MKI67 and neoplasm: Immunohistochemical staining for marker of proliferation Ki-67 (Ki-67) and H&E staining in tumor slices showed that the most cell death and the least cell proliferation occurred in the X-ray + Mn-ZIF-8 MNs treatment group (Figure 5I), further revealing the Mn-ZIF-8 MNs-induced RT enhancement.