FOXP3 and glioblastoma: The frequency of tumor-infiltrating CD3+ (range = 3–23%; median = 9.5%), CD4+FOXP3− effector memory (TEM) (range = 1–12%; median = 3.2%), CD4+FOXP3+ regulatory T (Treg) cells (range = 0–2.5%; median = 0.3%) and CD8+ T cells (range = 1–9%; median = 4.3%) were also variable in the pretreatment GBM specimens (Extended Data Fig. 3).