What is CA 279 (Cancer Antigen 279)?
CA 279 is not a recognized or established tumor marker in clinical oncology. There is no evidence in the medical literature supporting the existence of a tumor marker called CA 279.
Established Cancer Antigen Markers
The most commonly used cancer antigen (CA) markers in clinical practice include:
CA 15-3 and CA 27.29: Both target epitopes on the same glycoprotein (Mucin 1/MUC1) and are primarily used in breast cancer monitoring 1. These markers:
- Are not recommended for screening, diagnosis, or staging of breast cancer
- May be used to monitor response to treatment in metastatic breast cancer when other measurable disease is not available 2
- Can detect recurrence after primary treatment, though the clinical benefit of early detection remains unestablished 2
CA 19-9: Used primarily in pancreatic cancer, but insufficient evidence supports its use in colorectal cancer 2
CA 125: Used primarily in ovarian cancer monitoring
Clinical Application of Tumor Markers
When considering tumor markers in clinical practice:
Limitations in screening: None of the established CA markers are recommended for cancer screening in the general population due to insufficient specificity and sensitivity 2
Monitoring disease: Tumor markers may be useful for monitoring treatment response in patients with established cancer when:
- No other simple tests are available to indicate response
- Baseline levels are obtained at the start of treatment
- Serial measurements are performed every 2-3 months during active treatment 2
False positives: Elevated tumor marker levels can occur in benign conditions:
- CA 27.29 may be elevated in patients with pulmonary fibrosis 3
- CA markers can be elevated in benign breast disease, ovarian cysts, and liver disease
Practical Considerations
If you are looking for a tumor marker for breast cancer monitoring, CA 15-3 or CA 27.29 would be appropriate choices, as they:
- Have similar clinical utility (correlation coefficient: 0.967) 1
- Show concordance in approximately 94% of paired samples 1
- Demonstrate similar trends in individual patients over time 1
However, performing both tests routinely provides no added clinical value 1.
For colorectal cancer monitoring, CEA remains the marker of choice 2.