Improved diagnosis of mesothelioma by a combination of soluble mesothelin-related peptide and CYFRA 21-1

Background: Soluble mesothelin-related peptide (sMRP) has shown great potential for malignant mesothelioma detection. However, data on comparison with other cancer and benign diseases as well as with other established lung cancer biomarkers are rare. Methods: In this study, SMRP was investigated in sera from 1506 individuals including 147 healthy donors, 285 patients with diverse benign diseases and 1074 patients with mesothelioma (n=39) and various malignant tumors (lung, gastrointestinal, gynecological, urological). For differential diagnosis of lung diseases, carcinoembryonic antigen, cytokeratin 19-fragments (CYFRA 21-1), neuron-specific enolase and squamous cell cancer antigen were determined additionally. Results: Ninety-fifth percentiles of sMRP serum levels in healthy persons were 1.2 nM, in patients with benign diseases between 2.0 and 3.8 nM and in cancer patients between 1.5 and 44.3 nM. Highest values were observed in mesothelioma (median 2.3 nM; 95th percentile 44.3 nM). When differential diagnostic capacity of cancer detection vs. the relevant benign control group was tested, sMRP showed best results for mesothelioma and ovarian cancer with a sensitivity of 45% and 37%, respectively, at 95% specificity. At 100% specificity vs. normal controls, sensitivity for mesothelioma detection was found to be 59% for sMRP, 73% for CYFRA 21-1 and 88% for the combination of both. At 95% specificity vs. all other lung diseases, sensitivity for mesothelioma was 48% for sMRP, 15% for CYFRA 21-1 and 46% for the combination of both. Conclusions: In summary, SMRP is a valuable serum biomarker that is specific at high concentrations for the detection of malignant mesothelioma. For screening purposes, the combination with CYFRA 21-1 improves the sensitivity at high specificity.