Figure 2. Hierarchical clustering of the top 15 differentially expressed genes identified by the SSH technique and validated by microarray. UVM gene expression profile was compared to those of UM primary tumors with good (UM I) or bad prognosis (UM II). The color scale above the heat map diagram illustrates the relative expression level of mRNAs (log2 expression): red color represents a high expression level; blue color represents a low expression level.