Fig. 1.

Tumor cell-derived soluble factors activate STAT5 signaling in macrophages. A Immunoblot for pSTAT5 and total STAT5 (STAT5) protein in THP-1 cells treated with the CM from the indicated human breast cancer cells for indicated times in minutes. B Immunoblot for pSTAT5, STAT5, and β-tubulin (loading control) protein in PBMC-derived macrophages treated with the CM from the indicated human breast cancer cells. C CM from B/B-stimulated HC11, HC11/R1, HC11/R1-LM and 4T1 cells was used to stimulate BMDMs. Immunoblot analysis for pSTAT5, STAT5, and β-tubulin. D 4T1 tumor sections were stained for F4/80 (red) and pSTAT5 (green). White arrows indicate co-stained cells. Scale bar: 50 μm. Quantification of percent of F4/80 + cells that were also pSTAT5 + from 5 representative tumors