Figure 5.

Tumor myeloid-derived lymphatic endothelial cell progenitors are derived from the myeloid lineage. A–D: Human breast cancer specimens were costained with antibodies against lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1) and markers for lymphoid cell lineage CD3 (A), CD4 (B), CD8 (C), and CD56 (D). E–I: Specimens were also costained for LYVE-1 and markers of myeloid-macrophage lineage toll-like receptor 4 (TLR4; E), MD2 (F), CD11b (G), CD14 (H), and CD18 (I). White boxed areas in images in the third panels are shown in higher magnification in the fourth panels. The white arrows point to macrophages positive for LYVE-1. The white arrowheads highlight macrophages and lymphocytes negative for LYVE-1. Nuclei in merged images are identified by Hoechst stain. The frequency of LYVE-1 expression in cells costained with lymphoid (J) and myeloid (K) markers was quantified in 100 randomly selected LYVE-1⁺ cells identified in five tumor specimens. The percentages of peritumoral and intratumoral LYVE-1⁺ cells positive for markers of each of the examined lineages and located in the tumor-adjacent fat and inside the tumor mass, respectively, are presented. Original magnification: ×400 (A–D and E–I, first, second, and third panels); ×800 (E–I, fourth panels).