Tumor Markers: Their Role, Advantages, and Limitations
What Are Tumor Markers?
Tumor markers are substances produced either by cancer cells or by the body in response to cancer. These can be found in blood, urine, stool, body fluids, or tissues.
| Marker | English Name | Reference Range | Remarks |
|---|---|---|---|
| AFP | Alpha-Fetoprotein | <10 ng/mL | Liver cancer, testicular cancer |
| CEA | Carcinoembryonic Antigen | <5 ng/mL | Colorectal cancer, lung cancer, gastric cancer |
| PSA | Prostate-Specific Antigen | <4 ng/mL | Prostate cancer |
| CA125 | Cancer Antigen 125 | <35 U/mL | Ovarian cancer, uterine cancer |
| CA19-9 | Cancer Antigen 19-9 | <37 U/mL | Pancreatic cancer, bile duct cancer |
| hCG | Human Chorionic Gonadotropin | <5 mIU/mL | Pregnancy, testicular cancer |
| CA15-3 | Cancer Antigen 15-3 | <30 U/mL | Breast cancer |
Note: Reference ranges may vary slightly depending on the lab.
Common Tumor Markers and Reference Ranges
Tumor Markers: Their Role, Advantages, and Limitations
How should the general public interpret tumor markers?
Tumor markers must be interpreted by a physician. The values alone cannot confirm cancer, so they are not recommended for routine health screening in healthy individuals.
For confirmed cancer patients, doctors may test tumor marker levels during and after treatment to monitor effectiveness and detect potential recurrence.
The table below lists common tumor markers and their reference values:
| Tumor Marker | Reference Range | Possible Indications |
|---|---|---|
| AFP (Alpha-Fetoprotein) | 5–10 ng/mL | Liver cancer, cirrhosis, hepatitis, pregnancy (fetal anomalies) |
| CEA (Carcinoembryonic Antigen) | 0–2.9 ng/mL | Lung, gastric, colorectal, ovarian, breast cancer; smokers |
| PSA (Prostate-Specific Antigen) |
Age 40–49: <2.5 Age 50–59: <3.5 Age 60–69: <4.5 Age ≥70: <6.5 ng/mL |
Prostate cancer or benign prostatic hyperplasia (BPH) |
| CA125 | 0–35 U/mL | Ovarian cancer, uterine cancer, menstruation, fibroids, pelvic inflammation |
| CA19-9 | <37 U/mL | Pancreatic, gastric, colorectal cancer; cysts; gallstones |
| hCG (Human Chorionic Gonadotropin) | 0.02–0.8 IU/L | Pregnancy, ovarian cancer, testicular cancer |
| CA15-3 | ≤30 U/mL | Breast cancer, hepatitis, benign breast tumors |
Advantages
- Monitor recurrence or treatment effectiveness.
- Mostly requires simple blood tests.
- Complements imaging to support diagnosis.
Limitations and Misinterpretations
- High marker ≠ cancer. Benign conditions (e.g. fibroids, hepatitis, pregnancy) may elevate levels.
- Normal levels ≠ no cancer. Early-stage cancers may not trigger elevation.
- Lacks specificity—cannot indicate exact type or location.
- May cause undue anxiety if misinterpreted by the general public.
Why Tumor Markers Should Not Be Used for Cancer Screening
- Not reliable for early detection.
- High risk of false positives and false negatives.
- Requires confirmation through imaging or biopsy.
- Not recommended by global screening guidelines for general populations.
When Should Tumor Markers Be Used?
| User | Suggested Use |
|---|---|
| General healthy individuals | Not recommended as a screening tool |
| High-risk individuals (e.g. family history) | Use under physician guidance for monitoring |
| Cancer patients | Evaluate treatment response and monitor recurrence risk |
| Cancer survivors | Regular follow-up; should be combined with clinical and imaging data |
Circulating tumor cell (CTC) and PBMC (peripheral blood mononuclear cell) technology
Tumor Markers Lack Precision
Due to the low sensitivity and specificity of tumor markers, they offer limited accuracy in clinical practice. Advanced technologies like Circulating Tumor Cells (CTC) and Peripheral Blood Mononuclear Cells (PBMC) offer improved cancer tracking and early risk detection.
| Test Technology | Description and Application |
|---|---|
| CTC Cancer Early Detection Technology |
CTC refers to cancer cells shed from tumors into the bloodstream, providing real-time information on tumor activity. It is used for early cancer risk assessment (for those with clinical background), monitoring treatment response, recurrence, and drug resistance. Not suitable for screening healthy individuals. |
| PBMC Immune Monitoring Technology for Carcinogenic Changes Screening |
PBMCs are immune cells in the blood reflecting the body's immune response to abnormalities or early carcinogenic changes. Suitable for healthy individuals to assess early carcinogenesis and provide warnings before tumor formation. Especially suited for preventive monitoring in high-risk groups. |
Conclusion :Tumor markers serve as an auxiliary tool in cancer care, not as a standalone diagnostic or screening method. Understanding their strengths and limitations helps prevent misjudgment and unnecessary panic.
Medical Disclaimer:
The information provided in this article is for educational and reference purposes only and does not constitute medical advice or be used as a substitute for professional medical diagnosis, treatment, or advice. ALWAYS CONSULT ANY QUESTIONS YOU MAY HAVE ABOUT YOUR MEDICAL CONDITION OR MEDICAL PROBLEM THAT YOU HAVE ALWAYS CONSULT YOUR PHYSICIAN OR OTHER QUALIFIED HEALTH PROFESSIONAL. The content of this article is not intended to recommend any specific test, treatment, or medication and should not be construed as such. If you develop symptoms or require medical assistance, please contact a healthcare professional promptly.