To assess if the pharmacological inhibition of HSP90 by PU-H71 could also induce programmed cell death in glioma cells, we treated GSC811 and U251-HF cells with vehicle control (DMSO) or PU-H71 (0.25 or 1.0 μM), stained them with annexin V–FITC, and subjected them to flow cytometry. The gene discussed is HSP90AB1; the disease is central nervous system cancer.