Aims: Non-small-cell lung cancer (NSCLC) is the most common clinical lung cancer. Polymorphonuclear-myeloid derived suppressor cells (PMN-MDSCs), which are the major population of MDSCs, are involved in NSCLC progression. Recently, it was found that lectin-type oxidized LDL receptor 1 (LOX-1) could identify humsn PMN-MDSCs. However, the role of CD15+LOX-1+ PMN-MDSCs in NSCLC early diagnosis has not been revealed. Here, we tried to confirm the application of the newly-identified CD15+LOX-1+ PMN-MDSCs in the early diagnosis of NSCLC. Methods: Flow cytometry (FCM) was used to detect the proportion of CD15+LOX-1+ PMN-MDSCs in the peripheral blood (PB) of healthy controls (HC) and NSCLC patients. The correlation of CD15+LOX-1+ PMN-MDSC frequency with levels of cytokeratin 19-fragments (CYFRA21-1), carcinoembryonic antigen (CEA), and carbohydrate antigen 125 (CA125) was analyzed. Receiver operating characteristic (ROC) curve was used to estimate the diagnostic efficacy of CD15+LOX-1+ PMN-MDSCs for NSCLC. Additionally, the association of CD15+LOX-1+ PMN-MDSC frequency with NSCLC prognosis/recurrence after surgery was explored. Results: The proportion of CD15+LOX-1+ PMN-MDSCs increased in PB of NSCLC patients. CD15+LOX-1+ PMN-MDSC proportion was positively correlated with levels of CEA and CYFRA21-1. The area under the ROC curve (AUC) of PMN-MDSC percentage was higher than CYFRA21-1, CEA and CA125. The proportion of CD15+LOX-1+ PMN-MDSCs decreased in patients after surgery. The frequency of CD15+LOX-1+ PMN-MDSCs was lower in NSCLC patients without recurrence compared to those with recurrence after surgery. Conclusions: Circulating CD15+LOX-1+ PMN-MDSCs are a potential diagnostic marker for NSCLC, and are associated with NSCLC prognosis and recurrence after surgery.

Aims: As a population of immunosuppressive cells, polymorphonuclear-myeloid derived suppressor cells (PMN-MDSCs) are responsible for lung cancer metastasis, and metastasis is a main cause of the recurrence after surgery of non-small-cell lung cancer (NSCLC). Lectin-type oxidized LDL receptor 1 (LOX-1) is a newly confirmed maker for identifying PMN-MDSCs in human. In this study, we tried to confirm the relationship between the frequency of newly identified CD15+LOX-1+ PMN-MDSCs and NSCLC recurrence after surgery. Methods: Flow cytometry (FCM) was used to detect the proportion of CD15+LOX-1+ PMN-MDSCs in the peripheral blood (PB) cells of healthy controls (HC) and NSCLC patients. The correlation of CD15+LOX-1+ PMN-MDSC frequency with levels of cytokeratin 19-fragments (CYFRA21-1), carcinoembryonic antigen (CEA), and carbohydrate antigen 125 (CA125) was analyzed. Receiver operating characteristic (ROC) curve was used to estimate the diagnostic efficacy of CD15+LOX-1+ PMN-MDSC frequency for NSCLC. Additionally, the association of CD15+LOX-1+ PMN-MDSCs with NSCLC prognosis and recurrence after surgery was explored. Results: The proportion of CD15+LOX-1+ PMN-MDSCs increased significantly in PB of NSCLC patients. CD15+LOX-1+ PMN-MDSC proportion was positively correlated with levels of CEA and CYFRA21-1, but not CA125. The area under the ROC curve (AUC) of PMN-MDSC percentage was higher than CYFRA21-1, CEA and CA125. Compared to NSCLC patients before surgery, the proportion of CD15+LOX-1+ PMN-MDSCs decreased in patients after surgery. The frequency of CD15+LOX-1+ PMN-MDSCs was lower in NSCLC patients without recurrence compared to those with recurrence after surgery. Conclusions: Circulating CD15+LOX-1+ PMN-MDSCs are a potential diagnostic marker for NSCLC, and are associated with NSCLC recurrence after surgery.