Innervation by the sympathetic nervous system is typically a boon to tumors. But researchers from Weill Cornell Medicine and colleagues have shown that in some cases, the relationship between tumors and the nervous system is more complex. Depending on context, innervation can either assist or obstruct tumor growth. “The nervous system typically has been considered as a driver of cancer growth, but here we’ve found that it can be a brake on cancer growth in some contexts,” said David Simon, an assistant professor of biochemistry and biophysics at Weill Cornell Medicine.