To determine the roles of OPN in MPM, immunohistochemical staining was performed to investigate the concentration of OPN in the pleural tumor of patients with mesothelioma; cell adhesion, proliferation and migration assays of H28 cells, an MPM cell line, were also carried out in vitro.
We report that persistent C. trachomatis infection increases the expression of inflammatory tumour cytokines and upregulates molecular biomarkers such as podoplanin, Wilms' tumour gene 1 and osteopontin in primary cultures of mesothelial cells (Mes1) and human mesothelioma cells (NCI).
Subgroup analysis comparing patients with stage I mesothelioma with subjects with exposure to asbestos revealed a sensitivity of 84.6 percent and a specificity of 88.4 percent at a cutoff value of 62.4 ng of osteopontin per milliliter.
Osteopontin and MPF were unable to differentiate patients with mesothelioma from patients with other malignancies or those presenting with transudative pleural effusions.
Frequent OPN expression is typical of, but not specific for MM, whereas it appears to select adenocarcinoma cases with p65 and MMP-9 expression, suggesting a link with EGFR signalling pathways.