Pathway activation through the stabilisation and nuclear accumulation of CTNNB1 has been shown in sporadic medulloblastomas (Eberhart et al, 2000; Koch et al, 2001; Yokota et al, 2002; Ellison et al, 2005; Clifford et al, 2006; Gajjar et al, 2006; Thompson et al, 2006). Here, CTNNB1 is linked to medulloblastoma.