SPARC and medulloblastoma: The SPARC expression inhibited tumour cell-induced tube formation by endothelial cells in an in vitro co-culture assay and abrogated induction of angiogenesis in a dorsal window air sac assay in vivo. To investigate the function of SPARC in the regulation of medulloblastoma tumour growth in vivo, Daoy-SP cells were compared for their ability to form tumours in an intracranial model.