STAT1 protects tumours from ionizing radiation-induced decreases in the expression of energy metabolic pathways. (A) Changes in the expression of glycolysis/gluconeogenesis (GG), citrate cycle (CC) and oxidative phosphorylation (OP) energy metabolic pathways in response to ionizing radiation(IR) treatment of STAT1 wild-type (WT) and knockdown (KD) tumours. There was no significant decrease in the expression of the GG pathway in STAT1 WT tumours in the response to IR (mean irradiated/untreated ratio = 0.91; 95% confidence interval [0.77, 1.05]). P-values indicate significant differences (Student's 2-tailed t-tests) between STAT1 WT and KD tumours. Points, mean value of the ratio of irradiated to untreated for the pathway; error bars, SEM. See Additional file 4 for further details. (B) Expressional clustering of the 24-gene STAT1 pathway in STAT1 KD and WT tumours indicates a significant 3.8-fold up-regulation of the STAT1 pathway (Student's 1-tailed t-test; P = 7.44e-5). Relative expression values are in log2 scale: red, up-regulated; green, down-regulated.