Psychological stress on cancer progression and immunosenescence.

Diagnosis and treatment of cancer constitute a deeply stressful experience that involves unique and common problems and generates uncertainty, fear and emotional distress. Furthermore, there are reciprocal interactions between psychological stress and cancer in the clinical settings. Therefore, it is crucial to understand the links of stress with cancer. A growing body of epidemiological and preclinical studies have suggested that stress affects cancer progression, and metastasis and treatment outcomes. Furthermore, stress elicits premature aging and deterioration of the immune system (known as immunosenescence), causing vulnerability to infections, autoimmune diseases, and cancers. In this review, we describe recent advances in how stress affects cancer progression through specific stress hormones and receptor systems as well as intracellular molecular processes, and discuss how stress-evoked neuroendocrine molecules regulate local and systemic immune responses in the tumor microenvironment. Furthermore, we review the molecular mechanisms of immunosenescence and evidence of psychological stress-evoked immunosenescence, highlighting the clinical value for available psychological and/or pharmacological interventions for psychological stress in patients with cancer. Based on existing evidence and emerging mechanistic insights, factors linked with psychological stress, immunosenescence and complications in cancer survivors need to be determined in future studies, and screening programs should be added to follow-up.