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Estudo de polimorfismos dos genes TP53 e VEGFA como marcadores prognósticos no adenocarcinoma colorretal / Study of polymorphisms of genes TP53 and VEGFA as prognostic markers in colorectal adenocarcinoma

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Previous issue date: 2014 / Fundação de Amparo à Pesquisa do Estado de Mato Grosso - FAPEMAT / O cancer colorretal (CCR) e a segunda neoplasia maligna mais prevalente no mundo, sendo quarto tumor mais incidente entre os homens e o terceiro entre as mulheres. Aproximadamente 608.700 mortes por ano sao atribuidas a esta causa. Sua etiologia multifatorial envolve complexa interacao entre fatores ambientais e geneticos, o que resulta em um risco acumulado de 6% de desenvolver CCR ao longo da vida. Os fatores prognosticos histopatologicos habitualmente utilizados como parametros de tratamento e prognostico tem divergencias inerentes ao metodo. Mesmo com tratamento adequado, aproximadamente 40% dos pacientes com CCR apresentarao recidivas, muitas vezes sem haver fatores de mau prognostico previos tornando necessaria a busca por novos marcadores mais precisos e uniformes. Dentre estes, os polimorfismos geneticos surgem como candidatos a fatores de risco para etiologia, prognostico e resposta terapeutica, porem com resultados nao consensuais, nao havendo no Brasil muitas informacoes e nenhuma em Mato Grosso. O objetivo deste estudo foi identificar as frequencias dos polimorfismos dos genes TP53 codon 72 G>C (Arg/Pro) (rs1042522) e VEGFA: -1498C>T (rs833031), -634G>C (rs2010963), +936C>T (rs3025039) e investigar suas associacoes com fatores prognosticos clinicos, anatomopatologicos e a sobrevida, por meio de estudo epidemiologico tipo coorte prospectivo constituido por 131 pacientes operados consecutivamente por CCR em Cuiaba- Mato Grosso. O DNA foi extraido de sangue periferico e sua amplificacao e discriminacao alelica para cada polimorfismo estudado foi realizada atraves da tecnica de reacao em cadeia de polimerase em tempo real. A analise de associacao entre as variaveis categoricas foi feita atraves da regressao logistica, a sobrevida pelo metodo de Kaplan e Meier e para a analise multivariada a regressao de Cox. Os resultados mostraram que as frequencias dos polimorfismos dos genes TP53 e VEGFA foram semelhantes as encontradas nos diferentes estudos. Conclusao: Houve associacao entre o genotipo C/C do VEGFA-1498C>T e metastase hepatica (p=0,048) e entre o genotipo C/T do VEGFA+936C>T com invasao perineural (p=0,026). Os genotipos C/T (HR=2,79) e C/C (HR=4,67) do gene VEGFA -1498C>T e C/C (HR=3,76) do gene VEGFA -634C>G atuaram como fatores prognosticos independentes para o risco de obito / Colorectal cancer (CRC) is the second most prevalent malignancy in the world being the fourth most frequent tumor among men and third among women. Approximately 608,700 deaths per year are attributed to this cause. Multifactorial etiology involves a complex interaction between genetic and environmental factors, resulting in a 6 % cumulative risk of developing CRC lifelong. The histopathological prognostic factors commonly used as parameters of treatment and prognosis have differences inherent to the method. Even with proper treatment, approximately 40 % of patients with CRC present recurrences, often with no previous risk factors for poor prognosis making it necessary to search for new markers more accurate and uniform. Among these markers, genetic polymorphisms arise as candidate to risk factor for etiology, prognosis and response to therapy, but the results were not consensual, not having a lot of information in Brazil and none in Mato Grosso. The aim of this study was to identify the frequencies of polymorphisms of TP53 codon 72 G> C (Arg/Pro) (rs1042522) and VEGFA : -1498C > T (rs833031) , -634G > C (rs2010963) , +936 C > T (rs3025039) and investigate their associations with clinical prognostic factors, pathological and survival through epidemiological prospective cohort consisting of 131 patients consecutively operated by CRC in Cuiabá, Mato Grosso . DNA was extracted from peripheral blood and its amplification and allelic discrimination for each polymorphism was performed using the technique of polymerase chain reaction in real time. The analysis of association between categorical variables was performed using logistic regression, survival by Kaplan and Meier method and multivariate analysis for the Cox regression. Results showed that the frequencies of polymorphisms of TP53 and VEGFA were similar to those in different studies. An association between genotype C / C of VEGFA -1498C > T and liver metastasis (p = 0.048) and between genotype C / T VEGFA +936 C> T with perineural invasion (p =0.026). The genotype C / T (HR = 2.79) and C / C (HR = 4.67) gene VEGFA -1498C > T and C / C (HR = 3.76) gene VEGFA -634C > G acted as independent prognostic factors for the risk of death by CRC. / FAPEMAT: 732622/2008 / FAPEMAT: 752508/2011 / BV UNIFESP: Teses e dissertações

Identiferoai:union.ndltd.org:IBICT/oai:repositorio.unifesp.br:11600/23177
Date January 2014
CreatorsEspirito Santo, Gilmar Ferreira [UNIFESP]
ContributorsUniversidade Federal de São Paulo (UNIFESP), Waisberg, Jaques [UNIFESP]
PublisherUniversidade Federal de São Paulo (UNIFESP)
Source SetsIBICT Brazilian ETDs
LanguagePortuguese
Detected LanguageEnglish
Typeinfo:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis
Formatxx, 109f. p.
Sourcereponame:Repositório Institucional da UNIFESP, instname:Universidade Federal de São Paulo, instacron:UNIFESP
Rightsinfo:eu-repo/semantics/openAccess

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