In 2009, NCI and the Chilean government signed a letter of intent to join forces to identify reasons for the high risk of gallbladder cancer in Chile in hopes of developing strategies for cancer prevention. Subsequently, DCEG and NCI s Office of Latin America Cancer Program Development (OLACPD) organized a gallbladder workshop for U.S. and Chilean scientists in Santiago, Chile. Workshop participants concluded that a large-scale multidisciplinary epidemiologic investigation in Chile is urgently needed to clarify risk factors specific to the Chilean population and to help derive preventive strategies to reduce the burden of gallbladder cancer in Chile. Before NCI/DCEG commits substantial resources to support a large field effort, we propose to evaluate the feasibility of successfully carrying out a high quality multidisciplinary epidemiologic study in Chile. We are requesting TEP approval for the This protocol describes a pilot study of gallbladder cancer in Chile with a case-control in four hospitals (120 subjects, including 40 cancer cases, 40 gallstone cases, and 40 population controls) to assess the feasibility of conducting a large study in Chile component, including gallbladder cancer cases, gallstone patients, and population-based controls, and a gallstone expansion recruiting additional patients undergoing cholecystectomy and population-based controls to further explore gallstones in this high-risk population. The total number of participants recruited will be 420.