Blood Tests and Biomarkers

While imaging tests and tissue biopsies are the most common methods for diagnosing mesothelioma, blood tests can also help doctors identify the disease. These blood tests look for certain indicators of disease, known as biomarkers, in a patient's blood.

Although the broadest definition of biomarker also includes the measurement of physiological and anatomical criteria, for mesothelioma blood tests the term refers to measuring the levels of biological molecules associated with the disease, such as specific proteins or genes. If these biomarkers are detected in the blood in abnormally high concentrations, it may suggest a diagnosis.

Diagnostic sensitivity of three different blood-based biomarkers

In addition to their diagnostic benefits, biomarkers can also be used to predict the progression and aggressiveness of a patient's mesothelioma. This can affect a patient's prognosis and help doctors identify the patients who will respond best to certain treatments.

The MESOMARK assay is the most well-known blood test for mesothelioma. This FDA-approved test was the world's first blood serum-based test sensitive for the disease. The MESOMARK kit scans a patient's blood for levels of soluble mesothelin-related peptide (SMRP), a protein released into the blood by the cancerous cells of this illness.

Other blood tests can scan a patient's blood for the biomarkers osteopontin and megakaryocyte potentiating factor (MPF). However, these tests are less readily available, and doctors still do not consider them accurate enough to replace histology as the gold standard for diagnosis.
While the term “tumor marker” is often used interchangeably with biomarker, the definitions of these two terms are slightly different. Tumor markers are substances found in or expressed by the actual tumor, while biomarkers are not necessarily expressed by tumor cells.