Esophageal Cancer Genetics Studies

Overview

The overall goal of this project is to understand the role of genetics in the etiology and prevention of upper gastrointestinal cancer, primarily esophageal cancer, but also cancers of the gastric cardia and body. Esophageal cancer is the second most common cause of cancer death in China and the seventh most common cause of cancer death worldwide. Evidence suggests that genetic factors may play an important role in the etiology of this malignancy, and identification of esophageal cancer susceptibility genes may allow screening of populations to identify persons at particularly high risk, who could then be targeted for prevention strategies (e.g., chemoprevention or early detection). There are several lines of evidence supporting the idea that there is genetic susceptibility for esophageal cancer in high-risk Chinese populations, including an association of positive family history with increased risk, evidence of familial aggregation of cases, and segregation analyses suggesting Mendelian inheritance in high-risk families. Several different but complementary approaches will be used to identify esophageal cancer susceptibility genes. (Because of etiologic similarities and for logistic reasons, parallel efforts will be made with gastric cardia and body cancers.) First, a tumor/non-tumor study will be conducted in which a biological specimen bank consisting of samples (tumor, non-tumor, venous blood, finger stick blood, and buccal cells) from several hundred cases of esophageal, gastric cardia, and gastric body cancers will be developed in Taiyuan that can be used for the identification of esophageal (as well as gastric cardia and body) cancer susceptibility genes and potential early genetic markers of these cancers. High-density genome-wide scans with microsatellite markers will be used in a limited number of cases to identify potential hot spots followed by further testing of these hot spots and other candidate markers in additional tumor/non-tumor samples. Premalignant morphologic lesions will also be examined. Second, blood samples for DNA will be collected from approximately 100 healthy individuals from high-risk (Yangcheng County) and low-risk (Beijing) areas to examine potential population differences in polymorphisms for selected genomic markers. Third, a large case-control study with cancers of the esophagus, cardia, and body of stomach will be conducted to evaluate polymorphisms in the candidate markers identified in other components of this project, and to evaluate gene-environment interactions. Finally, a family study will be conducted to evaluate linkage of candidate markers with cancer in families having 2 or more cases with cancers of the esophagus, cardia, and/or body of stomach.

The overall goal of this project is to understand the role of genetics in the etiology and prevention of upper gastrointestinal cancer, primarily esophageal cancer, but also cancers of the gastric cardia and body. Esophageal cancer is the fourth most common cause of cancer death in China and the seventh most common cause of cancer death worldwide. Evidence suggests that genetic factors may play an important role in the etiology of this malignancy, and identification of esophageal cancer susceptibility genes may allow screening of populations to identify persons at particularly high risk, who could then be targeted for prevention strategies (e.g., chemoprevention or early detection). There are several lines of evidence supporting the idea that there is genetic susceptibility for esophageal cancer in high-risk Chinese populations, including an association of positive family history with increased risk, evidence of familial aggregation of cases, and segregation analyses suggesting Mendelian inheritance in high-risk families. Several different but complementary approaches are proposed to identify esophageal cancer susceptibility genes. (Because of etiologic similarities and for logistic reasons, parallel efforts will be made with gastric cardia and body cancers.) First, a tumor/nontumor study will be conducted in which a biological specimen bank consisting of samples (tumor, nontumor, venous blood, finger stick blood, and buccal cells) from a total of approximately 150 cases each of esophageal, gastric cardia, and gastric body cancers will be developed in Taiyuan that can be used for the identification of esophageal (as well as gastric cardia and body) cancer susceptibility genes and potential early genetic markers of these cancers. Comparative genomic hybridization and microsatellite markers will be used to scan the genome in up to 20 cases to identify potential hot spots followed by further testing of these hot spots and other candidate markers in additional tumor/nontumor samples. Second, blood samples for DNA will be collected from approximately 100 healthy individuals from high-risk (Yangcheng County) and low-risk (Beijing) areas to examine potential differences in polymorphisms for selected genomic markers. Third, a casecontrol study will be conducted to evaluate hot spots and candidate markers identified from the tumor/nontumor study and potential gene-environment interactions. Finally, a linkage study will be conducted by identifying and collecting information and DNA from cases and first degree relatives in special highly informative families (those with 2 or more cases having obtainable DNA) as well as population-based ascertainment and collection of information and DNA from all new cases from Yangcheng County.