"There is no part of the body that isn't well innervated," says Michelle Monje of the Stanford University School of Medicine, who co-authored the article with PhD candidate Humsa Venkatesh. "The nervous system is an extremely arborized tree that reaches every aspect of every tissue and contributes importantly to tissue development. Those growth signals are already there, so why shouldn't cancer cells co-opt them?"
Cancer treatments often target tumors by cutting off blood vessels and other nutrient supply routes, so Monje and others are interested to learn whether it may be possible to target nerves via analogous therapies or by simply blocking secreted neural growth factors. The challenge is that growth-promoting signals vary by neuron and cancer type. Furthermore, blocking neural activity can be dangerous.
"In the brain, modulating neuronal activity isn't a great option because we don't want to silence the brain. Brains need to be active and functioning," says Monje. "But we can interrupt the specific molecular pathways that are being co-opted by the tumor."
Monje first became interested in neurons' role supporting tumors while working on childhood glioma, a cancer that strikes in the precursors to glial cells in the developing brain. In 2015, her lab published a paper in Cell (DOI: 10.1016/j.cell.2015.04.012) that found that both adult and pediatric glioma cells grew faster when adjacent to highly active neurons.