CD44-intact Tcl1-tg leukemic cells have a proliferative advantage in spleen that can be attributed to differential gene expression signatures (eg, NF-κB signaling) compared with CD44-deficient cells. (Ai) CD86 surface expression and (ii) intracellular Ki-67 expression of freshly isolated SPL- and BM-derived CD5⁺/CD19⁺ cells from diseased Tcl1-tg (n = 12) and Cd44ΔB Tcl1-tg (n = 12) were determined. (B) Sorted splenic CD5⁺/CD19⁺ of diseased Tcl1-tg and Cd44ΔB Tcl1-tg mice (n = 4 of each genotype) were used to perform Clariom-S microarray. Hierarchical clustering of differentially expressed genes was performed using Transcriptome Analysis Console (Affymetrix). A list of those genes with fold change and P value is available in supplemental Table 4. (Ci) Representative enrichment plots for NF-κB signaling (JAIN_NFKB_SIGNALING) (normalized enrichment score [NES] = 1.66, nominal P = .0 via 1000 permutations, FDR q value = 0.049), (ii) and MYC signaling (HALLMARK_MYC_TARGETS_V2) (NES = 1.62, nominal P = .03 via 1000 permutations, FDR q value = 0.046) are shown. Heatmaps for genes included in the core enrichments are depicted underneath.