CD15+LOX-1+ PMN-MDSC frequency is increased in PB of NSCLC patients
MDSCs that consist of PMN-MDSCs and M-MDSCs are immune suppressors in NSCLC. PMN-MDSCs have been identified as the major population of MDSCs in cancer patients, which induce the immune suppression in TME [25]. LOX-1 is a newly identified marker for distinguishing human PMN-MDSCs [29]. To compare the CD15+LOX-1+PMN-MDSC frequency in NSCLC patients with that in healthy donors, we detected the proportion of CD15+LOX-1+ PMN-MDSCs in PB of the two groups. Detailed information of NSCLC patients were listed in Table 1. Based on the results of FCM, it was indicated that CD15+LOX-1+ PMN-MDSC frequency was significantly upregulated in the circulation of NSCLC patients (20.84±1.342 %) compared to healthy individuals (3.215±0.1346 %) (Figure 1A, P <0.0001). ARG1 is the main suppressor released by PMN-MDSCs, and we found that ARG1 expression in PB cells increased significantly in NSCLC patients compared to health donors (0.1679±0.0145 vs 0.04951±0.0044) (Figure 1B,P <0.0001). Moreover, the CD15+LOX-1+ PMN-MDSC frequency was positively correlated with the ARG1 expression in NSCLC patients (r=0.5951, P <0.0001) (Figure 1C).