**5. Conclusions**

Taken together, candidate biomarkers (Galectin-1, Mesothelin, Osteopontin, shed SDC-1, VEGF, MMP-7, HGF, TIMP-1 and NRG1-β1) identified in the current study could be diagnostic biomarkers for distinguishing malignant pleural mesothelioma and metastatic adenocarcinoma from benign patients. Shed SDC-1 and VEGF are prognostic biomarkers for malignant pleural mesothelioma.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2218-273X/10/8/1113/s1, Figure S1: Pleural effusion levels of diagnostic biomarkers in metastatic adenocarcinoma patients.

**Author Contributions:** Conceptualization, A.H. and K.D.; methodology, A.H., K.D. and J.J.; software, A.H. and J.J.; validation, J.J.; investigation, J.J.; writing—original draft preparation, J.J.; writing—review and editing, A.H., K.D. and J.J.; visualization, J.J.; supervision, A.H.; project administration, K.D.; funding acquisition, K.D. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by The Swedish Cancer Society, grant number CAN 2018/653; Stockholm County Council, grant number LS 2015-1198; and The Cancer Society in Stockholm, grant number 174073.

**Acknowledgments:** The authors thank student Hanna Kann, Department of Laboratory Medicine, Division of Pathology, Karolinska Institute, for her skillful help with the Luminex® 100/200™ analyzer.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
