The Gastric Cancer Registry will combine data acquired directly from patients with gastric cancer; with a family history of gastric cancer in a first or second degree relative; or persons with a known germline mutation in their CDH1 (E-Cadherin) gene via an online questionnaire with genomic data obtained from saliva, blood and tissue samples. The purpose of this registry is to gain better understanding of the causes of gastric cancer, both environmental and genetic; whether certain genomic data can predict outcomes of treatment and survival.