Figure 4.

Mouse lung developmental expression profile at E12 to more than P60 of 2552 genes represented in their first two temporal principal components (PC1-2), and murine homologs of genes twofold regulated in human squamous cell lung carcinoma (SCL), with respect to normal human cerebella, on the mouse lung developmental background. (A) Expression profile of 2552 genes in the developing mouse lung represented as dots in the lung temporal PC1 (49.10% temporal variance) and PC2 (13.68% temporal variance). Magenta dots mark Lung Early Mouse Partition (LEMP) genes. Green dots mark Lung Late Mouse Partition (LLMP) genes. The units for PC1-2 are normalized (mean zero, variance one across samples) Affymetrix signal intensity. (B) Representative lung expression profiles of genes at different sectors of the temporal PC1-2 representation (number-matched, A). Genes from the LLMP (e.g., 1-3, 8) and LEMP (e.g., 4-7) hemispheres fluctuate over time in inverse profiles. (C) Expression profile of 155 mouse genes whose human homologs are twofold regulated in human SCL on a mouse lung developmental background (A). Magenta crosses mark genes twofold up-regulated in SCL; green triangles are genes twofold down-regulated in SCL. Interestingly, we note the focused and higher concentration of SCL up-regulated genes to the 10-o'clock sector, despite the higher density of normal developmental genes that map to the 8-o'clock sector (A). (D) Histograms of the mouse lung temporal PC1 coordinates of twofold up-regulated (top magenta histogram) and down-regulated (bottom green histogram) genes in human SCL. The number of the 155 genes in each compartment is indicated. The odds ratio (o.r.) and its 95% confidence interval ([left endpoint, right endpoint]), χ², and its associated p value are given. These data indicate a significant and strong association between genes up-regulated in the SCL tumors with the LEMP and down-regulated tumor genes with the LLMP.