There is no established single diagnostic marker for
malignant pleural mesothelioma (MPM). CD26 is a 110 kDa, multifunctional, membrane-bound
glycoprotein that has
dipeptidyl peptidase IV (DPPIV)
enzyme activity. The aim of this study was to evaluate the clinical significance of soluble CD26 (sCD26) in patients with MPM. The study included 80 MPM patients, 79 subjects with past
asbestos exposure (SPE), and 134 patients with other benign
pleural diseases (OPD) that were included as a control group. sCD26 levels and DPPIV activity in serum and/or pleural fluid were determined using an ELISA kit. Serum sCD26 levels and DPPIV
enzyme activity in patients with MPM were significantly decreased compared with those in the SPE group (P = 0.000). The level of serum sCD26 was significantly decreased in patients with advanced stages of MPM compared with those with earlier stages (P = 0.047). The median OS of patients with MPM who had higher DPPIV
enzyme activity was significantly longer than that of those with lower DPPIV
enzyme activity (P = 0.032). The sCD26 levels in the pleural fluid of MPM patients with an epithelioid subtype were significantly increased compared with the OPD cohort (P = 0.012). Moreover, DPPIV
enzyme activity in the pleural fluid of patients with MPM with an epithelioid subtype were significantly increased compared with those in the OPD cohort (P = 0.009). Patients with MPM who had lower specific DPPIV activity, determined as DPPIV/sCD26, showed significantly prolonged survival compared with those with higher specific DPPIV activity (P = 0.028). Serum sCD26 and DPPIV
enzyme activity appear to be useful
biomarkers for differentiating patients with MPM from SPE. The sCD26 levels or DPPIV
enzyme activity in pleural fluid appear to be
biomarkers in patients with an epithelioid subtype of MPM. DPPIV activity in serum or pleural fluid appears to be predictive for the prognosis of patients with MPM.