The place and importance of new blood biomarkers in diagnosis and prognosis of patients with malignant mesothelioma

INTRODUCTION Malignant mesothelioma (MM) is an agressive tumor which is mostly originating from pleura and then mesothelial cells on the surfaces of peritoneum, pericardium and tunica vaginalis and serous layer of testicle (1). 60%-90% of the diagnosed patients of MPM (average 80%) has a history of asbestos exposure. 25% of the cases have 6 months of symptoms and average of diagnosing period is 2-3 months. The diagnosis on MPM is also based on cytological and histopathological investigation. In our study, we aimed to evaluate the effect of the serum megakaryocyte potentiating factor (MPF), osteopontin, galectin-3, soluble mesothelin-related peptides (SMRP), hyaluranic acid, tenascin-C, fibronectin, platelet-derived growth factor (PDGF), biomarker levels on diagnosis and prognosis, and relation with age, gender, asbestos exposure, exposure period, stage and histopathological type. MATERIALS AND METHODS Study was carried with 49 examined and/or treated patients who has pleural or peritoneal malignant mesothelioma at Dicle University's Pulmonology, Thoracic Surgery and Medical Oncology departments from August 2012 to December 2013. 23 of all patients were women and 26 of all patients were men. Age (≤60 or >60 years), gender, asbestos exposure and period of exposure (≤20 or >20 years), histopathological subtypes and stages were saved in standard forms. About 10 cc of blood was sampled from patients and preserved at -80˚C. Following eight biomarkers were assessed in the serum samples which resolved on the assessment day by using commercially available kit: megakaryocyte potentiating factor (MPF), osteopontin, galectin-3, soluble mesothelin-related peptides (SMRP), hyaluronic asit, tenascin-C, fibronectin, platelet-derived growth factor (PDGF). RESULTS Levels of fibronectin, tenascin c, MPF, osteopontin were found higher in women than in men, levels of hyaluronic acid, SMRP, PDGF, galectin 3 were higher in men than in women. However, there was no significant difference between them (p>0,05). 24(49%) of the patients were under 60 and 25 (51%)of the patients were more than 60 years old. All biomarker levels were observed in a decreasing pattern by age but this was statistically significant only for PDGF, MPF, galectin 3 (p<0,05). 7 patients did not have asbestos exposure (14%), 42 patients had the history of asbestos exposure. All biomarker levels were found higher in the group of asbestos exposure than the unexposed group, however, there was no statistical significance (p>0,05). 18 of 44 patients with malignant plevral mesothelioma (41%) had stage 1 or stage 2 disease, and 26 patients had stage 3 or stage 4 disease. All biomarker levels were found higher in the group of patients with stage 3 or 4 disease than the group of patients with stage 1 or 2 disease. However, only tenascin c, fibronectin, MPF, galectin levels were statistically significant (p<0,05). 35 patients (71%) had epithelial type disease, 14 patients (29%) had non-epithelial type disease. All biomarkers were higher in epithelial type disease than in non-epithelial type disease except of tenascin c. However, statisctically significance was detected only for tenascin c (p<0,05). In the follow up period of one and half year, 22 (45%)of patients were alive, and 27 (55%)patients died. Levels of Fibronectin, hyaluronic acid, SMRP, PDGF, MPF were found higher in the group of died patients, however, there was no statistically significant difference (p>0,05). DISCUSSION Asbestos exposure was related to biomarker levels. Besides the levels were increased by higher stages. tenascin c,fibronektin, MPF, galectin 3 levels were found higher as statistically significant in the patients with higher grade diseases (p<0,05). A significant relation on prognosis could not be detected due to lack of number of patients. We think that there is a need of studies with larger series about these biomarkers.