MKI67 and neoplasm: Immunofluorescence of brain tissue revealed extensive localization of DiD-labeled R-EVs, accompanied by increased expression of stem cell markers (SOX2, Nestin) and the Ki67 proliferation marker in the tumor region (Figure 2J-L) and associated statistics indicated the Ki67, SOX2 and Nestin area to DAPI (%) (Supplementary Figure 5).