Serum levels of soluble mesothelin-related peptides in malignant and nonmalignant asbestos-related pleural disease: relation with past asbestos exposure.

BACKGROUND Malignant pleural mesothelioma (MPM) results from malignant transformation of mesothelial cells. Past asbestos exposure represents a major risk factor for MPM and other benign pleural disease. Soluble mesothelin-related peptides (SMRP) have been regarded as a promising serum biomarker for MPM. The aim of this study was to investigate serum levels of SMRP in malignant and nonmalignant asbestos-related pleural disease. PATIENTS Four groups of patients were investigated: group 1 composed of 48 healthy subjects, group 2 composed of 177 patients with previous asbestos exposure and no pleural disease, group 3 composed of 36 patients with MPM, and group 4 composed of 101 patients with previous asbestos exposure and benign pleural disease. Serum SMRP levels were determined by ELISA. RESULTS Serum SMRP levels were significantly higher among group 3 than the other three groups. There were no differences in SMRP concentrations between groups 2 and 4. Subjects exposed to asbestos had higher SMRP concentrations than normal control subjects regardless of the presence of pleural disease. The area under the receiver operating characteristic curve for SMRP values was 0.75 (95% confidence interval, 0.68-0.83). The SMRP level at 0.55 nmol/L/L was determined as the most optimal cutoff value with resulting sensitivity and specificity of 72% and 72% for the diagnosis of MPM. CONCLUSIONS These data attest to good diagnostic sensitivity and specificity of SMRP for the diagnosis of malignant mesothelioma. We have also shown that serum SMRP levels might serve as a marker of asbestos exposure.