B16F10 subcutaneous tumors were collected after 14 days of injection. (A) Paraffin sections were stained with endomucin and SMA specific antibodies. (B and C) Endomucin-stained sections were subjected to quantitative analysis using Leica’s Digital Pathology capture and analysis platform to analyze vessel density (B) and total vessel area (C). Mann-Whitney statistical analysis was performed (n = 5 per group). (D) Lung sections from experimental metastasis assays were also collected, and paraffin sections were stained with endomucin and nestin specific antibodies. Representative single nodules for each genotype are shown. Arrows denote preexisting, nesting-negative vessels in the periphery of the nodules. Scale bars: 100 μm (A, right, and D); 500 μm (A, middle); 1,000 μm (A, left).