The high number of FoxP3+ Treg cells in glioblastoma tissue [37-41], as compared to its complete absence in normal brain tissue, suggests that glioblastoma growth may benefit from the immunosuppressive activity of Tregs, and that glioblastoma patients will benefit from inhibiting Treg development with acyclovir. The gene discussed is FOXP3; the disease is glioblastoma.