Tumour Markers

Key points

• Tumour markers are broadly divided into monoclonal antibodies, tumour antigens, enzymes, and hormones
• Monoclonal antibody markers: CA 125 (ovarian cancer), CA 19-9 (pancreatic cancer), CA 15-3 (breast cancer)
• Tumour antigens: PSA (prostate cancer), alpha-fetoprotein/AFP (hepatocellular carcinoma, germ cell tumours), CEA (colorectal cancer)
• Enzymes: alkaline phosphatase, neurone-specific enolase (small cell lung cancer, neuroblastoma)
• Hormones: calcitonin (medullary thyroid cancer), ADH/ACTH (paraneoplastic, e.g. small cell lung cancer)
• Tumour markers generally have low specificity and are mainly used to monitor treatment response and detect recurrence, not for primary diagnosis