If you agree to participate in this study, your doctor will provide information to a data registry about your physical and clinical traits, the past and current medical care you have received to treat your GIST, and clinically-related, economically-related, and health-related quality of life information. About 200 doctors will provide information on their patients for the Registry. Your doctor will collect this information when you first join the Registry and at each regularly scheduled visit you make to your doctor's office. The information collection will continue for as long as you and your doctor feel it is appropriate. The information that is entered into the Registry will remain there indefinitely. It is hoped that this sharing of information will lead to a better understanding of how to best treat patients with GIST.