Meanwhile, the lower mean Ki67 in D21 despite increased number and lumen area of blood vessels is due to the presence of abnormal/dysmorphic vasculature common in gliomas and replicated in the Gl261 model [31–33]; expanded vessels, increased leakage, and loss of branching complexity [33] leading to reduced Ki67 proliferation and regions of geographic necrosis. Here, MKI67 is linked to central nervous system cancer.