
Oka et al evaluated in vitro and in vivo effects of VEGF on the properties of cancer stem cells (CSCs) derived from human glioblastomas. Evidence from previous studies had suggested that CSCs are found in malignant tumor cells and play a pivotal role in tumor initiation, growth, and recurrence. Oka at el demonstrated that VEGF did not affect the property of CSCs in vitro. However, the injection of mouse brains with VEGF-expressing CSCs led to massive expansion of vascular-rich glioblastoma and was associated with high morbidity. Based on these results, the authors suggested that VEGF promotes tumorigenesis via angiogenesis and that VEGF induces the proliferation of vascular endothelial cells in the vascular-rich tumor environment of glioblastoma.1,11
