Glioblastoma Stem Cells and Tumour Microenvironment: Interactions Across Hypoxia, Vasculature and Immune Modulation.

Glioblastoma (GBM) is an aggressive brain tumour known for its ability to resist the current treatment protocols. A major reason for this resistance is a minor group of cells within the tumour called glioblastoma stem cells (GSCs). These cells drive tumour growth, invasion, and recurrence after therapy. GSCs survive and expand within a specific microenvironment that protects and supports them. Three of the most important niches are: hypoxic (low oxygen) regions, which trigger survival pathways and make GSCs more resistant to treatment; perivascular areas near blood vessels, which provide nutrients and signals that maintain stem-like properties; and immune-related zones, where inflammatory and suppressive signals help GSCs escape the body's defences. Together, these environments allow GSCs to thrive and contribute to the tumour's persistence. This review highlights how hypoxia, blood vessel niches, and immune interactions work together to sustain GSCs and promote GBM progression. A clearer understanding of these supportive environments may lead to new treatment approaches aimed at disrupting GSC survival and improving patient outcomes.