Figure 1

Supervised hierarchic clustering of 28 paired breast cancer samples by using methylation microarray data from differentially methylated genes. Heat map and clustering of 76 significant (FRD-corrected, P < 0.001) differences between tumors (red) compared with adjacent tissues (green) shows that 30 of the differences (corresponding to 25 genes) are increases of methylation, whereas 47 (corresponding to 37 genes) are decreases of promoter methylation in tumors. Heat-map colors symbolize DNA methylation, as indicated in the color key. The full list of genes is presented in Table S2 in Additional file 2.