MKI67 and neoplasm: Furthermore, images of hematoxylin and eosin–stained tumor tissue, Ki67-stained tumor tissues, and lipid peroxide 4-HNE-stained immunohistochemical sections of tumors showed that the number of tumor foci was much lower in the combinational treatment group than in the empty-vector or single-agent group, and combination groups showed a more significant inhibitory effect on the amount of Ki67 (proliferation marker) positive cells and significantly increased expression of 4-HNE (Fig. 7F, G).