Mesothelioma Diagnosis Improved with New Biomarkers

Three important biomarkers have emerged for less invasive diagnosis of the asbestos-linked cancer mesothelioma.

Levels of a protein biomarker called mesothelin, which is found in the pleural fluid of patients with malignant mesothelioma, were studied. Mesothelin is a protein produced by mesothelioma cells and released into the fluid around the lungs.

Compared with cytology, pleural-fluid mesothelin had better sensitivity, similar specificity, and superior negative predictive value. "Pleural effusion … can be maddeningly difficult to diagnose, as a wide variety of malignant and benign causes exist,” noted Helen E. Davies, M.D., from the Oxford Pleural Unit, Oxford Center for Respiratory Medicine, University of Oxford (Oxford, United Kingdom) "One of the causes, malignant pleural mesothelioma, is a relatively rare cancer, but its incidence is rapidly increasing on a global scale.”

Calretinin is a vitamin-D dependent calcium-binding protein and another well-established immunohistochemical marker for malignant mesothelioma. A group of German researchers developed an enzyme-linked immunosorbent assay (ELISA) blood test of calretinin and tested it on 97 healthy volunteers, 35 asbestos-exposed workers and 42 mesothelioma patients. Calretinin levels were found to be elevated in both the asbestos-exposed group and among those with mesothelioma. This study appeared in the journal BMC Cancer on May 28, 2010.

A more recent report noted that the calretinin test might not be as helpful in patients who have the rare sarcomatoid type of pleural mesothelioma. A group of Danish researchers cautioned that most sarcomatoid-mesothelioma cases test negative for the presence of calretinin. Their findings were published in the September 27, 2010 edition of Ugeskr Laeger.

University of Pisa (Italy) investigators examined the value of another potential diagnostic biomarker called osteopontin, found in the plasma and serum of mesothelioma patients. After testing for osteopontin in 94 healthy volunteers, 113 patients with benign respiratory diseases (BRD) and 32 patients with malignant pleural mesothelioma, the team found levels to be "significantly higher” in patients with malignant mesothelioma than in either the healthy control group or those with BRD. The report appeared ahead of print in the September 27, 2010, edition of the International Journal of Biological Markers. The authors wrote, "Plasma and serum osteopontin may be useful markers in the diagnosis of epithelial MPM in addition to traditional radiological exams.”

Mesothelioma is very difficult to diagnose as it mimics many other conditions. It needs to be recognized early in order to treat patients appropriately and produce better outcomes. These three biomarkers should help to diagnose the dangerous condition.

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University of Oxford
University of Pisa