Most are lousy for screening, using for risk stratification and monitor response. frequent false positive with infection, pregnancy, smoking, PPIs etc.
1. Germ Cell Tumours
AFP (α-fetoprotein): ↑ in non-seminomatous testicular cancer, hepatocellular carcinoma. Not raised in seminoma.
β-hCG: Testicular cancer (especially choriocarcinoma), gestational trophoblastic disease.
LDH: Non-specific, reflects tumour burden.
2. Gastrointestinal Cancers
CEA (Carcinoembryonic Antigen): Colorectal cancer (not for screening; used for recurrence/monitoring).
CA 19-9: Pancreatic cancer, cholangiocarcinoma (can be raised in benign biliary obstruction).
AFP: Hepatocellular carcinoma (also germ cell tumours, as above).
3. Breast & Gynaecological Cancers
CA 15-3 / CA 27-29: Breast cancer (monitoring, not diagnostic).
CA-125: Ovarian epithelial cancers (used in diagnosis, follow-up, recurrence).
β-hCG & AFP: Germ cell ovarian tumours.
4. Urologic Cancers
PSA (Prostate Specific Antigen): Prostate cancer (screening, staging, monitoring; false positives with BPH, prostatitis).
Prostatic Acid Phosphatase (PAP): Rarely used now; historical marker.
5. Endocrine & Neuroendocrine Tumours
Calcitonin: Medullary thyroid carcinoma.
Thyroglobulin: Papillary/follicular thyroid carcinoma (monitoring recurrence).
Chromogranin A: Neuroendocrine tumours (carcinoid, pheochromocytoma).
ACTH, Cortisol: Paraneoplastic syndromes.
6. Others
S-100, HMB-45, LDH: Melanoma.
Bence Jones Proteins (urine), M protein (SPEP/UPEP): Multiple myeloma.
β2-microglobulin: Lymphoma, myeloma, prognosis indicator.