Accordingly, pharmacological blockade of apelin (Figs 6, 7 and Supplementary Fig. 3), but not the reduction of APLNR expression in GSCs (Supplementary Fig. 2D), may also contribute to the reduction of tumour volume observed in this study in vivo, by blocking angiogenesis and depriving tumour cells of the nutrients they require to survive. The gene discussed is APLN; the disease is neoplasm.