Immunohistochemistry (IHC) for glial fibrillary acidic protein (GFAP) and synaptophysin showed that the expression pattern of both GFAP and synaptophysin in medulloblastoma in both Ptch1+/−; Gadd34+/− mice and Ptch1+/−;Gadd34−/− mice was comparable with Ptch1+/−; Gadd34+/+ mice (Figure 3D–3I). This evidence concerns the gene PPP1R15A and medulloblastoma.