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)
- Carcinoembryonic antigen (CEA)
