WM cells exhibit a block in the PC gene-expression program. (A) Hierarchically clustered heat map of differentially expressed genes between healthy and WM samples in day-6 in vitro–generated cells from R848 or CD40L conditions. The threshold for significance was a false discovery rate <0.05. WM samples with CXCR4 mutations are indicated in red (WM4 and WM7). (B) Venn diagrams depicting the significantly differentially expressed genes for each stated comparison. The number of upregulated genes is displayed in red, the number of downregulated genes is displayed in blue, and the number of nonsignificant genes is shown in the center. (C) The interaction between key genes involved in PC differentiation is depicted for cells stimulated with CD40L (upper panel) or R848 (lower panel). Genes that are upregulated in WM samples compared with healthy samples are in larger and bold type, whereas those that are downregulated are shown in smaller and italicized type.