(A) Immune cell profiles of liver metastases (metas) based on the SU2C PCa dataset (n = 26). Neutro, neutrophils; Mac-M1, M1 macrophages; Mac-M2, M2 macrophages; Mono, monocytes. (B) Neutrophils are the most enriched immune cell component in liver metastases based on the SU2C dataset (adrenal metastases, n = 2; bone metastases, n = 82; liver metastases, n = 26; lymph node metastases, n = 79; prostate tumor, n = 5; soft tissue, n = 14). (C and D) Flow cytometric plots (C) and quantification (D) of CD11b⁺Ly6G⁺ neutrophils in liver (n = 4 mice). (E and F) IHC and IF staining (E) and quantification (F) of NETs in liver (n = 5 mice). Scale bars: 50 μm; 25μm (inserts); original magnification, ×9 (inserts). (G and H) IF staining (G) and quantification (H) of NETs (H3cit⁺) in MPO⁺ neutrophils in livers from vehicle- and DNase-I–treated NEPC tumor–bearing mice (n = 6 mice). Scale bar: 50 μm. (I and J) H&E-stained images (I) of livers from vehicle- and DNase-I–treated NEPC tumor–bearing mice (scale bars: 4 mm) and quantification (J) of liver metastases following vehicle or DNase-I treatment of mice inoculated by i.v. injection of Rb1^Δ/Δ Trp53^Δ/Δ organoids (n = 6 mice). (K) Survival curves for vehicle- and DNase-I–treated NEPC tumor–bearing mice (n = 8 mice). **P < 0.01, by log-rank test. (L) Quantification of migrated Rb1^Δ/Δ Trp53^Δ/Δ PCa cells in Boyden chambers recruited by murine primary neutrophils or NETs (n = 4 biological replicates). (M) Quantification of Rb1^Δ/Δ Trp53^Δ/Δ PCa cells adhesion in murine primary neutrophils or NETs (n = 4 biological replicates). *P < 0.05, **P < 0.01, and ***P < 0.001, by 2-tailed Student’s t test (H, J, L, and M), log-rank test (K), 1-way ANOVA followed by Tukey’s test (D and F), and 1-way ANOVA followed by Dunnett’s test (B). Data are shown as the mean ± SEM.