Furthermore, Smac peptides encompassing the N-terminal four amino acids that are highly conserved throughout evolution and critical for the interaction of Smac and IAP proteins have been shown to cooperate with recombinant TRAIL protein to induce apoptosis in glioblastoma cells in vitro and also in an orthotopic, intracranial glioblastoma model31. This evidence concerns the gene DIABLO and glioblastoma.