Spike profile distributions among the gene expression–defined MM subgroups.

GeneChip HuGeneFL analysis of FGFR3, CST6,IFI27, and CCND1 gene expression. The normalized AD value of fluorescence intensity of streptavidin-PE–stained biotinylated cRNA as hybridized to probe sets is on the vertical axis and samples are on the horizontal axis. The samples are ordered from left to right: normal PCs (NPCs; green), MM1 (light blue), MM2 (dark blue), MM3 (violet), and MM4 (red). Note relatively low expression in 31 NPCs and spiked expression in subsets of MM samples. TheP values of the test for significant nonrandom spike distributions are noted.