FOXP3 and astrocytoma (excluding glioblastoma): A study published by Heimberger et al. [25] reported significant differences in the prevalence of FOXP3+ Tregs between tumors of different grades and histologic tumor subtypes, and demonstrated that FOXP3+ Tregs were most frequently expressed in glioblastoma multiforme (GBM), but very rarely in low-grade astrocytomas.