What Are Mesothelioma Blood Tests?

Mesothelioma blood tests are laboratory analyses that detect the presence of asbestos cancer. These tests recognize proteins called biomarkers. They circulate through the blood when a person has mesothelioma.

There is no blood test for asbestos exposure. Instead, doctors use detailed imaging scans plus tissue biopsies. Together, they diagnose asbestos illnesses. A blood test may help confirm that diagnosis. In most cases, blood tests are too inaccurate or unaffordable. Doctors often use blood tests to verify that treatment is working.

Pathologists examine cancer cells collected during a surgical biopsy. They look for cell type and amount to determine the best treatment. Blood tests provide more information alongside a biopsy. 

Using sophisticated lab tests, these specialists differentiate mesothelioma from other tumor types. They can also determine the kind of cancer and its genetic makeup.

Immunohistochemical markers can provide a more accurate diagnosis. These complex laboratory studies offer more specificity. They allow your doctor to develop the best treatment plan for you.

How Do Mesothelioma Blood Tests Work?

Mesothelioma blood tests screen for biomarkers. Cancer cells produce these proteins, which circulate in the blood. They are present in healthy blood samples, but levels are higher in mesothelioma. These tests are not always accurate, so it is not definitive proof of a diagnosis.

For some tumors, biomarker proteins are unique to that specific cancer. Identifying them indicates that a person may have that cancer. 

Mesothelioma produces the biomarker mesothelin. Some clinical trials change immune cells to recognize mesothelin as a cancer target. In one recent study, 80% of patients in this therapy had stable disease after three years.

A 2022 study identified one biomarker as a target for new mesothelioma therapy. The YAP biomarker handles the growth and stability of mesothelioma tumors.

A graphic with four images titled 'How Mesothelioma Blood Tests Work.' The first image is a hand grasping a test tube with the caption: A medical professional takes a blood sample from the patient. The second image shows a microscope with the caption: A pathologist analyzes the sample and biomarkers in a lab. The third image shows DNA with a test tube and the caption: Blood biomarkers indicate that cancer cells could be present. The fourth image shows DNA under a magnifying glass with the caption: Normal biomarker levels suggest an absence of mesothelioma.

MESOMARK Assay

The MESOMARK assay measures the quantity of SMRP in blood. SMRP is the serum-measured soluble mesothelin-related peptide. High SMRP levels may show the presence of mesothelioma. 

A 2021 clinical study tested MESOMARK accuracy. Researchers found it was suitable for diagnosing mesothelioma and monitoring response to treatment.

Some types of mesothelioma, such as sarcomatoid tumors, do not release high levels of SMRP. The U.S. Food and Drug Administration recommends that doctors combine the MESOMARK assay with other tests. This ensures an accurate mesothelioma diagnosis.

Some insurance companies do not cover this blood test. If you have a history of asbestos exposure, ask your doctor if the MESOMARK blood test would be helpful.

The MESOMARK Assay Procedure

The MESOMARK assay has two steps. First, your doctor will collect a blood sample and send it to a laboratory for analysis. Next, laboratory technicians add antibodies to the blood sample. These antibodies bind to SMRP and fragments of this protein.

Computer software analyzes the blood sample and measures the levels of SMRP-bound antibodies. High levels suggest the presence of mesothelioma or another malignant pleural disease.

Elevated Serum SMRP levels bar graph Caption: Percent of patients who had elevated serum SMRP levels

A blood test is most helpful to determine whether treatment is working. Doctors often use the MESOMARK blood test to diagnose suspected cases. A biopsy is the most accurate test for diagnosis. 

N-ERC/Mesothelin Test

The N-ERC/Mesothelin test detects a specific form of mesothelin. This form is N-ERC/mesothelin.

The test is like MESOMARK but uses a special enzyme. This enzyme finds a particular version of the mesothelin molecule. This increases the test’s accuracy.

The N-ERC/mesothelin test is 95% effective at detecting mesothelioma. Yet, it is only 76% effective at ruling mesothelioma out. This is because a few other types of cancer can also produce mesothelin.

This test is more accurate than MESOMARK but cannot diagnose mesothelioma alone.

Fibulin-3 Test

Mesothelioma cells produce a protein called fibulin-3. Specific tests can detect this protein in pleural fluid and blood. Mesothelioma specialist Dr. Harvey Pass helped develop it for diagnosis.

He co-authored a study showing that the test is 96.7% effective at detecting mesothelioma. It is also 95.5% effective for ruling it out in people without the disease.

Other studies have found the test less effective for detecting mesothelioma. Its accuracy decreases on older blood samples collected from mesothelioma patients.

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Emerging Biomarker-Based Blood Tests

Some advanced mesothelioma blood tests sense levels of other biomarkers. Examples of newer tests include:

  • Osteopontin: Levels are high in mesothelioma patients, but other diseases can elevate osteopontin. Examples include lung, colon and breast cancers and tuberculosis. The test is too inaccurate for diagnosis. It can help predict the prognosis for mesothelioma patients.
  • Megakaryocyte Potentiation Factor (MPF): Doctors do not yet understand the function of MPF. Levels are high in mesothelioma but may decrease after surgery. This could show that MPF blood testing can help track a patient’s response to surgery.
  • 8OHdG: This biomarker indicates cell damage. It’s a sign of oxidation and may be present during the early stages of cancer. Researchers have linked elevated levels with asbestosis and occupational asbestos exposure.
  • Estrogen Receptor-β: A 2022 research study tested 46 patients for estrogen receptor-β. It identified the biomarker in 30.4% of cases. High levels also correlate with a better response to chemotherapy. ER-β could also be a potential target for future mesothelioma therapy.

  • Epidermal Growth Factor Receptor (EGFR): A 2022 research report noted that EGFR expression is high in 50% to 95% of pleural mesothelioma cases. Asbestos exposure activates EGFR. It may play a role in the development of mesothelioma.
  • Calretinin: A 2021 study detailed the possible use of a calretinin blood test for asbestos disease. Researchers found it performed similarly to mesothelin. Calretinin is less likely to improve the diagnosis of sarcomatoid cell mesothelioma.

Researchers have demonstrated that mesothelioma patients have higher concentrations of these biomarkers than healthy individuals or patients with other cancers.

Osteopontin and MPF blood tests alone are not dependable or accurate enough to diagnose mesothelioma. Still, they can monitor the disease once a diagnosis is confirmed with X-rays, CT scans and tissue biopsies.

When asbestos fibers enter the body, they cause damage to healthy cells and transform them into cancer. Doctors can monitor the byproducts of asbestos-related cancer cells to track the progression of asbestos-related diseases.

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