Gastrointestinal NeoplasmsTogoSemustineCarcinoid TumorGastrointestinal Stromal TumorsNeuroendocrine TumorsStomach NeoplasmsDuodenal NeoplasmsPancreatic NeoplasmsAdenocarcinomaColonic NeoplasmsRectal NeoplasmsCarcinoembryonic AntigenFluorouracilCell Line, TumorColorectal NeoplasmsEsophageal NeoplasmsLiver NeoplasmsAntineoplastic Combined Chemotherapy ProtocolsNeoplasmsTumor Cells, CulturedTumor Markers, BiologicalTumor BurdenTumor Necrosis Factor-alphaWilms TumorNeoplasms, ExperimentalGenes, Tumor SuppressorTumor Suppressor Protein p53Tumor Suppressor ProteinsBrain NeoplasmsTumor MicroenvironmentMammary Neoplasms, ExperimentalNeovascularization, PathologicNeoplasm MetastasisTransplantation, HeterologousXenograft Model Antitumor AssaysCell ProliferationMice, Inbred BALB CAntigens, NeoplasmNeoplasm ProteinsCell DivisionCarcinoma, Ehrlich TumorFibrosarcomaKidney NeoplasmsCell Transformation, NeoplasticMice, Inbred C57BLRNA, MessengerSkin NeoplasmsOvarian NeoplasmsGliomaNeoplasm StagingDNA, NeoplasmMice, SCIDSarcoma, ExperimentalSignal TransductionReverse Transcriptase Polymerase Chain ReactionRhabdoid TumorMelanoma, Experimental