CCL21 and glioblastoma: Orthotopic xenografts of human GBM cells into immunodeficient mice allowed us to further assess the expression of CCR7 and CCL21 proteins on sections of tumoral brain tissue with a predominant localization of CCR7 in Iba1+ TAMs (cyan), while CCL21 immunoreactivity localized predominantly in human vimentin+ tumor cells (green) but also in TAMs (Fig. 1e).