Synergistic tumor growth reduction and inhibition of angiogenesis by combination therapy with GW2580 and anti–VEGFR-2 antibody DC101. 3LL tumors were subcutaneously implanted and mice were treated with control diluent, GW2580 or DC101 alone, or a combination of DC101/GW2580 for 14 days. (A) Tumor volume was monitored by caliper measurements. Tumor volume is presented as the average tumor volume (mm³) per group over time and as a waterfall plot of tumor volume (% change) of each animal per group at day 14 (n = 5-9/group). At day 14, tumors were harvested and subjected to histologic analysis of hematoxylin and eosin (B), Gr-1⁺ MDSCs with DAPI (C), and CD31⁺ vessels with DAPI (D). Necrotic tissue area (E) and CD31⁺ area (F) were quantified using ImageJ software (n ≥ 5/group). Data represent combined averages from 2 independent animal experiments. Scale bars represent 100 μm.