Liquid Biopsies from Pleural Effusions and Plasma from Patients with Malignant Pleural Mesothelioma: A Feasibility Study

• Published in: Cancers Vol. 13; no. 10; p. 2445
• Main Authors: Moretti, Gabriele, Aretini, Paolo, Lessi, Francesca, Mazzanti, Chiara Maria, Ak, Guntulu, Metintaş, Muzaffer, Lando, Cecilia, Filiberti, Rosa Angela, Lucchi, Marco, Bonotti, Alessandra, Foddis, Rudy, Cristaudo, Alfonso, Bottari, Andrea, Apollo, Alessandro, Del Re, Marzia, Danesi, Romano, Mutti, Luciano, Gemignani, Federica, Landi, Stefano
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 18.05.2021; MDPI
• Subjects: Apoptosis; Biopsy; Cancer; cancer-specific mutations; circulating tumor DNA; Deoxyribonucleic acid; DNA; DNA sequencing; Feasibility studies; genomics; Invasiveness; liquid biopsies; malignant pleural mesothelioma; Mesothelioma; Mutation; Nucleotide sequence; Patients; Plasma; Pleural fluid; Polymerase chain reaction; Standard deviation; Statistical analysis; Tumors; United States > US; Italy; Turkey; malignant pleural mesothelioma; cancer-specific mutations; liquid biopsies; genomics; cancer biomarkers; plasma; circulating tumor DNA
• ISSN: 2072-6694; 2072-6694
• DOI: 10.3390/cancers13102445

Malignant pleural mesothelioma (MPM) is a fatal tumor with a poor prognosis. The recent developments of liquid biopsies could provide novel diagnostic and prognostic tools in oncology. However, there is limited information about the feasibility of this technique for MPMs. Here, we investigate whether cancer-specific DNA sequences can be detected in pleural fluids and plasma of MPM patients as free circulating tumor DNA (ctDNA). We performed whole-exome sequencing on 14 tumor biopsies from 14 patients, and we analyzed 20 patient-specific somatic mutations with digital droplet PCR (ddPCR) in pleural fluids and plasma, using them as cancer-specific tumor biomarkers. Most of the selected mutations could be detected in pleural fluids (94%) and, noteworthy, in plasma (83%) with the use of ddPCR. Pleural fluids showed similar levels of somatically mutated ctDNA (median = 12.75%, average = 16.3%, standard deviation = 12.3) as those detected in solid biopsies (median = 21.95%; average = 22.21%; standard deviation = 9.57), and their paired difference was weakly statistically significant ( = 0.048). On the other hand, the paired difference between solid biopsies and ctDNA from plasma (median = 0.29%, average = 0.89%, standard deviation = 1.40) was highly statistically significant ( = 2.5 × 10 ), corresponding to the important drop of circulating somatically mutated DNA in the bloodstream. However, despite the tiny amount of ctDNA in plasma, varying from 5.57% down to 0.14%, the mutations were detectable at rates similar to those possible for other tumors. We found robust evidence that mutated DNA is spilled from MPMs, mostly into pleural fluids, proving the concept that liquid biopsies are feasible for MPM patients.