Soluble CD157 in pleural effusions: a complementary tool for the diagnosis of malignant mesothelioma

// Stefania Augeri 1, * , Stefania Capano 1, * , Simona Morone 1 , Giulia Fissolo 1 , Alice Giacomino 1 , Silvia Peola 1 , Zahida Drace 1 , Ida Rapa 2 , Silvia Novello 2 , Marco Volante 2 , Luisella Righi 2 , Enza Ferrero 1 , Erika Ortolan 1 and Ada Funaro 1 1 Laboratory of Immunogenetics, Department of Medical Sciences, University of Torino, Torino 10126, Italy 2 Department of Oncology, University of Torino, San Luigi Hospital, Torino 10043, Italy * These authors contributed equally to this work Correspondence to: Ada Funaro, email: ada.funaro@unito.it Keywords: CD157/Bst1; mesothelioma; biomarker; pleural effusion; diagnosis Received: February 28, 2018      Accepted: April 07, 2018      Published: April 27, 2018 ABSTRACT Background: CD157/Bst1 glycoprotein is expressed in >85% of malignant pleural mesotheliomas and is a marker of enhanced tumor aggressiveness. Results: In vitro , mesothelial cells (malignant and non-malignant) released CD157 in soluble form or as an exosomal protein. In vivo , sCD157 is released and can be measured in pleural effusions by ELISA. Significantly higher levels of effusion sCD157 were detected in patients with malignant pleural mesothelioma than in patients with non-mesothelioma tumors or with non-malignant conditions. In our patient cohort, the area under the receiver-operating characteristic curve for sCD157 that discriminated malignant pleural mesothelioma from all other causes of pleural effusion was 0.685, cut-off (determined by the Youden Index) = 23.66 ng/ml (62.3% sensitivity; 73.93% specificity). Using a cut-off that yielded 95.58% specificity, measurement of sCD157 in cytology-negative effusions increased sensitivity of malignant pleural mesothelioma diagnosis from 34.42% to 49.18%. Conclusions: Evaluation of soluble CD157 in pleural effusions provides a diagnostic aid in malignant mesothelioma. Methods: Soluble CD157 (sCD157) was detected biochemically in culture supernatants of malignant and non-malignant mesothelial cells, and in pleural effusions from various pathological conditions. An ELISA system was established to measure the concentration of sCD157 in fluids, and extended to analyze sCD157 in pleural effusions from a cohort of 295 patients.