MKI67 and cancer: Accordingly, the immunohistochemical analysis showed that Exo treated tumors had a higher number of cells positive for the proliferative marker Ki-67 than control group, and Exo-c-Jun-KO had shown less number of cancer cells that Exo group, and Exo-c-Jun-KO plus miR-494 had higher number of cells than Exo-c-Jun-KO group (Figures 5C, D).