GliomaBrain NeoplasmsOptic Nerve GliomaGlioblastomaMice, NudeNeoplasm TransplantationNeovascularization, PathologicCell Line, TumorXenograft Model Antitumor AssaysCell ProliferationCell Growth ProcessesNeoplasm InvasivenessGene Expression Regulation, NeoplasticApoptosisTumor Cells, CulturedAntineoplastic AgentsCell DivisionDisease Models, AnimalAstrocytomaSignal TransductionBrain Stem NeoplasmsDacarbazineAntineoplastic Agents, AlkylatingSupratentorial Neoplasms