Negin Dorri - PhD, Health Psychology, Department of Psychology, University of Tehran, Tehran, Iran
Ahmad Alipour - Department of Psychology, Payame Noor University, Tehran, Iran
Delara Madahzad - PhD Candidate, Health Psychology, Department of Psychology, University of Tehran, Tehran, Iran
Arezo Aemmi - MS, Clinical Psychology, Department of Psychology, Islamic Azad University, Tehran, Iran

Objective: Various biological processes can influence the occurrence of cancer. Studies on patients with chronic diseases such as cancer show that interventions considering mental and physical aspects (e.g., stress management strategies) can reduce psychological distress, improve coping skills, and strengthen immune response through neuroendocrine-immune system modulation. Psychoneuroimmunology studies how psychological, neurological, and immunologic processes work together and influence the human body, health, and behavior. Method: The present work is a narrative review study in which the keywords of cancer, immune system, neurotransmitters, psychological factors, psychoneuroimmunology (PNI), and stress were searched in scientific databases, including PubMed, Scopus, and Science Direct. The search results were studied, and articles not directly related to the research subject were filtered out. Moreover, the papers reporting the same findings were excluded. Subsequently, the relevant studies were used to compile the results in this summary.Conclusion: The literature on psychoneuroimmunology indicates that stress can significantly change various biological responses. For instance, increased inflammation and altered immune response may be caused by chronic stress. Despite the limited data, a review of the literature suggests that psychological or behavioral factors may influence the occurrence or progression of cancer. Such effects may be mediated by hormone and immune system changes triggered by various psychological factors. Signaling pathways created by neurotransmitters can induce uncontrolled proliferation and dissemination of cancer cells. Moreover, neurotransmitters can influence immune and endothelial cells around the tumor to accelerate its progression.

Cancer, Psychoneuroimmunology, Psychological Factors, Immune System, Stress