Microglia are not the only non-neuronal cells that affect circuits: astrocytes, oligodendrocytes and endothelial cells also have considerable roles in maintaining circuit function.

But to the scientists’ surprise, the networks lacked the endothelial cells that line normal blood vessels, suggesting that the cancers themselves formed the channels.

For this study, Cooke and his colleagues cultured the cells that line the walls of blood vessels, which are called endothelial cells.