Gene Ontology (GO) categories overrepresented in the normal stroma and normal epithelium gene signatures. (a) GO terms overrepresented by genes expressed in normal stroma. (b) GO terms overrepresented by genes expressed in normal epithelium. Bars represent the fraction of genes in the category that were expressed. Terms of the same color are related in the GO hierarchy (gray terms are unrelated). P values for significance, and the total number of genes in a category are listed after the bar plot.