This paper examines whether it is possible to boost the immune system in patients with glioblastoma, such that the brain tumour-initiating cells (BTICs) are targeted and killed. The authors found that, although immune cells isolated from patients with glioblastoma could recognize BTICs in vitro, they were not effective at killing them. However, macrophages and microglia isolated from healthy individuals were more effective at restricting the growth of a population of BTICs in culture. Interestingly, a screen of a library of small molecules identified the antifungal drug amphotericin B as a stimulator of macrophages and microglia. Administration of this drug to mice with human BTIC-induced tumours significantly prolonged their survival. Caution is needed, however, as amphotericin B has substantial and potentially lethal side effects when given at high doses intravenously.