The incidence of esophageal adenocarcinoma (EA), a rapidly fatal disease, has increased faster than any other cancer in the US over the last three decades - over 500 percent. Gastroesophageal reflux and obesity have been found to be key modifiable risk factors for the development of EA and its main precursor, Barrett's esophagus (BE). However, while reflux appears to be crucial to the neoplastic process, only about 10 - 15 percent of individuals with long-standing reflux symptoms develop BE in their lifetimes;among those who do, most do not progress to EA. Similarly, the mechanisms by which obesity increases risk of EA are not known. Thus, there must be other cofactors modulating the reflux-related chronic inflammatory effects on the esophageal epithelium and the local and systemic consequences of being overweight, that largely determine risk. Many of these cofactors are likely to be genetically mediated, and while family, twin and candidate gene studies support this notion, no genes have been established yet as playing a causal role. Here, we propose a large-scale genome-wide association study which takes advantage of the extensive data collected by investigators in the Barrett's and Esophageal Adenocarcinoma Consortium (BEACON) in 18 epidemiologic studies, representing the vast majority of the well-designed largely population-based studies of these diseases in the world. The overall goal of our research is to evaluate the influence of genetic susceptibility on risk of EA and BE. The primary aim is to identify tagSNPs most strongly associated with risk of BE and EA. In secondary aims we will evaluate the extent to which the most significant associations vary according to key environmental and host risk factors for these conditions, including gender, obesity and cigarette smoking. We propose a single phase approach over three years involving 7,500 participants, all of whom have been previously interviewed regarding major environmental and host risk factors and have donated blood specimens. The Illumina Infinium Human 610-Quad Chip will be used to genotype approximately 1,500 cases of EA, 3,000 cases of BE and 3,000 population controls. Additional sources of samples and data have been identified to provide replication studies (funding to be requested separately.) The resources of BEACON, together with recent advances in genomic technology and analytic methods, present a unique and cost-effective opportunity to a) study the influence of genetic and environmental factors in the etiology of these important diseases, b) aid in the identification of key biological pathways in their pathogenesis, and c) help target persons at highest risk so that screening, prevention and surveillance efforts can be directed most effectively.
The incidence of esophageal adenocarcinoma, a rapidly fatal disease, has increased more than six-fold over the past 30 years. By conducting a large-scale genome-wide association study using pooled data and DNA from 18 epidemiologic studies, we propose to evaluate the influence of genetic susceptibility on risk of this cancer and its main precancerous condition, Barrett's esophagus, and determine the extent to which susceptibility factors vary according to key environmental and host risk factors for these conditions. These results will aid in the identification of biological pathways important in the etiology of this cancer, and help target persons at highest risk so that screening, prevention and surveillance efforts can be directed most effectively.
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