Fig. 6

Heatmap of gene expression differences of most frequently altered genes between patient-matched intra- and extracranial melanoma metastasis pairs. The heatmap shows the expression behavior of the 28 genes with increased and the 75 genes with decreased expression state predictions by the HMM that were altered in at least 11 or more patients. A color gradient from blue over white to red is used to visualize the log\(_2\)-ratios of the gene expression levels of the intra- compared to the corresponding extracranial metastasis of each patient-matched metastasis pair. The columns of the heatmap represent the individual metastasis pairs with labels color-coded by the tissue in which their extracranial metastasis occurred (blue: lung, green: lymph node, purple: soft tissue, yellow: skin, pink: liver, cyan: small intestine). The rows of the heatmap represent the individual candidate genes. The annotation block on the left side of the heatmap shows general gene function groups of individual genes and the expression behavior of each gene in three related studies (Fischer et al. [26], Chen et al. [18] and Biermann et al. [22])