Three separate teams of international researchers have confirmed that proteins found in the blood can reveal some vital information for the diagnosis, treatment, and prognosis of pleural mesothelioma. These new studies on mesothelioma biomarkers indicate that all three of the studied proteins have value, but for different reasons.
The most recent study comes from researchers in the Czech Republic who found that serum mesothelin, a protein overexpressed in several types of cancer, is valuable to measure the severity of mesothelioma in people who have already been diagnosed, but is unlikely to help doctors find the disease earlier.
Doctors in the Department of Respiratory Medicine in Palacky University Olomouc followed 239 asbestos-exposed workers for nearly 20 years. They found that mesothelin levels tended to be higher in those with anomalies on their X-rays – even if they were benign – than they were in people with normal X-rays. In those with mesothelioma, levels were even higher than they were in those with benign disease.
Mesothelin was able to correctly identify mesothelioma in 75% of positive cases and was able to correctly rule out mesothelioma in 90.6% of negative cases. Although the doctors conclude that mesothelin is not a reliable marker for early-stage mesothelioma, they conclude that it is “an additional criterion for examination of the followed-up individuals”.
In contrast, Chinese researchers say their meta-analysis shows that another protein called osteopontin does have the potential to help diagnose malignant pleural mesothelioma. After analyzing six osteopontin studies through March, 2013, the team found that osteopontin had an overall diagnostic sensitivity for mesothelioma of 95%. The diagnostic accuracy of osteopontin was comparable whether it came from the blood serum or the plasma. The Chinese team is calling for larger osteopontin studies.
Finally, researchers in Austria, Hungary, and Croatia say the glycoprotein fibrinogen has the potential to be “a novel independent prognostic biomarker for malignant pleural mesothelioma”. They performed a retrospective multicenter study on 176 mesothelioma patients and found that patients with the lowest levels of fibrinogen had significantly longer overall survival than mesothelioma patients with the lowest fibrinogen levels.
“Most importantly, fibrinogen predicted treatment benefit achieved by surgery within multimodality therapy,” writes lead author, Bahil Ghanim of the Medical University of Vienna. According Ghanim and his colleagues, mesothelioma patients with fibrinogen levels below the 75th percentile are most likely to benefit from surgery and multimodal therapy.
Blood tests for mesothelioma biomarkers offer a non-invasive method for guiding clinicians in the management of this hard-to-treat cancer.
Ghanim, B et al, “Circulating fibrinogen is a prognostic and predictive biomarker in malignant pleural mesothelioma”, February 18, 2014, British Journal of Cancer, pp. 984-990
Hu, ZD, “Diagnostic accuracy of osteopontin for malignant pleural mesothelioma: A systematic review and meta-analysis”, March 2014, International Journal of Clinical Chemistry
Jakubec, P et al, “Significance of serum mesothelin in an asbestos-exposed population in the Czech Republic”, April 29, 2014, Biomedical Papers of the Medical Faculty, Epub ahead of print