Functional groups and pathways associated with PDX models and tumor progression. Genes (columns) involved in 46 up-regulated pathways (rows; red), and genes (columns) involved in 26 down-regulated pathways (rows; blue). Pathways are shown on the right, with colored highlighting representing functional groups. There are two up-regulated and three down-regulated functional groups. For both up-regulated and down-regulated pathways, only the most significantly differentially expressed genes are shown. Additional file2 lists core genes from each pathway with the expression frequency value in the PDX models and human primary tumors.