MKI67 and neoplasm: Ki67 staining of the tumor sections revealed that, compared with the other groups, the GB4-BPL@siCXCR2/pPTEN group presented a markedly diminished green fluorescent signal (Figure 5, J and L), indicating that the lowest level of Ki67-positive tumor cell proliferation was observed in the combination treatment group, which was in line with the results observed via TUNEL staining.