Figure 2

Differential gene expression in lesional (PP), non-lesional (PN) and normal (NN) skin tissue. Gene expression was analysed to reveal probe sets that were differentially expressed between pairwise comparisons of PP, PN and NN tissue groups. (A) The Venn diagram shows the number of probe sets identified in each of the three differential analyses performed. Probe sets common to all three pairwise comparisons were 228 (206 genes). (B) Microarray analysis of 108 skin tissue samples (in columns) for 206 genes (in rows) common to all tissue types, identified through differential expression analysis. Tissues have been grouped according to disease phenotype (normal NN, non-lesional PN and lesional PP) and heatmap colours indicate z-score of each gene expression value against the mean of corresponding normal values, (green: decreased expression, red: increased expression, inset). Similarity of gene expression vectors across all samples is represented by the dendrogram on the left. (C) Principal Component Analysis to suggest sample clustering across skin types according to gene expression patterns. Good separation of inflamed (PP) and non-inflamed (PN, NN) tissues was observed, indicating a progression from normal (red) to lesional skin (blue) through the non-lesional cases (green).