Figure 4: Hierarchical clustering results for the 12 test samples. Under the same clustering conditions (i.e., hierarchical clustering with Spearman distance and average linkage), the gene expression profiles of the 192 marker genes classified the 12 test samples into 2 groups. One group consisted of the L2A2, L2A1, L2A3, L2C3, L2C2, and L2D1 samples and the other consisted of the L2D2, L2B3, L2D3, L2B2, L2C1, and L2B1 samples. Except for the L2D1 and L2C1 samples, all of the samples were correctly grouped into SDP and non-SDP groups. In this figure, the gene expression values that used to do the clustering are the relative expressions of the labeled sample.