Blood levels of the protein mesothelin have moderate sensitivity and high specificity in distinguishing malignant pleural mesothelioma (MPM) from other pleural diseases, but levels of a protein called midkine may be a useful marker to predict patients’ prognosis, a Turkish study says.
The study, “Midkine is a potential novel marker for malignant mesothelioma with different prognostic and diagnostic values from mesothelin,” appeared in the journal BMC Cancer.
Clinicians may have a hard time distinguishing between mesothelioma and other pleural diseases due to the lack of specific biomarkers for each condition. No known biomarkers predict patients’ prognosis, which would be valuable not only for precise diagnosis but also to improve treatment. To date, the only blood-based biomarker available for diagnosis and prognosis of mesothelioma is mesothelin, which is highly expressed in patients with this disease.
Researchers at Eskişehir Osmangazi University Hospital in Eskişehir investigated the potential diagnostic and prognostic use of blood midkine levels, compared to those of blood mesothelin. The team analyzed both parameters in samples from 95 cases of MPM, 56 metastatic cancers to the pleura, 27 other types of benign pleural diseases, and 20 benign asbestos pleurisy cases.
Results showed that mesothelin assessment provided:
- 51.6 percent sensitivity and 71.4 percent specificity in differentiating mesothelioma from metastatic cancers to pleura;
- 51.6 percent sensitivity and 85.2 percent specificity in differentiating mesothelioma from other benign pleural diseases;
- 51.6 percent sensitivity and 85 percent specificity in differentiating mesothelioma from benign asbestos pleurisy.
Assessment of midkine levels had:
- 61.1 percent sensitivity and 41.1 percent specificity in differentiating mesothelioma from metastatic cancers to pleura;
- 61.1 percent sensitivity and 48.1 percent specificity in differentiating mesothelioma from other benign pleural diseases;
- 61.1 percent sensitivity and 75 percent specificity in differentiating mesothelioma from benign asbestos pleurisy.
A combination of both analyses did not improve diagnostic efficacy. Researchers also found that mesothelin levels were higher both in the epitheloid type of mesothelioma and in the advanced cases, but could not predict prognosis. Increased midkine levels, however, were associated with poor prognosis, independently of disease stage, mesothelioma subtype or response to chemotherapy.
“Mesothelin is a useful biomarker with a moderate sensitivity and a relatively high specificity for the diagnosis of mesothelioma, but the level was not associated with the patient prognosis,” researchers wrote. “In contrast, midkine can differentiate mesothelioma only from benign asbestos pleurisy but the baseline level of midkine predicted prognosis of mesothelioma patients. Midkine is thus a novel biomarker for mesothelioma and has a different clinical value from mesothelin.”
