Abstract
The brain and its central nervous system circuitry communicate with all peripheral tissues through neuroendocrine, neuroimmune and neurovascular systems as well as peripheral neuronal networks. This applies to the abnormal situation of a tumour as much as normal biological function. The central nervous system can affect tumour development and metastases though activation or dysregulation of specific brain centres. It has also become apparent that the tumour is capable of building up local autonomic and sensory nerve networks and along with adipokines, cytokines, neurotrophic factors and afferent nerve inputs which can signal back to the brain to promote cancer initiation, growth and dissemination. An attempt is made to unravel this complex of relationships with an understanding that there is a common language spoken between the elements but also with an appreciation that these mechanisms are still only partially understood.