Figure 12.

Myeloid cell recruitment and density of tumor myeloid-derived lymphatic endothelial cell progenitors are drastically reduced by the colony-stimulating factor 1 receptor inhibitor PLX3397. A: Transgenic MMTV-PyMT tumors were treated with vehicle or PLX3397. Tumors were harvested and costained for lymphatic vessel endothelial hyaluronan receptor 1 (Lyve-1) and CD11b proteins. White arrows and arrowheads indicate CD11b⁺ cells that coexpress and lack Lyve-1, respectively. The white asterisk indicates a luminal lymphatic vessel that coexpresses both markers. The yellow arrow indicates a lymphatic vessel that does not coexpress CD11b. Nuclei in merged images are identified by Hoechst stain. B: Total number of recruited CD11b⁺ cells was calculated by determining the total number of pixels per field. C: The percentage of Lyve-1 colocalization with tumor-associated macrophages was determined in CD11b⁺ cells per tumor section. D: The total number of lymphatic vessels was quantified on the entire cross-section and normalized per mm². N = 4 per group (A); n = 50 (C). **P < 0.01, ***P < 0.001 (determined by t-test). Scale bar = 20 μm (A). Original magnification, ×400 (A).