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Elucidation of the occurrence of extracolonic cancers in Lynch syndrome

Includes abstract.

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Main Author: Kalideen, Kusha
Other Authors: Ramesar, R
Format: Thesis
Language:English
Published: Department of Clinical Laboratory Sciences 2014
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access_status_str Open Access
author Kalideen, Kusha
author2 Ramesar, R
author_browse Kalideen, Kusha
Ramesar, R
author_facet Ramesar, R
Kalideen, Kusha
author_sort Kalideen, Kusha
collection Thesis
description Includes abstract.
format Thesis
id oai:open.uct.ac.za:11427/3167
institution University of Cape Town (South Africa)
language eng
last_indexed 2026-06-10T12:33:35.758Z
license_str Not specified — see source repository
provenance_str_mv Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository
publishDate 2014
publishDateRange 2014
publishDateSort 2014
publisher Department of Clinical Laboratory Sciences
publisherStr Department of Clinical Laboratory Sciences
record_format dspace
source_str UCTD — University of Cape Town Open Access Repository
spelling oai:open.uct.ac.za:11427/3167 Elucidation of the occurrence of extracolonic cancers in Lynch syndrome Kalideen, Kusha Ramesar, R Medicine Includes abstract. Includes bibliographical references (leaves 126-147). Lynch Syndrome, also known as Hereditary Non-Polyposis Colorectal Cancer (HNPCC) (OMIM #120435), is a familial disorder resulting from mutations within DNA MMR genes. Effective surveillance, diagnosis and treatment of the disorder is complicated due to the phenotypic and genetic heterogeneity of lynch syndrome, which exhibits an autosomal dominant mode of inheritance. Determine the molecular pathology of extracolonic cancers in Lynch syndrome and to elucidate whether or not the occurrence of these extracolonic cancers are a direct result of the mismatch repair deficiency. First, a modifier study was performed assessing the effect of a variant within the DNA MMR gene hMLH1 in a cohort of individuals predisposed to Lynch syndrome in order to examine a potential epistatic effect in the gene. In order to obtain a genetic signature of Lynch associated tumours, germline DNA and corresponding tumour DNA was isolated from Lynch syndrome patients. The genetic material was assessed via a panel of microsatellite rich genes and MS-MLPA. Finally, in silico analyses were undertaken assessing microarray data from microsatellite unstable colorectal and endometrial cancers to characterise novel candidate genes. The modifier study did not prove fruitful as no association was found between the hMLH1 promoter variant and site of cancer in individuals predisposed to Lynch syndrome. An association was observed heterozygous and homozygous variant genotypes and an increased risk of colorectal cancer, regardless of predisposing mutation (p = 0.000181). Two tumour suppressor genes; HIC1 and TIMP3, were found to be methylated in the tumour samples in the germline/tumour tissue study. This study also showed instability of the Erβ gene in the majority of tumour samples. Bioinformatic analysis utilising existing microarray data resulted in common under-expression of four genes and common overexpression in three genes in microsatellite unstable colorectal and endometrial cancers. Further investigation into the modifier study and elucidation of a genetic signature in MMR deficient, MSI cancers. The results obtained in this study contribute to the increasing body of knowledge in the field and the various stages of malignancies should be assessed for a more informative result. Genetic and functional studies should be performed on the information garnered from the bioinformatics analysis. Overall evaluation and molecular classification of Lynch syndrome tumours may guide better diagnosis, surveillance and treatment of those at risk. 2014-07-28T14:57:29Z 2014-07-28T14:57:29Z 2008 Master Thesis Masters MSc http://hdl.handle.net/11427/3167 eng application/pdf Department of Clinical Laboratory Sciences Faculty of Health Sciences University of Cape Town
spellingShingle Medicine
Kalideen, Kusha
Elucidation of the occurrence of extracolonic cancers in Lynch syndrome
thesis_degree_str Master's
title Elucidation of the occurrence of extracolonic cancers in Lynch syndrome
title_full Elucidation of the occurrence of extracolonic cancers in Lynch syndrome
title_fullStr Elucidation of the occurrence of extracolonic cancers in Lynch syndrome
title_full_unstemmed Elucidation of the occurrence of extracolonic cancers in Lynch syndrome
title_short Elucidation of the occurrence of extracolonic cancers in Lynch syndrome
title_sort elucidation of the occurrence of extracolonic cancers in lynch syndrome
topic Medicine
url http://hdl.handle.net/11427/3167
work_keys_str_mv AT kalideenkusha elucidationoftheoccurrenceofextracoloniccancersinlynchsyndrome