Towards a psychobiological model of cancer: biological considerations.

The control of tissue homeostasis is extremely complex and many factors contribute to the growth and development of tumours. Although the immune system has been regarded as an essential intermediary between putative psychological factors and the development or restraint of malignant tumours, this review indicates that many other possible mechanisms also exist. Current aspects of tumour biology, immunology and hormonal control systems are reviewed, and detailed psychobiological mediating mechanisms are considered at each stage of tumour development. An approach to the future investigation of this difficult field is proposed.