A recent study demonstrated that a soluble CD44 protein secreted by the GBM cells is the link between GBM and neurodegenerative disorders, as it induces neuronal degeneration through the activation of tau pathology in the brain, which is known to be the underlying mechanism of some neurodegenerative disorders such as Alzheimer’s disease [26]. Here, CD44 is linked to early-onset autosomal dominant Alzheimer disease.