Mesothelin and osteopontin as circulating markers of diffuse malignant peritoneal mesothelioma: A preliminary study.

BACKGROUND: The differential diagnosis between diffuse malignant peritoneal mesothelioma (DMPM) and other peritoneal surface malignancies (PSM) is still challenging. Serum mesothelin and osteopontin are increasingly used as markers of pleural mesothelioma, but their role in DMPM is unclear. We assessed the diagnostic and prognostic values of mesothelin, osteopontin, CEA, CA19.9, CA125, and CA15.3 in DMPM patients. METHODS: Markers were dosed before cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) by enzyme-linked immunosorbent assay (ELISA) in 30 DMPM patients and 14 controls with other PSMs. Receiver-operating characteristics (ROC) curve were plotted. The performance of each marker was assessed by the area under the ROC curve (AUC-ROC). RESULTS: Mean mesothelin levels were 7.84 ng/dl (SD = 5.14) in DMPM group and 3.00 ng/dl (SD = 1.25) in controls (P = 0.001). Mean CEA levels were 5.3 ng/dl (SD = 4.7), and 61.96 ng/dl (SD = 112.5) in the two groups (P = 0.008). No statistical difference was seen for osteopontin (P = 0.738), CA19.9 (P = 0.081), CA125 (P = 0.600), and CA15.3 (P = 0.365). AUC-ROC was 0.836 for CA19.9, 0.812 for mesothelin, 0.793 for CEA, and lower for CA125 (0.652), osteopontin (0.531), and CA15.3 (0.481). Using diagnostic cut-offs selected by ROC methodology, sensitivity, specificity, positive and negative predictive values were 70.0%, 100.0%, 100.0%, and 60.9% for mesothelin >5.21 ng/dl, and 90.0%, 85.7%, 93.1%, and 80.0% for CA19.9 < 8.8 U/dl. At multivariate analysis, osteopontin correlated with survival (hazard rate 6.46; 95%CI 1.81-23.05; P = 0.004). CONCLUSION: When assessing PSMs of unknown origin, elevated mesothelin with low CA19.9 may increase the suspicion index for DMPM. Ospeopontin warrants further investigations as a prognostic marker for DMPM.