‘n variant op HAMP geenuitdrukking te ondersoek, en hierdie resultate te korreleer met yster-parameter statistieke wat verkry is. Luciferase verklikkertoetse dui aan dat die -188C/T en -429G/T variante tot verminderde, en die -582A/G variant lei tot die verhoogte uitdrukking op die basale vlak lei, relatief tot die onderskeie wilde-tipe konstukte. Korrelasie van die luciferase data met die yster-parameter statistieke, dui aan dat die -429G/T-variant gekoppel is aan aansienlik hoër vlakke van feritien en C-reaktiewe proteïen (CRP) en beduidend laer vlakke van serum-yster en transferrien in vergelyking is met individue sonder die variant. Met oorweging van slegs die pasiënt-groep, is die teenwoordigheid van die -188C/T en -429G/T variante beduidend gekoppel aan laer vlakke van transferrien in pasiënte met die variant, in vergelyking met pasiënte daarsonder. Variante binne die HAMP promotor is dus in staat om geenregulasie te verander tot so 'n mate dat die yster-parameters afwyk tussen gesonde en SK geaffekteerde individue, sowel as tussen pasiënte met en sonder ’n variant. Hierdie wanregulering in yster homeostase kan 'n rol speel in die ontwikkeling en/ of die progressie van SK. Karakterisering van die 5’ regulerende area van die HAMP geen kan grootliks bydra om ysterregulasie te verbind met die implementering van ‘n effektiewe siftingsprogram, en sodoende die vroeë opsporing van SK fasiliteer.

Resumo: o paciente com câncer de esôfago tem a desnutrição protéico-energética como principal fator de risco. A taurina é um composto sulfurado que participa de funções fisiológicas importantes, como a manutenção do sistema de defesa do organismo. O objetivo deste trabalho foi estudar o metabolismo da taurina e seus precursores e a associação destes, com os indicadores nuíricionais de pacientes com câncer de esôfago. Para tanto, realizou-se estudo prospectivo com corte vertical e grupo controle, em 18 pacientes (43-73 anos) portadores de neoplasia maligna de esôfago, e 20 voluntários (27-65 anos) controles sadios. Em todos foram realizadas dosagens plasmáticas de taurina, cisteína e homocisteína e avaliação do estado nutricional antropométrico e bioquímico. Paralelamente, foram coletados dados referentes à história e ao diagnóstico clínico e período de sobrevivência dos pacientes. Os dados foram analisados por meio do teste t de Sfudenf e correlação de Pearson. O câncer de esôfago foi mais predominante no sexo masculino e na raça branca. Houve maior freqüência do carcinoma espino celular e localização no terço superior. A maioria dos pacientes. no momento do diagnóstico, apresentou estágio avançado da doença (estadio IV). A perda de peso nos pacientes foi de 14,9%, entretanto, variáveis CMB e %GC não apresentaram diferença estatística com o controle. Adicionalmente, no grupo de estudo, foram observadas hipoalbuminemia e elevação da PCR (55,5% e 50% dos pacientes, respectivamente). Os níveis de Hb, Ht, Colesterol total, HOL e cisteína foram menores, e os de TGO, TGP, taurina e homocisteína maiores significativamente do que o grupo controle (p<0,05). A taurina se correlacionou positivamente com CTL (r=0,49 e p=O,03) e a sobrevida... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The main risk factor of the esophagus' cancer patient is pratein-energetic malnourishment. Taurine is a sulphur-containing amino acid which takes part in important physiological functions such as organíc defense system maintenance. The objective of this work was to study the metabolism of taurine and its precursors and their association with nutritional indicators in patients with esophagus cancer whose main risk factor is protein-energy undemutrition. This was a prospective study with a vertical cut and control group with 18 malignant esophageal neoplasia (4373yrs) and 20 healthy volunteers (27-65yrs). Ali individuais were scrutinized with respect to their plasma levels of taurine, cysteine, and homocysteine and underwent nutritional, anthropometrical, and biomedical state evaluation. Also data were collected on patient history, clínical diagnosis, and survival time. Data were analyzed by Student t and Pearson Correlatíon tests. Esophagus cancer was more predominant in white males. Squamous cel! carcinoma and superior third location were frequent Most patients were in the advanced stage when diagnosed (Stage IV). Patient weight loss was 14.9%, however, AMC and %BF were not statistically different to contrais. Additionally hypoalbuminemia and elevaíed PCR (in 55.5% & 50% of patients, respectively). Hb, Ht, total cholesterol, HDL, and cysteine were significantly lower, and GOT, GPT, taurine, and homocysteine significantly higher than controls (p<0.05). Taurine positively correlated with CTL... (Complete abstract click eletronic address below) / Orientador: Maria Aparecida Arruda Coelho Henry / Coorientador: Roberto Carlos Burini / Mestre

Orientador: Akebo Yamakami / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-09T21:49:58Z (GMT). No. of bitstreams: 1 Kawamura_Jorge_M.pdf: 1810800 bytes, checksum: 1fe99baac150732c9cf14dacf6188caf (MD5) Previous issue date: 2007 / Resumo: Este trabalho tem como objetivo a utilização de métodos de inteligência artificial para diagnosticar câncer do esôfago. Este estudo concentrou-se na utilização dos conceitos de sistemas fuzzy. O emprego de sistemas fuzzy ou sistemas difusos para a área de saúde foi motivado pela deficiência de sistemas inteligentes nesta área e pela simplicidade na sua utilização. O sistema fuzzy apresenta características como a existência de uma região duvidosa (ou região vaga) na análise das informações e seu método de interpretação é mais próximo à linguagem do ser humano. Os modelos de inferência utilizados foram o método de Mamdani e o método Sugeno. São analisadas as vantagens e desvantagens de cada método. A partir das características do câncer do esôfago e dos conceitos de sistemas fuzzy foi desenvolvido um sistema para diagnóstico de câncer do esôfago / Abstract: The aim of this work is to use the artificial intelligent methods to diagnose esophagus cancer. The artificial intelligence theme has many areas, so this study concentrated in fuzzy system concepts. The lack of intelligent system in health's area motivated this study and fuzzy theory was chosen by its simplicity. This type of system has characteristics like existence of a doubt region in the information analysis and its interpretation's methods is closer to human language. The inference models used are Mamdani and Sugeno models. The advantages and disadvantages are checked too. From esophagus cancer characteristics and fuzzy system concepts, a system to diagnose esophagus cancer was built / Mestrado / Telecomunicações e Telemática / Mestre em Engenharia Elétrica

First, expression profiling of ZNFs with CpG islands at 10 clusters of Chr19 was examined in a panel of NPC and ESCC cell lines by semi-quantitative RT-PCR, with adult normal tissues - larynx and esophagus as controls. Several down-regulated genes were identified, and I further focused on 5 candidates: ZNF382, ZNF545, ZFP30, ZNFT1 and ZNFT2. These genes were frequently downregulated in NPC, ESCC, lung, gastric, colon and breast carcinomas. Their promoters were frequently methylated in multiple downregulated cell lines but less in non-tumor cell lines as revealed by methylation-specific PCR (MSP) and bisulfite genomic sequencing (BGS). Their expression could be restored by pharmacologic or genetic demethylation, suggesting that DNA methylation was directly involved in their silencing. The frequent methylation of these genes indicated they could act as potential biomarkers. / In conclusion, several novel candidate TSGs epigenetically silenced in tumor cells were identified in this study. Their downregulation by promoter methylation was tumor-specific, which could be use as epigenetic biomarkers for diagnosis. / More functional studies were done for ZNF382 and ZNF545, I found that ectopic expression of ZNF382 and ZNF545 in tumor cells lacking endogenous expression could inhibit tumor cell clonogenicity, proliferation and induce apoptosis. I found that ZNF382 suppressed tumorigenesis through mediating heterochromatin formation, as ZNF382 was revealed to be co-localized and interacts with heterochromatin protein. For ZNF545, I found that it is a transcriptional repressor. I further showed that ZNF545 was located in the nucleus and sequestered in the nucleolus. ZNF545 could inhibit tumorigenesis at least partially through downregulating the transcription of target genes or regulating nucleolus function such as ribosome biogenesis. / The development of a tumor from a normal cell is a complex and multi-step process. A large number of oncogenes, tumor suppressor genes (TSGs) and signal transduction pathways are involved in this process. Tumor-specific methylation of TSGs in multiple tumors indicated that it could be used as epigenetic biomarker for molecular diagnosis and therapeutics. / The functions of KRAB-containing proteins are critical to cell differentiation, proliferation, apoptosis and neoplastic transformation. A large number of ZNF genes are located in 10 clusters at chromosome 19. Some of the KRAB-ZNF may function as potential TSGs with epigenetic alterations. Thus, I try to identify silenced novel KRAB-ZNF candidate TSGs through screening chromosome 19. / Cheng, yingduan. / Adviser: Tao Qian. / Source: Dissertation Abstracts International, Volume: 73-02, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 110-136). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.