Psychoneuroimmunology of Cancer - Recent Findings and Perspectives

Gallen observed that psychosocial factors influence tumor incidence. Findings of the last decades have enabled us to understand the mechanisms and pathways responsible for this influence. Ader, Solomon, Besedovsky, and other pioneers of psychoneuroimmunology demonstrated that the nervous system can regulate the activity of immune cells. Based on their findings, the mechanisms via which psychosocial stressors potentiate tumor growth indirectly through inhibition of anti-tumor immune cells have been reported. Human tumor innervation, the presence of β-adrenergic receptors on tumor cells, and the stimulating effect of noradrenaline on tumor growth and metastasis development have revealed that psychosocial stressors have a direct stimulatory effect on tumor growth, mainly via sympathetic nerves. In recent years, the possibility of modulating signal transduction between the nervous system, immune system, and tumor cells, with the intention of inhibiting tumor growth and metastasis, has been intensively investigated.

The aim of this review paper is to provide an overview of recent experimental and clinical findings from psychoneuroimmunological research, which reveal an increasingly complex link between stress and the onset and progression of tumor diseases and provide a basis for the introduction of new therapeutic approaches for the treatment of cancer patients.

Some approaches tested in psychoneuroimmunological studies reported that they had inhibitory eff ects on cancer growth and used already clinically-approved drugs and psychological procedures, which may facilitate their application in oncology in the near future.