(A) t-SNE clustering of flow cytometry marker expression profiles in live CD45⁺ cells of PBMCs from metastatic NSCLC patients enrolled in a clinical trial (NCT03223155). Expression intensity of CD33, CD14, HLA-DR, and BAMBI. (B) MFI of BAMBI in different immune cells in PBMCs from metastatic NSCLC patients enrolled in a clinical trial (NCT03223155). We show the markers (CD33⁺CD14^hiHLA-DR^lo) used to gate m-MDSC. (C) Heatmap showing the changes of Bambi mRNA expression in different myeloid cell clusters in control (Ctrl) and IR tumors, respectively, based on the scRNA-Seq data of CD45⁺ cells. CD45⁺ cells were obtained from 4 pooled MC38 tumors 4 days after IR. P values were calculated by a Wilcoxon-Mann-Whitney test. (D and E) MFI of BAMBI (D) and representative flow cytometry analysis of BAMBI expression (E) in MC38 tumor–infiltrating MDSCs 3 days after IR. n = 5 per group for D. (F) TmRNA levels (log₂ fold change-log₂FC) of Bambi based on RNA-Seq data of CD11b⁺ myeloid cells isolated from nonirradiated or irradiated MC38 tumors 3 days after IR. (G) qPCR analysis of Bambi in MDSCs (CD45⁺CD11b⁺Ly6C^hi) isolated from nonirradiated or irradiated MC38 tumors, 3 days after IR (20 Gy). n = 5 per group. (H) Flow cytometry analysis of BAMBI expression (MFI of BAMBI) in different immune cells in PBMCs from 5 metastatic NSCLC patients (enrolled in clinical trial NCT03223155) (pre-RT versus post-RT). The blood samples were collected immediately after hypofractionated radiation, approximately 1 to 3 weeks (median 14 days) after the pre-RT samples. Data are represented as means ± SEM. One of 2 or 3 representative experiments is shown (D, E, and G). Statistical analysis was performed using 2-sided, unpaired Student’s t test (D, E, and G). *P < 0.05; **P < 0.01.