Endometrial cancer (EC) is the fourth most common cancer affecting women in the UK. Those with a family history of EC have an increased risk compared with the general population. Highly penetrant germline mutations in mismatch repair (MMR) genes and DNA polymerases account for only a small proportion of the familial aggregation. The aim of this thesis is to investigate the genetic susceptibility to EC in the general population using cases and controls of European ancestry. A GWAS meta-analysis totalling 7,737 EC cases and 37,144 controls yielded five novel EC risk loci of genome-wide significance (P < 5x10<sup>−8</sup>). In decreasing order of significance, these were at chromosomes 13q22.1 (rs11841589, near KLF5), 6q22.31 (rs13328298, in LOC643623 and near HEY2 and NCOA7), 8q24.21 (rs4733613, telomeric to MYC), 15q15.1 (rs937213, in EIF2AK4, near BMF) and 14q32.33 (rs2498796, in AKT1, near SIVA1). A second independent EC signal was found in the 8q24 locus. The association found in a previous EC GWAS at HNF1B on chromosome 17 was replicated at a higher significance, with the most significant SNP being rs11263763. CYP19A1 SNPs have previously been associated with EC and higher circulating levels of oestrogen from candidate studies, but I confirmed this locus to be genome-wide significant for the first time. Functional annotation and in vitro studies for the EC risk loci at the intergenic region of chromosome 13q22 suggested that the functional SNP sits within a transcriptional repressor for KLF5, with the higher-risk allele reducing repressor activity. The propensity for germline MMR and DNA polymerase muations to cause both EC and colorectal cancer (CRC) prompted me to search for common variants associated with both cancer phenotypes. An EC CRC GWAS meta-analysis showed little evidence of shared susceptibility loci. However, this meta-analysis revealed a novel genome-wide significant risk locus: rs3184504, a missense SH2B3 SNP that has not previously been associated with either EC or CRC. This thesis has enhanced the understanding of genetic susceptibility to sporadic EC and increased the number of genome-wide EC-associated variants to seven.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:658527 |
| Date | January 2015 |
| Creators | Cheng, Timothy |
| Contributors | Tomlinson, Ian |
| Publisher | University of Oxford |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://ora.ox.ac.uk/objects/uuid:3a559ae0-156f-48a2-a64e-b03a13c562df |
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