Comparison of gene expression by microarray and qRT-PCR. Relative gene expression is plotted as log2 (fold change) compared to matched sham-irradiated controls for irradiated (a) and bystander (b) samples at 0.5 hour after treatment. Each histogram is the mean of four biological replicates. Underlined genes are from class comparison results at 0.5 hour, the remaining genes were selected in our previous study  as responding at 4 hours. Microarray measurements (blue bars) and qRT-PCR measurements (red bars) are log 2 transformed ratios to controls; both up-regulated (right of the y-axis) and down-regulated genes (left of the y-axis) are shown.