Figure 1. A network of neighbours.

Osswald et al.³ report that, in some types of brain tumour, structures called microtubes connect tumour cells, allowing them to act as a single, organism-like unit. Tumour microtubes facilitate invasion into healthy brain tissue. They permit the spread of toxic molecules such as calcium ions (Ca²⁺) that build up during radiation therapy, allowing the whole unit to share the burden of toxicity. Furthermore, if tumour tissue is surgically removed, newly synthesized nuclei donated by tumour cells can travel down the microtube to the cell-free site to form new tumour cells.