3k - STRESS, DEPRESSION, IMMUNE SYSTEM & CANCER

Question 1

Psycho neuro immunology & cancer

Answer 1

• Psychoneuroimmunology (PNI): The study of how psychological factors (like stress & depression) influence
  immune system &, consequently, cancer risk & progression
• Key Hypothesis: Chronic stress & depression lead to persistent activation of hypothalamic-pituitary-adrenal
  (HPA) axis, impairing immune responses & contributing to cancer development & progression

Question 2

Biological mechanisms:
- HPA axis
- immune system dysregulation
- genomic instability

Answer 2

HPA Axis Activation
- Cortisol Release: Stress & depression trigger release of cortisol, hormone that modulates immune function
- Chronic Activation: Persistent activation lead to immune suppression & increased susceptibility to cancer

Immune System Dysregulation
- Cellular Level:
o Decreased cytotoxic T-cell and natural killer (NK) cell activities, impairing tumor surveillance
o Increased circulating neutrophils and leukocytosis
o Reduced lymphocyte proliferation and neutrophil phagocytosis
- Molecular Level :
o Elevated levels of pro-inflammatory cytokines (IL-1, IL-6, TNF-α)
o Altered balance between Th1 & Th2 immune responses
o Increased levels of acute-phase proteins & antibodies against certain viruses

Genomic Instability
- Somatic Mutations: Chronic stress & depression can lead to accumulation of mutations in DNA
- Impaired DNA Repair: Reduced efficiency in repairing DNA damage, contributing to genomic instability

Question 3

Clinical implications

Answer 3

• Immune Surveillance: Impaired immune surveillance due to decreased NK and T-cell activities can allow tumor cells to evade detection.
• Cancer Progression: Dysregulated immune responses can promote tumor growth, angiogenesis, and metastasis.
• Therapeutic Strategies:
  o Psychological interventions to reduce stress and depression.
  o Immunomodulatory therapies to restore immune function

Question 4

Future research directions

Answer 4

• Bidirectional Communication: Investigate interactions between neuroendocrine & immune systems in cancer
• Therapeutic Development: Develop treatments targeting both psychological & immune dysfunctions in cancer patients

Question 5

Key takeaways

Answer 5

• Stress & Depression: Chronic stress & depression can impair immune function, increasing cancer risk & progression
• Immune System Dysregulation: Alterations in immune cell activities & cytokine production contribute to
  tumor development
• Clinical Implications: Addressing psychological factors & restoring immune function are crucial in cancer
  therapy