Ectopic Wnt activation in primary patient-derived medulloblastoma lines proved that the activation of the Wnt/β-catenin pathway in WNT3A-conditioned medium significantly reduced the self-renewal capacity along with the Sox2 and Bmi1 expression in Group 3 and Group 4 medulloblastoma lines. The gene discussed is BMI1; the disease is medulloblastoma.