Figure 1.

Correlation of overall gene expression of large airway epithelium air–liquid interface (ALI; n = 12) with brushed large airway epithelia of healthy nonsmokers (n = 12). Ordinate indicates relative gene expression in large airway epithelium ALI cultured cells. Abscissa indicates relative gene expression in brushed cells from large airway epithelia. Each is plotted on a logarithmic scale. Triangles represent each probe set that was present in at least 20% of samples. Gray rectangle indicates an up or down twofold change. Tight clustering indicates a good correlation between cultured cells and brushed cells (Spearman rank correlation coefficient, 0.89; P < 0.001). Overall, 81% of probe sets were similarly expressed within twofold.