Gastrointestinal Stromal TumorsBenzamidesPiperazinesPyrimidinesProto-Oncogene Proteins c-kitGastrointestinal NeoplasmsAntineoplastic AgentsReceptor, Platelet-Derived Growth Factor alphaStromal CellsMesenchymomaNeoplasms, Connective TissuePyrrolesDuodenal NeoplasmsEpithelioid CellsMitotic IndexLeiomyosarcomaImmunohistochemistryIleal NeoplasmsNeoplasms, Multiple PrimaryJejunal NeoplasmsIntestinal NeoplasmsStomach NeoplasmsTomography, X-Ray ComputedTumor Markers, BiologicalMutationIndolesSex Cord-Gonadal Stromal TumorsProtein Kinase InhibitorsTreatment OutcomeDigestive System Surgical ProceduresDNA Mutational AnalysisPrognosisSarcomaNeurofibromatosis 1Liver NeoplasmsDisease-Free SurvivalGastrectomyCarney ComplexLeiomyomaAntigens, CD34Drug Resistance, NeoplasmEndosonographyLaparotomyInterstitial Cells of Cajal