Fig. 4

Effect of tumor invasion on the mouse brain transcriptome. Mouse gene expression profiles included PODX samples and one mock injected mouse brain (mB). The heatmap (a) illustrates the normalized expression of the 208 mouse genes selected by SPCA and consolidated by bootstrap (≥ 0.1). The genes were classified in 3 clusters (consensus k-means clustering for 100 repetitions). (B-D) The samples are projected onto the first two axes of the PCA for the selected genes, where the human read proportion b, the sample type c and tumor origin d were added as supplementary variables, annotated with the color code. The contribution of each gene cluster to explain the variance is evaluated by variation partitioning e represented by a Venn diagram of variation fractions (percentage) for the three supplementary variables (frequency of human reads, FreqHum; sample origin, Origin; type if tissue, Type). (F) The averaged gene expression of the significant pathways emerging from GSEA (p ≤ 0.1) of cluster 3 is illustrated in a heatmap. The pathways are annotated with the adjusted p-value and the gene ratio (number of selected genes in pathway/number of selected genes in the analysis)