To explore the metastatic properties of Group 3 medulloblastoma cells, we used two patient-derived Group 3 medulloblastoma primary xenograft lines (MB0026,7 and Med2112FH, see Methods section), two human Group 3 medulloblastoma cell lines (D283 and D425), and a MYC-driven mouse medulloblastoma cell line (MP8) that gave rise to spontaneous leptomeningeal metastasis in vivo, recapitulating the human disease (Fig. 1a, b). The gene discussed is MYC; the disease is medulloblastoma.