Mesothelin Flawed But Still the Best Mesothelioma Biomarker

Patients who are suspected of having mesothelioma often want to know whether there is a test to determine for certain if they have the disease. Unfortunately, no such test exists.

Instead, mesothelioma diagnosis typically involves a complex combination of work and family history, symptoms, scans, biopsies and, often, a test for a protein called mesothelin. While mesothelin is not a perfect biomarker for malignant mesothelioma, a team of Australian mesothelioma researchers has confirmed that it is probably still the best one available.

Biomarkers are measurable substances that can help indicate whether a patient has a particular disease. As the search for the most effective mesothelioma biomarkers continues, doctors at the University of Western Australia’s National Center for Asbestos Related Diseases say mesothelin, which is overexpressed in several types of cancer, still stands head-and-shoulders above a newly-proposed marker called fibulin-3, an extracellular matrix protein expressed in the membranes of blood vessels.

But the authors say both biomarkers have flaws. Their evaluation of recent studies on the mesothelin test – including a study they conducted last year – indicate that it has a sensitivity, or “true positive”, rate of about 60 percent. On the other hand, the researchers say the findings on fibulin-3 are too inconsistent for it to be useful in the clinical management of mesothelioma. Their conclusion? Mesothelin is still the gold standard mesothelioma biomarker.

“To date, soluble mesothelin remains the best available biomarker for mesothelioma and a positive result is clinically useful in patients with pleural effusions in whom the diagnosis is uncertain,” writes lead author Jenette Creaney, PhD.

Last year, Dr. Creaney led a multi-center study of mesothelin and fibulin-3 levels in 153 patients with mesothelioma or other malignancies. That study concluded that, while mesothelin was a better diagnostic marker, fibulin-3 was a more accurate prognostic indicator.

Source:

Creaney, J, et al, “Comparison of mesothelin and fibulin-3 in pleural fluid and serum as markers in malignant mesothelioma”, Mary 26, 2015, Current Opinions in Pulmonary Medicine, Epub ahead of print, http://www.ncbi.nlm.nih.gov/pubmed/26016578