Correlation between circulating myeloid-derived suppressor cells and serum miRNA21 in non-small cell lung cancer and its clinical significance

Objective: To investigate the effect and clinical significance of myeloid-derived suppressor cells (MDSCs) levels and serum miRNA-21 expression in advanced non-small cell lung cancer (NSCLC) patients. Methods: Advanced NSCLC patients treated at the First People’s Hospital of Tongxiang City, Zhejiang Province, between July 2021 and June 2022 were included in this study. MDSCs in the peripheral circulation were assessed by flow cytometry, and serum miRNA-21 expression was assessed by q-PCR. The effects of miRNA-21 on MDSC proliferation and ARG-1 and inducible nitric oxide synthase (iNOS) secretion from MDSCs were examined using in vitro cell experiments. In addition, the correlation between MDSC and CEA, CRP and Ki67 was analyzed. Results: Compared with those in the peripheral circulation of individuals in the control group, the expression levels of polymorphonuclear-MDSCs (PMN-MDSCs) and miRNA-21 in the peripheral circulation of NSCLC patients were significantly higher, and the two groups were significantly positively correlated. In in vitro cell experiments, miRNA-21 mimics promoted MDSC proliferation and increased ARG-1 and iNOS secretion and miRNA-21 inhibtor has an opposite result. In addition, PMN-MDSCs in the peripheral circulation of NSCLC patients were significantly positively correlated with carcinoembryonic antigen (CEA), C-reactive protein (CRP), and Ki67. Conclusion: The blood of advanced NSCLC patients contains high levels of MDSCs and miRNA-21, and the two may interact to impact on NSCLC.