Ki-67 + Caspase-3 can provide information on cell death vs. cell proliferation in the same tissue section. The Ki-67 nuclear antigen is associated with cell proliferation and is used to grade proliferation rates of tumors. Ki-67 is found throughout the cell cycle that includes the G1, S, G2, and M phases; but not the G0 phase. Apoptosis has gained central importance in the study of many biological processes, including neoplasia, neurodegenerative diseases, and development. Cleaved caspase-3 detects endogenous levels of the large fragment of activated caspase-3, a protease that mediates apoptosis. Caspase-3 does not cross react with other cleaved caspases.