Protein tumor markers are key biomolecules used in the early detection, diagnosis, and monitoring of cancer. These biomarkers help identify abnormal biological processes related to tumor growth and are widely applied in both laboratory testing and clinical oncology to assess disease progression and treatment response.
What is a Biomarker?
A biomarker is defined as any substance, structure, or process that can be measured in the body or its products and can predict, indicate, or monitor the course of a disease.
Among the various biomolecules, proteins and peptides are widely used as biomarkers because they are easy to detect and quantify in blood, urine, or saliva, providing valuable insights into physiological or pathological changes.
The Role of Biomarkers in Cancer Diagnosis
Tumor markers are a specific subset of biomarkers associated with cancer.
They are produced by both normal cells and cancer cells, but their levels are significantly higher in patients with malignant tumors.
By measuring these proteins in body fluids, clinicians can:
- Facilitate early cancer detection
- Monitor disease progression
- Evaluate the effectiveness of cancer therapies
Main Types of Protein Tumor Markers
Clinically relevant protein tumor markers can be classified based on their biological function, detection method, or sample type. Major categories include:
- Oncofetal antigens
- Tumor-associated antigens
- Hormones and hormone receptors
- Enzymes and isoenzymes
- Serum and tissue proteins
- Cancer stem cell markers
- Other tumor markers, including genetic markers and specific biomolecules
Why Are Tumor Markers Important?
- Early cancer detection through blood or urine testing
- Monitoring tumor progression and overall tumor burden
- Optimizing treatment strategies by tracking therapy response
| Tumor Marker | Associated Cancers | Clickable PDF (Scientific Source) |
|---|---|---|
| AFP (Alpha‑fetoprotein) | Liver cancer, germ cell tumors | Serum Biomarkers AFP, CEA and CA 19‑9 Combined (PMC) |
| CEA (Carcinoembryonic Antigen) | Colorectal, gastric, pancreatic, breast cancer | Clinical Performance of CEA, CA 19‑9, CA 15‑3, CA 125 (PDF) |
| CA 125 (MUC16) | Ovarian and endometrial cancer | Diagnostic and Prognostic Value of CEA, CA 19‑9, AFP, CA 125 (BMC) |
| CA 15‑3 / CA 27.29 | Breast cancer | A Primer on Commonly Used Cancer Markers (PMC) |
| CA 19‑9 | Pancreatic, biliary, gastric cancers | CA 19‑9 Tumor Marker: Past, Present, and Future (PDF) |
| PIVKA‑II | Hepatocellular carcinoma (HCC) | Diagnostic Efficacy of AFP, CA 19‑9, and CEA in HCC (ResearchGate) |
| PSA (Prostate‑Specific Antigen) | Prostate cancer | A Primer on Commonly Used Cancer Markers (PMC) |
| B2M (Beta‑2 microglobulin) | Multiple myeloma, lymphoma, leukemia | A Primer on Commonly Used Cancer Markers (PMC) |