CTen validation and robustness of the enrichment score rankings. From an additional cell-specific gene expression database, we took the top 5% most highly expressed genes for five kinds of tissue (lung, bone marrow, kidney, spleen and liver) and three lymphocytes in different cellular states (CD4+ and CD8+ T cells, B cells and macrophages that were unstimulated or collected 7 hours after simulation with LPS). Each list was analyzed in CTen and we show the top 5 enrichments scores for (A) the tissue (B) lymphocyte test lists. To evaluate the robustness of these results, we repeated this procedure for the top 2-10% most highly expressed genes in each cell type. The enrichment scores from CTen were ranked from highest to lowest, and (C) the heatmap illustrates the top 3 most enriched cell types identified by CTen (columns) for each lymphocyte data tested (row labels). The bar plot on the right hand side summarizes the number of genes per test list. The heatmap for the tissue data is available as Additional file 5.