Catecholamine and serotonin injected i.p. to new-born mice caused gliomas, ependymomas and choroid plexus papilloma together with multiple APUDomas within 48 hours after injection. We consider that an error in neural crest DNA may be caused through an adenylate-cyclic AMP system and Ca++ during replication and/or transcription. Multiple brain tumors caused by catecholamine and serotonin give the presumptive evidence that stem cells of neuroglia may be of neural crest origin.