Tumor Markers

Definition

Tumor markers are substances that can be found in the body, often in blood, urine, or tissues, that provide information about the presence of blood cancer and solid organ tumor or the behavior of tumors. They may be proteins produced by cancer cells or by normal cells in response to cancer. Tumor markers can help in diagnosing cancer, monitoring treatment effectiveness, and assessing prognosis.

Types of Tumor Markers

Circulating Tumor Markers: These markers are found in bodily fluids such as blood or urine. Common examples include:

• Prostate-Specific Antigen (PSA): Elevated levels can indicate prostate cancer.
• Carcinoembryonic Antigen (CEA): Often elevated in colorectal and other cancers.
• CA-125: Primarily associated with ovarian cancer.

Tissue Tumor Markers: These are found in tumor tissue samples obtained through biopsies. They provide information about the characteristics of the tumor itself.

Uses of Tumor Markers

• Diagnosis: While tumor markers alone cannot definitively diagnose cancer, they can indicate the presence of cancer when combined with other diagnostic tests such as imaging or biopsies.
• Monitoring Treatment: Measuring tumor marker levels during and after treatment can help determine how well the treatment is working. A decrease in marker levels may suggest a positive response to therapy.
• Prognosis: Certain tumor markers can provide information about the likely course of the disease and help guide treatment decisions.
• Screening: Some tumor markers are used for screening purposes, although they are not universally reliable for early detection.

Limitations

• Specificity and Sensitivity: Not all tumors produce detectable markers, and some non-cancerous conditions can also elevate marker levels. Therefore, elevated tumor markers do not always indicate cancer.
• Variability: Levels of tumor markers can fluctuate due to various factors, including treatment effects and individual patient differences.

Commonly Used Tumor Markers

Carcinoembryonic Antigen (CEA):

• Cancer Types: Colorectal cancer, pancreatic cancer, breast cancer, lung cancer.
• Use: Monitoring treatment response and detecting recurrence.

Alpha-Fetoprotein (AFP):

• Cancer Types: Hepatocellular carcinoma, germ cell tumors.
• Use: Diagnosis and monitoring of liver cancer and certain testicular cancers.

Carbohydrate Antigen 19-9 (CA 19-9):

• Cancer Types: Pancreatic adenocarcinoma, cholangiocarcinoma, colorectal cancer.
• Use: Monitoring treatment and disease progression.

Cancer Antigen 125 (CA 125):

• Cancer Types: Ovarian cancer.
• Use: Monitoring treatment response and recurrence.

Cancer Antigen 15-3 (CA 15-3):

• Cancer Types: Breast cancer.
• Use: Monitoring treatment response and recurrence.

Beta-Human Chorionic Gonadotropin (Beta-hCG):

• Cancer Types: Choriocarcinoma, germ cell tumors.
• Use: Diagnosis and monitoring treatment effectiveness.

Neuron-Specific Enolase (NSE):

• Cancer Types: Small cell lung cancer, neuroblastoma.
• Use: Monitoring disease progression and treatment response.

Lactate Dehydrogenase (LDH):

• Cancer Types: Lymphoma, melanoma, leukemia.
• Use: Indicator of tumor burden and prognosis.

Prostate-Specific Antigen (PSA):

• Cancer Types: Prostate cancer.
• Use: Screening, diagnosis, and monitoring treatment response.

Chromogranin A:

• Cancer Types: Neuroendocrine tumors.
• Use: Monitoring disease progression.

Calcitonin:

• Cancer Types: Medullary thyroid cancer.
• Use: Diagnosis and monitoring treatment effectiveness.

Bence-Jones Proteins:

• Cancer Types: Multiple myeloma.
• Use: Diagnosis and monitoring of disease progression.

Beta-2-Microglobulin (B2M):

• Cancer Types: Multiple myeloma, chronic lymphocytic leukemia.
• Use: Prognosis and monitoring treatment response.

Bladder Tumor Antigen (BTA):

• Cancer Types: Bladder cancer.
• Use: Surveillance in patients with known bladder cancer.

Cytokeratin Fragment 21-1 (CYFRA 21-1):

• Cancer Types: Non-small cell lung cancer.
• Use: Monitoring for recurrence.

Conclusion

Tumor markers are valuable tools in oncology for diagnosing, monitoring, and managing cancer. However, they should be used in conjunction with other diagnostic methods to ensure accurate assessment and treatment planning.

Consult with Our Team of Experts Now!

References

1. Cleveland Clinic. (2023). What Are Tumor Marker? Retrieved from Cleveland Clinic.
2. Wikipedia contributors. (2023). Tumor Marker. In Wikipedia, The Free Encyclopedia. Retrieved from Wikipedia.
3. National Cancer Institute (NCI). (2023). Tumor Marker – NCI Fact Sheet. Retrieved from NCI.
4. National Center for Biotechnology Information (NCBI). (2009). Tumor marker in clinical practice: General principles and guidelines. Retrieved from NCBI.