We also highlight that two separate pathways are activated during the apoptotic death of GBM cells treated with the combined chemotherapeutic agents, TRAIL and the Mcl-1-targeting, cyclin-dependent kinase inhibitor, R-roscovitine, one which leads to caspase-8 and caspase-3 activation and a second pathway, involving a Mcl-1:Noxa axis. The gene discussed is PMAIP1; the disease is glioblastoma.