MedulloblastomaCerebellar NeoplasmsHedgehog ProteinsNeuroectodermal Tumors, PrimitiveBrain NeoplasmsInfratentorial NeoplasmsCranial IrradiationCerebellumAnaplasiaGranuloma, Lethal MidlineCranial Fossa, PosteriorMidline Thalamic NucleiEpendymomaVeratrum AlkaloidsBasal Cell Nevus SyndromeCell Line, TumorSignal TransductionBody PatterningGene Expression Regulation, DevelopmentalAxonsCentral Nervous SystemCell ProliferationChromosomes, Human, Pair 17Gene Expression Regulation, NeoplasticNerve Tissue ProteinsReceptors, Cell SurfaceImmunohistochemistryCombined Modality TherapyMutism