IRF5 inhibits in vivo tumor formation and in vitro metastasis/invasion. A. MCF-7/pBIRF5 (MCF7-IRF5) and MCF-7/pBabe (MCF7-EV) control cells were inoculated into NCr nu/nu mice. The number of mice with tumors over the total number of mice is shown. B. Same as in (A), except 3 × 106 MDA-MB-231 control cells (231-EV) or MDA-MB-231 IRF5 overexpressing cells (231-IRF5) were inoculated into NCr nu/nu mice and monitored over seven weeks. C. Growth of MCF-7 and MDA-MB-231 cells were examined by 3-D culture. An equal number of cells were plated and pictures taken 10 days later at 10 × magnification.