An orthotopic mouse model using U87 cells was performed to further determine the role of CBX7 in gliomagenesis. U87 cells were initially transfected with luciferase expressing lentiviruses and then these cells were transfected with Lenti-ctrl or Lenti-CBX7. After implantation of U87 cells in mice, intracranial tumor volume was measured weekly via in vivo optical imaging system. Results from bioluminescence imaging showed that growth of glioma was significantly suppressed by CBX7 overexpression (Figure 5A). Concomitant with inhibition of tumor formation, mice treated with Lenti-CBX7 had prolonged survival times (Figure 5B). In addition, immunohistochemistry (IHC) revealed that upregulated CBX7 was accompanied by decreased cyclin E1, which was consistent with the in vitro results (Figure 5C). In summary, these findings showed that CBX7 inhibits glioma cell proliferation in vivo.