Given our observations that loss-of Usp9X function impaired expression of 1) the anti-apoptotic Bcl-2 family member Mcl-1, which has been previously shown to enhance TRAIL-mediated apoptosis [35], and 2) also of the IAPs, Survivin and XIAP [36, 37] we determined whether antagonism of Usp9X function also primes glioblastoma cells to the cytotoxic effects of the death ligand TRAIL [37–43]. The gene discussed is XIAP; the disease is glioblastoma.