MSLN and metastatic malignant neoplasm: The AUC of serum mesothelin to distinguish patients with mesothelioma from those with all the other diseases, including metastatic cancers, benign asbestos pleurisy and benign pleural diseases, was higher than that of midkine (p < 0.0001), whereas it was not different from that of the combination of the two biomarkers (p = 0.5598) (Fig. 2d).