GFAP and medulloblastoma: This result was further verified in the medulloblastoma tissues from GFAP-Cre;SmoM2+/- mice, where constitutively active Smo (SmoM2) is expressed in cerebellar granule neuron precursors (GNPs) by using a human glial fibrillary acidic protein promoter-driven Cre (GFAP-Cre) (Figure 2I, J).