Overexpression of CXCR4 in WM cells leads to increased disease dissemination in vivo and enhanced adhesion properties and growth in vitro. CXCR4 overexpressing cells (CXCR4⁺) presented with a more aggressive ability to disseminate to BM (A), liver (B), and kidneys (C) compared with the related empty vector–infected cells (Hematoxylin Eosin ×10; Ab staining ×20 and ×10, magnifications). Quantification of human CD20 and CXCR4 staining is shown in supplemental Figure 2. In addition, CXCR4⁺ and control cells were detected ex vivo by using immunofluorescence on BM, liver, and kidney tissues (D) (×10 and ×20 magnifications). (E) Kaplan-Meier curve showing decreased survival in CXCR4⁺ cell–injected mice vs empty vector cell–injected mice (n = 7/group). Death for empty vector cell–injected mice was observed at days 40, 50, and 62. P indicates P value (log-rank test). (F-G) CXCR4 overexpression led to increased WM cell adhesion to primary BM-MSCs, and increased cell proliferation in contrast with CXCR4-silenced WM cells (CXCR4-K.D.), in which reduced adhesion to BM-MSCs and reduced cell proliferation were observed. Bars indicate standard deviation. DAPI, 4′,6 diamidino-2-phenylindole; NS, not significant.