Hierarchical clustering of MDS samples. In the analysis, 135 MDS cases are displayed based on the 534-probe set signature from the diagnostic classifier. Euclidean distance was used to measure the dissimilarity between the MDS cases, and Ward's minimum-variance method was used to determine the hierarchy and to define the groups. The average width of the clustering structure was represented as dendrogram in the clustering tree. The samples are annotated according to diagnostic category (Class), laboratory where the microarray analyses were performed (Center), results of the DC model (Classification), IPSS score (IPSS), and percentages of blast cells (Blast %).