Expression levels of the 52 MGUS genes in PC of healthy donors and patients with MGUS and MM. A colorgram of the expression of the 52 genes in NPC (n = 22), MGUS, MM from MGUS (n = 72), and MM (n = 351) (based on their location in either of the 2 major branches of the dendrogram in Figure 2) and multiple myeloma cell lines (MMCLs) (n = 22). MGUS and MM from MGUS on the left side of the figure represent clusters in the MGUS-L MM branch of Figure 2, and those on the right side represent clusters in the non–MGUS-L MM branch. Genes are indicated along the vertical axis and samples on the horizontal axis. The normalized expression value for each gene is indicated by a color, with red representing high expression and blue representing low expression. Note that NPCs have a distinct pattern of overexpressed and underexpressed genes that progressively inverts with transition to MGUS, MGUS-L MM, non–MGUS-L MM, and finally to MMCL.