Subgroups are characterized by unique expression patterns. The Affymetrix signal (expression level: vertical axis) of MAF, MAFB, FGFR3, MMSET, CCND1, CCND2, CCND3, FRZB, and DKK1 from the 256 and 158 cases based on the clustergram sample distribution from Figure 2A and B, respectively. The expression levels for each gene are proportional to the height of each bar (representing a single patient sample). Note that spiked expression of CCND1, MAF and MAFB, and FGFR3 and MMSET is strongly correlated with specific subgroup designations. Also note that cases retaining the MMSET spike but lacking FGFR3 spikes maintain similar cluster designation, and MAF and MAFB spikes cluster in the same subgroups. Several MMSET spike–positive cases cluster in the proliferation subgroup. CCND2 expression was mutually exclusive of CCND1 expression. While highly correlated with the hyperdiploid subgroup, FRZB and DKK1 were both significantly underexpressed in groups LB and MF.