IRF1 and neoplasm: Bevacizumab significantly decreased tumor volume in IRF1 down-regulated tumors (Figure 5C, 46.6±6.9 vs 9.0±2.6, P < 0.01), whereas tumor volume was not decreased by bevacizumab in control shRNA tumors (71.5±16.8 vs 42.0±11.1, P = 0.18, Figure 5C).