Creaney J, Yeoman D, et al.
Patients diagnosed with malignant mesothelioma often present to physicians with a pleural or peritoneal effusion. The researchers at the University of Western Australia investigated whether levels of the MESOMARK assay (mesothelin), were elevated in the pleural effusion and if that fluid measurement could add value to existing tests in the differential diagnosis of mesothelioma. The study evaluated pleural effusions from 192 patients, 52 who were diagnosed with mesothelioma and the remainder with exudative effusions or non-mesothelioma malignancies. As has been previously reported in the serum of patients with mesothelioma the mesothelin fluid level was reported at higher values in patients with mesothelioma than in patients with non-malignant effusions. This suggests that the test could be useful in evaluating patients with an undiagnosed pleural or peritoneal effusion, specifically when there is no definitive diagnosis with cytology.
In addition to evaluating the biomarker in pleural effusion the research also looked at the value of the test when comparing matched serum and pleural effusion samples. The authors do show that there is a correlation between the serum and pleural effusion measurements in patients with mesothelioma. However, there was no correlation between values in patients with non-mesothelioma malignancies. Mesothelin was elevated in 10 of the 13 patients prior to diagnosis. When combining all of this data there are a number of conclusions. Mesothelin levels greater than 20 nM suggest the presence of a malignancy, specifically mesothelioma and could be of use in pleural effusion where cytology is negative. The increase in the mesothelin levels in the effusion prior to diagnosis, suggests that the assay may be beneficial in the early diagnosis of patients with mesothelioma.