P3.03-009 Role of microRNAs as Biomarkers of Malignant Mesothelioma in Patients with Pleural Effusion: Topic: Mesothelioma Transitional

Abstract

Pleural effusion (PE) is a common clinical presentation of a large number of different diseases including malignant pleural mesothelioma (MPM). The approach to patients with PE is not simple and pre-operative cytological examinations or even intra-operative frozen sections are often unhelpful in the differential diagnosis. This fact makes critical the management of PE, especially when MPM is suspected. Changes in the expression of microRNAs (miRNAs) have been implicated in several diseases, making miRNAs attractive biomarkers. Our aim was to determine whether a miRNA signature in plasma or in Exhaled Breath Condensate (EBC) may help to discriminate between PE related to MPM and PE of patients affected by other pleural diseases (NM). We prospectively enrolled consecutive patients with PE from suspected MPM, scheduled for thoracoscopic pleural biopsy. We recorded clinical data and definitive histological diagnosis. Exclusion criteria were age < 18 years, history of previous tumor or immunological disorder. Ethics committee approval was achieved. Written informed consent was obtained from all participants. We collected a sample of plasma and EBC from each patient before the biopsy. We screened 733 miRNAs in blood and EBC by high-throughput Open Array and compared their expression in the two groups. We used a multiple linear regression model adjusted for four principal variables (age, sex, BMI and smoking habits) to compare MPM and NM. We enrolled 32 patients; the figure below shows main clinical data. After miRNA screening, we identified 3 miRNAs which were upregulated in EBC and 44 in plasma. In particular, in EBC: miR-378, miR-206, miR-9 with a fold-change (FC) of 1.54, 1.4, 1.23 respectively (p-value= 0.019, 0.04 and 0.04 respectively). The most significant in plasma was miR-489 (FC= 1.35, p-value= 0.0001). We identified a miRNAs panel that might be useful for developing a non-invasive procedure for MPM diagnosis in patients with PE.