Transfection of a DKK-1 gene construct into D283 cell lines suppressed medulloblastoma tumor growth in colony focus assays by 60% (P < 0.001), and adenoviral vector-mediated expression of DKK-1 in medulloblastoma cells increased apoptosis fourfold (P < 0.001) [33]. Here, DKK1 is linked to medulloblastoma.