Role of immune system : Cancer

Role of immune system

• Immune response is to reject or destroy cancer cells
  • May be inadequate as cancer cells arise from normal human cells
• Some cancer cells have changes on their surface antigens
  • Tumor-associated antigens (TAAs)
• Cytotoxic  T cells
  • Kill tumor cells directly
  • Produce cytokines
• Natural killer cells and activated macrophages can lyse tumor cells
• B cells produce antibodies that bind to tumor cells
• Oncofetal antigens
  • Found on tumor cell surfaces, inside tumor cells, and fetal cells
• Examples of oncofetal antigens
  • Carcinoembryonic antigen (CEA)
    • On cancer cells of GI tract
    • Normal cells (fetal gut, liver, and pancreas)
  • α-Fetoprotein (AFP)
    • Malignant liver cells and fetal liver cells
  • CA-125 (ovarian carcinoma)
  • CA-19-9 (pancreatic and gallbladder cancer)
  • PSA (prostate cancer)
  • CA 15-3, CA 27-29, HER-2 (breast cancer)
  • kRAS (colon cancer oncogenes)
  • EGFR (lung cancer)