The nervous system with its complex organizational features and functions is well-known for its impressive ability to process information and drive countless biological processes. It has come to the surprise of many that the nervous system can also be intimately involved in an unwelcome area of human life: the initiation and progression of cancer. For brain tumors, the parallels to neurodevelopment and nervous system function can be found on multiple levels. First, cancer cells of incurable gliomas interconnect with long cellular extensions to a large communicating multicellular network. Second, indirect and direct neuronal input can generate, activate, and control brain tumor growth. Third, it is becoming increasingly clear that those features not only drive brain tumor progression but also the notorious resistance of these tumors against standard antitumor therapies. Remarkably, these recent insights have already generated novel ideas for better antitumor therapies.