Hereditary Gastric Cancer Syndromes: An Integrated Genomic and Clinicopathologic Study of the Predisposition to Gastric Cancer

Background: An estimated 1-3% of gastric cancer cases occur within a familial background as part of an inherited cancer syndrome. Hereditary Diffuse Gastric Cancer (HDGC) is the most frequent form of familial gastric cancer and has been linked to a germline mutation in the CDH1 gene. Gastric Adenocarcinoma and Proximal Polyposis of the Stomach (GAPPS) is a more recently described autosomal dominant syndrome characterized by fundic gland polyposis with antral sparing. Other germline mutations that predispose to gastric cancer such as SDH (succinate dehydrogenase protein subunits) gene and CTNNA1 (alpha catenin). Objectives: Characterize the natural and clinical histories of hereditary gastric cancer syndromes. Eligibility: Individuals, and family members, who fulfill clinical criteria for a hereditary gastric cancer syndrome irrespective of previous genetic testing or treatment. Design: These rare families will be recruited to genetically confirm diagnosis and study the natural history of hereditary gastric cancers. Genetic testing will be offered to gain appreciation of the effect of mutations on the relative activity of various germline and somatic mutations. We will determine if there is a relationship between mutation and disease phenotype.