National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran TANAFFOS (Respiration) 1735-0344 20 1 2021 01 01 Circulating Levels of Monocytic Myeloid-Derived Suppressor Cells (M-MDSC) and CXCL-8 in Non-Small Cell Lung Cancer (NSCLC) 15 21 245199 EN Seyed Sajjad Zadian Department of Immunology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran Ian M Adcock National Heart and Lung Institute, Imperial College London, London, United Kingdom Priority Research Centre for Asthma and Respiratory Diseases, Hunter Medical Research Institute, The University of Newcastle, Newcastle, NSW, Australia Babak Salimi Clinical Tuberculosis and Epidemiology Research Center, National Research Institute of Tuberculosis and Lung Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran Esmaeil Mortaz Department of Immunology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran Clinical Tuberculosis and Epidemiology Research Center, National Research Institute of Tuberculosis and Lung Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran Journal Article 2021 08 01 <strong>Background: </strong>Myeloid-derived suppressor cells (MDSC) are categorized as granulocytic (G-MDSCs) and monocytic (M-MDSCs) and their expansion play a role in cancer progression. Recruitment to the cancer site depends upon the presence of a chemoattractant. We aimed to investigate the presence of MDSC subtypes and of interleukin-8 (CXCL-8) in the peripheral blood in lung cancer subtypes including non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) patients. <strong>Materials and Methods: </strong>Peripheral blood samples of 26 NSCLC patients, 18 SCLC patients, and 8 healthy control donors (HDs) were harvested and the surface expression of CD14, CD15, CD11b, and HLA-DR on MDSCs was measured using flow cytometry. The level of serum CXCL8 was measured by the ELISA method. <strong>Results: </strong>The frequency of circulating M-MDSCs was significantly higher in patients with NSCLC than in SCLC and HDs. In contrast, there was no statistical difference concerning the frequency of circulating G-MDSCs between the three groups. The concentration of CXCL-8 was significantly higher in the NSCLC and SCLC patients than in HD control with no significant difference between NSCLC and SCLC groups. There was no correlation between serum CXCL8 and G-MDSC levels. <strong>Conclusion: </strong>Our data confirm a higher frequency of circulating M-MDSCs, but not G-MDSCs, in the blood of those suffering from NSCLC but not for SCLC cases. Measuring MDSC subtypes and serum chemotactic factors may have implications for the differential diagnosis of NSCLC. https://www.tanaffosjournal.ir/article_245199_04310a4a98b53711416ebacb993fa318.pdf