Recent studies (19, 20) have shown that HIF-1α downregulation reduces MGMT expression in GBM stem cells, thus suggesting a possible correlation between the two proteins (11, 19, 21–25), and we have previously shown that the negative modulation of HIF-1α is related to the response of U251 GBM cells to TMZ in vitro and in vivo (13). The gene discussed is MGMT; the disease is glioblastoma.