Parallel to the role that normal stem cells play in organogenesis, cancer stem cells are thought to be crucial for tumorigenesis. Understanding normal development might therefore lead to better treatments of cancer. We review recent data that stem cells of glioblastoma, a highly malignant brain tumour, seem to be dependent on cues from aberrant vascular niches that mimic the normal neural stem cell niche. These data have direct implications for cancer, highlighting the similarity between normal and malignant stem cells and identifying the tumour microenvironment as a target for new therapies.