In this study, when CUSP9v3 was combined with the Bcl-2/Bcl-xL inhibitor ABT-263, synergistic inhibition of cellular viability and strong pro-apoptotic activity was noted among a broad panel of established and primary cultured glioblastoma as well as glioblastoma stem-like cells, despite a dose reduction down to 1/20th of the original CUSP9v3 dose. Here, BCL2L1 is linked to glioblastoma.