Possible future avenues of investigation of PEG in malignant glioma patients could include (1) PEG combined with TMZ and XRT in the up-front GBM setting (using MGMT methylation status or IFNα gene content as an enrolment criteria), (2) the addition of IFN or PEG to an intensified TMZ regimen at recurrence (Wick et al, 2007), (3) the addition of PEG to alternative cytotoxic chemotherapies, looking for improvement in outcomes, or (4) the addition of PEG to other non-cytotoxic therapies, as a potential synergistic agent. This evidence concerns the gene MGMT and glioblastoma.