MKI67 and cancer: Moreover, a qualitative decline of Ki-67 immunostaining and a complementary appearance of cleaved caspase-3 positive areas were detected in representative tumors isolated from mice co-treated with FK866 and α-TOS compared with the other three groups (Supplementary Fig. 4H), indicating that the anti-tumor effects observed were associated with both a decrease in proliferation and induction of apoptosis of cancer cells in vivo.