Stable Pf4 silencing significantly enhances the metastatic capability of melanoma cells in NOD/SCID mice. (A, E) Photographic representation of macroscopic metastases of NOD/SCID mice 4 weeks after tail vein injection of control and Pf4 knockdown cells (POL-Sec23a-OE-shPf4 and OL-shPf4) (Four mice per group); (B, F) Quantitative analysis of the surface metastatic foci in control and Pf4 knockdown cells; (C,G) representative whole-lung images to visualize metastases on the lung (asterisk) by H&E staining; (D,H) body weight changes of mice receiving control and Pf4 knockdown cells (*p<.05,**p<.01,***p<.001).