Colon cancer is one of the most common cancers diagnosed in both men and women. It begins as small clumps of cells called polyps that form on the inside lining of the colon. Over time, some of these polyps can become cancerous. Screening tests like colonoscopies allow doctors to find and remove precancerous polyps before they turn into cancer.
But what if there was a simple blood test that could detect early signs of colon cancer? Researchers have been studying different biomarkers in the blood that may indicate the presence of colon cancer. These cancer biomarkers are produced by the tumor itself or by the body in response to cancerous changes and can often be detected before the cancer spreads or causes symptoms.
Carcinoembryonic antigen (CEA)
Carcinoembryonic antigen (CEA) is a protein that is usually found in fetal development but can also be produced by cancerous tumors. High levels of CEA in the blood can be an early sign of colon cancer as well as other gastrointestinal cancers like stomach, pancreas, and liver.
| CEA Level | Indication |
|---|---|
| Less than 3 ng/mL | Normal |
| 3-5 ng/mL | May indicate early cancer |
| Higher than 5 ng/mL | Suggests presence of cancer |
Doctors may test CEA levels before colon cancer treatment or monitor it during and after treatment to check for recurrence. But CEA levels alone aren’t definitive – they may be elevated due to other medical conditions. CEA is more useful when tracked over time and combined with other clinical information.
Tissue inhibitor of metalloproteinases-1 (TIMP-1)
Tissue inhibitor of metalloproteinases-1 (TIMP-1) helps regulate the activity of enzymes that break down proteins in the extracellular matrix. Cancerous tumors produce more TIMP-1, which allows them to spread more aggressively. Elevated TIMP-1 levels in the blood are associated with colon cancer.
| TIMP-1 Level | Indication |
|---|---|
| Less than 150 ng/mL | Normal |
| 150-400 ng/mL | May suggest cancer risk |
| Higher than 400 ng/mL | Highly predictive of colon cancer |
In studies, TIMP-1 has been shown to detect early stage colon cancer with high sensitivity. It can differentiate between precancerous polyps and advanced cancer better than CEA. TIMP-1 levels also decrease after colon cancer surgery, so it may be useful for post-treatment monitoring.
Platelet-derived growth factors (PDGF)
Platelet-derived growth factors (PDGF) regulate cell growth and division. Tumors secrete abnormally high levels of PDGF to stimulate blood vessel formation (angiogenesis), allowing the tumor to access oxygen and nutrients it needs to grow. PDGF levels are elevated in many cancer patients, including those with colon cancer.
| PDGF Level | Indication |
|---|---|
| Less than 9 ng/mL | Normal |
| 10-20 ng/mL | May suggest cancer risk |
| Higher than 20 ng/mL | High probability of colon cancer |
Research indicates that PDGF levels correspond with colon cancer stage – higher levels are seen in later stage colon cancers. Checking PDGF levels over time may help track cancer progression and determine if treatment is working. But more studies are needed before PDGF can be used conclusively as a biomarker.
Vascular endothelial growth factor (VEGF)
Like PDGF, vascular endothelial growth factor (VEGF) stimulates new blood vessel formation in tumors. VEGF helps supply nutrients and oxygen that allow cancer cells to grow and spread. Many solid tumor cancers, including colon cancer, show elevated VEGF levels.
| VEGF Level | Indication |
|---|---|
| Less than 35 pg/mL | Normal |
| 36-100 pg/mL | May suggest cancer risk |
| Higher than 100 pg/mL | High probability of colon cancer |
Studies indicate VEGF levels correspond with colon cancer progression – higher levels are associated with metastases. VEGF levels may help determine prognosis and monitor treatment efficacy. But factors like age, sex, and medications can also impact VEGF levels.
Matrix metalloproteinases (MMP)
Matrix metalloproteinases (MMPs) are enzymes that break down proteins in the extracellular matrix. This allows cancer cells to spread beyond the original tumor site and metastasize. Many types of MMP are found at high levels in colon cancer patients.
Two specific MMPs – MMP-7 and MMP-9 – stand out as potential colon cancer biomarkers. Elevated levels of MMP-7 and MMP-9 in the blood indicate greater risk of colon cancer metastasis and poorer prognosis:
| MMP-7 Level | Indication |
|---|---|
| Less than 9.0 ng/mL | Normal |
| 9.1-12.0 ng/mL | Some increased risk |
| Greater than 12.0 ng/mL | High risk of metastasis |
| MMP-9 Level | Indication |
|---|---|
| Less than 200 ng/mL | Normal |
| 201-600 ng/mL | Some increased risk |
| Greater than 600 ng/mL | High risk of metastasis |
Checking MMP levels may help identify colon cancer patients at higher risk for poor outcomes who may need more aggressive treatment.
Conclusion
Research into blood biomarkers for colon cancer is very promising. Measuring levels of proteins like CEA, TIMP-1, PDGF, VEGF, and MMPs may allow earlier cancer detection, better prognostic information, and more effective post-treatment monitoring.
But more large-scale studies are needed to validate and standardize testing methods before any of these biomarkers can be used conclusively in routine clinical practice. For now, colon cancer screening is still best done through traditional methods like colonoscopy.
Blood biomarker tests will likely become a vital complement to current screening methods over the next 5-10 years. They may detect warning signs of colon cancer long before symptoms appear. Doctors could then take a personalized approach for monitoring, treatment, and survivorship care optimized to each patient’s biomarker profile and risk factors.
The future looks bright for new innovations that will reduce the burden of colon cancer worldwide. Blood-based biomarker testing is poised to become an invaluable tool in early colon cancer detection and management. Patients and doctors alike can look forward to the continued decline in colon cancer incidence and mortality these advances will bring.
