Prospective Evaluation and Molecular Profiling in People With Gastric Tumors

Background: * Greater than 90% of gastric tumors are of epithelial origin and are classified as adenocarcinomas; the remainders include GIST, carcinoid and lymphoma. * Gastric adenocarcinoma is rare in the United States (incidence 7.4 per 100,000). * Mortality rates are high with an estimated 5-year overall survival of 25% - 30%. * Up to 3% of gastric adenocarcinomas occur as part of a heritable cancer syndrome. * Molecular sub-classification of gastric adenocarcinomas has been reported, however translation of these findings into clinical management of patients has yet to occur. Objectives: * To permit clinical and laboratory evaluation and molecular profiling of tumor tissue from patients with gastric malignancies or non-invasive (neoplastic) conditions. * Assess eligibility for enrollment in studies of gastric cancer conducted in the CCR. * To allow long-term follow up of patients with gastric tumors, or heritable gastric malignancy syndromes, to support clinical and preclinical research particularly related to molecular alterations in gastric tumors and their response to therapy. Eligibility: Patients with any of the following are eligible: * Malignant or non-invasive, neoplastic lesions of the stomach confirmed by histopathology or cytopathology; * Suspicious lesions not yet confirmed, but considered likely related to the stomach pending further evaluation; * Confirmed, deleterious germline mutation (including but not limited to HDGC, GAPPS) known to predispose to gastric tumors; * Confirmed or suspicious heritable gastric malignancy disorder; * Clinically suspicious personal or family medical history of gastric cancer or gastric cancer syndrome that warrants genetics evaluation. * Age greater than or equal to 2 years. Design: * This protocol is designed to facilitate clinical evaluation, molecular tumor profiling, and long-term follow up of patients with gastric tumors. * Patients will be screened and clinical evaluation performed to determine eligibility for other CCR trials for gastric tumors. * No investigational treatment will be administered and no procedures will be done for only research purposes on this protocol. * It is anticipated that the protocol will enroll a maximum of 250 patients.