Vessel normalization by Ly6G⁺ WBC depletion with GPVI blockade reverts its effect on tumor growth. AT-3 tumor-bearing C57BL/6 mice were treated with RB6-8C5 antibody to deplete Ly6G⁺/Ly6C⁺ cells or with a vehicle control (saline) 48 hours before treatment with IgG control, R300, or the GPVI-blocking antibody. (A) After 18 hours, the relative hemoglobin content was measured (n ≥ 10; 2-way analysis of variance with Tukey’s multiple comparison test). (B) The tumor volume was measured every second day. Data are presented as mean ± SEM. ***/###P < .001, **/##P < .01, and */#P < .05 (where * stands for the group threated with the RB6-8C5 and # for the vehicle in the respective color); Kruskal-Wallis with Dunn’s multiple comparisons test. (C) Representative images of AT-3 tumor sections stained for CD31. Scale bars, 100 µm. (D) Vessel density after depletion of Ly6G⁺/Ly6C⁺ cells (n = 10; mean ± SEM). (E) Vessel diameter after depletion of Ly6G⁺/Ly6C⁺ cells. (F) Tumor sections stained for CD34 and the pericyte marker NG2. Scale bars, 100 µm. (G) Quantification of CD34⁺ and NG2⁺ areas in tumor sections after depletion of Ly6G⁺/Ly6C⁺ cells (n = 4; mean ± SD). ***P < .001, **P < .01, and *P < .05; Kruskal-Wallis with Dunn’s multiple comparisons test. ns, not significant.