Shared gene expression profiles for TC groups. (A) Two hundred thirty MM samples were categorized into the 8 TC groups. Five hundred seventy-six genes significantly different between the 8 subtypes (P < .05; Benjamin and Hochberg analysis was used to adjust for the multiple univariate hypothesis tests, with multiple testing correction) were identified. The genes were subjected to hierarchical clustering (Supplemental Worksheet, Table S2). A color code on the bottom identifies the color associated with each TC group. (B) Differences in gene expression between TC groups. A list of 576 genes that differs between the 8 TC groups with a P value less than .05 was generated, and the 13 probe sets corresponding to the genes used to assign the TC class (CCND1, CCND2, CCND3, FGFR3, MMSET, MAF, ITGB7, CX3CR1) were removed. The number of genes from this list that are statistically different (P < .05) in pair-wise comparisons between TC groups is shown, with the intensity of pink shading highlighting the more profound differences. 6 indicates 6p21; 11, 11q13; N, none; 4, 4p16; and M, maf.