Mesothelioma Tumor Markers
Tumor markers, also referred to as biomarkers, are proteins produced by tumor cells that can be measured. These substances are also manufactured by normal cells, but not in as large a quantity as that produced by tumor cells. Tumor markers are found in bodily fluids like blood and urine.
Do Tumor Markers Provide a Definitive Diagnosis of Mesothelioma?
In an article titled “Biomarkers for Malignant Pleural Mesothelioma: Current Status”, published in 2008 in Molecular Diagnosis and Therapy, researchers noted that biomarkers are useful for early diagnosis of the disease, determining the prognosis, and predicting how well patients are responding to treatment. However, the chief difficulty in making use of biomarkers is that the typical ones like cytokeratins and proteins found on the surface of cells do not differentiate malignant pleural mesothelioma from other types of malignancies or non-malignant conditions.
Although osteopontin, mesothelin, and megakaryocyte potentiating factor (MPF) are the most promising of the recently discovered biomarkers, they still present certain problems. Osteopontin is not a biomarker that is specific to mesothelioma, mesothelin and MPF do not detect sarcomatoid or biphasic mesothelioma cell types.
Researchers have tried using panels made up of a set of biomarkers, but this didn’t improve diagnostic accuracy. Research into profiling molecules is just at its beginning stages and is not useful in daily clinical practice.
A variety of biomarkers have been evaluated in body fluids and tumor tissue for their value as indicators of prognosis, but none of these play a real role in clinical practice. Information regarding predictive biomarkers is very limited.
The value of biomarkers is still an important question that needs to be addressed. That’s why these researchers made the following recommendations:
“Additional prospective studies, in large and independent samples of patients, with rigorous statistical methodology and standardized laboratory techniques are now warranted to validate and define the precise value of diagnostic and prognostic MPM (malignant pleural mesothelioma) biomarkers. Future research efforts should focus on biomarkers predictive of the efficacy and toxicity of standard chemotherapy.”
New Research Suggests that SMRP Levels may Hold the Key to Diagnosing Mesothelioma
Japanese researchers have found that soluble mesothelin-related peptide (SMRP) is extremely sensitive to mesothelioma, but it does not always detect every cell subtype. In a study titled Exploratory study on the detection of markers for diagnosing early-stage malignant mesothelioma, published May 2011 in Nihon Eiseigaku Zasshi (Japanese Journal of Hygiene), they noted that SMRP levels measured in pleural fluid were elevated not only in advanced stage malignant pleural mesothelioma , but also in early stage disease.
Circulating tumor cells (CTCs) and circulating endothelial cells (CECs) were good additional markers of disease progression, but they were not always accurate in diagnosing the disease in its early stages. A cell analysis with gene profiling is more effective in diagnosing early stage mesothelioma.
The Food and Drug Administration approved a test to determine if mesothelioma has progressed.
On January 24, 2007, the Food and Drug Administration (FDA) approved the MESOMARK™ test for patients who have been diagnosed with malignant mesothelioma with epithelioid features, and who are under treatment after surgery. It measures the amount of soluble mesothelin related peptides (SMRPs) in a patient’s blood sample to determine whether the disease has gotten worse.